Earthquake/landslide coverage is excluded from your standard homeowners Fire insurance policy. And often the carrier that insures the home for fire, is not the best carrier to insure your home for Earthquake landslide. California law requires insurers to offer earthquake insurance, but often times we can find a less expensive policy from a specialty earth quake insurer.
Typical Deductible examples are like 20%
CAE - California Earthquake Authority http://www.earthquakeauthority.com/Pages/Calc.aspx
Geovera - Earthquake quote https://www.mygeosource.com/Quoting/Quote.aspx