This icon is based ancient Japanese folklore, which held that earthquakes were caused by the thrashing of a giant catfish ("Namazu") beneath the ground (e.g., see the book Earthquakes by B.A. Bolt). The hook symbolizes that OpenSHA is in some sense trying to catch earthquakes.

This logo was conceived and constructed by Ned Field. The catfish and building were drawn by Mike Rider Illustration, and the liquid-style coloring was created using the Aquatint shareware.