Activity for the week of 24 July-30 July 2002
The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program. Updated by 2300 UTC every Wednesday, notices of volcanic activity posted on these pages are preliminary and subject to change as events are studied in more detail. This is not a comprehensive list of all of Earth's volcanoes erupting during the week, but rather a summary of activity at volcanoes that meet criteria discussed in detail in the "Criteria and Disclaimers" section. Carefully reviewed, detailed reports on various volcanoes are published monthly in the Bulletin of the Global Volcanism Network.
New Activity / Unrest
| DR Congo
| 1.408°S, 29.2°E
| Elevation 3058 m
An eruption began at Nyamuragira on the evening of 25 July that produced a cloud composed of steam, gas, and ash, 100- to 200-m-high lava fountains, and lava flows down the volcano's N and S flanks. According to the seismic record, the eruption began on the 25th at about 1310. National Park guards saw "smoke" rising above the volcano about an hour earlier. Around 1700, lava was seen pouring out of a fracture. Scientists who visited the crater later that day saw that the crater had been cut in two parts by a fracture: NW and SE. Sustained 100- to 200-m-high lava fountains were visible along the fracture. One lava flow traveled to the N from the several-km-long fracture, while a smaller one traveled to the S. On the 27th the lava flows were 6-7 km long and ~1 km wide. Neither flow was a threat to inhabited areas, but they caused large amounts of damage to vegetation within the National Park.
Volcanic clouds produced during the eruption were detected by several satellites. Beginning on 26 July around 0000, a steam-and-ash plume was visible on METEOSAT satellite imagery, below 6 km a.s.l., drifting to the WSW. From the 26th to the 28th TOMS detected 125 to 330 kt of SO2 in a cloud that may have come from the neighboring volcano Nyiragongo, but is believed to be from Nyamuragira. A NASA satellite detected a very large plume that was 400 km long, 300 km wide, and extended to the WSW. Nyamuragira is ~20 km NW of Nyiragongo and 40 km NW of the city of Goma, which was devastated by an eruption at Nyiragongo in January 2002. Scientists do not think the eruption of Nyamuragira is a threat to residents of Goma, but the ash cloud may cause respiratory problems, and threaten animals and crops in its path.
Sources: Associated Press, Toulouse Volcanic Ash Advisory Centre (VAAC), UN Office for the Coordination of Humanitarian Affairs (OCHA), US Air Force Weather Agency, TOMS Volcanic Emissions Group
| DR Congo
| 1.52°S, 29.25°E
| Elevation 3470 m
Scientists were able to see Nyiragongo's crater on 27 July after 2 weeks without observations. They found that a very large white plume, which rose almost 3 km above the volcano, was being emitted from a small spatter cone inside the main crater. Lava was visible inside the spatter cone. They also noted a very active lava lake inside the main crater that was smaller than they expected it to be based on the size of the plume. While authorities did not order the evacuation of towns near the volcano, news articles reported that aid workers prepared emergency items such as makeshift shelters in case a large eruption occurs.
Sources: Associated Press, Reuters, UN Office for the Coordination of Humanitarian Affairs (OCHA)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
During 19-26 July, seismicity remained above background levels at Shiveluch. Individual earthquakes up to M 1.9, as well as a number of smaller earthquakes at depths of 0-6 km, were recorded. Other local seismic signals indicated that possible weak, ash-poor explosions rose to 1 km above the dome. Avalanches were also registered. Gas-and-steam emissions, some possibly including small amounts of fine ash, rose to ~1.5 km above the lava dome. A small, likely ash-rich plume was visible on AVHRR satellite imagery on 22 July at 1804. The plume appeared to be centered over the volcano's summit at a height of about 5.3 km. On 29 July at 2000 the intensity of volcanic tremor increased noticeably in comparison with the previous few days. On 30 July at 0946 a short-lived explosion produced a plume to a height of ~3 km above the dome. KVERT raised the Concern Color Code from Yellow ("volcano is restless") to Orange ("explosive eruption is possible within a few days and may occur with little or no warning").
