Four notable earthquakes have occurred in the Chino Hills, just north ofYorba Linda, since yesterday. The recent quakes have greatly accelerated aswarm that last week was called 'curious' and 'unusual' by one of SouthernCalifornia's top seismologists.The largest of the quakes was felt throughout much of Orange county.
All four quakes occurred in a region that's had a 'swarm' of quakes sinceearly March. The quakes are also close to the area of the Chino Hills -- theso-called Yorba Linda trend -- that produced a 5.4 quake last July. The regionis close to the Chino and Elsinore fault zones.
Susan Hough, head of the USGS's Pasadena office, called the earthquakeswarms curious earlier this month.
one of those sequences that doesnmold,that we understand what a swarm is, or why they happen!Story by Senior Meteorologist Henry Margusity
