Activity for the week of 7 February-13 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
Ijen
| Eastern Java (Indonesia)
| 8.058°S, 114.242°E
| Elevation 2769 m
During 30 January to 5 February, seismic activity increased at Ijen volcano. This increase was marked by a large number of shallow volcanic earthquakes (75). In addition, 2 small explosion events, 6 tectonic events, and 2 tremor earthquakes occurred. The volcano is at Alert Level 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Inielika
| Flores Island (Indonesia)
| 8.73°S, 120.98°E
| Elevation 1559 m
During 6-11 February, Inielika volcano remained active and the VSI reported no significant change in volcanic activity. An ash plume was observed rising 25-500 m above the volcano and there was a slight increase in the number of deep volcanic earthquakes in comparison to the previous week. The Alert Level at the volcano was reduced from 3 to 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Kelut
| Eastern Java (Indonesia)
| 7.93°S, 112.308°E
| Elevation 1731 m
VSI scientists found that the temperature of Kelut's crater lake had increased and its pH dropped as follows. During 29 January to 7 February the lake's temperature ranged from 50.1 °C to 51 °C, compared with 47.5 °C on 18 January and 38.5 °C on 8 January. On 7 February the pH of the water was 5, compared with measurements of 6.3 in January 2001 and 6.9 in November 2000. The volcano remained at Alert Level 2 (ranging from 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Lokon-Empung
| Sulawesi (Indonesia)
| 1.358°N, 124.792°E
| Elevation 1580 m
After explosions occurred on 28 January, volcanic activity decreased. During 30 January to 5 February an ash plume was observed rising 200-350 m above the volcano. The seismograph on the volcano broke on 30 January. The volcano remained at Alert Level 3 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Mayon
| Luzon (Philippines)
| 13.257°N, 123.685°E
| Elevation 2462 m
The PHIVOLCS reported that volcanic activity remained high at Mayon. Abundant low-frequency volcanic earthquakes associated with dome growth took place on 7, 8, 9, 11, and 12 February and consisted of 29, 30, 29, 45, and 30 events, respectively. Also on 12 February seismometers detected 2 rockfalls. The crater emitted voluminous steam and sulfur, with a maximum of ~7,100 metric tons of SO2 detected on 12 February. Tiltmeters on the volcano's N flank continued to detect slight edifice inflation. On 11 February, PHIVOLCS reported that most of the springs in the E and S quadrants of the volcano showed a decrease in discharge, despite increasing rainfall. Inclement weather prevented observations of the volcano. Mayon remained at Alert Level 3 (on a scale of 0-5).
Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)
Merapi
| Central Java (Indonesia)
| 7.54°S, 110.446°E
| Elevation 2910 m
Intense and dangerous volcanic activity continued at Merapi with hot lava avalanches, near-continuous pyroclastic flows, and an eruption on 10 February that deposited ash on many cities out to 60 km E of the volcano. During 30 January to 5 February, continuous hot lava avalanches and pyroclastic flows traveled down the SW flank of the volcano along the Sat, Senowo, and Bebeng rivers to a maximum runout distance of ~4.5 km. Lava avalanches also traveled down the Lamat River, a drainage that avalanches had not previously traveled down during the current period of volcanic activity. Approximately 25 pyroclastic flows occurred daily. Ash associated with the pyroclastic flows fell around Merapi. During 0430 to 0630 on 3 February heavy rain mixed with ash and produced minor lahars. On 6 February the dome was reported as being 1 million cubic meters in volume and growing at 45 cubic meters per day.
Pyroclastic-flow activity began at 2100 on 9 February and lasted up to 1 hour. At 0200 on 10 February, a medium-sized pyroclastic flow lasted for ~30 minutes. At 0330 the same day "lava dome 1998," which was under the new lava dome ("lava dome 2001"), partially collapsed. The collapse triggered a large and continuous pyroclastic flow that lasted as long as 2.5 hours. The pyroclastic flow traveled up to 7 km SW of the summit towards the Sat River, and 4.5 WSW to the Lamat River. The resultant ash cloud rose up to 5-8 km above the summit, spread ~60 km towards the E, and deposited ash on the towns of Klaten, Solo, Sukoharjo, and Boyolali. The greatest ash thickness was ~1 cm, reported within a 5 km radius around the volcano. At 0530 the Alert Level at the volcano was raised from 3 to 4, the highest level. News articles reported that ~12,000 residents near the volcano were evacuated on 10 February, though many people returned to their property the next day despite the evacuation order. By 11 February, lava dome 2001 was estimated to be 1.4 million cubic meters in volume and unstable, especially after the 10 February collapse of "lava dome 1998."
