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Types and Processes Gallery - Volcanoes and Humans

Volcanoes and Humans
Volcanoes and humans have an uneasy coexistence. Volcanic eruptions can cause severe destruction. More than three dozen historical eruptions have caused more than 1000 fatalities. The heavy weight of ashfall can demolish the roofs of houses and buildings. Lahars, debris avalanches, and tsunamis can extend the devastating effects of an eruption well beyond the volcano. The beneficial aspects of volcanoes, in contrast, are less well known. Volcanoes provide essential soil nutrients for agriculture; volcanic soils cover more than 1.5 million sq km and form a significant component of the surface area in countries along the Pacific Rim of Fire. It is no accident that some of the most densely populated areas on Earth are in proximity to volcanoes. Volcanic materials are a source of aggregate for construction and additives used in a wide variety of commercial products. Geothermal heat is a major source of electrical power. Volcanoes provide spectacular scenic destinations that are featured in many national parks and whose aesthetic attractions are of great economic benefit to surrounding communities.

A major S-flank eruption of Etna beginning on 28 March 1983 produced lava flows that damaged tourist facilities. Extensive efforts at lava diversion, such as the gray embankment at the left of this photo, were made to divert the flows from populated areas. The flows eventually descended to 1,080 m altitude and stopped short of several villages.

Photo by Romolo Romano, 1983 (IIV-CNR, Catania, Italy).

A March 1981 lava flow from vents on the upper NW flank of Mount Etna in Sicily descended 8 km into populated areas and caused extensive damage to orchards and farm buildings. This photo shows the steaming lava flow front as it overran a railroad bed and highway.

Photo by Romolo Romano, 1981 (IIV-CNR, Catania, Italy).

Fresh black lava flows overrun a highway and tourist facility buildings the day after the start of an eruption at Sicily's Mount Etna on 28 March 1983. The lava flows originated from a fissure 4 km S of the summit, and over a 5-month period formed a complex lava field as much as 1 km wide.

Photo by Romolo Romano, 1983 (IIV-CNR, Catania, Italy).

Heavy ashfall from explosive eruptions from Galunggung volcano in 1982 damaged or destroyed hundreds of houses, including these in a village near Kadong. The eruptions forced evacuation of 62,000 people living in densely populated areas near the volcano.

Photo by Jack Lockwood, 1982 (U.S. Geological Survey).

Dieng Volcanic Complex
A stone monument is inscribed with a list of eruptions from the Dieng volcanic complex in central Java. The second column from the right lists fatalities (most recently 149 in 1979), which have occurred many times as a result of phreatic explosions and toxic gas emissions.

Photo by Tom Casadevall, 1986 (U.S. Geological Survey).

A sulfur miner carries baskets of elementally pure sulfur from a geothermal area near the shore of Kawah Ijen lake in eastern Java. Large blocks of sulfur are broken off and carried out of the crater in baskets before being transported to a sulfur mill on the SE flank of the Ijen caldera. The perspective in this view from near the SE crater lake rim looks down on the surface of the crater lake.

Photo by Lee Siebert, 2000 (Smithsonian Institution).

Banda Api
At the onset of the eruption of Banda Api on 9 May 1988, residents of Neira moved to the west side of the island to begin evacuations. Residents of nearby Gunung Api Island, where the eruption occurred, had been evacuated over the previous two days. As many as 10,000 people were evacuated during the eruption; the only people to lose their lives were four who remained in the evacuation zone.

Photo by Tom Casadevall, 1988 (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).

Residents of the city of Bacolor in the Philippines, 38 km SE of Pinatubo, persevere in the face of widespread devastation from lahars. They are walking on the surface of a solidified 5-m-deep deposit of volcanic debris next to wires that are the original electrical power lines formerly high above the street level. Houses and businesses in the background of this September 1995 photo are buried to 2nd-floor levels.

Photo by Chris Newhall, 1995 (U.S. Geological Survey).

Weathering of volcanic ash releases nutrients that contribute to fertile soils for agriculture, such as these fields at the foot of Kaimon volcano in southern Kyushu. Because of this, population density is often high near volcanoes and results in communities developing in increasingly hazardous areas. Volcanic soils support crops such as rice fields in Indonesia, the Philippines, and Japan, sugar cane in Hawaii and Central America, and vineyards in Italy.

Photo by Lee Siebert, 1988 (Smithsonian Institution).

Mount Fuji is a popular tourist destination, seen here providing the backdrop to a fireworks display at Lake Yamanaka, one of five lakes at the northern base of the volcano. The line of diagonal lights extending up the right-hand side of Fuji are mountain huts along the ten stations of the Fuji-Yoshida climbing route, the most popular of the six major summer ascent routes.

Photo by Lee Siebert, 1963 (Smithsonian Institution).

Housing development on a mudflow deposit that originated from Mount Rainier, partially obscured by clouds in the center background. The tree stump in the foreground was buried by the Electron mudflow about 500 years ago, that began as an avalanche of hydrothermally altered rock on Rainier's W flank.

Photo by Lee Siebert, 1994 (Smithsonian Institution).

St. Helens
This vehicle was parked near Meta Lake, 13 km NE of Mount St. Helens, within the area affected by the devastating lateral blast of 18 May 1980. Tree blowdown occurred to distances of about 30 km from the volcano. Most of the 57 fatalities caused by the eruption resulted from the lateral blast.

Photo by Terry Leighley, 1980 (U.S. Geological Survey).

Crater Lake
Volcanoes form some of Earth's most spectacular scenery and have been designated as national parks in many countries. The natural landscapes in these parks are a source of visual inspiration and varied recreational opportunities, and can also provide economic benefit to surrounding communities. Crater Lake National Park in the Oregon Cascade Range was established in 1902. This image looks across to Wizard Island and the western caldera rim from near the park visitor center and the Crater Lake Lodge.

Photo by Lee Siebert, 1997 (Smithsonian Institution)

Long Valley
The Casa Diablo geothermal plant in the Long Valley caldera taps the high heat flow originating from the magma system below. Several commercial and scientific exploratory holes have been drilled here to depths of 100 to 2,000 m.

Photo by Larry Mastin, 1991 (U.S. Geological Survey).

Lava flows from the East Rift Zone eruption that began in 1983 at Hawaii's Kilauea volcano frequently overran the coastal highway, enveloping traffic signs such as this one. Lava flows can travel fast enough to block roads and evacuation routes, closing off access to communities and trapping residents.

Photo by Lee Siebert, 1987 (Smithsonian Institution).

Pyroclastic surge, or base surge deposits from the 1957 phreatomagmatic Capelinhos eruption lap up against a lighthouse near the western coast of Fayal Island in the Azores. Pyroclastic surges produced by magma-water interaction during the Surtseyan eruption nearly buried the lower floor of the lighthouse building. The initially submarine eruption began off the western tip of Fayal, forming a small island that was eventually joined to the main island.

Photo by R. V. Fisher, 1979 (University of California Santa Barbara).