Robin Lacassin @RobinLacassin@qoto.org

Oh. I forgot to give the answer about the mysterious cartographic exercises from the previous post of this thread. Sorry.
Here they are 👇🏼

In a recent Science paper, Proud et al. estimated that the Hunga Tonga-Hunga Ha’apai volcanic plume reached an altitude of 57km "well past the stratosphere and into the mesosphere and higher than any volcanic plume previously recorded".

They used geostationary weather satellite imagery. The different satellites recorded the #volcano eruption with multiple viewing geometries. This allowed the researchers to compute plume altitude based on the parallax effect.

https://www.science.org/doi/10.1126/science.abo4076

NIWA also made an excellent video explaining their research on the Hunga-Tonga Hunga-Ha'apai #volcano.

https://youtu.be/xYhCEeIO25k

New Zealand's National Institute for Water and Atmospheric Research (NIWA) press release about January Hunga-Tonga #volcano eruption. https://niwa.co.nz/news/tonga-eruption-confirmed-as-largest-ever-recorded

"Hunga-Tonga Hunga-Ha'apai (HT-HH) emitted the biggest atmospheric explosion recorded on Earth in more than 100 years (…) almost 10km3 of seafloor was displaced (…) the caldera, or crater, is now 700m deeper than before the eruption."

"NIWA scientists have also unravelled one of the biggest unknowns of the eruption – the pyroclastic flows (…) Samples showed [underwater] pyroclastic deposits [at least] 80km away from the volcano."

Magnitude Mw 7 #earthquake offshore #Guadalcanal island in #Solomon archipelagos. Small #tsunami waves in Honiara on other side of the island.

There, at the San Christobal trench, the Australian plate is subducting beneath the Solomon arc.

Moment tensor solution ("beach ball" on the map) implies rupture either on a vertical fault or a nearly horizontal one. More data and models will be needed to understand if the earthquake happened on the subduction megathrust or within the downgoing plate.

MT and source function from http://geoscope.ipgp.fr/index.php/en/catalog/earthquake-description?seis=us7000irfb
Sea level graph from https://webcritech.jrc.ec.europa.eu/SeaLevelsDb/Device/1695

"Tonga's strange volcanic eruption was even more massive than we knew", by Maya Wei Haas in National Geographic

https://www.nationalgeographic.com/science/article/tonga-volcano-largest-eruption-pacific-ocean-tallest-plume

I finally succeeded to get the green "verified" mark 😆

First I started pasting the html instruction not into the head and in the wrong file. Nothing happened. When I put it at the root of my personal IPGP page (in index.html) it suddenly worked 🤓

This recalls that even in contexts like #Java or #Sumatra, where the #subduction #megathrust may produce very big #earthquakes, much smaller shallow crustal ruptures may present significant hazards because closer to towns.
2/2

Today's #earthquake in W Java has a strike-slip mechanism according to moment tensor solution by BMKG, Indonesian Meteorology, Climatology, and Geophysical Agency - https://inatews.bmkg.go.id/

See map 👇🏼 with the "beach ball" showing the fault mechanism with two possible very steep fault planes.

Hypocenter shallow depth ~11km and closeness to Cianjur town (less than 10km), where damages are reported, likely explains its destructive character. Strong shaking also reported in Jakarta at ~80km from the epicenter.

According to posts on twitter, there are significant damages and at least 2 fatalities after a moderate magnitude M5.6 #earthquake in western Java island, Indonesia. Inland shallow fault rupture, close to towns, likely explain the destructions.

RT 👇🏼 https://twitter.com/BNPB_Indonesia/status/1594596756205244418?s=20&t=N0QFeOPMmCQp1ReAfiCnjw
and
https://twitter.com/pamumpuni/status/1594599955037028354?s=20&t=N0QFeOPMmCQp1ReAfiCnjw