Many modern buildings are designed to withstand earthquakes of some magnitude; this is what reasonable prevention means.

You can’t prevent any natural force unless your uncle knows god (and is on good terms with them). What was stated was the ‘reasonable prevention of damage’. insurance companies that sell earthquake insurance won’t insure buildings that are not up to code, which in turn is based on locally expected disasters, their expected commonality, their expected severity, and what is considered to be reasonable measures for the prevention of damage (or an excess of e.g. mitigation).

For example, where I live you can’t get hail insurance unless you have impact resistant shingles. I had and have exactly that so I got hail insurance; after a particularly bad hail storm (and 8 previous years of wear) I filed a claim and had my entire roof redone at my insurer’s expense. I was kind of surprised how straight forward the process was and the stark absence of bullshittery, but I may have just gotten lucky. The area I’m in gets a lot of hail so it may also be in the insurer’s best interesting not to get a name for denying for hail damage.