#megathrust

William Andrew Connawilliamconna
2024-08-14

Orang pada omongin , kalo saya utamakan dekat kepada Tuhan. 😇

Smitha 🌸🌋🎻smitha@kind.social
2024-05-17

Really was not expecting to hear the name #Shimanto (AKA #KochiPrefecture) in a lecture about the #Cascadia / #JuanDeFuca fault.

The Shimanto Mountains were mentioned as an analog of our own #OlympicMountains - both are non-volcanic, near a #megathrust #SubductionZone (#NankaiTrough for Japan: major #earthquake every 100-200 years), and contain remnants of paleomegathrust (new fave word) fault lines thanks to historic and ongoing subduction.

As terrifying as it can be, I love #geology so much.

scinexx - das wissensmagazinscinexx@nrw.social
2023-10-23

Abgetauchte Vulkane lösen Erdbeben-Rätsel. Riesiges Wasserreservoir in subduziertem Vulkanplateau vor Neuseeland entdeckt. #Geologie #Neuseeland #Vulkane #Erdbeben #Megathrust #Subduktion
scinexx.de/news/geowissen/abge

HistoPol (#HP) 🏴 🇺🇸 🏴HistoPol
2023-04-16

@dustcircle

"Warm liquid spewing from seafloor comes from , could offer clues to hazards

"...hence increases the friction between the oceanic and .

“The fault zone is like an air hockey table,” ...“If the fluid pressure is high, it’s like the air is turned on, meaning there’s less friction and the two ..."

washington.edu/news/2023/04/10

2023-03-18

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

#BritishColumbia #Canada #PNW #PacificNorthwest #EarthquakeProofing #PlanningAhead #Cascadia #YVR

2023-01-11

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.

Fac-simile of Maria Graham's description of coastal uplift near Valparaiso in 1822Fac-simile of Charles Darwin's description of the uplift due to the 1835 earthquake
2022-11-21

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

Jascha Poletjascha
2022-11-18

Today’s M6.9 shallow (approximate location as purple blob) in the context of the areas of (numerous) previous events near on a map from Putra et al. (2016)

2022-11-18

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)

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