Robin Lacassin @RobinLacassin@qoto.org

@vickyveritas Here on qoto.org we don’t have this limit (max ~65000). I hope people on other instances can read my posts longer than 500… 🤞

Just received the big #climate book coordinated by Greta Thunberg @gretathunberg
Hours of interesting but frightening reading to come. Thanks in advance to all the authors.

@skanman Just to start I would recommend the books by Susan Hough:
• Predicting the Unpredictable: The Tumultuous Science of Earthquake Prediction
• Earthshaking Science: What We Know (and Don't Know) about Earthquakes

@skanman No. It's a recurrent question when #earthquakes happen grouped in time, but it's purely statistical.

There are between, let's say, 110 and 150 earthquakes with magnitude 6 to 6.9 each year (140 in 2021). In 2022 we got 113 so far, which is totally normal. Note also that no magnitude 8+ happened this year, which is low but also statistically normal.

Media often give the wrong impression of a temporary increase when several earthquakes happen in inhabited areas and are damaging. Media, and even geoscientists, generally do not speak of the numerous magnitude 5+ events (several per day) which is the magnitude of the Java #earthquake few days ago.

In 1999 the North Anatolian Fault (NAF), Turkey, broke during two destructive #earthquakes east of Istanbul (Mw7.4 Izmit and Mw7.2 Düzce earthquakes respectively on 17 Aug and 12 Nov).

Today's Mw6.1 #earthquake happened just east of Düzce with a faulting mechanism very similar to the 12 Nov 1999 event (strike-slip with small normal component). Its epicenter is located little to the north of the main NAF fault trace.

Map with MT and source function from #IPGP #Geoscope http://geoscope.ipgp.fr/index.php/fr/catalogue/description-d-un-seisme?seis=us7000irp8

Other map shows in red the fault broken by the two 1999 events (purple and red stars locate epicenters, yellow circles show aftershocks). From C ̧akir et al. GJI 2003 https://doi.org/10.1046/j.1365-246X.2003.02001.x.

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 🤓