A magnitude 7.0 earthquake off the coast of Northern California was followed by dozens of aftershocks and a brief tsunami warning.
By Friday morning, nine of the approximately 200 aftershocks reported by the USGS were of magnitude 4.0 or higher. The strongest aftershock, a magnitude 4.7 one, occurred at 10:44 a.m. Thursday, about two minutes after the main shock, shaking parts of California’s coast and interior.
Click here to view the latest USGS maps of recent earthquakes.
There have been no reports of serious damage, but residents and business owners in the area have reported broken windows and burst water pipes. The tremor caused items to fall off store shelves.
About 5 million people were under temporary tsunami warnings, which stretched from Oregon to the Bay Area. The warning expired after seismologists determined that an undersea earthquake in California’s most seismically active region was unlikely to cause rising water levels or significant coastal flooding.
USGS USGS maps show earthquakes that occurred off the coast of Northern California during a nearly 24-hour period from Thursday, December 6, 2024 to Friday, December 7, 2024.
The quake’s epicenter was west of Ferndale, a small city in coastal Humboldt County about 130 miles from the Oregon state line. In San Francisco, about 440 miles away, residents said the quake shook them sideways for several seconds.
The region, which has a history of active earthquakes, was hit by a magnitude 6.4 earthquake in 2022, leaving thousands without power and water. California’s northwest corner, where three tectonic plates meet, is the most seismically active area in the state, said seismologist Lucy Jones.
This earthquake was a sideslip earthquake that moved more horizontally than vertically. Therefore, strike-slip earthquakes are less likely to cause tsunamis.
Dr. Lucy Jones said Thursday’s earthquake caused land to move sideways, but not much water movement. This segment aired on NBC4 News on Thursday, December 5, 2024 at 3:00 p.m.
Some earthquakes are followed by larger earthquakes, in which case the first earthquake is called a foreshock. For example, a magnitude 7.3 foreshock occurred two days before the 2011 magnitude 9.1 earthquake and tsunami in Japan.
Aftershocks can last for days, weeks, months, or years. The USGS provides aftershock forecasts.
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