An eruption from White Island (also called Whakaari) on 12 February 1977 is viewed from off the NE coast. The ash plume originates from the Christmas Crater vent, formed the previous year, shortly after the start of the eruption on 18 December. The first 20th century eruption to produce new magmatic material took place a month after the date of this photo. Intermittent phreatomagmatic eruptions continued until late 1981.

Photo by Simon Nathan, 1977 (New Zealand Geological Survey). This 4-m-wide, water-filled impact crater was formed when the block in background, with volcanologist Ian Nairn providing scale, was ejected during an eruption from White Island in New Zealand in late March 1977. The block, composed of pre-existing crater wall rock, bounced to form the impact crater, and then slid to its present location, 250 m from the source vent.

Photo by Bruce Houghton, 1977 (Wairakei Research Center). Pyroclastic flows traveling down the flanks of Ngāuruhoe volcano on 19 February 1975 as an ash plume rises above the summit crater. The eruption column rose 12 km above the vent and ash fell 160 km away in Hamilton City. Explosive activity had begun on the 12th and continued until the 23rd.

Photo by Graham Hancocks, 1975 (New Zealand Geological Survey). A Vulcanian explosion from the Ngāuruhoe cone of Tongariro volcano in New Zealand on 19 February ejects an ash plume and ballistic ejecta. Blocks up to 20 m across reached hundreds of meters above the vent before impacting the flanks.

Photo by Ian Nairn, 1975 (New Zealand Geological Survey). An ash plume on 29 March 1974, is directed by the wind from the summit of Ngāuruhoe volcano one day after powerful explosions that were accompanied by pyroclastic flows. Intermittent explosive eruptions had been occurring since 22 November 1972 and continued until 19 August 1974. Eruptions in January and March 1974 were the largest in two decades from Ngāuruhoe.

Photo by Jim Cole, 1974 (University of Canterbury). An ash plume rises above the summit of Karkar volcano in 1979. There are two nested summit calderas at the summit of the forested volcano resulting in a broad, low profile. The 5.5-km-wide outer caldera was formed during one or more eruptions, the last of which occurred 9,000 years ago. The 3.2-km-wide inner caldera was formed sometime between 1,500 and 800 years ago. Most historical eruptions, like this one in 1979, have originated from Bagiai cone within the 300-m-deep inner caldera.

Photo by Wally Johnson, 1979 (Australia Bureau of Mineral Resources). An ash plume rises above Motmot Island within the Lake Wisdom caldera of Long Island in 1953. Explosions that ejected ash and lapilli began on 8 May. Intermittent explosive activity continued until 7 January 1954.

Photo by John Best, 1953 (courtesy of Wally Johnson, Australia Bureau of Mineral Resources). An explosive eruption from Ulawun began on 15 January 1970. On 22 January pyroclastic flows were produced, followed by periodic lava emission that produced a flow reaching 5 km SW of the crater. This photo shows an ash plume rising above the summit on 23 January.

Photo by Wally Johnson, 1970 (Australia Bureau of Mineral Resources). Members of a scientific team approach the crater of Mount Lamington through the avalanche valley on 11 February 1951. Explosions occurred from a vent behind the new lava dome growing in the summit crater produce gas and ash plumes. Growth of the lava dome began soon after the catastrophic 21 January explosive eruption. At the time of this photo, the smooth-surfaced lava dome was uplifting the floor of the new crater. The dome eventually grew to the height of the crater rim.

Photo by Tony Taylor, 1951 (Australia Bureau of Mineral Resources). This photograph of the catastrophic eruption of 21 January 1951 was taken by the pilot flying from Port Moresby to Rabaul. From about 40 km NW, the pilot observed this ash plume rising to a height of about 13 km within two minutes. Shortly afterwards, the cloud expanded horizontally away from the volcano as devastating pyroclastic flows and surges swept radially up to 12 km from the crater.

Photo by Capt. Jacobson, 1951 (published in Taylor, 1958). Submarine explosions from Kavachi volcano eject a cock’s-tail plume of water, steam, and ash above the sea surface in July 1977. Large ejected blocks are visible falling from the plume and impacting the sea surface. Similar activity was observed over a period of less than a week.

Photo by W.G. Muller, 1978 (Barrier Reef Cruises, Queensland, Australia; courtesy of D. Tuni). An ash-rich eruption column rises above the 1978 crater of Anak Krakatau on 12 September 1979. Explosive activity began in mid-July 1979 and continued until November. A lava flow was emplaced during 18-21 September. Verlaten Island, part of the rim of Krakatau caldera, appears in the background to the NW.

Copyrighted photo by Katia and Maurice Krafft, 1979 (published in SEAN Bulletin, 1979). One week after the onset of an eruption of Krakatau volcano in May 1883, an eruption column rises above Perboewatan vent on Krakatau Island. Initially three vents on Krakatau Island were active. Three months later a paroxysmal eruption destroyed much of the island and formed a large caldera. Pyroclastic flows swept across the sea to Sumatra and tsunamis swept the coastlines of Sumatra and Java.

Photo courtesy of the family of R. Breon, published in Simkin and Fiske (1983). An ash plume from Galunggung volcano towers above the city of Tasikmalaya on 22 July 1982. This was one of a series of strong explosive eruptions between May and October that sometimes deposited ash and pumice on the city, located 17 km ESE of the volcano.

Photo by Bob Koyanagi, 1982 (U.S. Geological Survey). An eruption plume rises above the summit crater of Semeru on 17 August 1985. Semeru has been in near-continuous activity since 1818, producing frequent small-to-moderate explosions that eject ash and volcanic bombs. Some larger eruptions have produced pyroclastic flows and lahars that have reached the foot of the volcano.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey). An explosive eruption at the summit crater of Semeru on 17 August 1985. This activity is typical of Semeru, which has been in near-continuous eruptive activity since 1818, producing frequent small-to-moderate explosions that eject ash and volcanic bombs. Some larger eruptions have produced pyroclastic flows and lahars that have reached the foot of the volcano.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey). Semeru volcano rises above the coastal plain in Java, shown here producing a small ash plume in 1985. Larger eruptions occasionally produce pyroclastic flows and lahars that reach as far as the lower flanks of the volcano. Semeru (also known as Mahameru: "Great Mountain") has been in near-continuous activity since 1818.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey). Ash plume rose above Raung volcano on 10 and 12 September, and 3 October 1991. Although the initial report was of flank vent activity, photographs such as this one on 12 September taken from the south, show the eruption occurring at the summit caldera and the plume being dispersed by the wind to the NW.

Photo by Jeff Post, 1991 (Smithsonian Institution). An ash plume rises above the Doro Api peak of Sangeang Api volcano on 25 August 1985. The eruption, which began on 30 July and lasted until February 1988, included explosive activity, pyroclastic flows, and a lava flow that traveled 4-5 km down the W flank.

Photo by Tom Casadevall, 1985 (U.S. Geological Survey). An eruption of Indonesia's Banda Api volcano, seen here on 10 May 1988, took place from a N-SSW-trending fissure that cut across the island. Both explosive activity and lava effusion occurred along the fissure. Billowing, ash-rich eruption plumes rose from vents along the N end of the fissure. Minor lava fountaining can be seen here at the lower-center, near the N coast. White steam marks the entry of the lava flow into the sea after overrunning two villages.

Photo by Willem Rohi, 1988 (Volcanological Survey of Indonesia). A light-colored plume rises above the summit of Mayon volcano on 14 September 1984, seen here from Cagsawa on the SSE flank. The darker and denser column to its left is an ash plume rising from the pyroclastic flow moving down the SW flank.

Photo by Ernesto Corpuz, 1984 (Philippine Institute of Volcanology and Seismology). An ash plume rises above a pyroclastic flow traveling down the Buang valley on the upper NW flank of Mayon volcano in the Philippines on 12 September 1984. The front of the advancing pyroclastic flow is visible at the lower right. These pyroclastic flows traveled down to 100 m elevation at rates of about 20 m/s.

Photo by Olimpio Pena, 1984 (Philippine Institute of Volcanology and Seismology). This time-lapse photo taken on 12 September 1984 shows incandescent blocks that were ejected by explosive eruptions and are cascading down the flanks of Mayon. The incandescence is reflected in the base of the ash plume to the right.

Photo by Rene Arcante, 1984 (courtesy Philippine Institute of Volcanology and Seismology). A large Plinian ash plume towers above Pinatubo in the Philippines on 12 June 1991, reaching an altitude of 19 km. This was the first in a series of powerful eruptions that culminated on 15 June with major pyroclastic flows that traveled down all sides of the volcano. Collapse of the summit then created a 2.5-km-wide caldera. This photo was taken from Clark Air Base, about 25 km ENE of Pinatubo.

Photo by Karin Jackson, 1991 (U.S. Air Force). A powerful eruption of Pinatubo that began at 0555 on 15 June 1991 viewed from Clark Air Base ENE of the volcano. The broad ash column, which appears to be as wide as the volcano, is a result of pyroclastic flows that are sweeping radially down the volcano's flanks. Eruptions producing pyroclastic flows began on 12 June and continued intermittently until the climactic eruption that began at 1342 on the 15th and resulted in caldera collapse during sustained eruptions that lasted more than 6 hours.

Photo by Robert LaPointe, 1991 (U.S. Air Force). An ash plume rises from the new caldera of Pinatubo volcano on 22 June 1991. The 2.5-km-wide caldera, seen here from the N, was formed by collapse of the summit following a Plinian eruption on 15 June. Ash plumes continued for about a month before becoming intermittent prior to the end of the eruption on 2 September. Light-colored ash deposits cover the flanks of the formerly forest-covered volcano.

Photo by R. Batalon, 1991 (U.S. Air Force). The beginning of a small explosion within the new summit caldera of Pinatubo is seen from the NE on 1 August 1991. After the 2.5-km-wide caldera formed during the 15 June climactic eruption, frequent ash emission lasted through much of July. The caldera floor became visible for the first time when activity changed to intermittent explosions. By September 1991 a lake began to form from the accumulation of rainwater and groundwater from within the volcano; it eventually expanded to cover the caldera floor.

Photo by Tom Casadevall, 1991 (U.S. Geological Survey). Volcanic ash is composed of heavy pulverized rock. Ashfall from the 15 June 1991 eruption of Pinatubo in the Philippines accumulated on this this World Airways DC-10, shifting the center of gravity and causing the nose to tip up. About 4 km³ of ash was erupted on 15 June. It accumulated to depths of 10-15 cm at this airfield at the Cubi Point Naval Air Station, 40 km SSW of Pinatubo.

Photo by R.L. Rieger, 1991 (U.S. Navy). Heavy ashfall from the 15 June 1991 eruption of Pinatubo volcano caused the roof of this warehouse at Clark Air Base to collapse. The base had been evacuated prior to the major explosion on the 15th.

Photo by R. Batalon, 1991 (U.S. Air Force). The 1991 eruption of Pinatubo began on 2 April with a small phreatic eruption on the upper NW flank. The eruptions formed several craters along a 1.5-km-long, E-W-trending alignment. Steam rises from a vent at the SW end of the fissure. Activity continued at two of these vents through April-May and increased prior to extrusion of a small lava dome at a NW-flank vent on 7 June.

Photo by Chris Newhall,1991 (U.S. Geological Survey). The unconsolidated pyroclastic flow and ash deposits emplaced during the June 1991 eruption of Pinatubo were remobilized by rain water as lahars for years after activity ceased. This photo shows erosion patterns in the deposits along the Maraunot River valley NW of Pinatubo on 27 November 1991.

Photo by Chris Newhall, 1991 (U.S. Geological Survey). An ash-rich eruption column rises above a town at the western foot of Sumatra's Marapi volcano on 10 May 1992. The activity was part of an ongoing eruption that began in January 1987 from Verbeek crater. The explosions frequently produced light ashfall in surrounding areas, but did not cause damage. The eruption included growth of a lava dome in the summit crater.

Photo by Gede Suantika, 1992 (Volcanological Survey of Indonesia). An eruption column rises above Perboewatan crater on Krakatau Island on 27 May 1883. Three months later one of history's most noted eruptions destroyed much of the island, forming a submarine caldera. Detonations were heard as far away as Australia, pyroclastic flows swept across the sea to the coast of Sumatra, and powerful tsunamis devastated the shores of Sumatra and Java.

Photo courtesy Volcanological Survey of Indonesia, 1883. Submarine eruptions within Krakatau caldera were first observed in December 1927 and an ephemeral island appeared the following month. This 1929 view shows an ash-rich cock’s tail jet typical of shallow submarine explosions. Material ejected by earlier eruptions forms an island visible to the left. By August 1930 Anak Krakatau became a permanent island.

Photo by C.E. Stehn, 1929 (courtesy Volcanological Survey of Indonesia). A submarine eruption from Anak Krakatau on 13 June 1930, produces both a vertical eruption plume and a base surge extending radially from the vent along the surface of the sea. Submarine eruptions were first observed in December 1927, forming several ephemeral islands. By 12 August 1930 Anak Krakatau had become a permanent island.

Photo by W. Petroschevsky, 1930 (courtesy Volcanological Survey of Indonesia). An eruption plume rises above Anak Krakatau on 13 February 1960. Explosive activity at Anak Krakatau was almost continuous from December 1959 until 1963. The construction of a new cone displaced the crater lake. A lava flow that reached the sea was emplaced sometime between 1960 and 1963.

Photo courtesy Volcanological Survey of Indonesia, 1960. An ash plume erupting from the cone in the summit crater of Anak Krakatau on 2 May 1961. Anak Krakatau was in almost continuous activity from December 1959 until 1963. The newly formed cone displaced a lake that had filled the crater prior to the start of the eruption.

Photo by D. Hadikusumo, 1961 (Volcanological Survey of Indonesia). An ash plume rises above Anak Krakatau on 4 January 1973. The eruption began in June 1972 and lasted until mid-1973. Frequent explosions from June to September 1972 were followed in December by renewed explosive activity and the effusion of a lava flow, which ceased flowing in January 1973.

Photo by S. Wikartadipura, 1973 (Volcanological Survey of Indonesia). Explosive eruptions, such as this one in October 1978, occurred at Anak Krakatau from July to November. Initially, explosions occurred at intervals of 15-30 minutes, decreasing to intervals of 30-60 minutes in October before the eruption ended in November.

Photo by J. Matahelumual, 1978 (Volcanological Survey of Indonesia). A small dark ash plume begins rising from the crater of Anak Krakatau in October 1978. Explosive activity began in July and lasted until November. A lava flow from a previous eruption forms the coast in the foreground.

Photo by J. Matahelumual, 1978 (Volcanological Survey of Indonesia). An explosive eruption in 1979 from Anak Krakatau is seen in an aerial view from the north. The island of Anak Krakatau, a post-caldera cone that has grown within the submarine caldera of 1883, first breached the surface in 1928.

Photo by Adjat Sudradjat, 1979 (Volcanological Survey of Indonesia). An ash plume rising above Galunggung in October 1982. Intermittent explosive eruptions had taken place since the start of the eruption on 5 April, accompanied by pyroclastic flows and lahars that devastated nearby areas. More than 40,000 people were evacuated during the eruption.

Photo by Ruska Hadian, 1982 (Volcanological Survey of Indonesia). Explosive eruption of Kelud in February 1990 seen from the Volcanological Survey of Indonesia observation post on the west side of the volcano. This eruption emptied the crater lake and produced pyroclastic flows that traveled 7-8 km. A series of lava domes gives the summit of Kelud a broad, irregular profile.

Photo by Ruska Hadian, 1990 (Volcanological Survey of Indonesia). An ash plume rises above a pyroclastic flow descending a west side valley of Kelud volcano in February 1990. During the 10 to 16-17 February eruption pyroclastic flows traveled 7-8 km from the volcano and lahars destroyed nearby agricultural land.

Photo by Ruska Hadian, 1990 (Volcanological Survey of Indonesia). Semeru, Java's highest volcano, is seen in eruption on the skyline at the southern end of a volcanic chain extending from Tengger caldera on the north. The eroded post-caldera cone of Batok is the center foreground and Bromo in the left foreground producing a white plume.

