Transcript for Seismologists Concerned Earthquake Could Trigger Bigger Quake
And this quakes appears to have hit along the dor Mund fault line. It could trigger a bigger quake along the major fault lines in the area. Ginger is here to explain how that works. Sounds like a real concern. Absolutely. I think it helps to see it on map. The San Andreas fault is closer to the coast. This is the west napa fault, only 20 miles long, and this only ran half of it. It could have been so much worse. The west napa fault is part of a network, they are concerned this is a precursor for a lot more activity. We have more than 150 earthquakes in the last 24 hours. You can see some aftershocks for up to seven days after go up to 5.0 magnitude. The threat not over. Thanks very much. And the latest now on the American journalist free this
This transcript has been automatically generated and may not be 100% accurate.