California-Mexico border hit by second earthquake swarm in a week. What is going on?
A magnitude 4.1 earthquake struck at 5:17 a.m. Monday near an active swarm of smaller quakes that began Saturday. A separate swarm of quakes occurred a week ago.
A magnitude 4.1 earthquake struck at 5:17 a.m. Monday near an active swarm of smaller quakes that began Saturday. A separate swarm of quakes occurred a week ago.