Kelut volcano (East Java, Indonesia): eruption update - ash plume drifting hundreds of km into the Indian Ocean
An important warning for aircraft using routes in this part of SE Asia was issued by VAAC Darwin. The eruption plume is well visible on satellite data.
According to VSI, the eruption started at 21:15 local time, following a rapid build-up in seismic activity during the same day. Monitoring staff were forced to evacuate their observation post as the eruption began to increase and a heavy rain of gravel-sized lapilli set in.
It is still unclear how large exactly the eruption was and what type exactly is was. An important question is whether fresh magma was involved (which seems rather likely) or whether it was phreatic (no new magma involved) and simply the result of a brutal release of pressure that had accumulated beneath the 2007 lava dome. In the first scenario, there would be a significant amount of fresh, viscous magma that has come to explosion. In this case, the eruption might still continue for a while, possibly with new violent explosions, until the portion of the new gas-rich magma that is able to erupt has been vented. It could then end with the emplacement of a new lava dome at the end of the eruption, corresponding to the last, relatively degassed magma that is able to reach the surface.
In the other case (no fresh magma involved) the eruption is likely to remain a single, short-lived event. Samples of the ash should help get a picture about the origin of the eruption.
Kelut is notorious among Indonesia's volcanoes for its violent, and often deadly explosive eruptions. One of the worst disasters occurred during the 1919 eruption, when the then very large crater lake drained and produced extensive mud-flows (lahars) that killed at least 5160 people. An eruption in 1586 is believed to have caused even more than 10,000 fatalities. The most recent prior explosive eruption in 1991 caused more than 50 deaths due to pyroclastic flows that swept down the flanks of the mountain. In contrast, the 2007 eruption was almost purely effusive and built a new lava dome, replacing the previous lake. This lava dome was with all likelihood completely destroyed during last night's explosion.
VSI raised the alert level to 4 (out of 4) and advises to stay at least 10 km away from the mountain. In particular, any valleys and low-lying areas should be avoided.
There are currently no reports about damage or fatalities.
Eruptive activity continued at least until the morning. Local newspapers reported heavy ash falls in areas up to 200 km distance and that the explosion sound was heard in Yogyakarta (170 km distance). The ash plume forced the closure of several important regional airports, including Yogyakarta, Solo, and Surabaya.
Links / Sources:
- Eruption of the Kelut volcano in Java, Indonesia (CIMSS Satellite Blog, with a great animation of the eruption plume seen on MTSAT)
CVGHM recommended that evacuees could return to their homes, but should stay clear of the mountain within a 3-km radius was restricted. [more]
The Center of Volcanology and Geological Hazard Mitigation (CVGHM) raised the altert status of Kelut volcano on 16 October from 3 to 4 (on a scale of 1-4). During 15-28 September, gas discharge from the crater lake increased and spread in a radius of 5 m. Inflation around the summit occurred during 13-16 October. On 16 October, the temperature in the crater lake increased to 37.8 degrees C.... [more]