On the morning of 23 Sept, an ash plume emitted by a strong explosion of Tungurahua volcano reached an altitude of 9 km a.s.l. (VAAC Washington). The geophysical institute of Ecuador reports increased levels of tremor and sulphur dioxide emission.
Seismic activity and lava extrusion from Mayon decreased during 6-12 September. Ground-deformation measurements showed an overall deflation. On 11 September, the Alert Level was lowered from 4 to 3 and around 30,000 people who had been evacuated early in August were allowed to return to their homes.
Phil went to the flows last night and reports the following: "...the lava is going off at the moment: Two entries still. E Ka`ili`ili has 6+ points of entry along the bench fed by at least 3 tube branches, with explosions and flying lava a common sight nowadays. Surface flows fairly extensive just a short distance inland and east, with lots of small breakouts over a tube branch that last week was feeding a flow onto the bench and into the ocean. There is a small, accessible skylight near the coast with clear views of fast-moving flowing lava and that amazing gurgling sound.
Two rivers of lava originate from a single point near the visible top of the pail, one flowing downhill to the east along the forest's edge, causing lots of smoke and visible flare-ups when trees would dry up enough to ignite, and the other flowing down to the west for the entire length of the pali, I perhaps up to a 1000 ft drop in elevation. Cheers, Phil"
Strombolian activity at the SE crater and lava emission from vents inside the crater continue at Etna volcano. Parts of the cone are collapsing, permitting viscous lava to flow out from the center.
The following in a detailed report published by the INGV Catania:
Visual observations show that the dome has grown substantially during the past week, with the main focus of growth being on the western part of the edifice. The two vigorous vents that opened on 31 August are still active. The one above the Gage’s wall is emitting a plume of hot gases, the more northerly vent, near the summit of the dome, is producing mostly ash and steam....more
Seismic tremor and emission of sulphur dioxide at Bromo is increasing and VSI set the alert level to 3 ("caution"). An eruption could be imminent. The last vulcanian eruption at Bromo occurred on 8 June 2004, killing two tourists who got surprised while on the stairs leading up to the crater rim.
Thick blocky lava lava continues to flow from Mayon volcano. The main active flow on the SE slope reaches about 800 m elevation where the flow front begins to disintegrate into loose blocks that roll into the Buyoan ravine.
Occasional explosions at Mayon continued during the past weeks. According to seismic data, four explosions were registered on 31 August. Ashfall was reported in surrounding cities including Tabaco (about 13 km NW) and Guinobatan (about 13 km SW). One small explosion was registered on 3 September.
Weak strombolian activity is ongoing at the SE crater. On the evening of 4 Sept. 2006 a fracture opened inside the crater and started to emit a lava flow into the collapse pit at the east flank of the cone.
Jorge Clavero, José A. Naranjo (Chilean Geological Survey) and Juan Cayupi (Chilean Emergency Office) sent the following report summarizing Lascar's activity over the past months:...more
On 1st Sept. 2006, the volcanological survey of Indonesia (VSI) issued a warning about famous Bromo volcano due to increased seismicity and raised the alert level from 1 (normal activity) to 2 (unrest).