Activity for the week of 9 November-15 November 2011
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
| 27.73°N, 18.03°W
| Elevation 1500 m
Instituto Geográfico Nacional (IGN) reported that during 9-15 November the submarine eruption continued S of El Hierro Island; mean amplitude of tremor was similar to that of the previous week. During the period, 245 seismic events were recorded, most of them located offshore to the N of the island, at depths of 16-23 km. Twenty one of these events were felt by residents at a maximum intensity value of IV-V using EMS-98 (European Macroseismic Scale). The maximum magnitude was 4.6, for an event located 2.5 km offshore to the N at 21 km depth on 11 November, and was the largest of the 11,604 total events detected since 16 July. GPS deformation analysis continued to show different behaviors between N and S stations; N stations showed deformations to the N up to the time of the M 4.6 event, when the deformation then changed to S. Stations located in the S showed deformation trends to the N.
On 9 November, access to two creeks (Tacorón and Punta Naos) in the S of the island was prohibited due to the possibility of significant concentration of volcanic gases. On 14 November, residents of La Restinga were allowed to return to their homes. That same day, many big steaming lava blocks (more than 1 m in diameter) were observed over the submarine emission center.
Source: Instituto Geográfico Nacional (IGN)
| DR Congo
| 1.408°S, 29.2°E
| Elevation 3058 m
According to GORISK (an initiative of the National Museum of Natural History, Luxembourg and Royal Museum for Central Africa, Belgium), the eruption at Nyamuragira that began on 6 November, after two days of intense seismic activity, was located along a fissure 11-12 km ENE of the main crater, close to one of the 1989 eruption sites.
Virunga National Park staff had previously been observing the eruption from a hilltop in Rumangabo, but on 9 November the staff and rangers traveled to the site. After a 3-hour hike, the team viewed the eruption from the S and noted roaring and lava fountains, as well as thunder and lightning. The observers also noted that the ground was covered by black pumice. On 11 November about 100 people, including staff, rangers, carpenters, porters, and volcanologists, traveled to a similar but safer location to set up a camp for visitors. The eruption site was described as a flat area with a 500-1,000-m-long fissure, oriented perpendicular to the Albertine (Western) rift. Lava fountains rose as high as 300 m above a cinder cone. Slow-moving lava traveled N.
GORISK noted that radar images acquired on 11 November showed the largest deformation ever detected by the method (InSAR) since the early 1990's over Nyamuragira. A very preliminary analysis of the observed deformation suggested an affected area of more than 250 square kilometers. The ground rose more than 50 cm at the eruptive site where the spatter cone was developing. Another 15 cm of deformation was detected within the Nyamuragira caldera accompanied by deflation on the flanks. Satellite images acquired on 12 November showed that the lava flow had traveled approximately 11.5 km during the six days of the eruption.
Sources: Virunga National Park, GORISK
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 9-12 and 14-15 November explosions from Sakura-jima produced plumes that rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted W, S, and SE. On 14 November a pilot reported that an ash plume rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SE. Satellite imagery during 14-15 November showed ash emissions that later dissipated.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Sicily (Italy)
| 37.748°N, 14.999°E
| Elevation 3320 m
Sezione di Catania - Osservatorio Etneo reported that the eighteenth paroxysmal eruptive episode of 2011 took place at the New SE Crater (New SEC) of Etna during the morning of 15 November. Thermal monitoring cameras at the observatory in Catania and at Montagnola, about 3.5 km S of the summit craters, recorded a small thermal anomaly at the lower end of the eruptive fissure on the SE flank of the cone at about 0700. The anomaly slowly grew in size and temperature, caused by the emission and expansion of a small lava flow. Mild Strombolian activity commenced at 0900 from within the New SEC, and spattering began from several vents along the fissure on the SE flank of the cone. This activity continued for nearly three hours, while increasing very slowly, and the lava flow spread out into several branches at the SE base of the cone, advancing only a few hundred meters. At about 1155, the activity markedly and rapidly increased both within the crater and along the fissure, and just after 1200 lava fountains and ash emissions rose from the crater. Lava fountains then rose from vents along the SE flank fissure. Bombs and scoria fell into the cone.
At 1230 ash emissions significantly increased, especially from a vent located in the SE portion of the New SEC, and a plume of ash and gas rose several kilometers above the summit and drifted SE. The most intense phase of the eruption occurred between 1245 and 1315 when jets heavily laden with incandescent bombs rose as high as 800 m above the crater. Pyroclastic material fell onto the New SEC cone, areas well beyond the base, and the nearby old SEC cone. During this phase explosions occurred from a vent on the N flank of the New SEC cone, likely the same vent that emitted small lava flows on 28 September and 8 October. At about 1325 the activity started to diminish and ceased abruptly at 1329, but was followed by passive ash emissions that lasted until just after 1400. Weak and discontinuous spattering accompanied by slow lava effusion continued for a few hours from a single vent in the central portion of the eruptive fissure on the SE flank of the New SEC cone.
