Four notable earthquakes have occurred in the Chino Hills, just north of YorbaLinda, since yesterday, greatly accelerating a swarm that was called 'curious'and 'unusual' last week by one of Southern California'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 since earlyMarch. 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 earthquake swarmscurious earlier this month.
doesncertainly isnwhy they happen!
