Activity for the week of 21 December-27 December 2005
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
| 14.473°N, 90.88°W
| Elevation 3763 m
On 27 December an eruption at Fuego produced an ash plume to a height of ~7.6 km (25,000 ft) a.s.l. that extended SSW and SSE of the volcano. The higher level ash (~7.6 km a.s.l.) drifted W to Honduras, while ash below ~6.1 km (20,000 ft) a.s.l. drifted E to the Pacific coast. According to news articles, two lava flows that were both ~2 km long traveled down the volcano's flanks, but posed no threat to inhabited areas. Articles also reported that about 25,000 local residents were put on alert, and emergency teams said that there was no immediate need for evacuations.
Sources: Washington Volcanic Ash Advisory Center (VAAC), Reuters
Piton de la Fournaise
| Reunion Island (France)
| 21.244°S, 55.708°E
| Elevation 2632 m
Following summit inflation that had been measured at Piton de la Fournaise since the last eruption on 29 November, a seismic crisis began beneath Dolomieu Crater on 26 December at 1444. During the next 2 hours, seismicity shifted to the NE in the direction of "Nez Coupe de Sainte Rose." A first fissure opened at 1715 at the NE base of Piton de la Fournaise. At 2200 eruptive fissures opened in the caldera wall ~500 m E of "Nez Coupe de Sainte Rose," and a lava flow traveled into the "Plaine des Osmondes." By the 28th, eruptive activity was almost constant and an aa lava flow slowly traveled in the "Grandes Brule" and had reached to within ~3 km of the national road.
Source: Observatoire Volcanologique du Piton de la Fournaise (OVPF)
| Sulawesi (Indonesia)
| 1.112°N, 124.737°E
| Elevation 1785 m
A phreatic eruption began at Soputan on 26 December around 1230 following heavy rain that contacted lava at the volcano's summit. On 27 December at 0400, a Strombolian eruption began that lasted ~50 minutes. Incandescent volcanic material was ejected ~35 m, and avalanches of volcanic material traveled as far as 750 m E. Around 0640 the avalanches became larger, as pyroclastic avalanches occurred from the edge of the lava. The avalanches extended 200 m E, and booming noises were heard as far as 5 km from the summit. The Darwin VAAC reported that an ash plume reached a height of ~5.8 km (~19,000 ft) a.s.l. and drifted SE.
As of 28 December, eruptive activity continued at Soputan, producing ash plumes to a height of ~1 km above the volcano (or 9,100 ft a.s.l.). Strombolian eruptions continued, ejecting incandescent volcanic material up to 200 m above the summit (or 6,500 ft a.s.l.). Pyroclastic avalanches traveled ~500 m E and SW. This was the fourth event at Soputan in 2005, with previous activity on 14 and 20 April, and on 12 September. The Alert Level remained at 2, since the volcano is about 11 km from the nearest settlement. Visitors are prohibited from climbing Soputan's summit and camping around Kawah Masem.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
| United States
| 59.363°N, 153.43°W
| Elevation 1252 m
During 16-23 December, unrest continued at Augustine, with elevated seismicity and several small steam explosions occurring. Thermal imaging of the summit area on 22 December using a helicopter-mounted FLIR (Forward Looking Infrared Radiometer) confirmed the presence of a new, high-temperature fumarole or gas vent high on the S flank of the volcano. A gas-measurement flight on 20 December detected sulfur dioxide for the first time at Augustine since routine airborne measurements began in the early 1990s. Aerial observations and analysis of photography and video of the summit area indicated that some deformation occurred within the summit crater area. A crack or fissure was noted cutting the 1986 lava dome and extending to the SE. Heavy steam from this feature, along with patches of bare ground, indicated that heat output at the summit had increased. Augustine remained at Concern Color Code Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| Andaman Islands (India)
| 12.278°N, 93.858°E
| Elevation 354 m
During 21-23 December, ash plumes from Barren Island were visible on satellite imagery at a maximum height of 4.6 km (15,000 ft) a.s.l. on the 21st.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 19.514°N, 103.62°W
| Elevation 3850 m
During 21-27 December, several small explosions occurred at Colima, producing ash plumes that reached ~6.7 km (22,000 ft) a.s.l. on 26 December.
