From the epicenter of the 2014 magnitude 6.0 Napa earthquake (red star), the P-wave (yellow circle) raced ahead of the more damaging S-wave (red circle). The late alert zone, formerly referred to as the blind zone, for which no warning was possible, is shown by the solid gray circle with a red slash. Small green circles show seismic stations. Credit: Incorporated Research Institutions for Seismology (IRIS).
California Earthquake Early Warning tested by moderate Bay Area earthquakes
By Alka Tripathy-Lang
October 28, 2019
Earlier this month, the Bay Area was gently reminded, twice, of the seismic hazards posed by the numerous faults lacing California. A magnitude-4.5 earthquake struck near Pleasant Hill on 14 October 2019, and a magnitude-4.7 temblor shook Hollister on 15 October 2019, with both felt throughout the greater Bay Area.
For more, head to Temblor.