An official report indicates that the first one was registered at 00:36 hours with a magnitude of 4.8 on the Ritcher scale.
The epicenter of this tremor was three kilometers from El Centro, a city in Imperial County, California, bordering Mexicali.
The report adds that between that hour and 1:00 a.m. 17 other oscillatory earthquakes with magnitudes between 2.0 and 4.0 were reported, which alerted the inhabitants of the capital of Baja California.
The U.S. Geological Survey reported 27 earthquakes in the last 24 hours in this border region.
Mexicali is located in a telluric zone due to tectonic faults, including the San Andres fault.
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