A series of powerful earthquakes affected Northern California on Thursday morning, and the strongest of them registered a magnitude of 7.0 as reported by the US Geological Survey (USGS).
The first of them was measured at 6.6 before it was being upgraded, and it struck near Petrolia at 10:45 a.m., about 50 miles south of Eureka in Humboldt County.
The second earthquake, which measured at a magnitude of 5.8, happened not far from the town of Ferndale.
A tsunami warning for the coastal area from Santa Cruz, California, to Douglas County, Oregon, was immediately issued by the National Weather Service.
Authorities also issued information to residents who stay along the coast to watch out for likely shockwaves and adhere to evacuation procedures if necessary.
Officials in both Humboldt and Mendocino counties have not mentioned any immediate injuries or damage as of 11 a.m. Assessments were being carried out as the region braced for aftershocks.
The series of earthquakes that occurred shows the seismic activity in the Pacific Ring of Fire, a place where California usually sees tectonic movement. Authorities have also issued a warning to residents to be watchful of updates on emergency alerts and be ready for possible developments.
More information in regards to the impact and response is being awaited for as information becomes available.