EQ is earthquake. According to USGS, California faces a ~75% chance of a major earthquake in the next 100 years.

Have a quick google of “California quake risk” for a slew of in-depth (and somewhat scary) articles and research papers.

I would have thought California EQ was the peril scaring them all away. Very expensive to reinsure - most commercial property catasrophy models (RMS & AIR are the big ones) peg it as the second most risky North American peril after Florida Hurricane.