During 26-31 October, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and low ash content. On 30 October, clouds with low ash content reached heights of 500-1,000 m above the volcano's crater (or 18,100-19,750 ft a.s.l.) and drifted W.
According to IG, an eruption began at Sierra Negra on the S end of Isabela Island on 22 October at 1730 when an explosion was heard by many people in the town of Villamil, 20 km SE of the volcano. The eruption was preceded by a seismic event on 22 October at 1438, and by earthquakes on 19 October and 2 weeks earlier. The Washington VAAC recorded an ash cloud on satellite imagery at 1745 at a height of ~15.2 km (50,000 ft) a.s.l. moving SW, and a very large hotspot.
Elevated seismicity below young volcanic vents on Tanaga Island continued during 21-28 October. Beginning on 24 October, AVO observed weak, nearly continuous volcanic tremor in the vicinity of Takawangha volcano of the Tanaga volcano cluster. This was the first time that tremor of this sort had been observed in the volcanic cluster since the seismic network was installed in 2003.
Growth of the new lava dome inside the crater of Mount St. Helens continued during 26-31 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.
Volcanic and seismic activity at Soufrière Hills remained at elevated levels during 21-28 October. On 26 October around 2400, a pyroclastic flow traveled ~2 km down the volcano's NE flank. The pyroclastic flow was confined to the Tar River Valley.
The growth of Shiveluch's lava dome continued during 21-28 October. Weak shallow earthquakes, hot avalanches, and low-intensity fumarolic activity occurred at the volcano during the week. On 22 and 24 October, incandescence was visible at the lava dome.
During 26-31 October, small-to-moderate explosions occurred at Santa María's Santiaguito lava-dome complex. Plumes were produced that rose to a maximum height of ~4.9 km (16,000 ft) a.s.l. on the 28th.
During 30-31 October, seismicity increased at Santa Ana. Volcanic activity appeared to slightly increase starting on 28 October. Sulfur-dioxide emission rates during 28 and 29 October averaged 257 metric tons per day.
Wed, 26 Oct 2005, 06:00
Based on information from IG, the Washington VAAC reported that ash was seen over Sangay on 26 October at 0758. No ash was visible on satellite imagery.
Read allWed, 26 Oct 2005, 06:00
GVO reported that as of 28 October Nyiragongo remained very active, but stable. There was a permanently active large lava lake in the volcano's crater. A gas plume was emitted from the volcano and incandescence was visible at night several tens of kilometers from Nyiragongo.
Read allWed, 26 Oct 2005, 06:00
Beginning on 23 October, GVO recorded heightened seismic activity along the East African Rift and around the Virunga volcanoes when a swarm of long-period earthquakes occurred N of Nyamuragira. More than 140 events were recorded at a station 19 km E of the volcano. On 27 October at 1500, another swarm of long-period earthquakes began beneath the same area.
Read allWed, 26 Oct 2005, 06:00
During 29-30 October, low-level eruptive activity continued at Manam with plumes visible on satellite imagery extending NW.
Read allWed, 26 Oct 2005, 06:00
On 29 October, a plume from Langila was visible on satellite imagery at a height of ~2.7 km (9,000 ft) a.s.l.
Read allWed, 26 Oct 2005, 06:00
Based on information from RVO and satellite imagery, the Darwin VAAC reported that on 25 October a pale gray ash cloud rose a few hundred meters above the summit of Garbuna, but no eruption was noted.
Read allWed, 26 Oct 2005, 06:00
During 26-31 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. Background volcanic tremor was near normal levels at Kilauea's summit. Volcanic tremor reached moderate levels at Pu`u `O`o.
Read allWed, 26 Oct 2005, 06:00
During 21-28 October, seismicity at Karymsky was above background levels. Based on interpretations of seismic data, five ash-and-gas plumes may have reached heights of 2.5-3.5 km (8,200-11,500 ft) a.s.l. on several days.
