Mount Semaru eruption (Indonesia)

[jim mcnamara]

TL;DR

Mount Semaru has erupted.

https://www.cnn.com/2021/12/04/asia/indonesia-mount-semeru-eruption-intl/index.html

There a short movie of what seems to be pyroclastic flow. Interesting and very scary at the same time.

 

[rsk]

Ooh! I have been fascinated by the canaries one for the last couple of months. WIll look out for this one as well now. This one sounds far more scary.

 

[berkeman]

Summary:: Mount Semaru has erupted.

There a short movie of what seems to be pyroclastic flow.

100-430km/hr?! Holy crap that's a fast flow...

 

[anorlunda]

100-430km/hr?! Holy crap that's a fast flow...

Yes, and tragically horrible for people trying to flee who can't move fast enough to survive. 57 people perished in the Mount St. Helen's eruption in 1980.

 

[Astronuc]

Mount Semeru’s deadly eruption was triggered by rain and storms, making it much harder to predict
The Conversation - https://theconversation.com/mount-s...torms-making-it-much-harder-to-predict-173240

Saturday’s eruption produced an ash plume that reached 15km into the atmosphere, along with hot pyroclastic flows – dense, fast-moving clouds of solidified lava, ash and gas. Volcanic mudflows called lahars also tumbled down the volcano’s steep slopes. Heavy ash blanketed nearby villages and plunged some areas into temporary darkness.

Several villages have been buried in up to 4 metres of volcanic material and debris, more than 3,000 buildings have been damaged, and Gladak Perak Bridge, which connected Lumajang with the nearby city of Malang, has collapsed.

The Volcano Observatory Notice for Aviation (VONA) has since reported further pyroclastic flows traveling down the the volcano’s slopes, and ash plumes reaching 4.5km above its summit. There are also reports of lava flows at the summit crater.

Saturday’s eruption was, unexpectedly, much larger than the ongoing background of activity. The Head of the Geological Agency of the Ministry of Energy and Mineral Resources, Eko Budi Lelono, said a thunderstorm and persistent rain had eroded part of the volcano’s lava dome – a “plug” of solidified lava at the summit. This caused the dome to collapse, triggering the eruption.

So it appears that the recent eruption of Mt. Seremu is an example of a 'phreatic eruption'
https://volcanoes.usgs.gov/vsc/glossary/phreatic_eruption.html
https://en.wikipedia.org/wiki/Phreatic_eruption
In - https://www.gns.cri.nz/Home/Learning/Science-Topics/Volcanoes/Types-of-Volcanoes-Eruptions
https://www.nps.gov/articles/000/phreatomagmatic-eruptions.htm

This mechanism could play a role in other active volcanoes, and perhaps had a role in the Mt. St. Helens eruption in March 1980.

CNN reports a similar story
https://www.cnn.com/2021/12/08/asia/indonesia-mount-semeru-volcano-eruption-cimate-intl/index.html