Indonesia tsunami from Krakatoa

[deaddirty]

Moe than 220 people have been killed by a tsunami that hit the shores of the Sunda Strait at night and without warning - Metalmachine has posted a vid of a rock concert being terminated as the tsunami bursts in from behind the stage.
Hardly surprising there was no warning as the tsunami seems to have been caused by an eruption of the Anak Krakatoa (son of Krakatoa) volcano which is only a few miles offshore. So no earthquake to be detected, and since the volcano was already erupting as it very often is there was no reason to think it might suddenly produce a tsunami that night.

Here's Anak Krakatoa smoking away in the middle of the huge caldera from the 1883 eruption of Krakatoa

and links to news article, timeline, and pics of the devastation;
https://www.theguardian.com/world/2...talities-as-tsunami-hits-beaches-in-indonesia
https://www.theguardian.com/world/l...d-hundreds-injured-after-anak-krakatoa-erupts
https://www.theguardian.com/world/gallery/2018/dec/23/arak-krakatoa-tsunami-in-pictures

And info on the 1883 mega-eruption:
https://en.wikipedia.org/wiki/Krakatoa
https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa
https://www.theatlantic.com/magazine/archive/1884/09/the-volcanic-eruption-of-krakatoa/376174/

 

[alexonedeath]

Thank you for this report, deaddirty, with it's many helpful links! I also appreciate your advising us of the live video from the rock concert, posted elsewhere. I might not have seen it otherwise.

 

[deaddirty]

Thanks Alex!
It's now confirmed that last weekend's tsunami was caused by an underwater landslide - aerial footage shows that the SW side of Anak Krakatoa has vanished -
https://www.theguardian.com/world/2018/dec/24/sunda-strait-tsunami-volcano-indonesia
And footage the day after the tsunami shows the whole volcano enveloped in pyroclastic flows pouring into the sea
https://www.theguardian.com/global/...volcano-erupts-before-and-after-tsunami-video
And latest news is that the threat level has been raised, with the exclusion zone and tsunami danger area extended and flights rerouted.
https://www.theguardian.com/world/2...r-anak-krakatau-volcano-as-eruptions-continue
https://youtu.be/Y6MNSG6z_Dg

So my guess is that there's some serious degassing of the magma chamber going on, and they're worried there may be a caldera collapse and/or seawater getting into the magma chamber and causing a major steam explosion.

 

[deaddirty]

Update:
Most of the volcano which had built up since 1927 has now gone - before last week it was about 400m high and 2km across, now it's about the same diameter but low, and the site of the former summit crater seems to be the current eruption centre in the sea in the last photos.

In 2008:


2011:


October 2018:


On 23rd or 24th December (ie just after the tsunami) - whole island enveloped in pyroclastic flows, clearly a lot going on but we can't see what shape the island is in):


And yesterday, 30th December - wow what a difference!: