Activity for the week of 25 September-1 October 2002
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
| Hawaiian Islands (USA)
| 19.475°N, 155.608°W
| Elevation 4170 m
HVO reported on 30 September that a pattern of slow deflation occurring at Mauna Loa for the past 9 years abruptly changed in mid-May when the summit area began to slowly swell and stretch. Global Positioning System measurements revealed that distances across the summit caldera (Moku`aweoweo) have been lengthening at a rate of 5-6 cm per year, and the caldera has widened about 2 cm since 12 May. The summit area was slightly higher than before mid-May, consistent with swelling. In addition, the upper part of the SE flank showed outward movement. Seismicity remained low at Mauna Loa, although it may have been slightly higher level than during the pre-inflation interval.
Sources: US Geological Survey Hawaiian Volcano Observatory (HVO), US Geological Survey Hawaiian Volcano Observatory (HVO), Associated Press
| Sangihe Islands (Indonesia)
| 2.3°N, 125.37°E
| Elevation 725 m
VSI reported that following the 25 September Ruang eruption there was no significant volcanic activity; only thin white clouds rose 100 m above the summit. On 30 September VSI decreased the Alert Level at Ruang from 4 to 3 (on a scale of 1-4).
Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)
| Hawaiian Islands (USA)
| 19.421°N, 155.287°W
| Elevation 1222 m
During 25-30 September at Kilauea, lava continued to travel SE down Paliuli and Pulama pali, and surface lava flows were visible on the coastal flat. Lava entered the sea at multiple points along the fronts of two lava deltas and visitors saw several sudden collapses of the front of the bench (land built out from the sea cliff). Generally, seismicity was at normal levels. The swarm of long-period earthquakes and tremor beneath Kilauea's caldera that originally began in June was fairly weak. Periods of small deflation and inflation occurred at Uwekahuna and Pu`u `O`o tiltmeters, but no significant deformation was recorded elsewhere.
Source: US Geological Survey Hawaiian Volcano Observatory (HVO)
| Central Kamchatka (Russia)
| 56.653°N, 161.36°E
| Elevation 3283 m
During 20-27 September, volcanic and seismic activity at Shiveluch were above background levels. There were four earthquakes with magnitudes 2-2.1, and many smaller ones. Seismic data indicated possible avalanches and ash-and-gas explosions that may have sent material to 5.5 km a.s.l. On 25 September continuous spasmodic volcanic tremor was recorded for 27 minutes. Short-lived gas-and-steam plumes were observed rising to 6.5 km a.s.l. Thermal anomalies were visible on satellite imagery during several days, but ash was not. Shiveluch remained at Concern Color Code Yellow.
Source: Kamchatkan Volcanic Eruption Response Team (KVERT)
| 16.72°N, 62.18°W
| Elevation 915 m
During 20-27 September, activity at Soufrière Hills' dome complex increased in comparison to the previous week, with a major change in direction of extrusion following a hybrid earthquake swarm the previous week. Growth of the previously active NE lobe stagnated during the 21st to 22nd. A near vertical spine was extruded in the central area around the 21st, possibly indicating a switch in growth direction. Observations on the 26th revealed a large new lobe that had extruded towards the W in the area previously known as Gages Wall. Material spalling off of this lobe produced rockfalls and small pyroclastic flows down Gages Valley for up to 1 km. The most notable events were pyroclastic flows on the evening of the 25th and the morning of the 27th. Growth and rockfall activity then changed towards the northern flanks, suggesting a possible stagnation of the recently extruded western lobe. Spectacular incandescence and semi-continuous rockfall activity were observed on the NE and N flanks of the dome on the night of the 26th and the early hours of the 27th. The Washington VAAC reported that a low-level ash cloud from an emission on the 29th at 1510 was visible over E Puerto Rico on satellite imagery through the following day. On the 30th a light dusting of white ash fell in E Puerto Rico at Roosevelt Roads Naval Air Station.
Sources: Montserrat Volcano Observatory (MVO), Washington Volcanic Ash Advisory Center (VAAC)
| 1.467°S, 78.442°W
| Elevation 5023 m
During 25 September-1 October, emissions of steam, gas, and ash continued at Tungurahua. Ash was seen rising to a maximum height of ~7 km a.s.l.
Source: Washington Volcanic Ash Advisory Center (VAAC)
| New Britain (Papua New Guinea)
| 5.05°S, 151.33°E
| Elevation 2334 m
On 28 September around 0400 an eruption occurred at Ulawun that produced an ash-and-steam cloud to ~3.7 km a.s.l. The cloud was visible on satellite imagery at 0632 drifting WSW.
Source: Darwin Volcanic Ash Advisory Centre (VAAC)
| United States
| 56.17°N, 159.38°W
| Elevation 2507 m
AVO reported that seismic unrest that began at Veniaminof on 10 September continued through the 27th. The intensity of tremor and small earthquakes under the volcano had decreased since the 10th, but remained above the background level established during the summer of 2002. Visual observations of Veniaminof were hampered by poor weather. On 24 September, residents of Perryville, 35 km S of the volcano, reported and photographed small bursts of steam, possibly containing minor amounts of ash, rising just above the historically active intracaldera cinder cone. Without additional observations, AVO could not determine if this indicated very low-level eruptive activity or vigorous steaming from the cone. On several occasions of relatively clear weather conditions, AVO observed no signs of elevated temperature or ash emission on satellite imagery. Due to the continuing seismicity and reports of unusual steaming, the Concern Color Code remained at Yellow.
Source: US Geological Survey Alaska Volcano Observatory (AVO)
| New Britain (Papua New Guinea)
| 5.576°S, 150.516°E
| Elevation 724 m
As of 30 September seismicity remained at low levels at Pago and lava continued to flow from the northeastern-most vent of the fissure system. A significant lava field had developed, with all lava flows contained within the caldera. Incandescence was visible at the lava-flow front.
Sources: The National, US Geological Survey
Weekly Reports Archive
|Antillanca Volcanic Complex
||Huila, Nevado del
||Hunga Tonga-Hunga Ha'apai
||Soufriere St. Vincent
||South Sarigan Seamount
||Tair, Jebel at
|Campi Flegrei del Mar di Sicilia
|Chillan, Nevados de
||Kick 'em Jenny
|Dieng Volcanic Complex
||Rincon de la Vieja
|Etorofu-Yakeyama [Grozny Group]
||Ruiz, Nevado del
||Lengai, Ol Doinyo
|Fournaise, Piton de la
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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:
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An RSS (Really Simple Syndication) feed for the Weekly Volcanic Activity Report first made available on 5 March 2008 can be utilized with the aid of various free downloadable readers. The report content of the news feed is identical to the Weekly Volcanic Activity Report minus some features including the header information (latitude and longitude and summit elevation), the Geologic Summary, and a link to the volcano's page from the Global Volcanism Program. Each volcano report includes a link from the volcano's name back to the more complete information in the Weekly Volcanic Activity Report on the Smithsonian website. On 12 March 2009, GeoRSS tags were added so that the latitude and longitude for each volcano could be included with the feed.
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