"The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years--most recently, the Lassen Peak eruption of 1914-17 in northern California--and future volcanic eruptions are inevitable. Based on the record of volcanic activity over the last five millennia, the probability of another small- to moderate-sized eruption in California in the next 30 years is estimated to be about 16 percent. This is similar to the forecast for a magnitude 6.7 or greater earthquake specific to the San Andreas Fault in the San Francisco Bay region, which is estimated to be about a 22 percent probability in 30 years, starting from 2014 (Aagaard and others, 2016)."
Scientific Investigations Report 2018-5159
Geological Survey: http://pubs.usgs.gov/