Hurricanes, flooding and snowstorms present far greater natural threats to Delaware residents than the devastation of earthquakes and tsunamis. And with millions reeling from killer quakes in Chile and Haiti this year, the question arises again: Could that happen here?
Wise scientists -- including Stefanie Baxter of the Delaware Geological Survey -- seldom say "impossible." "Anything is possible," Baxter said Saturday evening, "but the chances are very remote."
The largest earthquake in recorded Delaware history was a magnitude-4.1 quake that caused minor property damage in 1871. A magnitude-2.8 quake raised eyebrows last summer. But this is not a hotbed of quaking plates.
The stressors that cause earthquakes in this area come from the Mid-Atlantic Ridge, a boundary of tectonic plates that stretches down the length of the Atlantic Ocean, hundreds of miles offshore. Tectonic plates are large pieces of the earth's crust, solid rock, that shift and move and can be up to 60 miles thick, according to the U.S. Geological Survey. When the plates along the Mid-Atlantic Ridge move, they activate the small faults that produce earthquakes here, Baxter said. Though the faults that affect this area are hidden or buried, they are still here, though not visible like California's San Andreas Fault. Where there are earthquakes, there are faults, Baxter said.
The plates along the Mid-Atlantic Ridge are moving apart, she said. The plates in the Pacific region now experiencing earthquakes are moving together, one going beneath the other. Earthquakes occur routinely around the world, most of them underwater, in remote areas or too small to cause distress.
Among the scores of global earthquakes that exceeded 5.0 magnitude Saturday -- most of them in or near Chile after its massive 8.8 quake -- was an earthquake of magnitude 5.4 along the Northern Mid-Atlantic Ri