California Town Rattled by Earthquake a Second Time

The first quake had cracked and closed Fernbridge, a historic arched bridge that connects the neighboring city of Ferndale to Eureka, Humboldt County’s largest city, across the Eel River. The bridge was repaired and reopened, only to be closed again on Sunday for safety inspections, according to the California Department of Transportation. The bridge reopened by Sunday evening.

Thirty calls for emergency services came within the first two hours after the quake struck, fire officials said. Other fire departments were called in to help. As of Sunday afternoon, about 30 percent of the town was without water, and half were without power, officials said. Some homes had been damaged.

“There are new houses off their foundations,” Rio Dell’s fire chief, Shane Wilson, said. The damage for this quake seems to be a little more spread out in the central and eastern part of town rather than concentrated in the northern part of town, as with the last quake, he said.

The quake is considered an aftershock of the earthquake on December 20, Rafael Abreu Paris, a United States Geological Survey geophysicist, said. Aftershocks, typically lesser magnitude quakes than the first major one, are normal after a big earthquake, seismologists say. But even a moderate-size or smaller quake can feel violent and cause damage depending on its location, depth and type.

The Dec. 20 quake led to a series of offshore aftershocks, Mr. Paris said. More than 50 aftershocks followed the December earthquake, including a large one about five minutes after with a magnitude of 4.6.

The tremor on Jan. 1 was part of a different cluster of inland aftershocks but occurred in the same tectonic process, he said. More aftershocks are possible.

Jason Freitas, a local resident, said that the intensity of Sunday’s quake felt familiar. “It was very similar to the earthquake we just had,” he said. “It violently shook everything off the walls.” The difference, he said, was that his apartment sustained more damage this time. When it happened, he threw on a shirt and ran outside. “It was very part and parcel of living in California, really.”