Read allWed, 26 Oct 2005, 06:00
An ash plume from Dukono was visible on satellite imagery on 27 October, extending NNW.
Read allWed, 26 Oct 2005, 06:00
During 26-31 October, several small eruptions occurred at Colima, with ash plumes rising as high as ~6.1 km (20,000 ft) a.s.l. on 27 October.
Read allTue, 25 Oct 2005, 14:12
Eruption of Sierra Negre volcano on 25 Oct. 2005 (Photo: Jorge Penafiel / El Universo)
The eruption is continuing from a fissure inside the E part of the caldera of Sierra Negre, with lava fountains up to 200 m tall and large lava flows that have now covered about 20% of the caldera floor. Good eruption viewing possibilities are from a lookout on the caldera rim in the El Cura area.
Mon, 24 Oct 2005, 15:49
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Eruption plume of the opening phase of Sierra Negra volcano on 23 Oct. 2005 (photo: Greg Arancea, published on "El Universo" newspaper)
First photographs and more detailed information about the large eruption of Sierra Negre are emerging. As on Monday, 24 October, lava flows from a fissure have travelled 9-10 km away from the fissure. The eruption is accompanied by strong lava fountains. Near the eruption site, the terrain consists mainly of older, unvegetated lava flows. Two flows are travelling towards Elizabeth Bay, while a third one is heading towards Cartago Bay, both uninhabited areas.
The popoluation of Puerto Villamil is not threatened because of its sheltered position at the S of the island.
Read allSun, 23 Oct 2005, 22:24
Sierra Negra volcano, also called "El Chico", on Isabela Island, Galapagos, erupted yesterday at 17h30 local time. As the Ecuadorian newspaper "El Universo" reports, an ash column estimated between 20 to 30 km high was observed. According witnesses from Santa Cruz island, two lava flows reached Elizabeth Bay, an uninhabitated settlement area close to the volcano. The island's main town, Puerto Villamil, 25 kilometers (15 miles) away, is not threatened by the eruption. Sierra Negro last erupted 1978.
Read allThu, 20 Oct 2005, 20:35
Volcanic activity at Erta Ale reported previously actually occurred at Dabbahu:
Read allThu, 20 Oct 2005, 20:29
Explosions and pyroclastic ejections continued at Dukono during 10-16 October. Ash columns rose 100-950 m above the summit (or 1,200-7,000 ft a.s.l.) and mainly drifted SE. Seismicity was dominated by explosion earthquakes. Dukono remained at Alert Level 2.
Read allWed, 19 Oct 2005, 17:45
This year's second eruption of Piton de la Fournaise volcano was ufficially declared to have ended today, after tremor had ceased abruptly yesterday at 13:10h local time on the 18th of Oct. 2005 while visual observations had yesterday not been possible due to bad weather.
Wed, 19 Oct 2005, 06:00
During 19-25 October, volcanic activity at Tungurahua remained at low levels with small emissions of steam, gas, and low ash content. Heavy rain caused lahars to travel down some of the gorges on the volcano's flanks. During the morning of 25 October a steam cloud was seen rising 200 m (660 ft) above the crater and drifting E.
Read allWed, 19 Oct 2005, 06:00
A large eruption began at Sierra Negra on 22 October. According to the Washington VAAC, the eruption began around 1645, sending an ash cloud to ~12.8 km (42,000 ft) a.s.l. that drifted SW.
Read allWed, 19 Oct 2005, 06:00
Elevated seismic activity below young volcanic vents on Tanaga Island continued during 14-21 October, although the rate of small earthquakes reduced in comparison to peak values during early October. An unusual, several minute-long seismic signal on 17 October may have been a landslide or small phreatic explosion, but satellite images detected no airborne ash. 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.
Read allWed, 19 Oct 2005, 06:00
Growth of the new lava dome inside the crater of Mount St. Helens continued during 19-25 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.
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