An earthquake in an specific region or area won't have any impact over Bitcoin's prominence in the mainstream world. The fact that the Blockchain is distributed across many countries worldwide, tells us that Bitcoin will last regardless of situations occurring in a designated area. Unless a massive EMP strike or a worldwide earthquake takes place in the mainstream world, Bitcoin won't be going anywhere anytime soon.

While the network will still operate as usual, people living on a country affected by an earthquake will certainly find challenging to get access to Bitcoin due to lack of power and Internet access. In the case of traditional Fiat, it'll still be possible to participate in the mainstream economy by using paper money. There are solutions to use Bitcoin offline though. But they're quite difficult to understand for the average person. It's why Fiat is still king (and will always be) when it comes to natural disasters such as earthquakes, hurricanes, and tornadoes. This might change if Bitcoin becomes more popular in the mainstream world.

Nonetheless, we should be prepared for the worse in case something undesired happens in the future. The odds of a global earthquake or an EMP strike taking place in the mainstream world are very low. If it does happen, expect Bitcoin and other cryptocurrencies to become weaker than they are right now. It's always best to diversify your investment between Fiat and crypto in order to protect yourself against any natural disasters in the future. Just my thoughts