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Lucy Jones
@drlucyjones.bsky.social

This doesn't look like fault movement. Notice the crack forms in the concrete but doesn't offset the edges. This looks like shaking compacted the ground under the concrete and caused a crack.

Ryan J Hollister
@phaneritic.bsky.social

That was my first response… but then I watched it again when other seismo folk were excited. Try watching it again and ignore the foreground and look at the mound of brown behind the arched gateway-or anything to the right of the right fence. Just pick a single reference point and then you’ll see it

Tim Dawson
@timblor.bsky.social

I posted these zoomed in screenshots earlier and annotated them to help people see what is moving in a right-lateral sense. Note how pot A’ has slid past pot B in a right lateral sense, roughly 2-3 meters is my guess.

Paul Byrne
@theplanetaryguy.com

Yep. Often "P" is taken to mean "primary" and "S" for "secondary", on the basis of their relative arrival times (although often also used for "pressure", with its counterpart being "shear", given their longitudinal and transverse natures, respectively).

Kade Peregrine
@kadeperegrine.bsky.social

Wow. I've been playing with a tectonics mapper for world building. It's got this table for velocity magnitude. How far a plate moves over time. Values like 3cm per year are something I know about but somehow I didn't think the landscape could just jump a foot in 10 seconds.

Dilong
@dilong.bsky.social

Yeah that's pretty much how quakes work! The plates would like to slide smoothly past each other but they get stuck together and that (up to) 3cm/year just builds up as stress for decades or centuries until something gives and it slides meters in a minute or so.

Dilong
@dilong.bsky.social

There are lots of places where the slip is smooth (no quakes), like deep in the earth (too goopy) or some surface faults where conditions are right (I know of one in California). There's also places with tremor and slip where there are 100s of tiny quakes in swarms instead of single big ones

Maria Elena
@mariaerj.bsky.social

Fascinating. I was about 25-30 miles from the Loma Prieta epicenter in 1989. My house was structurally ok (things broke) but SF and Oakland had terrible damage farther away. I've seen a park along the San Andreas Fault where an old wooden fence is no longer aligned due to slip like in this video.

Morse Moose
@jerrywright.bsky.social

Wow! I keep rewatching and noticing more details... the top getting torn off the transmission tower on the right, the building in the upper left getting wrecked, the concrete cracking in the foreground. Unbelievable!

Ryan
@rgriffin37.bsky.social

I work in the geospatial field and all I can think of (beyond the obvious destruction) is how any existing mapping would become wildly less accurate in the span of a few seconds. I'm not sure if Myanmar has much in the way of terrain maps but a wild shift like that would wreak havoc. Crazy to watch.

Paul Byrne
@theplanetaryguy.com

Yes, absolutely. In fact, precision GPS (or satellite-based positioning systems more generally) is one of the main methods to track and characterise surface ruptures from quakes. If you mean whether maps will have to be redrawn, probably not—this rupture was "only" a few metres.

Zhanael
@zhanael.bsky.social

I just wish there was sound! I can't imagine what sort of sounds that kind of activity would make. Stone grinding on stone? A massive crack as the rupture appeared??

Aevs 🔜 NFC!
@aevs.bsky.social

This is LEGITIMATELY jaw-dropping. All I really noticed at first were the cracks in the pavement, but then when I put it in 2x speed I literally said "What!!" out loud! What!!!