Photo by Lee Siebert, 1995 (Smithsonian Institution) An ash plume from the scoria cone within the caldera rises above the rim of the 2-km-wide Raung caldera in July 1988. Raung has erupted frequently in historical time.

Photo by Willem Rohi, 1988 (Volcanological Survey of Indonesia). An eruption plume from a scoria cone on the floor of the 2-km-wide Raung caldera rises high above the caldera rim in July 1988. Frequent explosive eruptions occurred at Raung from 1987 through July 1989. During August and September 1988 more than 300-400 individual eruptions were recorded.

Photo by Willem Rohi, 1988 (Volcanological Survey of Indonesia). Raung volcano, near the eastern tip of Java, contains a 2-km-wide summit caldera. One of Java's most active volcanoes, Raung produces frequent moderate explosive eruptions, like this one in 1988 from a cone within the caldera, that keep the upper flanks of the volcano sparsely vegetated. Raung forms part of a NW-SE-trending chain of volcanoes constructed near the SW rim of Ijen caldera.

Photo by Willem Rohi, 1988 (Volcanological Survey of Indonesia). An ultralight aircraft was used by scientists from France and the Volcanological Survey of Indonesia to monitor activity at Raung in 1988. This July view shows an ash plume rising above the forested northern flank of Raung volcano. Hundreds of explosive eruptions were recorded during August and September 1988. This eruption began in 1987 and continued into 1989.

Photo by Willem Rohi, 1988 (Volcanological Survey of Indonesia). An ash plume towers above Bali's Agung volcano on 12 March 1963. Five days later a devastating eruption produced pyroclastic flows and lahars that killed 1,148 people. Another powerful eruption on 16 May caused additional fatalities. The eruption left tens of thousands homeless.

Photo by K. Kusumadinata, 1963 (Volcanological Survey of Indonesia). An ash plume rises above the summit crater of Agung volcano on 17 March 1963 during the first of two powerful explosive eruptions that caused much devastation to the island of Bali. The eruption began on 19 February with a lava flow that traveled down the N flank. Major explosive events occurred on 17 March and 16 May that produced devastating pyroclastic flows and lahars that killed more than 1,100 people.

Photo by Djazuli, 1963 (Volcanological Survey of Indonesia). A 2-km-high ash plume rises above Barujari cone at Rinjani volcano on 9 June 1994 in this view looking S across the caldera lake with the Segara Anak caldera wall in the background. A small pyroclastic flow can be seen descending from the crater. The 1994 eruption began on 3 June and lasted until 21 November.

Photo courtesy of Volcanological Survey of Indonesia, 1994. An ash plume rises above Barujari cone of Rinjani volcano on 30 June 1994, with the S Segara Anak caldera wall in the background. Intermittent eruptions took place from 3 June until 21 November and produced plumes up to 3 km above the crater and a lava flow on its N flank.

Photo courtesy of Volcanological Survey of Indonesia, 1994. An ash plume rises on 30 June 1994 above Barujari, a cone on the floor of Rinjani's Segara Anak caldera. A small plume is visible to the lower right from a lava flow that began erupting during the earlier stages of the eruption.

Photo courtesy of Volcanological Survey of Indonesia, 1994. A large Plinian ash plume from Pinatubo towers above Clark Air Base on 12 June 1991. The eruption column reached an altitude of 19 km. This was the first in a series of powerful eruptions that reached a climax on 15 June. The eruption that day produced a series of large pyroclastic flows that covered all sides of the volcano and resulted in collapse of the summit, creating a 2.5-km-wide caldera.

Photo by Dave Harlow, 1991 (U.S. Geological Survey). A large ash plume rises above the NW flank of Pinatubo at 0841 on 13 June 1991. Weather radar indicated that the plume reached an altitude of at least 24 km. Pyroclastic flows from this eruption extended 4-5 km down the Maraunot drainage on the NW flank. At the end of this eruption the NW-flank lava dome that had begun growing on 7 June was still intact.

Photo by Rick Hoblitt, 1991 (U.S. Geological Survey). An eruption plume from Sakurajima, one of Japan's most active volcanoes, rises above the city of Kagoshima. It is a post-caldera volcano of the Aira caldera at the northern half of Kagoshima Bay. Eruptions began around 13,000 years ago and built an island that joined the Osumi Peninsula during the eruption of 1914. Frequent eruptions have been recorded since the 8th century.

Photo courtesy of Richard Fiske (Smithsonian Institution). A space shuttle photograph taken on 6 October 1985 shows an ash plume dispersing E from Sakurajima across the Osumi Peninsula to the Pacific Ocean. Sakurajima is near the S rim of the 20-km-wide Aira caldera that encompasses much of the N end of Kagoshima Bay. The caldera formed during an eruption about 22,000 years ago. Kagoshima City is the lighter-colored area across the bay immediately W.

NASA Space shuttle image, 1985 (http://eol.jsc.nasa.gov/). Sakurajima entered a period of frequent intermittent moderate explosions in October 1955. Ashfall from the active vent at Minamidake has often deposited ash on Kagoshima, southern Kyushu's largest city located 7 km across the bay. Ash plumes typically reach heights of 1-3 km above the vent. Lahars and ballistic block ejection have intermittently affected populated areas on the island. This September 1981 view shows an ash plume from the W.

Photo by Dick Stoiber, 1981 (Dartmouth College). An ash plume rises above a restaurant on Sakurajima island in September 1981. Near-continuous periods of explosive eruptions have been occurring since 1955, frequently depositing ash on residential areas. Occasional larger explosions have ejected ballastic blocks that have penetrated concrete roofs of buildings. Villages are located along the island's coast, but most are only 3-5 km from the active Minamidake summit crater.

Photo by Dick Stoiber, 1981 (Dartmouth College). This photograph of Vesuvius looking east across the Bay of Naples depicts the major eruption of April 1872. A vigorous eruption plume rises from the summit crater and ash plumes also rise from a NW flank fissure that fed a lava flow that traveled far down the W flank, overrunning several villages. Steam also rises above another lava flow below and to the right of the summit. This eruption began with lava effusion in December 1870.

Photo courtesty of Roberto Scandone (University of Rome). An ash plume erupting from the crater of White Island (also called Whakaari) on 25 March 1988. This was one of many phreatomagmatic and magmatic eruptions that took place from 1986 to 1994 from the small island volcano 50 km NE of New Zealand's North Island. Large eruptions on 14 March and 27 April 1988, produced 3.5-km-high ash plumes.

Photo by Ian Nairn, 1988 (New Zealand Geological Survey). A New Zealand Geological Survey volcanologist on the crater floor of White Island (also called Whakaari) volcano observes an ash plume on 9 February 1989. This was one of many small-to-moderate explosive eruptions that took place between 1986 and 1994.

Photo by Ian Nairn, 1989 (Geological Survey of New Zealand). An ash plume rises above Ngāuruhoe volcano on 26 January 1974 in this view from the W. Small pyroclastic flows descend the upper flanks of the cone. Eruptions during 26-28 January and 27-29 March 1974 were the most powerful at Ngāuruhoe in two decades. Explosive activity had been occurring since November 1972 and lasted until August 1974. The dark streaks descending to the base of the cone to the left are lava flows from the 1954 eruption.

Photo by D.L. Homer, 1974 (New Zealand Geological Survey). An ash plume rises above a new vent behind Bagiai cone on the floor of Karkar's summit caldera on 17 April 1979. Phreatic eruptions had begun during the night of 12-13 January after six months of increasing seismicity and incandescence. Major phreatic explosions from the new vent on 8 March devastated the caldera rim area, killing two volcanologists who were monitoring the eruption. A new crater formed and intermittent moderate-to-strong explosive activity continued until 9 August.

Photo by William Melson, 1979 (Smithsonian Institution) A new vent on the floor of Karkar's inner caldera began erupting on 12 January 1979. On 8 March a major phreatic eruption from the vent produced a directed explosion that devastated an area on the southern caldera rim. The explosion enlarged the January crater to a diameter of 300 m and a depth of 200 m. This 17 April view from the NE shows a low ash plume rising from the new crater.

Photo by William Melson, 1979 (Smithsonian Institution) An ash plume from a phreatic explosion rises above a small crater lake at Karkar volcano on 22 April 1979. Following a major explosion from a new vent on the floor of the caldera on 8 March, minor explosions took place until May, after which activity intensified. A lake was briefly seen the day after this photo was taken. The lake disappeared after a strong explosion that night, which deposited ash on the SW caldera floor.

Photo by William Melson, 1979 (Smithsonian Institution) An ash plume rises above Tavurvur volcano on 3 October 1994, two weeks after the onset of a major eruption of Rabaul caldera. Tavurvur, one of two volcanoes that were active on opposite sides of the caldera, is seen here from the west at Kaputin Point on Matupit Island. The brown area in the foreground is a raft of floating pumice from the 19 September-2 October eruption of Vulcan volcano on the W side of the caldera.

Photo by Elliot Endo, 1994 (U.S. Geological Survey). Eruptions from Tavurvur and Vulcan began within about an hour of each other on 19 September 1994. Powerful explosions from Vulcan produced ash plumes estimated to be as high as 21-30 km, pyroclastic flows that extended about 3 km, and the large rafts of floating pumice seen in the foreground of this photo. About 53,000 people were evacuated from Rabaul and surrounding areas, and there were few fatalities. Vulcan stopped erupting on 2 October, but Tavurvur, seen here from the NW in October, continued erupting into 1995.

Photo by Elliot Endo, 1994 (U.S. Geological Survey). Tavurvur ejects an ash plume in October 1994, following an eruption that began on 19 September. It is seen here from a helicopter with Kombiu volcano (upper right) to the N. Intermittent eruptive activity continued at Tavurvur for several years after the 1994 eruption.

Photo by Elliot Endo, 1994 (U.S. Geological Survey). Thick deposits of ash from the 1994 eruption of Rabaul volcano covered the city of Rabaul, partially burying cars and houses. The eruption forced the abandonment of the town, once the largest on the island of New Britain, and a total of 53,000 people were evacuated from the city and surrounding areas. An estimated 30,000 people evacuated the day the eruption began, and the remainder left by land and by sea the following day.

Photo by Andy Lockhart, 1994 (U.S. Geological Survey). Lava in the center of the crater of Tavurvur volcano on 7 October 1994 as an ash plume rises from a vent to the E. Impact craters from volcanic bombs ejected by the volcano can be seen in the foreground on the flanks of the cone. Explosive eruptions from Tavurvur began on 19 September. Ash plumes initially reached a maximum height of 6 km, although typical heights were 1-2 km. A small lava flow was first seen in the summit crater of Tavurvur on 30 September.

Photo by Andy Lockhart, 1994 (U.S. Geological Survey). The city of Rabaul lies buried beneath a thick blanket of ash from the 1994 eruption. Mount Kombiu rises to the west above the deserted streets of the town. Ashfall from Tavurvur volcano during the first few days of the eruption caused widespread damage. Virtually every building in the south part of the town collapsed. Heavy rainfall at the time of the eruption produced lahars that caused additional damage.

Photo by Andy Lockhart, 1994 (U.S. Geological Survey). Tephra layers from the 1994 eruption of Rabaul volcano are exposed in this pit dug at the eastern end of Rabaul town in Papua New Guinea. Individual layers are ashfall deposits from discrete explosive eruptions that occurred over three weeks. The light-colored layer near the bottom was produced by an eruption from Vulcan cone at the western end of the caldera. Most other layers originated from periodic explosions at the Tavurvur cone, closer to this site. The numbers on the scale mark 10-cm increments.

Photo by Andy Lockhart, 1994 (U.S. Geological Survey). A Surtseyan cock’s-tail plume rises above the sea surface at Kavachi volcano on 17 or 18 July 1977. Additional explosions were seen 19-22 July, with vapor and ash clouds reaching several hundred feet above the sea surface. This activity is typical of submarine eruptions from Kavachi, one of the most active volcanoes of the Solomon Islands. At least eight new ephemeral islands have been formed since an eruption in 1939.

Photo by W.G. Muller, 1978 (Barrier Reef Cruises, Queensland, Australia; courtesy of D. Tuni). During 5-18 September 1990 Ambrym was observed to be ejecting ash and blocks from Niri Mbwelesu crater, which formed adjacent to Mbwelesu crater in 1989 when Mbwelesu was also active. It no longer contained an active lava lake. Mbwelesu, Niri Mbwelesu, and Niri Mbwelesu Taten craters remained almost constantly active into 1991.

Photo by Michel Lardy, 1990 (ORSTROM, Vanuatu). Explosive activity that ejected ash and blocks from Niri Mbwelesu crater was observed on 16 September 1990. The Niri Mbwelesu crater formed adjacent to Mbwelesu crater in 1989 when Mbwelesu was also active but no longer contained a lava lake. During 1990 activity was concentrated in Mbwelesu, Niri Mbwelesu and Niri Mbwelesu Taten craters. Activity remained more or less constant into 1991.

Photo by Michel Lardy, 1990 (ORSTROM, Vanuata). Barren Island erupted for the first time in the 20th century in April 1991. Strombolian eruptions from the central cone produced ash plumes and incandescent ejecta, and a lava flow that is visible in the foreground and reached the W coast of the island. By the time of this 25 September photograph, all subsidiary vents had merged to form an enlarged summit crater.

Photo courtesy of D. Haldar, 1991 (Geological Survey of India) An ash plume in 1991 rises above Barren Island along the volcanic arc connecting north of Sumatra. The 3-km-wide island contains a 1.6-km-wide crater that is partially filled by a scoria cone that has been the source of eruptions since the first was recorded in 1787. Lava flows reached the coast during several recent eruptions.

Photo courtesy of D. Haldar, 1991 (Geological Survey of India). Light-colored volcanic ash from the 1991 eruption mantles the surface of a lava flow from the same eruption, and the scoria cone in the center of the photo. The slopes of the central cone, the source of the ashfall, is the larger feature to the right.

Photo courtesy of D. Haldar, 1991 (Geological Survey of India). The central scoria cone of Barren Island is seen here from the SW erupting in May 1991. The 1991 eruption, the first of the 20th century from Barren Island, included explosive activity from a vent on the upper NE flank and lava flows that reached the west coast of the island.

Photo courtesy of V.K. Raina, 1991 (Geological Survey of India). Incandescent ejecta and an ash plume from Strombolian eruptions that began in April 1991 are seen in this 16 May 1991 view of the scoria cone in the center of Barren Island. The 1991 eruption was the first from Barren Island in the 20th century.

Photo courtesy V.K. Raina, 1991 (Geological Survey of India) An ash plume rising above Anak Krakatau on 2 March 1988, was part of an eruption that produced explosive and effusive activity from mid-February until April. The eruption took place from a fissure on the SSE side of the 1960-61 scoria cone.

Photo by Klaus Mehl, 1988 (Ruhr University, Germany). Intermittent explosions, such as this one on 2 March 1988, took place from a fissure on the SSE side of the 1960-1981 cone of Anak Krakatau from mid-February to April 1988. Two small lava flows were also produced during late February and March, accompanied by small explosions.

Photo by Klaus Mehl, 1988 (Ruhr University, Germany). As ash plume rises above the summit of Mayon volcano on 27 April 1968 as pyroclastic flows travel down the SW and S flanks. This view from the SSW flank shows the Camalig church to the right, which was damaged by pyroclastic flows during the 1814 eruption. The 1968 eruption began on 21 April and lasted until 20 May.

Photo courtesy of William Melson, Smithsonian Institution, 1968. Pyroclastic flows are hot avalanches of rock, ash, and gas that sweep down the flanks of volcanoes at high velocities. This photo shows a relatively small pyroclastic flow at Mayon volcano in the Philippines on 23 September 1984. These hot, ground-hugging flows can travel at velocities to about 100 km/hour and reach areas well beyond the flanks of a volcano. Their high temperatures make them lethal to anything in their path. Hot ash plumes rise above the denser basal portion that can contain abundant solid blocks and ash.

Photo by Chris Newhall, 1984 (U.S. Geological Survey). A small pyroclastic flow descends the Bonga valley on the E flank of Mayon in March 1993. Collapse of a lava flow front traveling down the valley produced many small pyroclastic flows during the 1993 eruption. A large pyroclastic flow on 2 February, the first day of the eruption, traveled 6 km down this same valley and killed 75 people.

