Activity for the week of 14 February-20 February 2001
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
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
The AVO reported that Cleveland volcano erupted explosively at 0600 on 19 February, producing an ash-and-steam cloud that was detected from the beginning of the eruption on GOES imagery and confirmed by pilot reports at 1310. Satellite imagery at 0945 showed that the cloud was in two sections; the lower section reached ~5.2 km a.s.l. and drifted SE of Cleveland, and the higher section reached 9.1-10.7 km a.s.l. and drifted to the N. By 1900 the cloud had extended at least 120 km to the N and drifted E towards Dutch Harbor, Akutan, and beyond. The National Weather Service via the Anchorage VAAC, and the Federal Aviation Administration, issued a volcanic ash advisory to divert aircraft away from the ash cloud. During 1200 to about 1600, light ash fell in the closest inhabited town to the volcano, Nikolski (~30 residents), 45 miles E of the volcano. The Anchorage VAAC reported that additional eruptions occurred through 1800. According to the AVO, explosive activity ended in the late afternoon and at 2130 a thermal anomaly was still visible on satellite imagery. Prior to the eruption the AVO had received pilot reports and photos of increased emissions on 2 February, but the reports could not be confirmed without ground-based monitoring instrumentation. The AVO warned that further eruptive activity could occur with little warning. Because Cleveland is not seismically monitored, the AVO did not assign a level of concern color code.
GOES images and animation of the 19 February ash cloud
Sources: US Geological Survey Alaska Volcano Observatory (AVO), Anchorage Volcanic Ash Advisory Center (VAAC), Reuters, Anchorage Daily News
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
PHIVOLCS reported that activity decreased at Mayon in comparison to the previous week with a slightly lower number of earthquakes and lower SO2 emission rates. Between 19 and 31 low-frequency volcanic earthquakes were recorded daily during 13-20 February. SO2 emission rates decreased from ~7,100 metric tons per day (t/d) on 12 February, to 2,700 t/d on 13 February. The highest SO2 emission rate recorded during the week was 4,800 t/d on 15 February. During the week there was an inflationary trend at Mayon. The volcano was obscured by clouds so that crater glow and steaming activity could not be observed. Mayon remained at Alert Level 3 (on a scale of 0-5). PHIVOLCS reported that they plan to lower the Alert Level to 2 if volcanic activity continues to decrease.
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
VSI reported that after the large 10 February eruption volcanic activity decreased in intensity. Lava avalanches and pyroclastic flows continued, but were smaller than they were the previous week. During 10 to 13 February pyroclastic flows entered the Sat, Lamat, Senowo, and Bebeng rivers to a maximum runout distance of 2-3 km, in comparison to ~4.5 km the previous week. After 13 February lava avalanches and pyroclastic flows traveled 1.5-2.5 km to the WSW and lasted 1-2 hours. According to the VSI, high temperatures around Merapi indicate that magma is near the surface. The W and S sides of "lava dome 2001" grew and covered "lava dome 1997" to the S. Several fumaroles appeared to mark a fracture along the area where the 10 February eruption occurred. Fractures formed in a similar matter prior to the November 1994 eruption. The volcano remained at Alert Level 4, the highest level.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
| DR Congo
| 1.408°S, 29.2°E
| Elevation 3058 m
According to a Reuters article, the eruption at Nyamuragira that was first observed on 6 February continued at least until 18 February. There were reports of lava flowing from three cones, "flames" rising 100 m above the volcano, and ash falling over an area of 20 to 30 km2 around the volcano. Lava flowed down the S flank of the volcano, threatening to reach roads running N from the town of Goma ~30 km away. Scientists from the Lwiro Natural Science Research Centre in Bukavu said abnormal activity was initially detected in December. There was a report of one injury from the volcanic activity; a man lost his leg after accidentally stepping into a lava flow. Officials said that the effect of ash fall on crops, pastures used for grazing, and the water supply could devastate the region.
Scientists from the University of Hawaii used MODIS to monitor the positions of the lava flows on the volcano. They created hot spot maps that show the positions of thermal anomalies that were detected on 7, 8, 11, and 12 February. An approximately 7x5 km large hot spot was detected on 7 February 7-10 km N of the summit. By 8 February the anomaly had increased in size and was oriented in a SSW-NNE direction; a second hot spot, ~13x6 km in size and oriented towards the E-ESE, was detected SSE of the summit. On 11 and 12 February the NNE-trending NE-flank hot spot reached a maximum distance of ~22 km and the E-trending S-flank hot spot extended ~17 km.
