Tsunami and earthquake damage can be both covered by insurance. As I mentioned before, though, you need to do some comparison shopping. Insurance agents will typically just sell one-size-fits-all packages that won’t necessarily cover your property in all the right ways.
Obviously if you customize your coverage your insurance premiums will be more expensive, so you may have to compromise somewhere. My recommendation is to talk to at least one specialist who can recommend special clauses related to earthquakes, tsunami and other potential risks specific to the property you’re going to buy. (I cover this in one of my blog entries, https://www.toshihikoyamamoto.jp/earthquake/.)
To Be Continued