Are the expenses caused by natural disasters borne by the passengers or by the travel company?

You can negotiate with the travel agency. Or arbitration by the court.

But both sides have to produce evidence.

According to your contract, tourists should be responsible for the losses caused by force majeure.

The earthquake is a force majeure factor and the ticket price can be refunded. But some expenses, such as tickets, room fees, meals and so on. , has not yet happened. The travel agency should return the goods.