Activity for the week of 26 September-2 October 2007
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
Jebel at Tair
| 15.55°N, 41.83°E
| Elevation 244 m
According to news reports, an eruption from the Jebel at Tair volcano was observed from several passing NATO ships on the evening of 30 September. Witnesses described a fissure eruption that produced lava fountains approximately 100 m high and ash plumes to a height of 300 m (1,000 ft) a.s.l. Multiple 1-km-long lava flows descended to the sea and a large landslide occurred on the W part of the island. Activity continued for at least two days.
The eruption prompted Yemeni authorities to evacuate about 50 soldiers from a military base on the island. A news article on 2 October reported that the Yemeni authorities lowered the death toll to three.
Two weeks prior to the eruption seismicity reportedly increased with earthquakes of M 2-3.6 recorded through 30 September.
Sources: Associated Press, Agence France-Presse (AFP), Agence France-Presse (AFP), IRIN News
| Eastern Java (Indonesia)
| 7.93°S, 112.308°E
| Elevation 1731 m
CVGHM reported that the Alert Status of Kelut was raised on 29 September from 2 to 3 (on a scale of 1-4) based on observations, increased seismic activity, deformation measurements, and changes of crater lake water chemistry and temperature. Villagers and tourists were advised not go within a 5 km radius of the active crater.
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Agence France-Presse (AFP)
| Bougainville (Papua New Guinea)
| 6.137°S, 155.196°E
| Elevation 1855 m
RVO reported that white vapor emissions from Bagana's summit crater continued during 24 August-30 September. Forceful emissions on 25 August and 12 September were occasionally accompanied by ash clouds produced by collapses at the edges of a lava flow on the SE flank.
Source: Rabaul Volcano Observatory (RVO)
| Paramushir Island (Russia)
| 50.324°N, 155.461°E
| Elevation 1781 m
KVERT reported that explosions from Chikurachki produced gas-and-ash plumes that were visible on satellite imagery and drifted ESE on 21 September. Clouds obscured views of the summit during 22-28 September. The Level of Concern Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| Eastern Kamchatka (Russia)
| 54.049°N, 159.443°E
| Elevation 1513 m
KVERT reported that seismic activity at Karymsky was above background levels during 21-28 September. Based on seismic interpretation, ash plumes may have risen to an altitude of 3.5 km (11,500 ft) a.s.l. during 20, 22, and 24-26 September. Observations of satellite imagery revealed that a thermal anomaly was present in the crater during 20-21 and 24-26 September and ash plumes drifted E during 24-27 September. The Level of Concern Color Code remained at Orange.
Based on information from KEMSD and pilot reports, the Tokyo VAAC reported that ash plumes rose to an altitude of 3.7 km (12,000 ft) a.s.l. on 28 September and 4.3 km (14,000 ft) a.s.l. on 2 October.
Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
HVO reported that during 26 September-2 October fissure segment D from Kilauea's 21 July fissure eruption continued to feed an advancing 'a'a lava flow that occasionally overflowed its channel edges. Lava flows that were advancing E and NE from the lower section of the channel shifted S during 26-27 September and burned a bit of kipuka (an "island" of vegetation) during 28 September-1 October. A few small earthquakes were located beneath Halema'uma'u crater, the summit area, and the S flank during the reporting period.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| New Britain (Papua New Guinea)
| 5.525°S, 148.42°E
| Elevation 1330 m
RVO reported that emission of ash and white vapor plumes from Langila's Crater 2 continued during 1 August-30 September. Ash plumes rose to altitudes of 1.8-3.3 km (5,900-10,800 ft) a.s.l. and drifted WNW. The ash emissions were occasionally accompanied by roaring and booming noises. On 8 August, a large explosion produced an ash plume that rose to an altitude of 5.3 km (17,400 ft) a.s.l. and drifted SW. Ashfall was reported in areas downwind. Incandescent fragments were ejected from the summit on 21 and 22 September. Crater 3 was quiet.
Source: Rabaul Volcano Observatory (RVO)
| New Britain (Papua New Guinea)
| 4.271°S, 152.203°E
| Elevation 688 m
RVO reported that ash plumes from Rabaul caldera's Tavurvur cone rose to altitudes of approximately 1.7-2.7 km (5,600-8,900 ft) a.s.l. and drifted N, NW, W and SW during 25-27 September and 30 September-2 October. Ashfall was reported from areas downwind, including Rabaul Town and Nonga. Roaring and rumbling noises occasionally accompanied the emissions. On 27 September, a large explosion was noted. During 30 September-2 October, incandescent fragments were ejected from the summit and rolled down the flanks.
Based on observations of satellite imagery, the Darwin VAAC reported that ash plumes rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 2 October.
Sources: Rabaul Volcano Observatory (RVO), Darwin Volcanic Ash Advisory Centre (VAAC)
| 14.757°N, 91.552°W
| Elevation 3745 m
On 25 September, INSIVUMEH reported that a lahar, about 18 m wide, descended S down Santa María's Nima I river.
Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
During 21-28 September, KVERT reported that seismic activity at Shiveluch was above background levels and hot avalanches occurred. Based on seismic interpretation, ash plumes rose to an altitude of 4.3 km (14,100 ft) a.s.l. on 20 and 25 September. Observations of video footage indicated that gas-and-ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. on 21, 24, 25, and 26 September. Plumes drifted E during 24-25 September. A thermal anomaly was present in the crater on satellite imagery during the reporting period. The Level of Concern Color Code remained at Orange.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
MVO reported that during 26 September-2 October the lava dome at Soufrière Hills changed very little, based on visual observations. Seismic activity was very low and low-level rockfall activity continued. On 26 September, lahars were noted in several drainages, including the Belham river valley to the NW. The Alert Level remained elevated at 4 (on a scale of 0-5).
Source: Montserrat Volcano Observatory (MVO)
| United States
| 46.2°N, 122.18°W
| Elevation 2549 m
Data from deformation-monitoring instruments indicated that during 26 September-2 October lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. Clouds occasionally inhibited visual observations.
Source: US Geological Survey Cascades Volcano Observatory (CVO)
| 1.467°S, 78.442°W
| Elevation 5023 m
IG reported that ash plumes from Tungurahua rose to altitudes of 6-7 km (19,700-23,000 ft) a.s.l. during 26 September-2 October and drifted SW, W, and NW. Ashfall was reported in areas to the SW, W, NW, on all days except 26 September. Roaring and "cannon shot" noises were occasionally heard from multiple areas. On 28 September, blocks were ejected above the summit and descended 500 m down the flanks.
Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)
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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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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