Lava flows from the eruption traveled less than 4 km toward the floor of the Valle del Bove, immediately to the N of the Serra Giannicola ridge, stagnating to the SW of Monte Centenari. The New SEC grew in height by 10 m on the S side, bringing the total height of the cone to about 180-200 m above its base. Ash and lapilli deposits affected the SE flank, including the towns of Zafferana Etnea (10 km SE) and Acireale (20 km SE).
Source: Sezione di Catania - Osservatorio Etneo (INGV)
| 14.473°N, 90.88°W
| Elevation 3763 m
INSIVUMEH reported that activity at Fuego increased during 8-9 November. Explosions produced shock waves that were detected up to 15 km away, rumbling sounds, and ash plumes that rose 1.5-2 km above the crater and drifted 20 km SW. Ash fell on the SW flank in Panimaché (6 km SW), Morelia (7 km SW), Sangre de Cristo (8 km WSW), and Santa Sofía. Block avalanches descended the flanks. During 9-10 November explosions generated ash plumes that rose 600-800 m above the crater and drifted 10 km S and SW. Avalanches descended the SW flank towards the Taniluya and Ceniza drainages.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
KVERT reported that seismic activity continued at a moderate level at Karymsky during 4-11 November, and indicated that possible ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. Satellite imagery showed either no activity, possibly due to cloud cover. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 9-15 November, HVO reported that the lava lake circulated and periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, remaining below the inner ledge (75 m below the crater floor). Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby. Incandescence emanated from the E and W edges of the Pu'u 'O'o crater floor and from the 21 September fissure on the SE flank of Pu'u 'O'o cone. Pahoehoe flows, fed through lava tubes from the fissure, continued to be active about 4.7 km SE of Pu'u 'O'o based on an overflight on 12 November and satellite images. Incandescence from a skylight on the lava tube was also observed.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Eastern Kamchatka (Russia)
| 55.131°N, 160.32°E
| Elevation 2334 m
KVERT reported moderate seismic activity at Kizimen during 4-11 November and that a thermal anomaly on the volcano was detected daily in satellite images. A large lava flow on the NE and E flanks continued to effuse and the crater was incandescent at night during 2-3 and 6-9 November. Video observations showed gas-and-steam activity during 4-9 November. The Aviation Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Papua New Guinea
| 4.08°S, 145.037°E
| Elevation 1807 m
Based on analysis of satellite imagery and a pilot observation, the Darwin VAAC reported that on 11 November an ash plume from Manam rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted about 90 km NE.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| Costa Rica
| 10.2°N, 84.233°W
| Elevation 2708 m
OVSICORI-UNA reported that during October fumarolic activity at Poás continued with bluish gas plumes rising from the lava dome; plumes rose more than 1 km and were reported by residents in Valle Central. Towards the end of the month, the fumarolic activity as well as incandescence from the lava dome decreased. The new craters at the N base of the dome united into a crater that was 25 m long and 7-10 m wide. Phreatic activity continued to occur from Laguna Caliente, the summit lake. The lake was 55 degrees Celsius, and the level had risen 22 cm between 14 September and 27 October.
Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA)
| 40.59°S, 72.117°W
| Elevation 2236 m
Based on seismicity during 9-13 November, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. During 9-10 November clouds prevented observations with an area web camera, but on 9 November satellite imagery showed an ash plume that drifted and dissipated to the E. During 11-12 November mostly gray plumes observed with the web camera rose 4-7 km above the crater. During the night the crater was incandescent and small explosions were observed. Satellite imagery showed ash plumes drifting 90 km NE on 11 November and 400 km SE on 12 November. Ash fell in areas on the border of Chile and Argentina at Paso Samore on 12 November. Cloud cover prevented web camera views on 13 November, but satellite imagery showed a plume drifting 250 km NE. A gray plume rose 6.5 km above the crater on 14 November. That same day a plume identified in satellite imagery drifted 200 km NW and ash clouds drifted from the SE to the NE. The Alert Level remained at Red.
Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that moderate seismic activity was detected at Shiveluch during 4-11 November, and indicated that possible ash plumes rose to a maximum altitude of 4.5 km (14,800 ft) a.s.l. Ground-based observers noted that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption. Strong fumarolic activity at the lava dome was observed during 2-3 and 5-9 November; cloud cover prevented observations on the other days. Satellite imagery showed a daily thermal anomaly over the lava dome and gas-and-steam plumes containing small amounts of ash that drifted 25 km E on 5 November. The Aviation Color Code remained at Orange.
Based on information from KVERT, the Tokyo VAAC reported that on 14 November an ash plume drifted E at an altitude of 3 km (10,000 ft) a.s.l.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
The Washington VAAC reported that on 9 November an ash plume from Tungurahua was identified by a pilot. A later report stated that IG noted no ash emissions from Tungurahua since June, and that only gas-and-steam emissions had been observed that day.
Source: 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.
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