I've always had earthquake insurance on my house and was surprised to learn that only 20% of  Oregon homeowners have coverage.  A number of insurers have withdrawn from the Oregon earthquake marketplace and I am on my third or fourth insurer in 20 years.  But, for $500 a year, it provides with me with peace of mind and I am happy to pay this modest premium.   If we had significant small earthquakes that might portend "the big one" then insurers might decline to write any new coverage at all.  It's all about the risk assessment.  I suggest that any homeowner worried about the 40% chance of a level 9 quake in the next 40 years make application for coverage sooner rather than later.