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC), ABC News - Australian Broadcasting Corporation, Associated Press
Ongoing Activity
Guagua Pichincha
| Ecuador
| 0.171°S, 78.598°W
| Elevation 4784 m
Lava dome growth continued at dome 9 at a rate similar to that of previous weeks. Rockfalls were observed travelling to the SW towards Cristal River. The volcano remained at Alert Level Yellow.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
Karangetang
| Siau Island (Indonesia)
| 2.781°N, 125.407°E
| Elevation 1797 m
The VSI reported that since the 28 January eruption there has been no significant change in activity observed at Karangetang. Seismicity remained dominated by multi-phase earthquakes. The volcano remained at Alert Level 2 (on a scale of 1-4).
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
Kilauea
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
Surface flows continued to travel down the Pulama pali, with no lava entering the sea. A tiltmeter near the HVO showed a small (about 0.4 microradian) deflation shortly before 1230 on 10 February. After 10 February, tiltmeters in the summit area and along the E rift zone showed flat signals. Volcanic tremor near Pu`u `O`o and in Kilauea's caldera was at low-to-moderate levels.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
Popocatepetl
| Mexico
| 19.023°N, 98.622°W
| Elevation 5393 m
The Washington VAAC reported several small ash-bearing eruptions during the week. At 1921 on 8 February an eruption produced a small ash cloud that rose up to ~7.6 km a.s.l. and blew to the NE. At 1400 on 9 February an eruption produced an ash cloud that rose up to ~6.7 km. A small ash plume produced from emissions that occurred at 1338 and 1348 on 11 February was visible in GOES-8 imagery. The ash plume rose up to ~7.9 km a.s.l. and blew to the S.
Sources: Centro Nacional de Prevencion de Desastres (CENAPRED), Washington Volcanic Ash Advisory Center (VAAC)
Sheveluch
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
The KVERT reported that during most of the week seismicity was at background levels. At 1100 on 2 February a powerful gas-and-ash eruption produced a plume that rose 800 m above the volcano and spread ~3 km towards the W. The same day, observations from Klyuchi town revealed that at 1804 a short-lived eruption produced an ash plume that rose up to ~5.3 km a.s.l. The event was accompanied by a 2-minute-long shallow seismic signal that was detected more than 110 km from the volcano. Afterwards, during 1807 to 1824 strong volcanic tremor was registered. The Concern Color Code remained at Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
Soufriere Hills
| Montserrat
| 16.72°N, 62.18°W
| Elevation 915 m
The MVO reported that during 2 to 9 February activity at the Soufrière Hills volcano was slightly higher than during the previous week as lava dome growth continued. Seismic activity remained similar to the previous week, although it increased towards the end of the report week. Rockfall activity was low during the beginning of the week, but significantly increased beginning on 6 February; only 9 rockfalls were recorded on 5 February, while 70 were recorded on 6 February. Brief observations revealed that volcanic activity remained concentrated on the E side of the lava dome and that two large near-vertical spines stood on the dome's summit. By 8 February new pyroclastic-flow deposits were emplaced at the head of Tuitt's Ghaut ~300 m to the N of the dome. The Washington VAAC reported that throughout the week low-level (up to ~2.1 km a.s.l.) ash clouds, presumably produced by rockfalls, and periodic hot-spot activity were visible on GOES-8 imagery.
Sources: Montserrat Volcano Observatory (MVO), 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.
2. Rapidly developing events lead to coverage that is often fragmentary. Volcanoes, their eruptions, and their plumes and associated atmospheric effects are complex phenomena that may require months to years of data analysis in order to create a comprehensive summary and interpretation of events.
3. Preliminary accounts sometimes contain exaggerations and "false alarms," and accordingly, this report may include some events ultimately found to be erroneous or misleading.
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