Photo by Philippine Institute of Volcanology and Seismology, 1993. A crowd of spectators watches a pyroclastic flow sweeping down the SE flank of Mayon volcano on 24 September 1984. They stand on the surface of a deposit from a large lahar emplaced during an eruption in 1814. The pyroclastic flow seen here traveled about 6 km. Strong explosions the previous day created notches in the SE and east crater rims that funneled pyroclastic flows down ravines in those directions.

Photo by Norm Banks, 1984 (U.S. Geological Survey). An ash plume rises above a vent on the SW side of Volcano Island at Taal on 30 September 1965, during a two-day eruption that began on the 28th. The white plume at the bottom is a horizontally moving base surge. The devastating pyroclastic surges caused 150 fatalities.

Photo by L.E. Andrews, 1965 (courtesy of Jim Moore, U.S. Geological Survey). This ash-covered newsstand on Clark Air Base holds a newspaper with the headline “Mt. Pinatubo showers Clark.” Powerful eruptions of Pinatubo volcano in June 1991 forced closure of the base.

Photo by Val Gempis, 1991 (U.S. Air Force). An Aeta couple returns to inspect their land along the Maraunot River on the NW flank of Pinatubo following the catastrophic eruption of 15 June 1991. At least 10,000 members of the nomadic Aeta peoples, whose native lands were on the slopes of Pinatubo, were displaced by the eruption.

Photo by Ray Punongbayan (Philippine Institute of Volcanology and Seismology). Thick pyroclastic flow deposits from the 1991 eruption of Pinatubo were rapidly eroded in the years following the eruption. This 7 September 1994 view of the upper Marella River valley from the SW, with the caldera rim on the skyline, shows the effects of the erosion of well over 100 m of pyroclastic flow deposits. Light-colored deposits in the channels at the middle right and lower left are post-1991 lahar deposits.

Photo by Chris Newhall, 1994 (U.S. Geological Survey). An ash plume rises above Sakurajima on 9 September 1985, where frequent explosive activity has occurred since October 1955. Eruption plumes typically rise 1-3 km above the vent, with occasional larger explosions. Ashfall commonly occurs over the island and periodically in Kagoshima City, 8 km to the west. Larger explosions eject ballistic blocks that have damaged structures on the island.

Photo by Tom Pierson, 1985 (U.S. Geological Survey). This torii, a Shinto shrine gate, was partially buried by ashfall from the 1914 eruption. The posts and chains surround the gate to protect this historical landmark. Originally 3 m high, the torii is located at the village of Kurokami on the E coast of Sakurajima, 5 km from the summit.

Photo by Norm Banks, 1981 (U.S. Geological Survey). A pyroclastic flow on 23 June 1993 at Unzen volcano in southern Japan travels down the flanks of the volcano into the Senbongi residential district of Shimabara city. Pyroclastic flows had been occurring at Unzen since May 1991 as a result of partial collapse of the lava dome growing at the summit of Fugendake. This pyroclastic flow traveled 1 km through inhabited areas that had been evacuated since August 1991. One resident who had returned to watch his house burn was killed by a second pyroclastic flow.

Photo by Setsuya Nakada, 1993 (Kyushu University). An ash plume rises from the summit crater of Fugendake on 4 June 1991, the day following deadly pyroclastic flows produced by collapse of a portion of the growing lava dome. The small pond in the foreground fills a crater formed by earlier exposions during the eruption that began in November 1990.

Photo courtesy Takashi Yamada, 1991 (Public Works Research Institute, Ministry of Construction). A block-and-ash flow travels down the flank of Fugendake in 1991. These were created by collapse of a lava dome that began on 24 May. The size of the flows gradually increased and on 3 June the largest flow of the eruption to that point swept 3 km down the Mizunashi River valley into Kita-Kamikoba village, killing 43 people and destroying many houses. On 8 June block-and-ash flows traveled 5.5 km to within 50 m of a major highway and destroyed an additional 73 houses.

Photo courtesy Willie Scott, 1991 (U.S. Geological Survey). An ash plume rises from the Shinzan lava dome at the summit of Chokaisan on 1 March 1974 after a repose of 140 years. Phreatic eruptions occurred in March and April that produced small lahars. The eruptions took place from an E-W-trending series of vents extending from the eastern caldera wall across the 1801 Shinzan lava dome and the Kojinyama cone. This view from the NW shows the eastern caldera wall behind the dome.

Photo courtesy of Japan Meteorological Agency, 1974. This outcrop at Oshima volcano, in the Izu Islands south of Tokyo, shows more than 100 individual tephra layers. They were produced by eruptions of Oshima at fairly regular intervals over a period of about 10,000 years. The lower layers follow the older preexisting topography. A prominent unconformity in the center of the outcrop is an erosional surface that truncated the earlier eruption deposits. The upper layers mantled this uneven surface.

Photo by Richard Fiske, 1961 (Smithsonian Institution). Lava fountains on 21 November 1996 reached 1.6 km above a fissure on the northern flank of Miharayama at Izu-Oshima. The horizontal line in the foreground is an advancing lava flow produced by molten ejecta from the fountains. The 1986 eruption began on 15 November with lava fountaining and lava flows lasting four days.

Photo by Katsuyuki Abe, 1986 (courtesy of the Volcanological Society of Japan). An eruption plume rising 3-4 km above Fukutoku-Oka-no-ba was witnessed from fishing boats on 18 Janaury 1986. A 4-km plume was detected by radar the following day. On 20 January a new island formed (seen here to the right of the eruption plume). The island reached maximum dimensions of 400 x 600 m, with a height of 15 m. Frequent strong explosions continued on 21 January, the day of this photo, and decreased in intensity that afternoon. Explosive activity ended by the next morning, and the island eroded to below sea level by 8 March.

Photo by G. Iwashita, 1986 (Japan Meteorological Agency). An ash plume towers above Pagan volcano on 18 May 1981, three days after the onset of the eruption. The initial eruption on 15 May produced ash plumes that rose to estimated heights of 16-20 km. Three vents along a fissure formed across the summit on 15 May. An upper NE flank cone produced a new scoria cone, and vents on the N and S summit crater rims produced lava flows that traveled down the flanks. Intermittent explosive activity continued until 1985.

Photo by Gary Haust, 1981 (courtesy Norm Banks, U.S. Geological Survey). An ash plume from the first of nine major explosions of Usu during 7-14 August 1977 towers above Lake Toya. The plume rapidly grew to a height of 12 km. The explosive eruptions were followed by slow growth of a cryptodome (a lava dome that does not breach the surface) over a period of five years. Phreatic explosions accompanied cryptodome growth in November 1977 and January-October 1978. By the end of the 1982 eruption Usu-Shinzan had grown to 180 m above the crater floor.

Photo by Asanuma, 1977. An ash plume rises above Usu on the afternoon of 7 August 1977, the first day of an eruption that lasted until 1982. Nine major explosive eruptions during 7-14 August 1977 were followed by slow growth of the Usu-Shinzan cryptodome. A crypotodome is a lava dome that uplifts the ground without breaking through to the surface.

Photo by T. Kobayashi, 1977 (courtesy Tokiko Tiba). Snowpack on the western flank of Tokachi preserves individual layers of pyroclastic surge and pyroclastic flow deposits from the 1988-89 eruption. Because the eruptions took place during the winter, snowfall proved very useful to scientists in distinguishing the deposits of small-scale eruptions that lasted only a very short time.

Photo courtesy of Japan Meteorological Agency, 1988. An ash plume rises above the North crater of Ebeko volcano at the northern end of Paramushir Island on 9 September 1989. An explosive eruption that began on 2 February 1989 continued until April 1990. Three summit craters located along a SSW-NNE line form the main edifice at the northern end of a complex consisting of five cones. Activity recorded since the late 18th century has included small-to-moderate explosive eruptions from the summit craters.

Photo courtesy of Kamchatka Volcanic Eruptions Response Team, 1989. An ash plume rises above Alaid on 30 April 1981, at the peak of an eruption that began on 27 April (seen here from the N). The plume extended 2,000 km to the SE. The volcano has a 1.5-km-wide summit crater and numerous cones across the lower flanks. Explosive eruptions in 1790 and 1981 were among the largest in the Kuril Islands.

Photo courtesy of Anatoli Khrenov, 1981 (Institute of Volcanology, Petropavlovsk). The 1972 eruption of Alaid in the northern Kuril Islands, seen here in August, was characterized by both explosive and effusive activity. An ash plume towers above a small scoria cone that formed on a 2-km-long fissure on the NW flank, while white gas-and-steam plumes rise from the margins of this lava flow that traveled 1 km into the Sea of Okhotsk. The eruption began on 18 June and ended by 11 September.

Photo by A.M. Chirkov, 1972 (courtesy of Oleg Volynets, Institute of Volcanology, Petropavlovsk). An ash plume from Gorely drifts to the N across Avachinsky Bay in this 1980 view from Petropavlovsk, Kamchatka's largest city. Explosive activity began in June 1980 and intermittent explosions took place until July 1981. An explosion on 31 July produced a plume that rose up to 5.5-km altitude, and a pyroclastic flow was produced on 3 December 1980.

Photo by Kamchatka Volcanic Eruptions Response Team, 1980 (courtesy of Dan Miller, U.S. Geological Survey). An ash plume rises from the summit crater of Avachinsky on 16 January 1991. An explosive eruption began on 13 January 1991 and produced ash plumes 4-5 km above the crater, resulting in ashfall on Petropavlovsk. During the eruption, lava filled the 260-m-wide summit crater. Small lava flows spilled over the crater rim and advanced 1.5 km down the SSE flank and a short distance down the SW flank. The lava flows melted snow to form small lahars down the S flank.

Photo by Oleg Volynets, 1991 (Institute of Volcanology, Petropavlovsk). A small ash plume rises from the summit crater of Karymsky in this photo taken during the 1970's. Near-continuous mild-to-moderate explosive eruptions took place during 1970-82. Lava flows were emitted from the summit crater in 1970, 1971, 1976, and 1979-82.

Photo by Yuri Doubik (Institute of Volcanology, Petropavlovsk). This ash plume rising above the summit of Karymsky during the early 1970's represents typical activity during its 1970-1982 eruption. It was constructed within a 5-km-wide caldera that formed about 6,000 years ago. The northern Karymsky caldera wall is seen across the center of the photo. It formed within the older Dvor caldera, with the caldera wall visible in the background.

Photo by Yuri Doubik, 1972 (Institute of Volcanology, Petropavlovsk). An ash plume rises above a scoria cone along the S-flank rift zone of Kamchatka's Tolbachik volcano in late July 1975. This was the first of three cones formed along the northern part of the rift zone during the early stage of the eruption and was only a few weeks old at the time of this photo. Lava fountains rose 1-2.5 km above the vent and ash plumes reached 10-18 km heights.

Photo by Oleg Volynets, 1975 (Institute of Volcanology, Petropavlovsk). Lava fountaining at a scoria cone along Kamchatka's Tolbachik S-flank rift zone in late-July 1975. This was the first of three large cones that formed along the northern part of the rift zone during the early stage of the eruption. The lava fountains reached heights up to 1-2.5 km above the vent and ash plumes rose 10-18 km. After 27 July, eruptions from the first cone were dominantly effusive. Activity at the first cone ceased on 9 August.

Photo by Oleg Volynets, 1975 (Institute of Volcanology, Petropavlovsk). Ash plumes and incandescent lava fragments are ejected from a new scoria cone in 1975. Following minor ash eruptions from the Plosky Tolbachik summit crater on 28 June, the "Great Tolbachik Fissure Eruption" began 18 km S of the summit on 6 July, producing a major eruption that lasted until 15 September. A dominantly effusive eruption began 28 km S of the summit on 18 September and continued until December 1976.

Photo by Yuri Doubik, 1975 (Institute of Volcanology, Petropavlovsk). Following a period of explosive eruptions and lava-dome growth beginning in October 1955, a major explosive eruption took place on 30 March 1956 at Bezymianny volcano in Kamchatka. The Plinian eruption, seen here from 100 km W, produced a 40-km-high ash column, pyroclastic flow to a distance of 18 km, lateral blast, and a debris avalanche when the summit of the volcano collapsed.

Photo by I. V. Yerov, 1956 (courtesy of G.S. Gorshkov, published in Green and Short, 1971). An ash plume erupting from the summit crater of Kamchatka's Kliuchevskoy volcano on 9 February 1987, traveling to the west. Ashfall from earlier eruptions darkens the southern flank of the volcano and several lahar deposits are visible. Explosive eruptions from the summit crater during 1986-1990 were accompanied by lava flows from both summit and flank vents.

Photo by Alexander Belousov, 1987 (Institute of Volcanology, Kamchatka, Russia). An ash plume erupts from the summit of Klyuchevskoy on 16 February 1987. Long-term activity includes both explosive and effusive activity from summit and flank vents. This view from the south shows Bezymianny producing a small plume at the lower left, Kamen at the left center, and the broader Ushkovsky on the left horizon.

Photo by Alexander Belousov, 1987 (Institute of Volcanology, Kamchatka, Russia). An ash plume from Klyuchevskoy in 1979 is dispersed in front of the sun in this view looking from the SW. This was part of a dominantly explosive eruption that took place from August 1977 until 1980. The eruption concluded with explosive activity and lava effusion from a flank vent during 5-12 March 1980. Ushkovsky is to the right, with the small Sredny cone in the center.

Photo by Yuri Doubik, 1979 (Institute of Volcanology, Petropavlovsk). An ash plume at Sheveluch volcano is observed in 1984 from the town of Klyuchi, 50 km to the SW. The eruption originated from a lava dome that began growing in 1980 within a crater that formed during flank collapse in 1964. No change in the geometry of the lava dome was noticed from 1983 until the onset of the 1984 eruption.

Photo by Kamchatka Volcanic Eruptions Response Team, 1984 (courtesy of Dan Miller, U.S. Geological Survey). Phreatomagmatic eruptions produced when magma came in contact with groundwater eject an ash plume at the Ukinrek Maars on the Alaska Peninsula. This photo from the south on 5 April 1977 shows explosive eruptions from East Maar, one of two new craters that formed in glacial sediments, in an area without previous volcanic activity. The hummocky, snow-covered surface in the foreground is a debris avalanche deposit from Peulik.

Photo by Jim Faro (Alaska Department of Fish and Game). An aerial view into East Maar on 3 April 1977 shows incandescent lava on the floor of the crater and a small vent above it that is producing an ash plume. The 1977 eruptions of Ukinrek Maars began on 30 March at West Maar, which formed during the first three days of the eruption. East Maar formed during the next seven days at a location 600 m E. A lava dome, now covered by a crater lake, formed on the floor of East Maar.

Photo by Ken Parker, 1977 (Alaska Department of Fish and Game). This Landsat thematic mapper image was acquired on 28 August 1986, as Augustine produced a powerful explosive eruption. An 11-km-high ash plume rises from the summit crater to the top of the false-color image. The red area in this false-color image is a hot pyroclastic flow deposit down the north flank. Snow and ice show up as shades of blue and vegetated areas along the coast are green. The dark areas descending the flanks are the paths of lahars and cooled pyroclastic flows.

NASA Landsat image, 1990. A series of phreatic eruptions beginning 27 March 1980 preceded the major eruption of 18 May. These relatively small steam-driven eruptions ejected ash and gas from the summit, creating a new crater and blanketing the flanks with ash. The material ejected consisted of fragments from the 350-year-old lava dome that formed the summit.

Photo by Don Swanson, 1980 (U.S. Geological Survey). On 11 April 1980, two weeks after the 27 March beginning of the eruption of Mount St. Helens, an area of fractured glacial ice is visible at the top of the volcano. Thin black streaks of volcanic mudflows are visible at the center and lower left that diverge around the undisturbed snowpack on Sugar Bowl lava dome.

Photo by William Melson, 1980 (Smithsonian Institution). The highly fractured area on the right side of this 3 May 1980 photo is the renowned N-flank "bulge" of Mount St. Helens. Intense deformation producing northward displacements up to 2.5 m per day and reduction of rock strength by hydrothermal alteration caused the catastrophic collapse of the N flank, triggering the devastating magmatic explosive eruptions of 18 May.

