Newswise — INDIANA, Pa. -- An earthquake and a hurricane, all in the same week, on the same coast. Are they related? “Probably not,” Indiana University of Pennsylvania Associate Professor of Geoscience Dr. Jon Lewis says. “I don’t think it’s prudent to link the hurricane to the earthquake. Atmospheric processes certainly influence Earth's crust over long (geological) time scales and vice versa. The Asian monsoons have, for example, been attributed to the rise of the Himalaya. Can Earth's crust influence atmospheric process on very short time scales, e.g., spawn hurricanes? As far as I know such a connection has not been made.” Why were tremors from this earthquake felt so far away from its epicenter, especially because it didn’t seem to cause large-scale damage or loss of life? “This earthquake occurred in an area of more or less unbroken solid bedrock,” Dr. Lewis explains. “This means that the energy can be distributed more widely through the rock. It’s like ringing a bell – the vibration from the clapper creates rings of sound waves to resonate over a large space. “But, if you compare the Virginia earthquake to an earthquake in California, for example, where there are many faults and inconsistencies in the rocks, the energy – the vibration -- from a similar earthquake doesn’t travel as consistently far.”
But are hurricanes and tornados related?
Very possibly, says Dr. John Benhart Jr., professor and chair of IUP’s Department of Geography and Regional Planning.
“Hurricanes, also known as tropical cyclones, have a tendency to spawn tornadoes because temperature instability tends to be found near or below 10,000 feet altitude in these strong low pressure systems, along with strong vertical wind shear -- the combination of which can lead to small supercell storms which have an enhanced likelihood of generating tornadoes,” Benhardt says.
“In the northern hemisphere, where hurricane systems display a counter clockwise rotation, the right front quadrant of the system is where a majority of the tornadoes are generated in outer rainbands from 50-200 miles from the hurricane eye (center).
“It was in areas exposed to this part of the Hurricane Irene storm system in North Carolina, Virginia, and Delaware that tornadoes formed, causing significant property damage and loss of life.
“Other significant impacts on human populations along the eastern seaboard from Hurricane Irene were caused by storm surge -- a rise in sea level caused by the extreme low pressure and the force of cyclonic winds of a hurricane system -- and large amounts of precipitation.
“Although storm surge forecasts for Hurricane Irene tended to be higher than what actually occurred along the coasts of North Carolina, Virginia, New Jersey, New York, Connecticut, Rhode Island and Massachusetts, massive amounts of rainfall from the system that extended to inland parts of those states as well as Pennsylvania, Vermont and New Hampshire caused intense flooding, property damage and loss of life in areas where people may not have felt that they were in danger from the effects of the hurricane.”
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