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3295 m
During a visit to Etna on 26 July it was revealed that Strombolian activity had continued at Northeast Crater. Activity consisted of volcanic bombs being thrown beyond the rim of the crater. There was very little activity at Voragine and Southeast craters. According to the Toulouse VAAC, ash was observed on 29 July at 0855, possibly around summit level.
Sources: Etna Volcan Sicilien (Charles Rivière), Toulouse Volcanic Ash Advisory Centre (VAAC)
| Siau Island (Indonesia)
| 2.781°N, 125.407°E
| Elevation 1797 m
According to VSI, on 15 July at 1355 an explosion at Karangetang's main crater produced an ash cloud to a height of 1.5 km above the crater. Ash fell to the N of the volcano. An accompanying lava avalanche traveled up to 1.5 km into Kahetang River Valley. During the rest of 15-21 July, low-level plumes continued to rise above Karangetang's main crater and Crater II. Based on information from a pilot report, the Darwin VAAC reported that a smoke plume was observed on 29 July at 1323 rising to an unknown height. Karangetang remained at Alert Level 2 (on a scale of 1-4).
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
During 20-26 July, seismicity was above background levels at Karymsky. Local, shallow seismic events occurred at a rate of ~10 events per hour. The character of the seismicity indicated that weak ash-and-gas explosions and gas blow-outs possibly occurred. Satellite imagery on 25 July indicated a possible small ash plume moving to the SW. Karymsky remained at Concern Color Code Yellow ("volcano is restless").
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Hundreds of spectators flocked to Kilauea to see the spectacular show of lava flowing into the sea at the end of easily accessible Chain of Craters Road. Surface lava flows were visible traveling down Pulama pali, Paliuli, and on the coastal flat. Generally, seismicity was at normal levels, except for the continued swarm of long-period earthquakes and tremor that has been ongoing since early June. The swarm increased slightly in the last several days of the report period. Brief inflation occurred at Pu`u` O`o on 26 July.
Sources: Associated Press, US Geological Survey Hawaiian Volcano Observatory (HVO)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
During 15-21 July, incandescent lava avalanches traveled predominately down Merapi's SW flank into the upstream portions of the Sat, Lamat, Senowo, and Bebeng rivers. The avalanches reached a maximum run-out distance of ~2.5 km. Seismicity was dominated by signals from 201 lava avalanches. Merapi remained at Alert Level 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| 34.094°N, 139.526°E
| Elevation 775 m
The Air Force Weather Agency reported that a low-level steam-and-ash cloud from Miyake-jima was visible on satellite imagery on 26 July at 0713 and on 27 July at 0606. Around this time a continuous plume was visible at a height of 2.4-3 km a.s.l.
Source: US Air Force Weather Agency
| 19.023°N, 98.622°W
| Elevation 5393 m
During 23-30 July, there were small-to-moderate emissions of steam, gas, and ash at Popocatépetl. Based on information from the Mexico City MWO, the Washington VAAC reported that on 26 July an ash cloud rose 5.5-6.7 km a.s.l.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
| Eastern Java (Indonesia)
| 8.108°S, 112.922°E
| Elevation 3657 m
When weather conditions were clear during 15-21 July, lava avalanches were observed traveling ~750 m from Semeru's crater rim E toward Besuk Kembar River. Explosions produced ash plumes reaching 300-500 m above the crater. Seismicity was dominated by 670 explosion earthquakes, while the number of other types of earthquakes decreased in comparison to the previous week. Semeru remained at Alert Level 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| 16.72°N, 62.18°W
| Elevation 915 m
Volcanic and seismic activity at Soufrière Hills during 19-26 July increased significantly in comparison to the previous week. A swarm of low-amplitude long-period earthquakes began on 19 July and increased in strength over the following 4 days. Observations of the lava dome on 21 July indicated that significant growth had recommenced, with the extrusion of a new lobe on the NE side of the summit region. Growth of the new lobe gave rise to rockfalls and small pyroclastic flows off the dome's NE flank. A notable event occurred on the morning of 23 July, when a minor collapse produced small but continuous pyroclastic flows for about an hour. These mainly flowed into the upper parts of Tuitt's Ghaut and down White's Ghaut for about half the distance to the coast. A few also flowed into the upper part of the Tar River Valley. A similar event, lasting for about 20 minutes, occurred in the early hours of the morning of 26 July. Sulphur dioxide flux was low at the beginning of the report period, but increased from 22 July onwards.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| Aeolian Islands (Italy)
| 38.789°N, 15.213°E
| Elevation 924 m
During 5-24 July, the level of volcanic activity fluctuated at Stromboli. Small explosions occasionally occurred at Northeast Crater, while fewer occurred at Southwest Crater. The central crater was inactive. On 24 July at about 0745 a relatively large explosion produced a mushroom-shaped plume to a height of ~0.5 km above the summit. It was not known from which crater the explosion occurred.