Photo by William Melson, 1980 (Smithsonian Institution). The fine-grained gray layer behind the ruler was produced by the 18 May 1980 lateral blast of Mount St. Helens. The deposit is about 50 cm thick at this location, 13 km NE of the volcano. The blast deposit is overlain by airfall pumice that was erupted later on 18 May and underlain by a pumice deposit from an eruption in 1482 CE.

Photo by Lee Siebert, 1982 (Smithsonian Institution). A second large explosive eruption took place from Mount St. Helens on 25 May 1980. It produced an ash plume that rose 14 km above the volcano, but the volume of ash was minor compared to the catastrophic eruption of 18 May a week earlier.

Photo by Darryl Lloyd, 1980 (courtesy U.S. Geological Survey). An ash plume rises above a rockfall on the south side of the Mount St. Helens dome during a period of lava dome growth in June 1985. Lava dome growth occurred intermittently from 1980 to 1986.

Photo by Gene Iwatsubo, 1985 (U.S. Geological Survey). A fissure opened across the summit of Pagan on 15 May 1981, the first day of the eruption. It is seen here on 26 May 1981, looking across a N-flank scoria cone that formed along the fissure. The trees in the foreground are from a devastated coconut plantation.

Photo by Norm Banks, 1981 (U.S. Geological Survey). A bulldozer works to create a barrier to lava flows threatening areas below the village of Kapoho, on the lower East Rift Zone of Kīlauea, in January 1960. Lava fountains tower in the background from the eruptive vent, which was less than 1 km from the center of the village. Lava flows eventually engulfed the entire village, but the 5 km of walls that were constructed may have helped prevent the flows from reaching houses and a lighthouse at the coast.

Photo by Hawaii Volcanoes National Park, 1960. A line of lava fountains rises above a fissure on the lower East Rift Zone of Kīlauea in January 1960. The eruption originated near the village of Kapoho, which was overrun by lava flows. Lava flows traveled to the coast, reaching the ocean along a broad front.

Photo by Hawaii Volcanoes National Park, 1960. An aerial view from the SE shows the Bárcena tuff cone, constructed during an eruption in the Revillagigedo Islands off the western coast of México during 1952-53. The 700-m-wide crater is partially filled by lava, and the lava delta at the lower right was fed from a vent on the flank. The tuff cone was constructed to a height of about 330 m from near sea level within the first few weeks of an eruption that began on 1 August. Lava was seen in the crater by mid-September and flank lava extrusion began on 8 December.

Photo by Adrian Richards, 1955 (U.S. Navy Electronics Laboratory). An ash plume towers above Colima on 7 March 1903 in this view from the south. A large explosive eruption on 15 February produced abundant ashfall and pyroclastic flows. The light-colored area down the flank to the left may be pyroclastic flow deposits. More than 20 large explosions, including this one, took place between 15 February and 14 March.

Photo courtesy Julian Flores (University of Guadalajara), 1903. An ash plume rises above a pyroclastic flow traveling down the SW flank of Colima on 16 April 1991, colored orange by the late-afternoon sun. The pyroclastic flow was produced by collapse of unstable parts of the summit lava dome. The black mass at the summit is a lava dome that began growing on 1 March. Later in the eruption, which ended in October, a lava flow traveled down the SW flank to 2,600 m elevation from the roughly 3,850-m-high summit.

Photo by Alfredo Ramirez (pilot Ernesto Gómez Hofman), 1991 (courtesy Melchor Urzua, Protección Civil de Colima). A convecting ash column rises above a small pyroclastic flow on the SW flank of Colima volcano in México on 16 April 1991. The pyroclastic flow, colored by the late-afternoon sun, was produced by the collapse of portions of the summit lava dome.

Photo by Alfredo Ramirez (pilot Ernesto Gómez Hofman), 1991 (courtesy Melchor Urzua, Protección Civil de Colima). This photo shows an ash plume rising above Parícutin on 9 June 1943, seen here from the Uruapan highway to the east. Prevailing winds distribute the ash plume to the south. Other scoria cones appear on the horizon, some of the 1,000-plus scoria cones within the massive Michoacán-Guanajuato volcanic field.

Photo by William Foshag, 1943 (Smithsonian Institution). An aerial view from the NNW on 5 March 1943, about two weeks after the start of the Parícutin eruption, shows the Quitzocho lava flow advancing to the NE as an ash plume rises from the scoria cone. The flow was about 6-15 m thick as it advanced.

Photo by Ezequiel Ordonez, 1943 (U.S. National Archives). An ash plume rises above the new Parícutin cone on 21 February 1943, the second day of the eruption. The new cone is about 30 m high and is just rising above the treetops in this view from the NE. During this early stage the cone had slope angles of 32 degrees toward the west and lower angles to the east. At this point lava had begun flowing to the east.

Photo by Salvador Ceja, 1943 (U.S. National Archives, published in Luhr and Simkin, 1993). An ash plume rises from Parícutin in October 1944. The photo was taken from the north at the outskirts of the town of San Juan Parangaricutiro. Lava flows in the foreground had already buried the town; the church tower seen in many other photos of the Parícutin eruption is hidden behind the small tree to the right.

Photo by Carl Fries, 1945 (U.S. Geological Survey, published in Luhr and Simkin, 1993). An ash plume at Parícutin in 1944 is photographed from the first observatory cabin 1.5 km north, with local resident Celedonio Gutierrez in the foreground. Gutierrez was born in the nearby town of San Juan Parangaricutiro, which was inundated by lava flows, and became actively involved in collaborations with U.S. scientists throughout the eruption.

Photo by Ken Segerstrom, 1944 (U.S. Geological Survey, published in Luhr and Simkin, 1993). The first lava flow from Parícutin, the Quitzocho flow, moves northward over cornfields prepared for planting. An ash plume rises from the new cone, which by the time of this photo on 25 February, the 5th day of the eruption, was already more than 150 m high. Gas plumes rise from the advancing lava flow.

Photo by Instituto de Geología, 1943 (published in Luhr and Simkin, 1993). In mid-November 1944 lava broke out of the SSW base of the cone, below the south vent in the crater, seen here from the S. The Ahuán flow advanced over the earlier Taquí flows in the foreground. A small lava intrusion was exposed in the flank of the cone a short distance above the vent. Ahuán flows traveled around the east side of the cone and to the north.

Photo by Frank Zierer, 1944 (published in Foshag and González-Reyna, 1956). A villager inspects the roof of a house in the village of Parícutin that was destroyed by heavy ashfall in the first year of the eruption. The village that the volcano was named after was located only 3 km NW of the new cone. Ashfall was particularly intense during the eruption's second to fifth months, and the town's 733 residents were forced to evacuate four months after the eruption began. The Mexican government provided new lands in Caltzontzín, 27 km to the SE.

Photo by Frederick Pough, 1943 (American Museum of Natural History). One of the first photographs taken of the Parícutin eruption shows an ash plume rising from the new volcano at 1800 on 20 February 1943, 1.5 hours after the start of the eruption. The photo was taken near Ticuiro, 5 km NNW of the volcano, with the fields of San Juan Parangaricutiro, later overrun by lava flows, in the foreground. Cerro de Canicjuata is the forested older cone to the right.

Photo by Luis Mora-Garcia, 1943 (published in Foshag and González-Reyna, 1956). A geologist observes an ash plume rising above the crater of Parícutin on 22 March 1944, as seen from 1 km SW at Mesa de Cocjarao. During March 1944 the eruptive activity ranged from small ash plumes accompanied by deep rumbling to large but almost soundless ash plumes, as was true with the plume shown here.

Photo by William Foshag, 1944 (Smithsonian Institution, published in Foshag and Gonzáles-Reyna, 1956). Villagers observe an ash plume rising above Parícutin in 1944 beyond the streets of San Juan Parangaricutiro, soon to be overrun by lava flows. In June and July 1944 lava advanced slowly through the town, which was incrementally evacuated as the flow progressed. Many residents, showing their deep attachment to the land, stayed until the lava overran the last segments of their property.

Photo by William Foshag, 1944 (Smithsonian Institution, published in Luhr and Simkin, 1993). Local Tarascan residents observe Parícutin volcano from Cerro de Equijuata, 2.5 km to the NNE, in March 1944. In this photo taken a little more than a year after the eruption began the Sapichu cone appears at the NE (left-hand) base of Parícutin. The rugged lava flows of June 1943 are visible in the middle of the photo. Heavy ashfall has defoliated trees and a thick ash deposit mantles the landscape.

Photo by Arno Brehme, 1944 (U.S. National Archives, published in Foshag and Gonzáles-Reyna, 1956). An ash plume towers 6 km above Parícutin on 24 March 1943, a little more than a month after the start of the eruption. The photo was taken from 3 km N in Tititzu and shows the advancing front of the Mesa del Corral lava flow in the middle ground, with the rim of the scoria cone behind it.

Photo by William Foshag, 1943 (Smithsonian Institution, published in Foshag and Gonzáles-Reyna, 1956). An ash plume rises from the summit crater of Parícutin sometime during 1946-48. A thick ash deposit covers the foreground. An estimated 4,500 cattle and 550 horses died during the heavy ashfall in the early months of the eruption, devastating the local people who depended on the animals for food, plowing, and transportation. Ashfall was deeper than 15 cm over a 300 km² area around the volcano and continued with varying intensity throughout the 9-year-long eruption.

Photo by Ray Wilcox (U.S. Geological Survey). An ash plume rises above Popocatépetl, whose Aztec name means "Smoking Mountain." This aerial view is of the NE side of the massive volcano, which towers more than 3,200 m above the Valley of Mexico to the right in this December 1994 photograph. Frequent eruptions have been recorded since the pre-Columbian era. El Ventorrillo, the small peak on the right, is a remnant of the eroded Nexpayantla volcano, a predecessor to the modern cone of Popocatépetl.

Photo courtesy of CENAPRED, Mexico City, 1994. Strong winds disperse an ash plume to the NE from the Popocatépetl summit crater in December 1994. Phreatic explosions that began on 21 December were the first at the volcano in nearly a half century, resulting in ashfall in the city of Puebla, 45 km E. Intermittent ash eruptions lasted until May 1995 and then resumed in March 1996. The explosions ejected a small lake from the crater floor, and three small new craters appeared at the base of the east crater wall.

Photo courtesy CENAPRED, Mexico City, 1994. A plume rises above the eastern side of the summit crater of Popocatépetl in December 1994. Ash deposits from previous eruptions darken the glaciers on the upper flank. This aerial view from the NE shows the El Ventorillo peak on the right-hand horizon, the remnant of an older edifice.

Photo courtesy CENAPRED, Mexico City, 1994. An ash plume rising from the summit crater of Popocatépetl in January 1995 as seen from the mountaineering lodge at Tlamacas, 4.5 km NNE of the summit. Phreatic eruptions that began on 21 December 1994 were the first from the volcano in almost a half century. Intermittent ash eruptions continued until May 1995 and then resumed in March 1996.

Photo by Dan Dzurisin, 1995 (U.S. Geological Survey). Ash deposited across the countryside around El Chichón volcano, seen in the background of this 19 April 1982 photo taken about two weeks after a series of major eruptions. Ash covered an area of more than 45,000 km² towards the ENE. At this location, 12 km NE of El Chichón, the ashfall deposit was 30 cm thick. Fine ash and sulfuric acid aerosols from the eruptions circled the globe and were responsible for brilliant sunsets in the northern hemisphere for the next few years.

Photo by Jim Luhr, 1982 (Smithsonian Institution). An ash plume rises above the Caliente vent in February 1968. Lava spines protrude from the easternmost vent of the Santiaguito lava dome. The flank of the Santa María edifice appears to the left in this view from the north.

Photo by Dick Stoiber, 1968 (Dartmouth College). An ash plume rises above the Santiaguito lava dome in March 1988. Explosive eruptions such as these are typical of the growing lava dome since activity began in 1922. The dome was constructed at the base of a large crater, seen here in profile from the Pacific coastal plain to the SE. The crater formed low on the SW flank and extended almost to the summit.

Photo by Lee Siebert, 1988 (Smithsonian Institution). Three distinct stages marked the growth of Santa María. The large edifice formed over a basement of older volcanic and plutonic rocks beginning about 30,000 years ago and ending about 500 to several thousand years ago. A massive eruption in 1902 then created the large crater on the SW flank seen in the shadow left of the summit. The third stage is marked by continued growth of the Santiaguito lava dome complex (left) in the new crater since 1922.

Photo by Lee Siebert, 1988 (Smithsonian Institution). This closeup view of an ash plume rising from the El Brujo lava dome was taken on 13 November 1967. Explosions such as these are common at the growing lava dome, sometimes occurring within minutes of each other. The crater wall is visible at the lower left.

Photo by Charles Pineo, 1967 (Dartmouth College, courtesy of Dick Stoiber). An ash plume with incandescent ejecta rises high above the summit of Fuego and produces hot avalanches down its flanks during this 12-13 August 1966 eruption. Ash fills much of the sky in this view. The ash plume rose to 12 km during this large but brief eruption.

Photo by Dick Stoiber, 1966 (Dartmouth College). Following mild eruptions that began on 7 February 1966, a powerful eruption in April produced this ash plume that towers above the summit (not visible in this view). Major eruptions during 20 April to 1 May were accompanied by pyroclastic flows and lava flows.

Photo by Bill Rose, 1966 (Michigan Technological University). An ash plume rises from the summit crater of Fuego in this March 1978 photo. Intermittent minor explosive eruptions took place from 11 September 1977 to 8 August 1979. The eruptions sometimes produced pyroclastic flows and lava flows, and originated from multiple vents in the summit crater.

Photo by Dick Stoiber, 1978 (Dartmouth College). A large ash plume towers above Fuego in October 1974 as pyroclastic flows travel down the eastern flank (left). This was the largest Fuego eruption since 1932 at the time, and produced pyroclastic flows that traveled up to 7 km down the E, SE, SW, and W flanks. Prevailing winds distributed ashfall primarily to the SW, in the opposite direction from this view.

Photo by William Buell, 1974. Residents of Antigua Guatemala have observed eruptions at Volcán de Fuego for several centuries. A larger ash plume towers above the city in this October 1974 view of one of Fuego's largest historical eruptions. Pyroclastic flows are also descending the east flank (left). The local topography diverted pyroclastic flows and lahars down drainages to the east and south.

Photo by Paul Newton, 1974. A large ash plume towers above Fuego in October 1974 as pyroclastic flows sweep down the SE (left) and NE flanks (center). Incandescent ejecta can be seen at the base of the ash plume. Prevailing winds distributed ashfall primarily to the SW. More than 0.2 km³ of ash was erupted during four distinct explosive pulses of 4 to 17 hours duration between 14 and 23 October.

Photo by William Buell, 1974. Pyroclastic flows travel down the east flank of Fuego volcano in Guatemala during October 1974 as part of one of the largest historical eruptions of the volcano. Ash plumes rise from the pyroclastic flows, which traveled up to 7 km from the summit at estimated average velocities of 60 km/hour. The denser basal portion of the pyroclastic flow follows topographic lows on the flanks of the volcano. A smaller pyroclastic flow is descending the gully to the right.

Photo by William Buell, 1974. Ash rises above a pyroclastic flow racing down the eastern flank of Fuego in October 1974 that fills the entire field of view. The direction of movement of the pyroclastic flow was from right to left. Pyroclastic flows of comparable magnitude also traveled down the W and SW flanks.

Photo by William Buell, 1974. A pyroclastic flow descending the east flank of Fuego on 8 January 1979, is viewed from the city of Antigua Guatemala to the NE. Intermittent explosive eruptions had been occurring since September 1977 and lasted until 8 August 1979.

Photo by Paulino Alquijay, 1979 (courtesy of Pete Newton). A lava fountain and ash plume rises above Pacaya, seen here in 1987 from the NW along the highway to Antigua Guatemala. Strombolian eruptions began in 1965 and were periodically interrupted by larger explosions such as this one, which deposited ash across wide areas.

Anonymous photo courtesy Norm Banks (U.S. Geological Survey), 1987. An eruption from Nicaragua's Cerro Negro volcano in 1968 produces an ash plume above the vent. Incandescent ejecta is visible at the base of the column. Gas and steam rise from fumaroles on the righthand side of the scoria cone. Ash and bombs fall from the eruption column at the left.

