mastouille.fr est l'un des nombreux serveurs Mastodon indépendants que vous pouvez utiliser pour participer au fédiverse.
Mastouille est une instance Mastodon durable, ouverte, et hébergée en France.

Administré par :

Statistiques du serveur :

649
comptes actifs

#megathrust

0 message0 participant0 message aujourd’hui

Work at the #PebbleHill #reservoir began in the fall of 2021 to prepare for #NaturalDisasters in the future.
Metro #Vancouver has been steadily #upgrading its reservoirs since the '90s to ensure it can provide #water to the region following the "#BigOne " — a #megathrust #earthquake expected to hit the #BCcoast someday.
cbc.ca/amp/1.6783105

CBCHow Metro Vancouver is earthquake-proofing its water reservoirs in preparation for the 'Big One'Par Yasmine Ghania

I am totally astounded by what I read when I compare these two texts: Maria Graham's description of the coastal #uplift due to the 1822 #Valparaiso #earthquake, versus Charles Darwin's text on very similar phenomena related to the 1835 #Concepción earthquake.

Read carefully, paying attention to the expressions used. It's like if #Darwin borrowed Maria Graham's words, but also her interpretation about the accumulation of earthquakes raising the coast on the long term. 🤔
Any comment ?

Both 1822 and 1835 earthquakes happened in Central #Chile on the #subduction #megathrust between Nazca and South America #tectonic_plates. Darwin's description, based on Fitz Roy (Beagle's captain) observations, is considered as seminal.

Thanks @haq for pointing me to the work by Maria Graham.

A magnitude Mw6.9 #earthquake offshore south-central #Sumatra.

Mechanism and location suggest rupture on the shallow part of the #subduction #megathrust close to the trench (on the very shallow dipping fault plane). However, modelled depth of ~19km, if true, seems little too deep given the closeness with the trench (USGS gives same depth and mechanism). This means that we cannot exclude a rupture on the steep fault plane within the oceanic plate.

Map with source time function from Geoscope IPGP
geoscope.ipgp.fr/index.php/en/
Larger map with epicenter of this event in red from USGS (both not yet on fediverse it seems)