SNET reported that a sudden eruption at Santa Ana (also called Ilamatepec) on 1 October around 0820 produced an ash-and-gas plume to a height of ~10 km above the volcano (or 40,600 ft a.s.l.). According to the Washington VAAC, ash was visible on satellite imagery at a height of ~14 km (46,000 ft) a.s.l. Ash fell in towns W of the volcano, including in Naranjos, Nahuizalco, Juayúa, Ahuachapán, and La Hachadura.
A group of scientists assessed the visible changes at Erta Ale on 26 September after activity began around 24 September. In comparison to observations made in November 2004, they found that the southern main crater/pit had widened significantly, with portions of the previous crater walls having collapsed into the lava lake. A new cone-shaped construct had grown within the southern main crater where there had been a platform.
During 28 September to 3 October, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and variable ash content. A pilot reported an ash plume on 29 September at a height of ~6.1 km (20,000 ft) a.s.l.
Growth of the new lava dome inside the crater of Mount St. Helens continued during 28 September to 4 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 and the level of eruptive activity remained similar to previous weeks.
Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 23-30 September. Slow lava-dome growth continued at the volcano. The daily sulfur-dioxide flux averaged 950 metric tons per day (t/d), above the long-term eruption average of 500 t/d.
Growth of Shiveluch's lava dome and heightened seismicity continued at the volcano during 23-30 September. Weak gas-and-steam plumes, thermal anomalies at the lava dome, and new pyroclastic-flow deposits, were noted during the report week. Shiveluch remained at Concern Color Code Orange.
During 19-25 September, several small explosions occurred at Reventador. An explosion on 20 September produced an ash plume to a height of ~5.8 m (19,000 ft) a.s.l. Small amounts of ash fell in the towns of El Chaco, San Francisco de Borja, and Baeza.
On 1 October, a pilot observed ash from Manam below a height of ~3 km (10,000 ft) a.s.l. extending NW. Ash was not visible on satellite imagery.
Wed, 28 Sep 2005, 06:00
During 28 September- 2 October, lava from Kilauea continued to enter the sea at the East Lae`apuki area, and surface lava flows were visible on the Pulama Pali fault scarp. During the report period, background volcanic tremor was near normal levels at Kilauea's summit. Volcanic tremor reached moderate levels at Pu`u `O`o.
Read allWed, 28 Sep 2005, 06:00
A thin low-level plume from Dukono was visible on satellite imagery on 28 September extending NE.
Read allWed, 28 Sep 2005, 06:00
During 28 September to 3 October, several small explosions occurred at Colima. Based on information from the Mexico City MWO, the Washington VAAC reported that a plume was emitted on 28 September that rose to a height of ~6.1 km (20,000 ft) a.s.l. and drifted NNW.
Read allWed, 28 Sep 2005, 06:00
A cluster of earthquakes that had been recorded at Cayambe since 16 September, with about 300 small earthquakes occurring during 16-18 September, decreased in number significantly after 19 September. During 19-25 September, an average of 5.3 earthquakes occurred daily.
Read allWed, 28 Sep 2005, 06:00
Low-level plumes from Barren Island were visible on satellite imagery on 28 September and 2 October. The current eruption of Barren Island began on 28 May 2005.
Read allMon, 26 Sep 2005, 18:58
Erta Ale volcano in northern Afar, Ethiopia, well-known for its long-lived active lava lake that had occupied its crater up until 2004, erupted yesterday according to unconfirmed reports from local authorities. The eruption followed a series of earthquakes of up to 5.5. magnitude Richter scale that occurred in the area the day before.
Fri, 23 Sep 2005, 11:42
Shiveluch volcano started a new eruption on Thursday-Friday night. An ash plume has reached 7.5 km above sea level, and a lava flow is descending 15 km from the summit.
Read allWed, 21 Sep 2005, 06:00
Cloudy weather during 16-23 September prohibited web camera and satellite observations of Veniaminof, but seismic data indicated diminishing activity. Some minor ash emissions may have occurred, with diffuse ash plumes rising less than ~3 km (10,000 ft) a.s.l. Veniaminof remained at Concern Color Code Yellow.