Photo by William Melson, 1968 (Smithsonian Institution). An ash plume rises above Rincón de la Vieja on 4 June 1922. No further eruptive activity was recorded until 1966, when eruptions began occurring more frequently.

Photo by José Tristan, 1922 (courtesy of Jorge Barquero). An eruption began at Arenal on 29 July 1968 with major explosions and pyroclastic flows that destroyed two towns and killed 78 people. Three new craters formed on the west flank. This 12 August 1968 view from the WNW flank shows an ash plume with part of the devastated zone in the foreground. Effusion of lava flows that began on 19 September formed an extensive lava field on the western flank.

Photo by William Melson, 1968 (Smithsonian Institution) Pyroclastic flows descend the flanks of Arenal on 7 July 1987. This was part of the long eruption that began in 1968. The largest pyroclastic flow in this photo taken from the volcano observatory (2.5 km SSW of the summit) is traveling down the SSE flank.

Photo by William Melson, 1987 (Smithsonian Institution) An increase in Strombolian eruptions at Arenal had begun in March 1990. An ash plume rises above the summit on 4 April 1990, seen here from the volcano observatory 2.5 km S. This was part of a long-lived eruption that began in 1968. Explosions produced ash plumes to heights of 1 km above the summit and were accompanied by a lava flow that descended the Río Tabacón on the NW flank down to 700 m altitude. Small pyroclastic flows were also produced.

Photo by William Melson, 1990 (Smithsonian Institution) An ash plume rises above the crater lake of Poás volcano in 1915. Intermittent eruptions producing ashfall during 8 October 1914 to 15 May 1915. The 10 April eruption was seen from San José, and the last of a series of eruptions during 15-19 April that produced ashfall across great distances.

Photo by R. Fernandez Peralta, 1915 (courtesy of Jorge Barquero, Universidad Nacional Costa Rica). A plume containing ash and mud erupts through the Poás crater lake in July 1977 when phreatic explosions were produced at 25-minute intervals. This activity had begun in May 1977.

Photo by S. Racchini, 1977 (Universidad Nacional Costa Rica, courtesy of Jorge Barquero). Phreatic eruptions resumed from Poás in June 1987, ejecting lake water and sediments to a maximum reported height of 75 m. This 23 January 1988 photo shows the typical ejection of plumes of gas, ash, and mud above the crater lake. The crater lake disappeared by 19 April 1989 then ash emission began. Phreatic activity began again after rainwater formed a new lake. During May 1989 ash plumes reached heights of 1.5-2 km above the crater.

Photo by Gerardo Soto, 1988 (Instituto Costarricense de Electridad). A geologist observes an ash plume rising 400 m above the summit crater of Poás on 25 April 1989. By 19 April, four days before this explosion, the crater lake had disappeared. In May 1989 ash plumes reached 1.5-2 km above the crater.

Photo by Gerardo Soto, 1989 (Instituto Costarricense de Electridad). The first of several major eruptions of Irazú between 1963 and 1965 took place on 13 March 1963. These eruptions produced heavy ashfall over much of central Costa Rica, severely affecting agricultural areas and causing major economic problems. Lahars caused fatalities and destroyed hundreds of houses.

Photo by Dick Stoiber, 1963 (Dartmouth College). An ash plume above the summit of Irazú is seen in March 1963 from the old San José airport. Eruptions during 1963-65 were among the largest in historical time from the volcano. Intermittent mild-to-moderate explosive activity produced heavy ashfall that severely affected agricultural areas and caused economic disruption.

Photo by Dick Stoiber, 1963 (Dartmouth College). An ash plume disperses to the south in mid-July 1986, three months after the start of an eruption of Pavlof that lasted nearly 2.5 years. This photo was taken from the west on a fishing boat in Pavlof Bay, with Pavlof Sister to the right. The 1986-88 eruption produced intermittent ashfall and lava flows from two vents near the summit, one halfway down the SE flank, and another 600 m below the summit on the NE flank. Lava flows traveled to the N, NE, SE, ESE, and SSE, the latter to within 600 m of the Pavlof Bay shoreline.

Photo by Richard Mack, 1986. An ash plume rises from vents near the summit of Pavlof on 10 June 1987 in this view from the NNE. Intermittent explosive eruptions took place from vents at the summit and flanks from April 1986 until August 1988, and lava flows descended the flanks in several direction. One lava flow reached to within 600 m of Pavlof Bay and another descended to the saddle between Pavlof and Pavlof Sister.

Photo by Harold Wilson, 1987 (Peninsula Airways). Intermittent explosive eruptions took place from the scoria cone in Akutan caldera during 31 January-2 March and 22-24 June 1987. This 11 February photo from the SE shows an ash plume rising from a crater at the top of the cone. Ash was deposited across the cone flank and the N side of the caldera floor.

Photo by Jerry Chisum (Mark Airways), 1987 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys). Akutan has a 2-km-wide summit caldera with a large scoria cone that rises above the caldera rim. It is seen here from the south in eruption on 11 February 1987. A small lake occupies part of the caldera floor. The caldera rim is breached narrowly on the north side through which a 1978 lava flow traveled to within 2 km of the sea.

Photo by Jerry Chisum (Mark Airways), 1987 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys). An ash plume rises above the scoria cone in the Akutan summit caldera of on 2 March 1987. This view from the WSW shows Mount Gilbert, a Pleistocene volcano on Akun Island and the peaks of Westdahl, Shishaldin, and Isanotski (left to right) on distant Unimak Island.

Photo by Harold Wilson (Peninsula Airways), 1987 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys). An aerial view of the Cleveland upper east flank taken at about 1100 local time on 24 June 1987 shows an active lava flow. Incandescent lava can be seen at several locations along the flow, which eventually traveled 2.5 km from the summit. The snow-covered flanks are darkened by ash deposition from an eruption that began on 19 June.

Photo by Harold Wilson, 1987 (Peninsula Airways), courtesy of John Reeder (Alaska Div. Geology Geophysical Surveys). Both Cleveland (left) and Carlisle (right) volcanoes in the Aleutian islands are snow-covered, but the flanks of Cleveland in this 24 June 1987 photo, seen from the ESE, are darkened by ashfall deposits from an explosive eruption that began on 19 June.

Photo by Harold Wilson, 1987 (Peninsula Airways), courtesy of John Reeder (Alaska Div. Geology Geophysical Surveys). A submarine eruption at Myojinsho lava dome on the rim of Beyonesu Rocks caldera in the central Izu Islands on 23 September 1952. This photo shows a vertically rising plume of ash and steam (cocks’s-tail plume) and a base surge traveling across the sea surface. This photo was taken 8 seconds after the explosion first breached the surface. The eruption began on 16 September when a lava dome rose towards the sea surface. Explosive activity then progressively destroyed the dome. This cycle occurred three times until October 1953.

Photo courtesy of Ryohei Morimoto (University of Tokyo). An ash plume rises about 1.5 km above the scoria cone in the Akutan summit caldera on 20 April 1988. This view from Akutan Harbor east of the volcano shows typical explosive activity. Intermittent ash eruptions began on 26 March and continued until 20 July.

Photo by Charlotte Jones, 1988 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys). An ash plume rises about 1 km and drifts to the NW above the Akutan caldera scoria cone on 2 June 1988. Dark ash deposits on the flanks extend across the caldera floor and western rim. The snow-covered ridge in the foreground is the SW caldera rim. Intermittent eruptions such as these are typical of Akutan. The 1988 eruption lasted from 26 March to 20 July.

Photo by Tom Madsen (Aleutian Air), 1988 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys). An ash plume rises above Caliente in the Santiaguito lava dome complex in November 1993 as a small pyroclastic flow descends its eastern flank. The headwall of the 1902 crater on the Santa María SW flank is to the right. The lava dome complex began growing in 1922 from the Caliente vent at the base of the 1902 explosion crater. Caliente has been frequently active since the early 1970s.

Photo by Lee Siebert, 1993 (Smithsonian Institution). A powerful eruption at Fuego produced this ash plume at sunrise in October 1974. This view from Antigua Guatemala to the NE shows major pyroclastic flows moving down the eastern flank. Pyroclastic flows traveled 7 km but caused no fatalities. The 1974 eruption, the largest at Fuego since 1932, began with mild eruptions and small pyroclastic flows on 10 October. The eruption intensified on 14 October, with major Vulcanian eruptions occurring on that day, as well as 17-18, 19-20, and 23 October.

Photo by William Buell, 1974. Caldera collapse in 1968 at the basaltic shield volcano, Fernandina, was preceded by lava effusion on the SE flank and a major explosive eruption on 11 June. The ash plume, seen here from Academy Bay on Santa Cruz Island within minutes of the explosion, is backlit by the late afternoon sun and was spreading at an estimated lateral speed of 80 km per hour. At the time of this photograph the ash plume was 175 km across with an altitude of 20-25 km.

Photo by J. Harte, 1968 (published in Simkin and Howard, 1970). The tuff cones of Tagus (upper left) and Beagle (lower right) were formed by phreatomagmatic eruptions at Darwin volcano in the Galápagos Islands. The rim of Tagus is breached by Tagus Cove that was visited by Charles Darwin's vessel, the Beagle. Tagus tuff cone has at least four nested craters, the youngest of which contains a small salt lake. Young black lava flows from fissures on the flanks largely surround the tuff cones.

Aerial photo by U.S. Air Force. Cabo Cowan is a tuff cone at the NW tip of Santiago Island in the Galápagos Islands. Wave erosion has truncated the flanks of the cone, forming vertical sea cliffs that expose its interior stratigraphy. The cone is located where the NW-trending rift zone along the crest of Santiago shield volcano encounters the sea.

Photo by Lee Siebert, 1978 (Smithsonian Institution). An eruption column is seen rising above a cloud layer over Hekla volcano on 17 August 1980. The eruption began with a Plinian phase producing this 15-km-high eruption column. Lava flows were simultaneously produced along the fissure that runs along the Hekla edifice. During the next three days, lava flows issued from nearly the full length of the fissure and produced six flows, primarily on the northern side of the summit ridge. One lava flow travelled about 8 km to the SW.

Photo courtesy of Gudmundar Sigvaldason (Nordic Volcanological Institute), 1980. A column of ash and steam rises above a new submarine vent off the western coast of Fayal Island in early October 1957. Horizontally traveling base surges form a ring at the base of the eruption column. Explosive eruptions began on September 27 and formed a small island that eventually was joined to the main island, partially burying the Capelinhos lighthouse, which is visible on the center shoreline (bottom). Lava effusion was continuous for the last five months of the 13-month eruption.

Photo by U.S. Air Force, 1957 (published in Green and Short, 1971). The second of three large explosive eruptions from Crater Peak, a satellite cone of Mount Spurr, 3.2 km south of the peak, occurred on 18 August 1992. This aerial view from the west shows the base of the vertical eruption plume that reached an altitude of about 13.5 km. This eruption lasted about 4.5 hours and resulted in ashfall in Anchorage, 125 km E, that resulted in closure of the international airport for 20 hours.

Photo by Game McGimsey, 1992 (Alaska Volcano Observatory, U.S. Geological Survey). This photo shows an ash plume during the eruption of Spurr on 18 August 1992. A lighter plume rises above pyroclastic flows descending the SE flank to the right, and the summit lava dome complex is to the left. The 18 August event was the second of three brief powerful explosive eruptions in 1992.

Photo by Game McGimsey, 1992 (Alaska Volcano Observatory, U.S. Geological Survey). A scientist from the Alaska Volcano Observatory studies tephra from the 1992 eruptions of the Crater Peak vent of Mount Spurr volcano. Three brief explosive eruptions blanketed narrow swaths of the surrounding area with ash. Detailed investigations of deposits are necessary to understand eruption characteristics and magnitude. In this view, about 15 cm of coarse ash and lapilli is exposed in the pit and blocks from the 16-17 September 1992 eruption are scattered across the surface.

Photo by Game McGimsey, 1992 (Alaska Volcano Observatory, U.S. Geological Survey). Pyroclastic flow deposits from the 15 April (lower 2/3 of section) and 21 April (upper 1/3 of section), 1990 eruptions of Redoubt in Alaska are exposed in a gully. The shovel at the base of the section provides scale. The larger 15 April pyroclastic flow carried large blocky fragments of a lava dome that had been growing in the summit crater.

Photo by Christina Neal, 1990 (Alaska Volcano Observatory, U.S. Geological Survey). An ash plume from the pyroclastic flow descending the N flank of Redoubt volcano on 21 April 1990. The ash plumes produced during the 1989-1990 eruption damaged five commercial jet liners, with an incident on 15 December 1989 causing a Boeing 747-400 aircraft to temporarily lose power of all four engines.

Photo by Joyce Warren, 1990 (courtesy of U.S. Geological Survey). A series of powerful eruptions at Redoubt began on 14 December 1989. This 18 December view from the Kenai Peninsula across Cook Inlet shows an umbrella cloud that appears to originate from a vent on the N flank, but is actually ash from a pyroclastic flow that is traveling down the Drift River valley to the north. Ash plumes during the initial days of the eruption reached heights of about 10 km. Several episodes of strong explosive activity and lava dome growth lasted until June.

Copyrighted photo by Robert Clucas, 1990. An ash plume rises above Augustine on 31 March 1986, eventually reaching a height of 12 km. Powerful explosions during the initial days of the 1986 eruption, which began on 27 March, removed portions of the 1976 summit lava dome. This view from the SW shows a darkened area of ash deposition downwind from the eruption plume.

Photo by Betsy Yount, 1986 (Alaska Volcano Observatory, U.S. Geological Survey). A pyroclastic flow travels down the north flank of Augustine volcano in Alaska on 30 March 1986, three days after the start of a five-month long eruption. An ash plume rises above the pyroclastic flow. As with many Augustine eruptions, early pyroclastic flows were pumice rich; later in the eruption block-and-ash flows were produced by collapse of a growing lava dome.

Photo by Betsy Yount, 1986 (Alaska Volcano Observatory, U.S. Geological Survey). An ash plume erupts from eastern crater of the newly formed Ukinrek Maars on 6 April 1977. West Maar formed during the initial days of the eruption that began on 30 March. Three days later explosions began at East Maar, 600 m away. At the peak of the eruption ash plumes reached up to 6 km above the vent. On the 4th day of the eruption a lava dome appeared within East Maar.

Photo by R. Russell, 1977 (Alaska Department of Fish and Game). The interaction of magma with groundwater produced this dark, ash-rich eruption column in 1977 from the Ukinrek Maars on the Alaska Peninsula. The eruption occurred in an area without previous volcanic activity, through surficial glacial deposits. The phreatomagmatic explosions created two new craters, which were named after the Yupik words for "two holes in the ground." This photo was taken from the WSW on 6 April 1977.

Photo by R. Russell, 1977 (Alaska Department of Fish and Game). Ash and incandescent lava fragments rise above a fissure on a scoria cone at the summit of Veniaminof on 13 July 1983. The eruptions began on 2 June and covered the cone and much of the caldera floor with ash. Note the ash-covered glacial crevasses on the flanks of the cone to the lower right. The rim of the 8 x 11 km caldera appears in the distance to the NE.

Photo by Betsy Yount, 1983 (Alaska Volcano Observatory, U.S. Geological Survey). Incandescent lava flows down the side of a scoria cone in Veniaminof caldera on 7 October 1983 as ash plumes rise above the vent. This view from the SW shows the upper flanks of the cone, which is located on the west side of the glacier-covered caldera.

Photo by Betsy Yount, 1983 (Alaska Volcano Observatory, U.S. Geological Survey). This weak, pulsating ash plume at Veniaminof, Alaska, on 7 October 1983 is being directed to the east by local winds. Dark ash deposits are visible on the cone and glacier, and a lava flow was traveling down the flank.

Photo by Betsy Yount, 1983 (Alaska Volcano Observatory, U.S. Geological Survey). In this 3 August 1993 photo a small ash plume rises from a scoria cone within the Veniaminof caldera. Intermittent explosive eruptions began on 30 July and continued for more than a year. The eruptions also formed a new cone SE of the main western cone. As during the 1983-84 eruption, lava flows erupted onto the ice-covered caldera floor. Ash darkens the left side of the caldera floor in this view, with the caldera wall in the background.

