You can break a lease whenever you want. Generally the most you can lose is the deposit plus rent until the unit can be filled. Compared to the transaction costs of selling a house it's negligible.
The concern about the place being damaged/destroyed by an earthquake is a big one in California. Unlike fires, earthquakes are not covered by standard home insurance. And standalone earthquake insurance is prohibitively expensive for many (less than 1/5th of CA homeowners have it). Add to that the fact that (again, unlike a fire) an earthquake is likely to damage many homes in the same area at the same time which will inflate the cost to rebuild in a timely manner and you start to see the large amount of risk many owners are exposed to here.
The concern about the place being damaged/destroyed by an earthquake is a big one in California. Unlike fires, earthquakes are not covered by standard home insurance. And standalone earthquake insurance is prohibitively expensive for many (less than 1/5th of CA homeowners have it). Add to that the fact that (again, unlike a fire) an earthquake is likely to damage many homes in the same area at the same time which will inflate the cost to rebuild in a timely manner and you start to see the large amount of risk many owners are exposed to here.