My concern is not Obsidian Butte, but the Laguna Salada fault zone. This fault zone produced a 7 plus magnitude quake in 1892, and would be very serious now. The proximity of the quakes in Obsidian Butte also has me concerned about the southern end of the San Jacinto and Coyote Creek faults. The recent activity in Anza is another concern. The recent swarm in Mexicali and Obsidian Butte is like a double wammy, I guess. Seems like a lot of activity out there recently.

glen