Pronouns usually replace nouns that refer to people, places, or things. Since an earthquake is a natural phenomenon and not a person or object, it doesn't have a specific pronoun.
Here are some ways to avoid using a pronoun for "earthquake":
* Use the noun itself: "The earthquake caused significant damage."
* Use a descriptive phrase: "The powerful tremor shook the city."
* Use a synonym: "The seismic event caused widespread destruction."
* Use a pronoun that refers to the effects of the earthquake: "It [referring to the earthquake's effects] caused significant damage."
Remember, pronouns are a useful tool to avoid repetition, but they are not always necessary. Choose the most appropriate way to express yourself in your writing.