Read allWed, 21 Sep 2005, 06:00
KVERT raised the Concern Color Code at Shiveluch from Orange to Red (the highest level) on 22 September. According to interpretations of seismic data, on the 22nd at 1715 a strong eruption began, with ash plumes reaching ~7.5 km (24,600 ft) a.s.l. [corrected by KVERT to 6.5 km (21,300 ft) a.s.l.] and hot avalanches and pyroclastic flows descending the volcano's flanks.
Read allWed, 21 Sep 2005, 06:00
According to unconfirmed reports from local authorities, Erta Ale began erupting on 24 September after a series of earthquakes occurred along the Afar western margin on the previous day. The earthquakes, with a maximum magnitude of 5.5, were recorded at the Geophysical Observatory of Addis Ababa University. A group of geologists and geophysicists were planning to travel to the field to make observations.
Read allWed, 21 Sep 2005, 06:00
During 21-26 September, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and variable ash content. A small amount of ash fell in the towns of Cusúa (NW) and Bilbao (8 km W of the volcano) during the morning of 21 September. Fumaroles on the outer edge of the crater were visible from Runtún after not being seen for 6 months.
Read allWed, 21 Sep 2005, 06:00
Based on information from JMA, the Tokyo VAAC reported that an emission from Suwanose-jima on 22 September reached a height of ~1.8 km (6,000 ft) a.s.l. and drifted W. Ash was not visible on satellite imagery.
Read allWed, 21 Sep 2005, 06:00
Growth of the new lava dome inside the crater of Mount St. Helens continued during 21-26 September, 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.
Read allWed, 21 Sep 2005, 06:00
Seismicity at Spurr during 16-23 September remained above background levels, but the overall rate continued to gradually decline. Preliminary data from a gas-sensing flight earlier in the week showed a substantial reduction in gas emissions compared to previous measurements taken in May 2005. The declining seismicity, reduced gas emission, and the changing summit-lake color (thought to reflect lower levels of acidity), all suggested a reduced level of volcanic activity.
Read allWed, 21 Sep 2005, 06:00
Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 16-23 September. Observations on 20 September suggested that slow lava-dome growth continued. The daily sulfur-dioxide flux averaged 680 metric tons per day (t/d), above the long-term eruption average of 500 t/d.
Read allWed, 21 Sep 2005, 06:00
During 21-26 September, seismicity and gas emissions were above normal levels at Santa Ana as they had been since 27 July. Microseismicity remained at relatively high levels. During the report period, gas plumes rose to a maximum height of ~1 km above the volcano (or 11,000 ft a.s.l.) on 26 September.
Read allWed, 21 Sep 2005, 06:00
During 21-27 September, there were intermittent emissions of ash from Reventador, with the highest rising plumes reaching ~8.5 km (28,000 ft) a.s.l. on 24 September. Hot spots were occasionally visible on satellite imagery during the report week.
Read allWed, 21 Sep 2005, 06:00
During 12-18 September, ash emissions continued at Rabaul caldera's active Tavurvur cone. Ash plumes rose 800-1,500 m above the volcano (or 4,900-7,200 ft a.s.l.) and drifted N and NW, depositing ash in most parts of Rabaul Town and beyond. Projections of incandescent volcanic material were visible at night during strong explosions.
Read allWed, 21 Sep 2005, 06:00
During 12-18 September, Manam's Main Crater continued to release weak emissions of ash. For a brief period on the 17th, a moderate amount of ash was emitted. Ash plumes drifted to the NW part of the island. Manam remained at Alert Level " Stage 1."
Read allWed, 21 Sep 2005, 06:00
During 12-18 September, Langila's Crater 2 continued to forcefully erupt ash at irregular intervals. The resultant ash plumes drifted NW and W. Incandescence and weak projections of volcanic material were visible on the evening of 13 September.
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