The Geysers Geothermal Power Plant
Eruptions reader (and former hallmate at Oregon State) Ed Kohut sent me a message today pointing out that there is an ongoing earthquake swarm in the area of the Geysers in northern California. Now, I don't know what the normal seismicity is underneath the Clear Lake area and this area is part of the San Andreas fault system, so these earthquake are likely not volcanically related, but I post them here just as a reminder of how difficult it can be to deconvolve these geologic signals.
The Geysers are part of the Clear Lake volcanic region, which is still considered active, last having erupted in ~10,000 years ago, producing maars and tuff cones. The Geysers geothermal field is believed to be heated by a remnant silicic magma chamber under the Clear Lake area. The Geysers area is the largest producing geothermal field in the world!