Photo by D. Sellers, 1993 (Alaska Department of Fish and Game). The entire upper flanks of Pavlof are darkened by ash in this November 1973 photo taken after a 12-13 November explosive eruption. Small plumes rise from the crater on the uppermost NE flank just below the normally snow-covered summit.

Photo by Tom Miller, 1973 (Alaska Volcano Observatory, U.S. Geological Survey). The summits of Pavlof Sister (left) and Pavlof (right) rise above a roughly 1,100-m-elevation saddle. They are viewed here in 1975 from lowlands to the NW. Pavlof is darkened by recent ash deposition and has been the source of frequent eruptions in historical time. Little Pavlof, a cone on the right flank of Pavlof, was also constructed along a line of vents trending NE from Emmons Lake caldera.

Photo by Tom Miller, 1975 (Alaska Volcano Observatory, U.S. Geological Survey). Akutan forms the west-central part of Akutan Island in the eastern Aleutians. The summit contains a 2-km-wide caldera with a large scoria cone, visible here through a low point in the northern caldera rim. The cone has been the site of frequent historical eruptive activity.

Photo courtesy of Alaska Volcano Observatory, U.S. Geological Survey. A gas-and-ash plume, seen here from the E, rises from a fissure across the summit of Kanaga on 27 January 1994. Eruptive activity began in mid-1993 and continued intermittently through most of 1995. Ash fell on the village of Adak 25 km to the E on at least one occasion. On 27-28 July incandescent lava flows were first visible on the flank and by the end of the month they reached the NW coast.

Photo by E.V. Kleff, 1994 (U.S. Fish and Wildlife Service, courtesy of Alaska Volcano Observatory). This view from the west on 4 November 1982 shows the impact of the El Chichón eruption about seven months later. Fumaroles are present around the new lake partially filling the crater, and the surrounding area was devastated by pyroclastic flows and surges. The 1982 crater is located within an older 1.5 x 1.9 km crater.

NASA Space Shuttle image, 1982 (http://eol.jsc.nasa.gov/). Snowpack on the western flank of Tokachi preserves individual layers of pyroclastic surge and pyroclastic flow deposits from the 1988-89 eruption. Because the eruptions took place during the winter, snowfall proved very useful to scientists in distinguishing the deposits of small-scale eruptions that lasted only a very short time.

Photo by Mario Yoshida, 1989 (Hokkaido University). An ash plume erupts from Tokachidake on 30 June 1962. A phreatic explosion on 29 June killed five sulfur mine workers and was followed by a magmatic eruption three hours later. It continued for 11 hours, producing a 12-km-high ash plume. Weak eruptions continued intermittently until September.

Photo by Asahi Shimbun, 1962 (courtesy of Mario Yoshida, Hokkaido University). Gas-and-steam plumes emanate from a new eruptive fissure cutting the summit of Japan's Komagatake volcano on 7 March 1996. A phreatic eruption began the evening of the 5th and deposited ash onto snow. The eruption took place from the 1929 crater and from a 200-m-long N-S fissure on the S flank. Eruptive activity, producing steam-rich ash plumes, was strong until 7 March and declined after 12 March.

Photo by the Shin Engineering Consultant Company, 1996 (courtesy of Mitsuhiro Yoshimoto, Hokkaido University). A Plinian ash plume rising above the summit of Komagatake on 17 June 1929, seen here from the town of Mori, NW of the volcano. This was one of the largest eruptions from Komagatake in historical time, producing pumice-rich pyroclastic flows that descended out to 8 km from the crater, and a thick blanket of ash and pumice that caused extensive damage. The maximum reported plume height was 13 km. Activity ceased on 19 June before briefly resuming on 6 September.

Photo courtesy of the Komaga-take Disaster Prevention Council, 1929. A Plinian eruption column rises above Komagatake volcano in northern Japan on 17 June, the beginning of a major eruption in 1929 that was one of the largest in historical times. The ash plume rose to a maximum height of 13 km and produced thick, pumice-rich fall deposits around the volcano. The eruption also produced pyroclastic flows that traveled down the flanks. This photo is from the shores of Onuma lake to the south.

Photo courtesy of the Komaga-take Disaster Prevention Council, 1929. Pumice from the 1929 eruption of Komagatake covers streets and buildings in the town of Shikabe.

Photo courtesy of the Komaga-take Disaster Prevention Council, 1929. Small plumes rise above rockfalls accompanying renewed lava-dome growth at Sheveluch volcano on 22 August 1993. Intermittent mild explosions with a maximum cloud height of 5 km began on 11 April 1992. A large explosive eruption on 22 April produced an 18-km-high ash plume and pyroclastic flows. Renewed dome growth began that month, and by 27 May the lava dome had doubled its pre-eruption height to 400 m. Dome growth along with intermittent mild explosive activity continued until at least July 1994.

Photo by Phil Kyle, New Mexico Institute of Mining and Technology, 1993 (courtesy of Vera Ponomareva, IUGG, Petropavlovsk). An aerial view from the SW on 22 July 1996 shows an ash plume rising above the summit crater of Karymsky with Maly Semyachik behind it. The 1996 eruption began on 2 January simultaneously with an eruption at nearby Akademia Nauk caldera, out of view to the right. The Akademia Nauk eruption lasted only a day, but long-term eruptions continued at Karymsky.

Photo by Phillip Kyle, 1996 (courtesy of Vera Ponomareva, Institute of Volcanic Geology and Geochemistry, Petropavlovsk). An ash plume rises above the summit of Karymsky in January 1996. Explosive eruptions began on 2 January from the summit and SW flank. On the same day a powerful explosive eruption took place from Akademia Nauk caldera, the smooth area to the right. The Akademia Nauk eruption lasted only a day, but long-term activity continued at Karymsky.

Photo by Nikolai Smelov, 1996 (courtesy of Vera Ponomareva, Institute of Volcanic Geology and Geochemistry, Petropavlovsk). Volcanologists from the Institute of Volcanic Geology and Geochemistry in Petropavlovsk and the New Mexico Institute of Mining and Technology excavate a section through layered tephra deposits from Ilyinsky volcano in southern Kamchatka. Detailed study of the products of individual eruptions are used to determine the timing, frequency, and magnitude of those eruptions. The sequence of tephra layers shown here was deposited by explosive eruptions from Ilyinsky during the last 5,000 years.

Photo by Phil Kyle, New Mexico Institute of Mining and Technology, 1996 (courtesy of Vera Ponomareva, IUGG, Petropavlovsk). Karymsky was constructed within a 5-km-wide caldera that formed during a major explosive eruption about 7,500 years ago. Much of the cone is mantled by lava flows less than 200 years old, seen here from a volcanological field camp on the SW flank. Frequent historical eruptions have produced explosive activity with occasional lava flows from the summit crater.

Photo by Nikolai Smelov, 1996 (courtesy of Vera Ponomareva, Institute of Volcanic Geology and Geochemistry, Petropavlovsk). An explosive eruption from Galunggung on 7 August 1982 is accompanied by a pyroclastic flow advancing over the crater rim towards a reflector station that was being measured using the tripod to the lower left. The photo was taken from Butik Pasir Bentag, about 2 km from the crater. The 1-km-high ash-covered cliff to the left is a wall of the breached caldera.

Photo by Jack Lockwood, 1982 (U.S. Geological Survey). The island of Heimaey, about 10 km off the south coast of Iceland, is part of the Vestmannaeyjar volcanic system, which comprises numerous islands and submarine vents. Heimaey probably formed in the Holocene, through numerous eruptions. Here, an ash-laden eruption plume rises above a volcanic cone behind the town of Vestmannaeyjar in 1973. The water pumping operation in the foreground was designed to cool the front of an advancing lava flow that threatened the town and its harbor.

Photo by Jack Lockwood, 1973 (U.S. Geological Survey). On 13 September 1984 groundwater gained access to the eruptive fissure at Krafla, producing these clouds of steam and ash. The two-week eruption, which began on 4 September 1984, was dominantly effusive, and produced 0.12 km³ of lava flows from an 8.5-km-long fissure.

Photo by Michael Ryan, 1984 (U.S. Geological Survey). Waiowa (also known as Goropu) is an isolated tuff cone that was formed during 1943-44 by explosive eruptions through Paleozoic to pre-Cambrian metamorphic rocks. The active vents, seen here on 14 February 1944, were formed in an area without previous volcanic activity. Intermittent minor explosions began on 18 September 1943. Larger explosions occurred on 27 December 1943, 13 February, and 23 July 1944. After the final eruption on 31 August, the volcano was capped by a 500-m-wide crater that now contains a small lake.

Photo courtesy of Jim Luhr (Smithsonian Institution, published in Baker, 1946). A devastating pyroclastic flow on 25 June 1997 sweeps across the lower NE flank of Soufrière Hills volcano on Montserrat. More than two dozen people within the officially evacuated zone were killed. This eruption sent an ash plume to ~10 km altitude and produced pyroclastic flows and surges that overran both vacated and partly inhabited NE-flank settlements, destroying 100-150 houses in eight villages within the restricted zone. The pyroclastic flow traveled 4.5 km and almost reached the sea.

Photo by Paul Cole, 1997 (Montserrat Volcano Observatory). A plume of ash and steam rises above Telefon Bay on 4 December 1967. The eruption occurred from submarine vents in Telefon Bay, in the northwest part of the caldera bay, forming a new island named Yelcho. A second eruption center opened on land to the east. During the peak of activity the plume rose over 10 km above the vent, and pyroclastic material covered most of Deception Island. Ashfall occurred throughout the South Shetland Islands.

Photo by British Antarctic Survey, 1967 (published in González-Ferrán, 1995). A wide, dark, ash-laden eruption plume towers above Pendulum Bay on 4 December 1967, originating from vents located about 2 km NW of the Chilean research station seen in the foreground. Heavy ashfall from the eruption severely damaged the Chilean base. The destruction of the base was completed by a subsequent eruption in 1969. Members of the research party walked about 6 km S to safety at the British research station on the first day of the eruption and were then evacuated by helicopter.

Photo by Bernardo Blass, 1967 (published in González-Ferrán, 1995). An eruption darkens the sky above Antarctica's Deception Island in December 1967. Falling ash can be seen trailing from the margins of the eruption cloud. Winds distributed the ash plume to the NE and deposited 30 cm of ash over a 2 km swath across Port Foster caldera bay onto the Chilean Antarctic research station, where this photo was taken.

Photo by Bernardo Blass, 1967 (published in González-Ferrán, 1995). A dark ash column rises above lava fountains from a fissure eruption on the island of Heimaey in 1973. This explosive activity produced the Eldfell cinder cone (left), followed by effusion of lava flows which threatened the town of Vestmannaeyjar (foreground). Helgafell cone, on the right, formed during an eruption 5,900 years ago.

Photo by Tom Simkin, 1973 (Smithsonian Institution). An ash plume expands above a pyroclastic flow sweeping down the E flank of the Soufrière Hills summit lava dome on 16 January 1997. The pyroclastic flow descended the Tar River valley to the sea, covering the new delta with new material that included blocks up to 5 m in diameter.

Photo by Richard Herd, 1997 (Montserrat Volcano Observatory). An eruption plume rises above the summit crater and a pyroclastic flow descends the southern flank of Semeru in this view from the Gunung Sanur Volcano Observation Post of the Volcanological Survey of Indonesia. The symmetrical stratovolcano is one of the most active in Java and has been in near-continual eruption since 1818. Frequent small-to-moderate explosive eruptions are occasionally punctuated by larger eruptions that produce pyroclastic flows and lahars that have reached the foot of the volcano.

Photo courtesy of Volcanological Survey of Indonesia, 1992. A small ash eruption from Batur III cone on the SW flank of Batur volcano was photographed from the southern rim of the caldera in 1972. An on 19 January produced strong explosions, continuous ashfall from 28 January to 12 February, and small ash plumes during March.

Photo by Jayadi Hadikusumo, 1972 (published in Kusumadinata 1979, "Data Dasar Gunungapi Indonesia). An ash plume rising above Iya is seen from Ende city on 27 January 1967. Iya erupted suddenly with no recognized precursory activity. The plume rose 5 km above the summit from a new 400-650 m wide crater on the upper SW flank, accompanied by a pyroclastic flow. Houses were damaged on the nearby island of Ende and one person was killed. Secondary lahars later caused another fatality in a village below the ash-covered cone of Raja. The eruption ended on 30 January.

Photo by Go Ciap Cing, 1969 (courtesy of Volcanological Survey of Indonesia). An ash plume rising above the crater of Aso on 11 October 1989 is observed by tourists from a nearby parking lot. Small ash plumes 30-50 m high occurred on 5 and 27 April 1989; additional plumes were frequent through May and June. Intermittent vigorous eruptions began on 16 July. Ash plumes reached 3,000 m on 7 and 27 September and heavy ashfall in October damaged crops. Intermittent eruptive activity continued until 9 February 1991.

Photo by Yukio Hayakawa, 1989 (Gunma University). A small explosion 8 February 1999 produced a plume of gas and minor ash that is seen here from the SE about 5 seconds after the explosion began. Rapid lava extrusion began on 20 November 1998 and produced a lava dome in the 1994 crater that soon flowed over the crater rim, producing lava flows that descended the SW flank in several lobes. Block-and-ash flows from collapse of the flow fronts traveled down SW flank drainages. Periodic larger explosions occurred later during this eruption.

Photo by Jim Luhr, 1999 (Smithsonian Institution). An ash plume rising above Popocatépetl is seen here from the western flank on 8 March 1995. The plume rose about 500 m above the crater and was dispersed by the wind toward the south. A phreatic eruption on 21 December 1994 resulted in light ashfall on the city of Puebla, 45 km east. Intermittent ash eruptions, such as the one pictured here, continued until May 1995 and then resumed in March 1996.

Photo by José Macías, 1995 (Universidad Nacional Autónoma de México). The Popocatépetl summit crater is seen here from the NW on 16 June 1997. The irregular crater floor has several vents and some active fumaroles. The photo was taken five days after an ash eruption on 11 June that produced a 4-km-high plume and was accompanied by lahars that reached several towns to the east. Another strong explosion on 30 June was followed by lava extrusion on the crater floor.

Photo by Roberto Quass, 1997 (Universidad Nacional Autónoma de México). An ash plume erupts from the small vents along the eastern edge of the crater in this 11 March 1996 photo. The plume rises up to the crater rim then is dispersed by the predominant winds to the east, becoming detached from the summit crater after the explosion ends. The glacier on the NW (right) side of the crater is partly covered with dark gray ash from previous eruptions.

Photo by José Macías, 1996 (Universidad Nacional Autónoma de México). Pyroclastic surge deposits exposed in gullies on the flanks of Cráter Elegante in the Pinacate volcanic field of NW México. This photo shows cross bedding produced by particles transported by saltation or dilute suspension in a high-velocity pyroclastic surge. The direction of movement of the surge cloud, seen by the truncation of dune beds on the near-vent side, was from right to left. This type of bedding is common in areas near the rim of the maar.

Photo by Bill Rose, 1997 (Michigan Technological University). The eastern rim of the 1982 crater at El Chichón is seen here from the rim of the larger, older crater. Erosional gullies formed within pyroclastic flow and surge deposits that traveled radially away from the 1982 crater. The rim rises about 50 m above the moat between the two craters. Prior to the 1982 eruption a lava dome reached several hundred meters above the crater floor.

Photo by Bill Rose, 1983 (Michigan Technological University). An ash plume rises above Caliente vent at Santiaguito in February 1988. Eruptions at this time took place at intervals of 1 or 2 per hour and consisted of brief 1-2 minute ash emissions that reached altitudes of about 4 km (slightly above the elevation of the summit of Santa María, from where the photo was taken). Light ashfall from these small explosions affected areas to about 6 km from the vent.

Photo by Jon Fink, Arizona State University, 1988 (courtesy of Bill Rose, Michigan Technological University). The summit of Santa María provides this vantage point for viewing eruptions of the Santiaguito lava dome. This February 1988 ash plume rose from the vent to a height slightly above the summit. The brief 1-2 minute explosions produced light ashfall to within about 6 km of the vent.