Sources: Centro Universitario de Estudios e Investigaciones de Vulcanologia - Universidad de Colima, Washington Volcanic Ash Advisory Center (VAAC)
| 1.22°N, 77.37°W
| Elevation 4276 m
Based on information from the US Geological Survey, the Washington VAAC reported that a pilot observed an ash plume from Galeras on 23 December at a height of ~7.3 km (24,000 ft) a.s.l. drifting W.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
Interpretations of seismic data from Karymsky suggested that ten ash plumes rose to ~3.6 km (11,800 ft) a.s.l. during 16-23 December. KVERT volcanologists reported that during 17-21 December, ash plumes rose 2.5-3 km (8,200-9,800 ft) a.s.l. and extended WSW and ENE of the volcano. They warned that such activity could affect low-flying aircraft in the vicinity of the volcano. Karymsky remained at Concern Color Code Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 22-27 December, lava from Kilauea continued to enter the sea at the East Lae`apuki area and surface lava flows were visible on the Pulama pali fault scarp. Background volcanic tremor was near normal levels at Kilauea's summit. Volcanic tremor reached moderate levels at Pu`u `O`o. Small amounts of deformation occurred at the volcano.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| El Salvador
| 13.853°N, 89.63°W
| Elevation 2381 m
During 21-23 December, seismicity at Santa Ana was above background levels. Small earthquakes occurred, which were interpreted as being associated with gas pulses. Gas emissions rose to low levels. The Alert Level remained at Red, the highest level, within a 5-km radius around the volcano's summit crater.
Source: Servicio Nacional de Estudios Territoriales (SNET)
| 16.72°N, 62.18°W
| Elevation 915 m
Volcanic and seismic activity at Soufrière Hills remained elevated during 16-23 December. Images revealed that the lava dome continued to grow during the report period. Growth occurred over a broad sector extending from the SW around to the NE. Vertical growth was focused to the S and SW, with lateral growth in the E and SE sectors. Numerous small rockfalls traveled down the S, E, and NE flanks of the lava dome, adding to the talus in the upper reaches of the Tar River Valley to the NE. The sulfur-dioxide flux averaged 415 metric tons per day.
Source: Montserrat Volcano Observatory (MVO)
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
Growth of the new lava dome inside the crater of Mount St. Helens continued during 21-27 December, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. Small rockfalls continued from the growing lava dome, with larger ones producing ash plumes that were visible above the crater rim. There were no significant changes in seismicity or deformation during the report period. Seismicity was marked by the repetitive small earthquakes, occurring every 2-3 minutes, that have come to characterize the past 15 months. Tiltmeters within 500 m of the new lava dome showed minute ground deformation; whereas the volcano's flanks were quiet. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
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.
4. Many news agencies do not archive the articles they post on the Internet, and therefore the links to some sources may not be active. To obtain information about the cited articles that are no longer available on the Internet contact the source.
5. USGS Disclaimer Statement for this Website:
Information presented on this website is considered public information and may be distributed or copied. Use of appropriate byline/photo/image credit is requested. We strongly recommend that USGS data be acquired directly from a USGS server and not through other sources that may change the data in some way. While USGS makes every effort to provide accurate and complete information, various data such as names, telephone numbers, etc. may change prior to updating. USGS welcomes suggestions on how to improve our home page and correct errors. USGS provides no warranty, expressed or implied, as to the accuracy, reliability or completeness of furnished data.
Some of the documents on this server may contain live references (or pointers) to information created and maintained by other organizations. Please note that USGS does not control and cannot guarantee the relevance, timeliness, or accuracy of these outside materials.
For site security purposes and to ensure that this service remains available to all users, this government computer system employs software programs to monitor network traffic to identify unauthorized attempts to upload or change information, or otherwise cause damage. Unauthorized attempts to upload information or change information on this website are strictly prohibited and may be punishable under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act. Information may also be used for authorized law enforcement investigations. (Last modified September 21, 1999.)
U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA