What are "tremblers" in the below passage of text from "Comprehending the Calamity?"

Text Passage: "Frequent "tremblers" sent us scurrying to the road, and as night came on, we gathered some bedding together and went into the Park, the Mecca of all the city. All day I had been feeding homeless ones who had drifted out from the Mission district, where great clouds of angry smoke were rising and large areas had already been devastated."

Twisting and shouting

Party poppers

Tremors

Wind chimes

1 answer

In the given passage, "tremblers" refers to frequent tremors or earthquakes.