Photo by Jon Fink, Arizona State University, 1988 (courtesy of Bill Rose, Michigan Technological University). A large pyroclastic flow travels down the flank of the Santiaguito lava dome on 19 July 1989. The pyroclastic flow and ash plume are seen here from just west of El Palmar (10 km S of the dome) about 5 minutes after the start of the explosion. The Santa María summit is visible to the right of the plume, which rose to 4 km above the vent. The pyroclastic flow traveled 5 km down the Río Nimá and was one of the larger events since the major 1929-34 activity.

Photo by Mike Conway, 1989 (Michigan Technological University). An ash plume rises above the Santiaguito lava dome complex in June 1976 nearly to the height of Santa María's summit. The dome complex was constructed within a large explosion crater that formed in the SW flank of during the major 1902 explosive eruption. The crater, seen in profile here, extends from just below the summit to 2.2 km elevation, below the bottom of the photo.

Photo by Bill Rose, 1976 (Michigan Technological University). A tephra layer from Acatenango is exposed NE of the volcano along the road between Antigua and Yepocapa. Pottery fragments within the tephra layer were dated between 1,400 and 1,500 CE. Most Holocene eruptions from Acatenango originated from Pico Mayor, the southernmost and highest of the two peaks. The scale bar marks 10 cm intervals.

Photo by Bill Rose, 1978 (Michigan Technological University). Two vents in the Fuego summit crater were active simultaneously at the time of this 24 February 1978 aerial photograph. A small ash plume rises above the vent at the far side of the crater, while the vent in the foreground ejects lava spatter. This vent feeds a degassing and faintly incandescent lava flow that can be seen to the lower right.

Photo by Bill Rose, 1978 (Michigan Technological University). Two ash plumes rise simultaneously from small vents in the Fuego summit crater on 27 February 1978. This view is from the NE with the Pacific coastal plain in the background. Intermittent minor eruptions took place from 11 September 1977 to 8 August 1979. Strombolian eruptions from vents in the crater formed small cones and produced incandescent fountains at night.

Photo by Bill Rose, 1978 (Michigan Technological University). Prevailing winds disperse an ash plume from Fuego to the SW in December 1978 as a small pyroclastic flow descends the SE (left) flank. Intermittent minor eruptions took place over a two-year interval from 11 September 1977 to 8 August 1979. Strombolian eruptions were sometimes accompanied by small pyroclastic flows and lava flows.

Photo by Bill Rose, 1978 (Michigan Technological University). A small ash plume from the summit of Fuego on 27 February 1978 is deflected to the south as a second plume rises from another vent immediately to the left. Volcán de Agua is in the distance. Fuego erupted intermittently from September 1977 to August 1979.

Photo by Bill Rose, 1978 (Michigan Technological University). A pyroclastic flow descends drainages on the east flank of Fuego in October 1975 as an ash plume (right) towers above the summit. Intermittent minor eruptions took place 28 May, 23 July to 4 August, and 19 September to 21 October 1975. On 11-12 and 16 October ash fell in, and west of, Antigua. This photo was taken from Finca Capetillo, near Alotenango. Pyroclastic flows frequently travel down these same drainages and had occurred during the two previous eruptions in 1973 and 1974.

Photo by Bill Rose, 1975 (Michigan Technological University). Winds deflect a small 27 February 1978 ash plume from the Fuego summit crater to the west. In the background is Acatenango, which rises about 700 m above the saddle between it and Fuego. Intermittent minor eruptions took place from 11 September 1977 to 8 August 1979, sometimes producing pyroclastic flows and lava flows.

Photo by Bill Rose, 1978 (Michigan Technological University). Pyroclastic flows occurred frequently during the October 1974 eruption, and residents of nearby fincas (farms) are seen here carrying goods across a field in front of the pyroclastic flow descending the eastern flank behind them. Despite the frequency and magnitude of the pyroclastic flows, they affected relatively sparsely populated flanks of the volcano and produced no fatalities.

Photo by William Buell, 1974. An ash plume rises above the crater of Popocatépetl on 21 February 1995. A phreatic eruption on 21 December 1994 ended a quiescent period that lasted roughly half a century. The eruption produced light ashfall in the city of Puebla, 45 km E. Intermittent ash eruptions, such as the one shown here, continued until May 1995 and then resumed in March 1996.

Photo by Hugo Delgado-Granados, 1995 (Universidad Nacional Autónoma de México). Ash from previous explosions covers the slopes of Popocatépetl on 21 February 1995, as another ash plume rises above the summit crater in this aerial view from the south. Repeated small-to-moderate eruptions had begun on 21 December 1994. The renewal of eruptive activity after a quiescence of about a half century prompted the initial temporary evacuation of 50,000 people living in towns east of the volcano.

Photo by Hugo Delgado-Granados, 1995 (Universidad Nacional Autónoma de México). The north side of Popocatépetl with the Ventorrillo glacier near the summit is shown here during an explosion on 26 April 1996. To the lower right is the El Ventorrillo peak at around 5,000 m elevation.

Photo by Hugo Delgado-Granados, 1996 (Universidad Nacional Autónoma de México). Two plumes are visible at Popocatépetl on 11 March 1996, six days after the renewal of explosive activity. A continuous diffuse plume disperses to the south at about 5,500 m elevation (roughly the height of the summit), while a second plume produced by a small explosion rises to about 8,000 m altitude. Beginning in 1996 multiple lava domes were extruded in the summit crater and periodically partially removed by explosions.

Photo by Hugo Delgado-Granados, 1996 (Universidad Nacional Autónoma de México). Ash deposits cleared from the streets of Ciudad Guzmán are piled up after the major explosive eruption of 20 January 1913. The eruption plume was calculated to have reached a height of 21 km, and the resulting ashfall caused significant disruption to the major city of Ciudad Guzmán, 25 km to the NE. Pyroclastic flows from this eruption reached as far as 17 km from the volcano.

Anonymous, 1913. A lava fountain and ash plumes erupt above MacKenney crater at Pacaya during a major eruptive episode on 16 January 2000. A lava flow is also descending the northern flank of the cone. After a quiescent period of nine months, eruptive activity had been more or less continuous at Pacaya since January 1990. Activity has consisted of frequent moderate eruptions that constructed the summit cone, punctuated by occasional larger explosions such as this one that enlarge the crater and reduce the height of the cone.

Photo by Gene West, 2000. A postcard photograph labeled "Excurcion de Atlixco - 1925" shows an ash plume rising above the summit crater of Popocatépetl as seen by visitors east of Paso de Cortés on the north side of the volcano. The peak on the right horizon is El Ventorrillo, part of a previous edifice.

Courtesy of Enrique Chavira (INAOE; from Elia Rascón Cano family archive). An ash plume rises above Arenal on 2 June 1998, seen here from the west flank. Routine intermittent explosive activity had resumed at this time following major pyroclastic flows on 5 May. Lava flows from the long-lived eruption that began in 1968 can be seen on the volcano's flanks.

Photo by Jorge Barquero, 1998 (OVSICORI-UNA). A pyroclastic flow travels down the NNW flank of Arenal on 5 May 1998, over light-colored deposits from earlier flows. As many as 23 pyroclastic flows took place during a 6-hour period that afternoon, descending the upper reaches of the Tabacón drainage basin. The pyroclastic flows reached estimated velocities of 60 km/hour.

Photo by Olger Aragón, 1998. Poás erupted intermittently from June 1987 to June 1990, producing ash plumes such as this one seen on 6 March 1989. Phreatic explosions had resumed from June 1987 until at least October 1988, punctuated by large explosions on 9 April 1988. The crater lake completely disappeared by April 1989, and during May ash plumes reached heights of 1.5-2 km above the crater.

Photo by Gerardo Soto, 1989 (Instituto Costarricense de Electricidad, published in Alvarado, 1989). An ash plume above the Irazú summit crater is seen here in 1917 from the national theater in San José. All summit craters were reported to be active on 27 September 1917, after which activity steadily intensified. Ash fell in Curridabat on 18 November and again a month later, when ash also fell in Tres Ríos. On 6 January 1918 ashfall reached San José, Heredia, and Puriscal. Intermittent explosive activity continued until 1921, with an explosion on 30 November 1918 producing ashfall as far as Nicoya.

Anonymous, 1917 (published in Alvarado, 1989). Ash plumes rise above vents in the Poás summit crater on 4 May 1990, near the end of an eruptive period that began in June 1987. At the time of this photo the crater lake had shrunk substantially to only several centimeters deep that fluctuated slightly with changes in rainfall recharge. Lake temperatures were over 72°C (measured by infrared thermometer), and small hot springs around the lake had temperatures of 85°C. Minor explosive eruptions continued into the following month.

Photo by Jorge Barquero, 1990 (Universidad Nacional Costa Rica). Intermittent explosive activity during the 1963-65 Irazú eruption cumulatively produced extensive ashfall that caused significant economic damage to San Jose and other populated areas of the Central Valley of Costa Rica. During the first weeks of January 1964 heavy ashfall was deposited as far away as Tamarindo beach on the Pacific coast and Lake Nicaragua, 180 km NE of the volcano.

Photo by W. Schaer (published in Barquero, 1998). Ashfall from the 1963-65 eruption of Irazú affected both populated areas and agricultural lands. In the weeks following the beginning of the eruption on 13 March 1963 ashfall at times restricted visibility to 30 m in the capital city of San José, paralyzing traffic. Ashfall caused extensive damage to farmlands, resulting in the death of livestock. Remobilization of ash during the rainy season caused lahars that destroyed houses, roads, and bridges, and caused fatalities.

Photo by W. Schaer (published in Barquero, 1998). Raung volcano, with its unvegetated summit caldera and Suket peak to the NE, is at the upper left in this aerial view from the eastern tip of Java. In the foreground are Gunung Rante (left-center) and Gunung Merapi (lower right), constructed near the margin of the Ijen caldera complex. The Semeru-Tengger caldera complex is on the far right-center horizon, and the Iyang-Argapura complex is on the upper right.

Photo by Lee Siebert, 2000 (Smithsonian Institution). An ash plume erupts from the Irazú summit crater on 14 April 1964, about midway through a major explosive eruption that began in 1963. The ash-covered plateau to the left is Playa Hermosa, an older buried crater. The road to the summit is to the lower left. Heavy ashfall from the 1963-65 eruption was deposited across the Central Valley and caused major economic disruption.

Photo by U.S. Geological Survey, 1964. Pyroclastic surges at about 0805 on 1 August 1952 travel across the sea at the western coast of the island, 20 minutes after the start of the eruption. Several inches of ash and lapilli up to 12 mm in diameter fell on the deck of the fishing boat from which this photo was taken as it sailed away from the volcano at full speed.

Photo by Robert Petrie, 1952 (U.S. Navy; courtesy of Sherman Neuschel, U.S. Geological Survey). A Vulcanian ash plume rises from the Bárcena crater on 9 September 1952, more than a month after the start of the eruption. The roughly 300-m-wide crater is seen here from the east. Explosions producing eruption columns that rose to about 600 m above sea level were observed at 20-minute intervals, along with occasional small pyroclastic surges that swept down the flanks of the cone and sometimes reached the coast. The roar of the eruption was heard above the noise of the plane's engine.

Photo by U.S. Navy, 1952 (courtesy of Sherman Neuschel, U.S. Geological Survey). A small eruption on 10 December 1952 took place from the moat between the inner (dark-colored) and outer lava domes in the Bárcena summit crater. A lava dome was first observed on 20 September, when it was about 8 m high and 55 m wide. On 15 November the dome was observed to fill about half of the 700-m-wide crater. At the time of this photo, an older outer dome littered with breadcrust bombs and ejecta surrounded the new inner dome.

Photo by L.W. Walker, 1952 (courtesy of Sherman Neuschel, U.S. Geological Survey). A new cone, Volcán Bárcena, was rapidly constructed during an eruption that began on 1 August 1952 at the southern end of Isla San Benedicto. This photo, taken from off the west coast of the island only four minutes after the start of the eruption, also shows the onset of pyroclastic surges. Lava extrusion occurred in September, November, and December. On 8 December activity shifted to a vent on the SE flank, producing a lava delta that extended about 700 m to sea. Activity ended in late February 1953.

Photo by Robert Petrie, 1952 (U.S. Navy; courtesy of Sherman Neuschel, U.S. Geological Survey). An ash plume rises from the active summit crater of Arenal in this April 1998 view from the south. A small saddle separates the unvegetated post-1968 cone from the pre-1968 cone (right). During April 1998 lava flows traveling down the northern-to-western flanks, and blocks on the NW Crater C wall, broke loose and tiggered small avalanches. This relatively minor activity preceded a larger eruption that produced pyroclastic flows on 5 May.

Photo by Federico Chavarria Kopper, 1998. This lake-filled maar and another small crater (left) are the Ukinrek Maars, which formed during an eruption in 1977 in a lowland area of the Alaska Peninsula west of the main volcanic chain. The contact between lighter and darker material in the walls of the lake-filled eastern maar marks the original pre-eruption surface, which is now buried by a dark apron of ejecta produced during the eruption.

Photo by Christina Neal, 1993 (Alaska Volcano Observatory, U.S. Geological Survey). Pyroclastic surges completely devastated vegetation on the flanks of El Chichón out to distances up to 8 km from the crater. Hot pyroclastic flow and surge deposits are seen in this early April 1982 photo at Francisco León, 5 km SSW of the crater. Three major pyroclastic flows occurred on 3 and 4 April, devasting an area of 153 km²; all three surges reached Francisco León. Pyroclastic surges traveled over ridges as high as 300 m.

Photo by Servando De la Cruz-Reyna, 1982 (Universidad Nacional Autónoma de México). Ashfall deposits whitened the landscape around El Chichón like snow and stripped many trees of their leaves, such as seen here near Villahermosa to the north. Ashfall deposits trending to the ENE blanketed an area of 45,000 km² within the 1 mm isopach. Ash plumes reached 17 km or higher on 28-29 March and 3-4 April 1982. The exceptionally high sulfur content of the magma produced an eruptive plume rich in sulfuric acid aerosols, which circled the globe in three weeks and led to warming of the stratosphere and cooling of the troposphere.

Photo by Servando De la Cruz-Reyna, 1982 (Universidad Nacional Autónoma de México). Soldiers search the town of El Naranjo, 7.5 km south of the crater, a few days after the end of the eruption amidst remobilized ash. Approximately 2,000 people were killed, among them were one geologist and 32 soldiers sent to the village of Francisco León, ~ 6 km SW of the summit, after the 28-29 March explosion. The pyroclastic flow that traveled through Francisco León left only a thin deposit, but the only remaining structure in the village was remnants of the church.

Photo by Servando De la Cruz-Reyna, 1982 (Universidad Nacional Autónoma de México). An incandescent pyroclastic flow (lower right) travels down the flanks of El Chichón with lightning produced in the ash plume (left) on 3 April 1982. Minutes later this plume reached an altitude of about 24 km. The eruption of large amounts of tephra and pyroclastic flows and surges caused extensive damage and fatalities. Explosive removal of the summit lava dome created a new 1-km-wide, 300-m-deep crater.

Photo by Servando De la Cruz-Reyna, 1982 (Universidad Nacional Autónoma de México). An ash plume rises from the summit crater of Marapi volcano in this undated photo, perhaps from the late 1980s or early 1990s. Marapi produces frequent small-to-moderate explosive eruptions that have been recorded since the 18th century.

Photo by Igan Sutawidjaja (Volcanological Survey of Indonesia). This photo taken on 12 August 2002 shows an ash plume rising from Torishima volcano, a 2.7-km-wide island in the southern Izu Islands. The unvegetated Iwoyama cone, seen here from the south, was constructed during an eruption in 1939 within a 1.5-km-wide caldera. The volcano is also referred to as Izu-Torishima to distinguish it from the several other Japanese island volcanoes called Torishima ("Bird Island").

Photo courtesy of Japan Meteorological Agency, 2002. An ash plume towers above Popocatépetl as viewed from Paso de Cortés NW of the volcano at 1032 on 11 June 1997. The photo was taken 18 minutes after a 15-minute-long volcanic tremor episode that accompanied the major ash emission, which reached an altitude of 4 km above the summit. Intermittent ash emission had begun on 5 March 1996, some of which produced ashfall that reached the Gulf of Mexico. This activity was accompanied by periodic growth and destruction of lava domes in the summit crater.

