Two unrelated earthquakes have rattled California in a little more than a 12-hour period.
A magnitude-4.7 earthquake hit a remote mountainous region in central California, 25 kilometers southeast of Hollister, just after noon on Tuesday.
It followed a 4.5 magnitude temblor near Pleasant Hill, northeast of San Francisco, late Monday.
Despite having occurred within a short time of each other, the quakes were centered too far apart to have been related, seismologist Lucy Jones said on Twitter.
Today’s M4.8 near Hollister is too far from yesterday’s M4.5 to be connected. When we look for patterns between quakes at long distances, we see triggering for ~3x length of the fault. The fault length in a M4.5 is less than 1 km.
— Dr. Lucy Jones (@DrLucyJones) October 15, 2019
The quakes come just three days before the 30th anniversary of one of the deadliest in San Francisco Bay Area history. In 1989, the 6.9-magnitude Loma Prieta earthquake killed 69 people and injured thousands.