Small earthquakes recently occurred consecutively on different fault systems near the US-Mexico border, causing mild shaking in certain areas of San Diego County.
The US Geological Survey detected the first quake at 5:13 p.m. local time approximately 5 miles west-southwest of Tecate, Mexico, and 15 miles west-southwest of Campo, and recorded the event at a magnitude 3.4.
Within a second, a second quake measuring in at a magnitude 3.6 was registered. The second event occurred around 23 miles west-southwest of Progreso, Mexico, and 31 miles east-southeast of Campo.
Seismologist Tom Rockwell from San Diego State University expressed surprise at the occurrence, stating it was unusual for earthquakes on separate fault systems to happen simultaneously.
Although the timing of the two quakes may appear interconnected, there is no immediate evidence to suggest the first quake triggered the second.
The region near the US-Mexico border frequently experiences minor earthquakes, but they seldom result in significant seismic events, according to Rockwell.