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Paul Byrne
@theplanetaryguy.com

I don't remember seeing the *formation* of a surface rupture like this before. This was a 7.7 Mw quake near Thazi in Myanmar on 28 March 2025. The fault rupture was strike-slip at a depth of 10 km, likely along a N-striking fault. Video credit: GP Energy Myanmar (h/t @longhairnasaguy.bsky.social)

3 reposts115 likes

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).