Sources: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team, Reuters
| El Salvador
| 13.595°N, 88.837°W
| Elevation 2182 m
There were reports of volcanic activity at San Vicente volcano after a M 6.6 earthquake occurred at 1422 on 13 February. The earthquake caused more than 25 landslides on the flanks of the volcano that reportedly killed 39 people. The Centro de Investigaciones Geotécnicas investigated the activity reports and determined that no volcanic activity had occurred. In addition, the government reported that there was no volcanic activity at San Miguel, San Salvador, or Santa Ana volcanoes.
Sources: La Prensa Grafica, Servicio Nacional de Estudios Territoriales (SNET), US Geological Survey Earthquake Hazards Program, US Geological Survey Volcano Disaster Assistance Program (VDAP), Diario del Hoy (elsalvador.com)
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3295 m
According to the Stromboli On-Line website, on 12 February a Stromboli On-Line research group observed lava flowing from the Southeast Crater's NE fissure as it has since late January. Lava and gas were emitted from a small tumulus in strong pulses and flowed several hundred meters into Valle Leone. On 14 February Voragine and Northeast craters were observed emitting steam and Strombolian activity occurred at both of Bocca Nuova Crater's vents. The Strombolian activity at the Bocca Nuova's NW vent was irregular and occasionally reached at least the height of the crater rim. Strombolian activity at the Bocca Nuova's SE vent was more vigorous with eruptions every few seconds. The explosions were directed roughly vertically and volcanic bombs reached up to several hundred meters above the crater rim.
Source: Stromboli On-Line
| 0.171°S, 78.598°W
| Elevation 4784 m
On 13 February the Civil Defense reported that a crack formed in dome 9 and a small rock collapse occurred on the W side of the dome. On 14 February a rock collapse occurred on the S side of the dome. During a flight over the volcano on 15 February, IG personnel confirmed that dome 9 had grown during the week. The volcano remained at Alert Level Yellow.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Lava flows continued to travel down the Pulama pali and across the coastal flat without entering the sea. During 17 and 19 February a weak swarm of shallow earthquakes occurred within the caldera. The HVO reported that the swarm was not unusual and appeared to be dying off by the end of the report period. Overall, volcanic tremor near Pu`u `O`o was at low-to-moderate levels. Tiltmeters in the summit area and along the E rift zone showed flat signals.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| 34.094°N, 139.526°E
| Elevation 775 m
The National Coordination of Volcanic Eruption Prediction committee reported on the status of Miyake-jima on 5 February. They stated that eruptions had not occurred since October 2000. High SO2 emission rates, ranging from 20 to 50 kilotons per day, continued to be detected. Most of the SO2 is considered to be from degassing magma. The temperature of the active crater increased in December 2000 and returned to normal by late January. Very little ground deformation has been detected. Seismic activity had been low since September, until low-frequency earthquakes occurred in late-January. Due to the high SO2 emission rates and the threat of lahars, volcanologists continue to closely monitor the volcano.
Source: Volcano Research Center-Earthquake Research Institute (University of Tokyo)
| 19.023°N, 98.622°W
| Elevation 5393 m
The Washington VAAC reported that an eruption occurred at 1642 on 15 February, producing an ash cloud that rose up to 7.9 km a.s.l. and drifted to the ENE. The cloud was visible on GOES-8 imagery and by 1802 it had traveled to the Gulf of Mexico. The volcano remained at Alert Level Yellow Phase III, with a restricted area of 12-km-radius.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
The KVERT reported that during 9-16 February seismicity was at background levels. On 9-10 February a gas-and-steam plume rose 1-1.2 km above the volcano. On 12-15 February a gas-and-steam plume rose 300-500 m above the volcano. The Concern Color Code remained at Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
The MVO reported that during 9 to 16 February activity at the Soufrière Hills volcano fluctuated markedly, as lava dome growth continued. The level of seismic activity varied considerably, with a pronounced peak in activity during 10 and 11 February, which was followed by a gradual decrease in rockfall activity. Observations revealed that the two large spines that were visible on the volcano's summit the previous week had collapsed, and a large lobe had formed on the eastern face of the dome above Tar River. New pyroclastic-flow deposits were observed down the Tar River extending to the old coastline. Small-volume deposits were observed down White River to the S and in Tuitt's Ghaut to the NE. The Washington VAAC reported that throughout the week low-level ash clouds (up to ~2.1 km a.s.l.), presumably produced by rockfalls, were visible on GOES-8 imagery.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
The IG reported that at 1050 on 19 February lahars were registered at a seismic station. The lahars traveled down the NW flank of the volcano via the Cusúa Gorge. The same day a steam column rose 1 km above the summit and drifted to the NE.
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.
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