Geology & Earth Science

Earthquake Focal Mechanism

sign(sin 2θ) double-couple radiation

A fault's slip radiates first-motion into four alternating quadrants — compressional (push) and dilatational (pull) — and plotting them makes the classic 'beach ball' whose black-and-white lobes reveal the orientation of the rupture.

Computed & rendered in pure C# on the frozen OnlyCSharp 1.8 library — animation baked to GIF with the library's own Gif encoder (no GPU, no ffmpeg, no external packages).