A man picks up fallen goods at a CVS store after an earthquake hit Friday near La Mirada, Calif. The magnitude-5.1 earthquake was widely felt in the Los Angeles area and surrounding counties. Jae C. Hong/AP hide caption

itoggle caption Jae C. Hong/AP

Multiple crews work to restore power after a winter storm on Thursday that brought down lines in Fairburn, Ga. Friday night's small quake was the latest event to rattle nerves in the region. John Amis/AP hide caption

itoggle caption John Amis/AP

People inspect damage to the Church of San Pedro in the town of Loboc, Bohol, after a powerful earthquake struck the region early on Tuesday. The quake hit near one of the Philippines' key tourist hubs, the U.S. Geological Survey reported. Robert Michael Poole/AFP/Getty Images hide caption

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A Pakistani youth stands in the doorway of a damaged house in the devastated district of Awaran Wednesday. A powerful 6.8-magnitude earthquake struck the same region Saturday. Banaras Khan/AFP/Getty Images hide caption

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As rocks and dirt tumble down a mountainside (at left), a police officer urges people to stay back on a road in Baoxing county, Sichuan province, on Monday. Rescuers are having a hard time getting to victims of Saturday's strong earthquake because of aftershocks and landslides. CHINA DAILY/Reuters /Landov hide caption

itoggle caption CHINA DAILY/Reuters /Landov

Chinese rescuers walk through wreckage to reach isolated Baoxing country after the earthquake in Ya'an, southwest China's Sichuan province on Sunday. AFP/Getty Images hide caption

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Allan Lichtman, a professor at American University, discusses his 13 keys to a successful election campaign on April 13 in his office in Washington, D.C. Paul J. Richards/AFP/Getty Images hide caption

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An inspector checks a wheel of Reggiano cheese at the Parmigiano-Reggiano storehouse in Bibbiano, Italy. Earthquakes rocked the region, sending the cheese toppling. Marco Vasini/AP hide caption

itoggle caption Marco Vasini/AP

Stereo photographs, called Kromograms, show the earthquake-damaged San Francisco of 1906. They are thought to be the first color photographs from one of the worst natural disasters in U.S. history. Frederick Eugene Ives/Smithsonian's National Museum of American History hide caption

itoggle caption Frederick Eugene Ives/Smithsonian's National Museum of American History

Volunteers prepare relief supplies for survivors and people displaced by the earthquake in Christchurch, New Zealand, nine days ago. The search for new survivors has been ended. Phil Walter/Getty Images hide caption

itoggle caption Phil Walter/Getty Images