The M3s made me notice a large swarm of M1s at the south coast of Salton Sea. The other night I watched part of the old Roger Moore James Bond "A view to a Kill" where the bad guy was pumping water into the Hayward fault trying to set it off along with the San Andreas to flood silicon valley. A Bond-Girl geologist figured it out.

There is a lot of geothermal production near Obsidian Butte and a lot of fluids being pumped in and withdrawn. There is a scientific core hole (drilled in 70s?) where sediments are being metamorphosed (cooked) at unusually shallow depths...2 or 3 km.

It is well understood that fluid pressure affects fault strength.
Chris