Sources: Italy's Volcanoes, Stromboli On-Line
| 1.467°S, 78.442°W
| Elevation 5023 m
Beginning on 22 July there was an increase in the number of explosive events at Tungurahua in comparison to the previous week. Explosions on 23 and 24 July reached an average height of ~2 km above the summit and drifted to the NW, W, and SW. Small amounts of ash fell in the sectors of Riobamba, SW of the volcano, and Baños, to the N. By 28 July, the level of volcanism had declined.
Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG), Washington Volcanic Ash Advisory Center (VAAC)
Criteria & Disclaimers
The Weekly Volcanic Activity Report does not necessarily include all volcanic activity that occurred on Earth during the week. More than a dozen volcanoes globally have displayed more-or-less continuous eruptive activity for decades or longer, and such routine activity is typically not reported here. Moreover, Earth's sea-floor volcanism is seldom reported even though in theory it represents the single most prolific source of erupted material. The Weekly Volcanic Activity Report summarizes volcanic activity that meets one or more of the following criteria:
- A volcano observatory raises or lowers the alert level at the volcano.
- A volcanic ash advisory has been released by a volcanic ash advisory center (VAAC) stating that an ash cloud has been produced from the volcano.
- A verifiable news report of new activity or a change in activity at the volcano has been issued.
- Observers have reported a significant change in volcanic activity. Such activity can include, but is not restricted to, pyroclastic flows, lahars, lava flows, dome collapse, or increased unrest.
Volcanoes are included in the "New Activity/Unrest" section of the Weekly Volcanic Activity Report if the activity occurs after at least 3 months of quiescence. Once a volcano is included in the "New Activity/Unrest" section, updates will remain in that section unless the activity continues for more than 1 month without escalating, after which time updates will be listed in the "Continuing Activity" section. Volcanoes are also included in the "New Activity/Unrest" section if the volcano is undergoing a period of relatively high unrest, or increasing unrest. This is commonly equal to Alert Level Orange on a scale of Green, Yellow, Orange, Red, where Red is the highest alert. Or alert level 3 on a scale of 1-4 or 1-5.
It is important to note that volcanic activity meeting one or more of these criteria may occur during the week, but may not be included in the Weekly Volcanic Activity Report because we did not receive a report.
1. The Weekly Volcanic Activity Report is intended to provide timely information about global volcanism on a weekly basis. Consequently, the report is generated rapidly by summarizing volcanic reports from various sources, with little time for fact checking. The accuracy of the Weekly Volcanic Activity Report is dependent upon the quality of the volcanic activity reports we receive. Reports published in the Bulletin of the Global Volcanism Network are monthly, and more carefully reviewed, although all of the volcanoes discussed in the Weekly Volcanic Activity Report are not necessarily reported in the Bulletin. Because of our emphasis on rapid reporting on the web we have avoided diacritical marks. Reports are updated on the Weekly Volcanic Activity Report web page as they are received, therefore information may be included regarding events that occurred before the current report period.
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