Volcanic activity at Erta Ale discussed in the 5-11 October 2005 Weekly Volcanic Activity Report actually occurred at Dabbahu. The correct report is below.

A team of scientists visited the Da'Ure locality immediately adjacent to the NE flank of the Quaternary Dabbahu (or Boina) felsic complex on 4 and 5 October after receiving reports of volcanic activity there on 26 September. People in the area noted that on 26 September at about 1300 a very strong earthquake shook the area, and was followed by a dark column of "smoke" that rose high into the atmosphere and spread out to form a cloud, which darkened the area for 3 days and 3 nights. The scientists determined that a minor explosive eruption occurred from two semi-circular vents, producing ashfall that was ~5 cm thick near the vent. Ash deposits extended more than 500 m from the vent. Boulders emitted during the eruption were as large as 3 m and were deposited as far as 20 meters away. The scientists noted intense degassing from the vents, the scent of sulfur dioxide, and the sound of boiling water in the vents. As of about 10 October, the Addis Ababa University Geophysical Observatory reported that seismic activity in the area was continuing.

Source: Gezahegn Yirgu, Department of Earth Sciences, Addis Ababa University

RVO reported that an eruption began at Garbuna on the afternoon of 16 October when "white vapor" rose above the volcano and a couple of felt earthquakes occurred. On 17 October, an eruption column rose 3-4 km above the volcano's summit (or 11,700-15,000 ft a.s.l.). At 1100 fine ash fell on the W and NW sides of the volcano, covering two plantations. Water sources originating from Garbuna were affected by the eruption. According to RVO, the volcano last erupted about 1,700 years ago.

Sources: Rabaul Volcano Observatory (RVO), The National, Darwin Volcanic Ash Advisory Centre (VAAC)

After a brief ash burst at Cleveland on 7 October, no further eruptive activity was recorded at the volcano. On 10 October, AVO reduced the Concern Color Code from Orange to Yellow. AVO warned that although there were no additional ash bursts noted, they consider the volcano restless. Explosive ash-producing events could occur at any time and without warning (owing to the lack of local seismic monitoring). AVO continued to monitor the volcano using satellite imagery.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

Explosions and pyroclastic ejections continued at Dukono during 10-16 October. Ash columns rose 100-950 m above the summit (or 4,200-7,000 ft a.s.l.) and mainly drifted SE. Seismicity was dominated by explosion earthquakes. Dukono remained at Alert Level 2.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

According to the Mt. Erebus activity log, several "small- to medium-sized" eruptions occurred during 12-18 October, with a "very large" eruption occurring on 14 October. The eruption sizes were based on comparisons of seismic data for known Erebus eruptions.

Source: Mount Erebus Volcano Observatory

Gas was emitted from Karangetang's North and Batukole craters during 10-16 October. Seismicity was dominated by multiphase events, which decreased in number in comparison to the previous week. The number of deep volcanic earthquakes increased. Karangetang remained at Alert Level 3 (on a scale of 1-4).

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

On 18 October, weak surface lava flows were visible at Kīlauea and one cascade of lava flowed off of the western front of the East Laeʻapuki delta. Background volcanic tremor was near normal levels at Kīlauea's summit. Volcanic tremor was at moderate levels at Puʻu ʻŌʻō. During 11-18 October, small amounts of inflation and deflation occurred at the volcano.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

An ASTER satellite image from 23 September showed a 3.5-km-long lava flow extending from the summit of Montagu Island (Mt. Belinda) into the sea. This was the largest effusive event observed during the 4-year-old eruption. Based on MODVOLC alerts, the flow appeared to have started sometime between 10 and 14 September. A conspicuous 90-m-wide channel was visible ~1 km from the vent. The image also showed a steam plume at the location of the ocean entry, and an ash-rich plume extending NE from the volcano's summit.

Sources: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team, British Antarctic Survey

SNET reported that activity had not changed at San Miguel after small clusters of earthquakes occurred at the volcano during 27 September to about 14 October. During a visit to the volcano on 13 October small rockfalls were seen, but there were no significant changes in the crater and sulfur-dioxide emissions were very weak.

Source: Servicio Nacional de Estudios Territoriales (SNET)

An ash plume emitted from Sangay was visible on satellite imagery on 16 October around 0645. The plume moved SSW very slowly, corresponding to a possible height of ~6.7 km (22,000 ft) a.s.l. By 0900 the plume was too thin to be visible on satellite imagery and thunderstorms developed in the area, further obscuring the ash cloud.

Source: Washington Volcanic Ash Advisory Center (VAAC)

During 12-17 October, seismicity was relatively stable and there were low-level gas emissions at Santa Ana. Storms on 12 October caused the generation of lahars that traveled towards Coatepeque.

Source: Servicio Nacional de Estudios Territoriales (SNET)

The first MODVOLC alerts at Mount Michael since May 2003 recently began, indicating an increased level of activity in the island's summit crater (and presumed lava lake). The alerts occurred on 3, 5, and 6 October.

Sources: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team, British Antarctic Survey

Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 7-14 October. Lava-dome growth mostly occurred on the W side of the dome, which was largely obscured by clouds and steam. Observations suggested that the lava-dome growth rate increased, with preliminary calculations suggesting a rate of at least 2 cubic meters per second. Incandescence was visible at the lava dome on a video camera at night. The sulfur-dioxide flux averaged 580 metric tons per day (t/d), above the long-term eruption average of 500 t/d. The hydrogen-chloride versus sulfur-dioxide ratio increased to about 1.

Source: Montserrat Volcano Observatory (MVO)

Growth of the new lava dome inside the crater of Mount St. Helens continued during 12-18 October, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. There were no significant changes in seismicity or deformation during the report period. During the previous few weeks, a prominent linear feature developed on the disintegrating "whaleback" that grew during the previous spring and summer and was currently located E of the actively growing part of the new lava dome. A digital elevation model of the active lava dome, which was created from aerial photographs taken on 10 August, showed that the volume had grown to 62 million cubic meters. The average rate of growth during late July and early August was about 2 cubic meters per second, a rate that typified most of 2005. St Helens remained at Volcano Advisory (Alert Level 2); aviation color code Orange.

Source: US Geological Survey Cascades Volcano Observatory (CVO)

A plume emitted from Stromboli that may have contained ash was visible on satellite imagery on 14 October at a height around 1.8-2.4 km (6,000-8,000 ft) a.s.l. The plume extended ~10 km NW of the volcano.

Source: Toulouse Volcanic Ash Advisory Centre (VAAC)

Elevated seismic activity below young volcanic vents on Tanaga Island continued during 7-14 October, although the rate of small earthquakes reduced slightly in comparison to the previous week. The activity that began at Tanaga on 1 October was at the highest level recorded since the seismic network was installed in 2003, so the Concern Color Code remained at Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)