A local professor says he expects the aftershocks from back to back earthquakes in southern California to last for up to a month.

Dr. Brian Zimmerman, chairman of Edinboro University's Geosciences Department, says the magnitude of the second earthquake, 7.1 on the Richter  scale is significant.

Only about 20 earthquakes of that size happen


worldwide annually.

The earthquakes centered near Death Valley, caused road and property damage, and caused books and groceries to fall off shelves.

But no one was killed.

Zimmerman says if the back to back quakes had hit a major city, the results would have been much, much worse.

He said, "Oh, if this had been in a much more populated area, there would have been certainly the loss of life and billions of dollars in property damage. A magnitude 7.0 earthquake is a significant quake."

Zimmerman says one unusual aspect of the quakes was they happened along two intersecting fault lines.