LA Native here for 54 years.
The LA real estate market is quite diverse. Pasadena market is different than the Westside, and much different than the San Fernando Valley. I live in the South Bay area and it is a great place to raise a family. Schools that are not part of LA Unified School District. Small cities with NIMBY groups that keep the areas liveable. Much less homelessness. Drawbacks: it is far from a lot of the key employment hubs, like downtown, the studios, the universities.
LA real estate took a big hit in the late 80's when the defense industry took the cold war "peace dividend". When I grew up in the 70s, half the dads of my classmates worked in the defense industry. Right now there is a boom on the westside driven by Google, Hulu, and others as part of "Silicon Beach". Prices in Westchester and El Segundo are just crazy. Building in Marina del Rey is out of control, as is traffic. Santa Monica streets are often at a standstill.
The other boom we are seeing is in Hollywood. More money is being spent on new TV production than ever before, and it's not close. The streaming wars have created so much new content (that nobody is watching), with much of that production in the LA area. It isn't sustainable, but LA is much more diversified than it was in the 80's. If the tech boom AND the TV production boom collapsed at the same time, you would see an impact.
As for earthquakes, it depends on where you live. After every major earthquake the building codes get better (and more expensive) as they learn more about what survives and what doesn't. For the most part, single family houses won't be a problem. The Northridge earthquake in '94 was a 6.7. Only 1000 homes were "red tagged" and had to be replaced. 6000 were yellow tagged and could be repaired. This is out of 1.7 million SFH in LA County. Earthquake insurance usually has a 15% deductible, so a $500,000 structure value (typical for a 1.5m house) would be $75,000. My location in the south bay and the high deductible has meant I have never bought earthquake insurance in my 30 years of home ownership. I might feel differently if I lived in Sylmar, or even Palm Springs (much closer to high risk faults).
Don't buy a house in the LAUSD unless you plan to send your kids to private school. Catholic schools are suffering from low enrollment these days and are a great value if you are either Catholic or you don't mind a little religion in their lives. At the High School level, the religion is greatly reduced and I could recommend a lot of great catholic High Schools, ranging from $10,000 - $20,000 per year. Non religious schools will run double that. Great practice for paying college tuition
As others have said, this is a lifestyle choice not a financial choice. With a 15 year time horizon you should do fine as long as you buy in a good area. Historically the upper middle market has held its value best. High end and low end tend to get clobbered in downturns here.