Remarkable Number of US Quakes

April 9, 2010, updated April 10
Holly Deyo

The shaking hasn't stopped after a 7.2 earthquake rattled the U.S. and Mexico Easter Sunday. The most events I can ever recall for the U.S. was 1,482 on May 3, 2008 (see event map below). Normally the USGS registers around 700-800 events in America.

Maps start to look interesting when they hit 1,100 shakes. Aftershocks from the Easter quake have rocketed this tally way beyond anything we've experienced in recent years. More than 3,500 earthquakes is a new benchmark.

Because so many earthquakes have occurred atop each other, it's hard to get a good grasp of just how many have struck since the jaw-rattling 7.2. Clicking the map to the right, it will bring up a much larger version showing Mexico and southern California.

Quakes are concentrated right on the border and extend southeast to the Baja Peninsula and north to the Salton Sea. The whole area is positively inflamed with earthquakes.

The small inset map only tracks Mag. 1+ quakes for a week and then they fall off. It's unfortunate that the larger "green" map plots events in gray since they're harder to see. However, the more you study the map, you'll be surprised how many "stars" your eyes pick up.

The May 4th major event is designated in red and looks like it happened after the rest. This quake had to be marked in again since it was buried in aftershocks and impossible to see locate.

The interesting thing to note on this map is the distinct march of quakes northward from the main shake. The greatest number of temblors isn't concentrated right at the heart of the 7.2 quake, but clustered on the border extending into both countries. Hopefully this is as far as they travel and leave San Diego and Los Angeles alone.