Activity for the week of 12 October-18 October 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 tremor, registered by every seismic station on El Hierro Island, continued during 12-18 October. Deformation decreased during this period, with significant inflation-deflation episodes registered by the stations located in the NW part of the island. On 12 October, at about 1430, the amplitude of the tremor signals abruptly decreased and smaller amplitudes persisted during the following days. During the afternoon of 12 October a large light-green colored area was observed in the sea to the S of La Restinga village (at the southernmost point of Hierro); the evolution of this anomaly was observed from land and by helicopter. The extension of the anomaly was controlled by the ocean currents, but a small area was detected as the emission center due to its intense discoloration and concentration. During a helicopter flight on 15 October, steamy lava fragments in this small area were observed. In the same area, during 15-17 October, frequent episodes of emission, forming big turbulent rings of gas and foaming, were observed on the sea surface. Since the night of 17 October, the amplitude of the tremor signal had decreased slowly. On 18 October, deformation further decreased and the sea-surface disruption from gases was not observed.
Source: Instituto Geográfico Nacional (IGN)
| 63.633°N, 19.083°W
| Elevation 1490 m
The Iceland Met Office reported increased seismic activity within Katla's caldera. Unrest was first noted in July, when a short-lived glacial flood burst from the Myrdalsjökull glacier that covers Katla occurred in connection with increased seismicity. Since then, several hundred micro-earthquakes had taken place within the area of the caldera. On 5 October an intense earthquake swarm was detected. Most of the earthquakes originated at 5 km depth; the largest one was approximately a M 3.7.
Source: Icelandic Met Office (IMO)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
KVERT reported that seismic activity at Shiveluch was moderate during 7-14 October. Ground-based observers noted hot avalanches from the lava dome and that plumes from those avalanches rose to an altitude of 5 km (16,400 ft) a.s.l. An ash explosion on 8 October produced an ash plume that rose to an altitude of 7 km (23,000 ft) a.s.l. Satellite imagery showed a daily thermal anomaly over the lava dome and ash plumes that drifted 160 km E on 6 and 8 October. The Aviation Color Code remained at Orange.
Based on information from KEMSD, the Tokyo VAAC reported that during 15-18 October eruptions produced plumes that rose to altitudes of 6.4-10.4 km (21,000-34,000 ft) a.s.l. An eruption on 16 October noted by KVERT produced a plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SE.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| Sumbawa Island (Indonesia)
| 8.25°S, 118°E
| Elevation 2850 m
CVGHM reported that during 22 September-9 October plumes did not rise from Tambora; seismicity fluctuated, but declined overall. Based on visual observations, deformation data, and seismicity, the Alert Level was lowered to 2 (on a scale of 1-4) on 9 October.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
| Kyushu (Japan)
| 31.593°N, 130.657°E
| Elevation 1117 m
Based on information from JMA, the Tokyo VAAC reported that during 12-13 and 15-18 October explosions from Sakura-jima produced plumes that rose to altitudes of 1.8-3.4 km (6,000-11,000 ft) a.s.l. and drifted SE and E. On 18 October a pilot observed an ash plume that rose to an altitude of 3 km (10,000 ft) a.s.l.
Source: Tokyo Volcanic Ash Advisory Center (VAAC)
| Chuginadak Island (USA)
| 52.825°N, 169.944°W
| Elevation 1730 m
AVO reported that during 12-13 October cloud cover over Cleveland prevented views of the lava dome in the summit crater. Partly cloudy satellite views during 14-18 October showed elevated surface temperatures from the crater indicative of continued growth of the lava dome. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| 14.473°N, 90.88°W
| Elevation 3763 m
INSIVUMEH reported that during 14-15 October explosions from Fuego produced shock waves that were detected nearby, rumbling sounds, and ash plumes that rose 700 m above the crater and drifted S. A small avalanche traveled S in the Santa Teresa drainage. Cloud cover prevented visual observations during 16-18 October; however, explosions and block avalanches were heard.
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 7-14 October and indicated that possible ash plumes rose to an altitude of 2.2 km (7,200 ft) a.s.l. Ash plumes possibly rose to an altitude of 3.8 km (12,500 ft) a.s.l. on 7 October. Satellite imagery showed a thermal anomaly on the volcano on 6 and 8 October. 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 12-18 October, 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 occasionally fresh spatter nearby. At the E rift zone, the fissure that formed on 21 September on the upper E flank of Pu'u 'O'o continued to periodically feed lava flows to the NE and SE of the fissure that did not significantly advance. Vents on the E and W edges of Pu'u 'O'o Crater floor were incandescent.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Eastern Kamchatka (Russia)
| 55.131°N, 160.32°E
| Elevation 2334 m
KVERT reported that during 7-14 October the magnitudes of the volcanic earthquakes at Kizimen decreased, as well as the numbers, from 500 to 100. Video data showed that a large lava flow on the NE flank continued to effuse and strong fumarolic activity was observed. A thermal anomaly on the volcano was detected daily in satellite images. 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, the Darwin VAAC reported that on 18 October ash plumes from Manam rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted 150-170 km NW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 0.38°S, 100.474°E
| Elevation 2885 m
Based on information from CVGHM, the Darwin VAAC reported that on 12 October an eruption from Marapi produced an ash plume that rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted E.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| 40.59°S, 72.117°W
| Elevation 2236 m
Based on seismicity during 11-12 October, 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. Plumes visible with an area web camera rose no higher than 4 km above the crater during 11-12 October. On 17 October a white plume rose 4.5 km above the crater and a diffuse ash plume observed in satellite imagery drifted 30 km SE. The next day, a white plume rose 3 km above the crater. Satellite imagery showed a plume drifting 50 km NE, and then later a diffuse ash plume drifting 200 km NE and SE. The Alert Level remained at Red.
According to news articles, several domestic and international flights in Argentina, Brazil, Chile and Uruguay were cancelled on 16 October due to re-suspended ash. OVDAS-SERNAGEOMIN also noted that there was not an increase in volcanic activity, but high winds in the region. Flights resumed the next day.
Sources: Servicio Nacional de Geología y Minería (SERNAGEOMIN), Associated Press
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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