[SpicyUme]

Interesting, the idea that a fault is a more of a line source makes sense it is hard for me to think of a way to have a single point source slip with enough energy. I guess I've thought in subduction faults the depth of the slip might explain why there is a point source. For example in the Pacific Northwest the earthquake from the Juan de Fuca plate look to be substantially deeper than this one. (50km vs 10km) Of course I expect the depth from today to be preliminary and be adjusted later, I can see the extent of red region in the shakemap changed to be longer from when I looked at it an hour or two ago.

Do you know if the line source model comes from having more and better seismographs or has there been a change in how people think about the motion of a fault in an earthquake?