Photo courtesy CENAPRED, Mexico City, 1997. An eruptive episode at Fuego began on 4 January 2002 and continued intermittently into 2003. This 8 January 2002 image taken from the east shows an ash plume. Effusion of lava flows down the east flank began in late January 2002. On 2 August 2002 explosive activity changed from Strombolian to Vulcanian.

Photo by Sid Halsor, 2002 (Wilkes University). The first historical eruption of Anatahan is seen here on 10 May 2003, with an ash plume from activity that began earlier that day. The plume rose to about 4.6 km and originated from the eastern crater. Intermittent explosive eruptions took place until 16 June. Lava flows were emplaced on the floor of the caldera beginning on 4 June and later coalesced to form a small lava dome in the new 300-m-wide crater. This view is toward the SW.

Photo courtesy of Commonwealth of Northern Mariana Islands, 2003. An ash plume rises from the east crater of Anatahan on 16 June 2003. The plume reached a maximum height of about 2.5 km in less than 40 seconds. This pulse of activity was accompanied by intense tremor and earthquakes that were recorded by the single seismic station on the island.

Photo by Hawaiian Volcano Observatory, U.S. Geological Survey, 2003. An ash plume erupts from the Suwanosejima summit crater, seen from a helicopter on 12 May 2001. Eruptions on the evening of 12 May and the morning of the 13th deposited up to 3 cm of ash in Toshima village, about 4 km NNW of the crater. After a quiet period of about 10 months eruptive activity had resumed on 19 December 2000 and continued intermittently until July 2004.

Photo courtesy of Japan Meteorological Agency, 2001. An ash plume rises from a new crater near the southern margin of Grímsvötn caldera in November 2004. Grímsvötn lies largely beneath the vast Vatnajökull icecap and the eruption melted its way through ice about 200 m thick. The plume extends towards the north due to the wind direction, coating the surface of the glacier in dark ash.

Photo by Freysteinn Sigmundsson, 2004 (Nordic Volcanological Center). A sequence of pyroclastic surge deposits exposed in a sea cliff on Niijima, in the northern part of the Izu Islands of Japan. These cross-bedded layers were produced during repeated erosion and deposition by multiple pyroclastic surge events. The eruptions accompanied the formation of a lava dome at Mukaijima on the southern part of the island. The flat airfall deposits cap the exposure.

Photo by R.V. Fisher, 1979 (University of California Santa Barbara). An ash plume extends across the length of Paramushir Island in the northern Kuril Islands on 26 April 2003 in this NASA Space Shuttle image (with N to the left). An explosive eruption of Chikurachki began on 18 April, producing ash plumes up to about 2 km above the crater. On 1 May ash fell on the town of Severo-Kurilsk (~60 km from the volcano), and intermittent activity continued until early July. Alaid volcano is at the far left.

NASA International Space Station image ISS006-E-52695, 2003 (http://eol.jsc.nasa.gov/). An ash plume rises above Tavurvur volcano at the eastern end of the island of New Britain in Papua New Guinea on 5 June 2005, seen from the SE. Explosive activity had resumed at Tavurvur on 25 January 2005 and continued intermittently until November of that year, occasionally depositing ash on the town of Rabaul. Incandescent ejecta was periodically observed at night time.

Photo by Roy Price, 2005 (University of South Florida). Tavurvur cone at Rabaul is seen in eruption in this 25 May 2005 view looking from the NW across Matupit Harbor. Two plumes, one white and the other dark gray, are originating from separate vents. Intermittent small-to-moderate explosive eruptions took place throughout much of the year. The conical peak in the background is Turanguna.

Photo by Roy Price, 2005 (University of South Florida). A small ash plume rises from the summit crater of Pavlof volcano on 28 May 1960 as the detached plume from an earlier explosion drifts away to the east. Ash deposits are visible on the flanks in this view from the north. Mild ash eruptions took place from about 1960 to 1963, especially during July 1962 to June 1963. The peak to the left is Pavlof Sister, and Little Pavlof forms the smaller peak to the right of Pavlof.

Photo by Ken Morin, 1960 (courtesy of Bill Rose, Michigan Technological University). An ash plume rises above the surface of a pyroclastic flow descending the flanks of Pavlof on the Alaska Peninsula in 1975. Incandescent lava can be seen on the upper cone. Intermittent phreatomagmatic to magmatic eruptions began 13 September 1975 and continued until at least March 1977. Possible lava flows or lahars were reported in October 1975 and December 1976.

Photo by U.S. Geological Survey, 1975. Tephra deposits left by Karthala's 16-18 April 2005 eruption altered the landscape and destroyed vegetation. This picture was taken at the entrance to the first caldera on the western trail, viewed looking to the S. A brief eruption from Chahalé crater beginning on the 16th produced ashfall that increased in intensity the following day, producing an ash plume and volcanic lightning. Ash deposits varied in thickness from a few millimeters on the coast to ~1.5 m at the summit.

Photo by Nicolas Villenueve, 2005 (Université de la Réunion). Karthala is seen in two images (10-m resolution) at nearly the same scales. The left image was acquired before the 2005 eruptions by SPOT4 on 13 July 2004. The right image is from after the 24 November 2005 eruption, taken by SPOT5 on 5 December 2005. Both images are partly masked by clouds. The right-hand photo shows ashfall deposits from the April and November eruptions blanketing the summit caldera and upper flanks.

Photo courtesy of United Nations, 2005 (UNOSAT) An image of the Karthala 25 November 2005 ash plume was obtained from NASA Terra MODIS. The image was centered over the Comoros islands and also shows Mayotte, Anjouan, and Moheli islands. Grand Comore is under the ash plume but the location of Karthala is indicated. For scale, the distance from Karthala to the south end of Mayotte Island is ~240 km. The image shows Air Force Weather Agency interpretations of the ash cloud extent.

Image courtesy of Charles Holliday (U S Air Force Weather Agency). A telephoto view looking approximately E from the crater rim on 4 December 2005 shows a Surtseyan eruption from Lake Voui, on Ambae volcano. This explosive eruption began in Lake Voui on 27 November and resulted in the formation of a new cone in the lake.

Photo by Philipson Bani, 2005 (Institut Recherche Développement, IRD). An explosive eruption from Lake Voui at Ambae on 4 December 2005 seen looking approximately E from the crater rim. A dark cock’s-tail plume and a lighter gas-and-ash plume can be seen rising above the vent within the late. Three small islands that formed prior to this eruption can also be distinguished.

Photo by Philipson Bani, 2005 (Institut Recherche Développement, IRD). Barren Island is shown erupting on 28 May 2005 from the WNW. The black lava flow in the foreground is from the 1994-95 eruption. A lava flow is being extruded from a flank vent below the white plume. Eruptions that began on 26 May occurred from the summit of the scoria cone as well as flank vents. Lava flows later reached the W coast along the same path as flows from the 1991 and 1994-95 eruptions.

Photo courtesy of Indian Coast Guard, 2005. A cock’s-tail plume rises above Kavachi volcano during a Surtseyan eruption on 15 March 2004. Projections of individual blocks and ash can be seen at the margins of the plume. The frequently-erupting submarine volcano had been inactive since August 2003.

Photo by Corey Howell, 2004. An ash plume rises from a vent at the E crater (far right) of Anatahan as seen from a helicopter looking NW on 24 August 2005. Eruptive activity had begun in 2004, when a new lava dome was seen on 12 April, along with fresh ejecta within the crater. Intermittent explosive activity occurred throughout the year. In 2005 the crater floor was almost entirely covered by fresh lava out to a diameter of ~1 km. Explosive eruptions in April, June, and July 2005 produced ash plumes to as high as 15 km.

Photo by Takeshi Matsushima, 2005 (Kyushu University). Eruption of Cleveland on 23 May 2006 as photographed from the International Space Station at an orbital altitude of approximately 400 km. The photograph shows the ash plume moving SW from the summit with N at the top and Carlisle Island to the NW.

Courtesy of Jeffrey N. Williams, Flight Engineer and NASA Science Officer, International Space Station Expedition 13 Crew, NASA Earth Observatory. A plume rises above Fourpeaked during its first observed eruption, on 7 September 2006, as seen from Main Street in Homer, across Cook Inlet. The plume rose to a maximum height of 6 km and resulted in a trace of ashfall at Nonvianuk Lake outlet (110 km WNW) and near Homer (150 km NE). The eruption produced a 1-km-long fissure that extended north from the summit.

Copyrighted photo by Lanny Simpson, 2006 (courtesy of USGS/AVO). Didicas volcano, 22 km NE of Camiguin Island, was a submarine volcano prior to becoming a permanent island in 1952. The first recorded submarine eruption of Didicas was in 1773. A 400-m-wide crater formed during the 1952 eruption, and two eruptions have occurred since then at a crater on the northern side of the island.

Photo courtesy of PHIVOLCS. Photograph of Ulawun taken from a helicopter on 25 November 1985. This view from the NE shows the ejection of lava into the air above the vent during Strombolian activity. The other large stratovolcano in the background is Bamus.

Photo by James Mori, Disaster Prevention Research Institute, Kyoto University. An ash plume from Anak Krakatau on 1 November 2007 is seen from the NW from a monitoring station on Sertung Island (also called Verlaten island). A detached ash plume from an earlier explosion drifts to the left as a new plume rises above the vent. Explosive activity had resumed at Krakatau on 23 October. Ash eruptions and ejection of incandescent material were accompanied by the effusion of lava flows. Rakata Island is in the background.

Photo by Center of Volcanology and Geological Hazard Mitigation (CVGHM), 2007. An ash plume from Sheveluch was photographed by NASA astronauts aboard the International Space Station (ISS) around 21 March 2007. Dome growth had recommenced in 1999 and resulted in ash plumes, avalanches, and occasional block-and-ash flows.

NASA International Space Station image ISS014-E-17165, 2007 (http://eol.jsc.nasa.gov/). An ash plume from Pavlof on the evening of 30 August 2007 at 2120 local time. This view is to the S, out of the right side of a plane flying to Anchorage from Cold Bay. The ash plume height was approximately 5.2-5.5 km.

Photo by Chris Waythomas, 2007 (Alaska Volcano Observatory, U.S. Geological Survey). A Vulcanian explosion typical of activity at Colima is seen here from the north on 10 March 2007. Intermittent explosive eruptions with occasional lava dome growth and associated pyroclastic flows had been continuing for nearly a decade at this time.

Photo courtesy of Colima Volcano Observatory, 2007. A plume rises above Egon volcano on 13 February 2005. Explosive eruptions on 6-7 February 2005 ejected ash and lapilli. On 14 February another explosion ejected ash and incandescent material to about 50 m above the summit. According to a news report, as of 17 February recent eruptive activity at Egon had prompted the local government to evacuate hundreds of residents living near the volcano. Minor ash plumes were reported during 25-27 February.

Photo by Gede S., 2005 (Centre of Volcanology & Geological Hazard Mitigation, Volcanological Survey of Indonesia). A satellite image on 4 July 2004 showed fresh ash deposits on the upper E flank of Korovin. This photo, taken from the SE, show ash emplaced on the upper slopes of the SE crater.

Photo by Game McGimsey, 2004 (Alaska Volcano Observatory, U.S. Geological Survey). This photo taken on 3 March 2007 shows a light-gray ash deposit on the W flank of Korovin. In late November 2006 satellite images showed a light dusting of ash on the E flank of the main crater along with several plumes and/or their shadows visible along the N side of the crater. On 11 and 21 December 2006 Atka residents again witnessed steam plumes, possibly containing ash on the latter date.

Photo by Kerry Moore, 2007 (courtesy of Alaska Volcano Observatory). Ash eruption from Ol Doinyo Lengai seen on 12 March 2008 from the NNE. This image shows that the E, N, and W flanks of the cone had buried the original crater rim. Oversteepening of the cone flank in places resulted in small landslides which can be seen just below the cone as dark material covering the lighter areas of older weathered carbonatite. The peak beyond the ash plume is the summit.

Photo by Benoît Wilhelmi, 2008. One of the largest recorded eruptions in the Kuril Islands took place 11-16 June from Sarychev Peak. This NASA Space Shuttle view on 12 June shows an eruption plume that rose to 16-21 km altitude; pyroclastic flows reached the sea and extended the shoreline in some areas. The main explosive phase ended on 16 June, but weak explosions producing ash plumes continued prior to arrival of a field team on 26-28 July, when no eruptive activity was observed.

NASA International Space Station image ISS020-E-9048, 2009 (http://eol.jsc.nasa.gov/). An erosional unconformity cutting diagonally across the center of the photo due to a glacial advance about 20,000-18,000 years ago separates two sequences of late-Pleistocene tephra layers from Ecuador's Chimborazo volcano. A less prominent unconformity below the light-colored tephra layer at the top of the sequence marks a 16,000-14,000 year old glacial advance. This ~12-m-thick exposure lies on the SW flank.

Photo by Lee Siebert, 2006 (Smithsonian Institution). An ash plume rises above Ebeko on 18 March 2009. Intermittent explosive eruptions began on 11 February 2009 and continued into July, producing plumes up to 3.4 km altitude.

Photo by Leonid Kotenko, 2009 (Institute of Volcanology and Seismology). This 18 February 2020 photo shows an example of a typical Vulcanian explosion at Fuego The view is from the lookout area on Volcán Acatenango, about 2 km N, with the ash plume dispersing to the W.

Photo by Ailsa Naismith, 2020. This outcrop within a barranca (ravine) on the western side of the Santa Ana summit area shows explosive deposits from the 2005, 1904, and older eruptions. The different ash and lapilli units have variable grain sizes, an indication of variations in explosivity. The yellow ruler is 72 cm long; photo taken in 2011.

Photo by Lis Gallant, 2011. The Ngāuruhoe summit of the Tongariro volcanic complex is in the foreground, while in the background is a weak plume produced during the 1995-96 Ruapehu eruption, dispersing to the SW. The scoria cone within the Ngāuruhoe crater largely formed during the 1954-55 eruption and produced lava flows down the NW to W flanks.

Photo by John A Krippner, 1995-1996. Ruapehu is seen here erupting on 17 June 1996 with a narrow ash plume that rose 8.5 km and extended 200 km NE from the vent. Ash is falling from the plume and is being carried by the wind below it. As well as impacting water, and power supplies, ash from this eruption effected agriculture and caused livestock fatalities.

Photo by John A Krippner, 1996. This 17 June 1996 photo shows the eruption of Ruapehu with an ash plume dispersing to the NE. The eruption varied in intensity, causing the differences in plume height with distance from the vent. Ashfall is visible across the flank and a lower plume is from the redispersal of the ash deposit.

Photo by John A Krippner, 1996. This 17 June 1996 photo shows the ash plume produced during the Ruapehu eruption that extended out to around 200 km, drifting over the Pacific Ocean. Below the main plume is the ash redispersing from the deposit emplaced across a narrow swath NE of the volcano.

Photo by John A Krippner, 1996. Ash was deposited across several flanks during the 1995-96 Ruapehu eruption. This weak ash plume was dispersed by the wind before it reached a significant height above the crater, with ash falling out of the plume across the dark deposit already covering the snow.

Photo by John A Krippner, 1995-1996. An ash plume erupts from the Ruapehu South Crater during the 1995-96 eruption, depositing ash across the flank. Ash was emplaced across a narrow swath on the NE North Island of New Zealand, out over the Pacific Ocean. This caused disruptions to water and power supplies and damage to the agricultural industry, with a cost of over $130 million New Zealand dollars to the tourism industry.

Photo by John A Krippner, 1995-1996. An avalanche descends the NE flank of the Sheveluch lava dome on 6 July 2015, seen above the 1964 flank collapse scarp rim. Fragmentation of the hot dome rock produces the beginning of an ash plume above it and degassing is also visible across the dome.

Photo by Janine Krippner, 2015. This 6 July 2015 photo of Sheveluch is from the Baidarnaya river channel to the SE. The higher edifice to the right is Old Sheveluch, and the rest of the edifice shown here is “Young Sheveluch”. An ash plume is rising from the lava dome, seen beyond the 1964 collapse scarp.

Photo by Janine Krippner, 2015.