Haiti Earthquake Captivates Paul Mann, MBA Class of '74, a Tectonic Authority

From THE TENNESSEAN/McCLATCHY NEWSPAPERS, 14 January 2010:

QUAKE HAPPENED CLOSE TO SURFACE FOR LARGE IMPACT

By Robert Samuels
MCCLATCHY NEWSPAPERS

[NB: "Paul Mann" quoted, ¶8]

MIAMI — Although earthquakes are typically associated with the West Coast, the Caribbean is actually a seismically active area, where plates and fault lines are still shifting below the surface.

"That's how you got all the islands in the first place," said Dale Grant, a geophysicist at the National Earthquake Information Center near Denver.

The earthquake that hit Haiti on Tuesday occurred at 3:53 p.m. CT and measured a 7.0 magnitude. It was centered 15 miles from Port-au-Prince, the capital city of nearly 1 million people.

While smaller quakes happen frequently in the Caribbean, none close to this size had been seen in Haiti in more than 25 years, Grant said. That was in June 1984, when a quake measuring 6.7 occurred about 150 miles from Port-au-Prince.

A tsunami watch was issued Tuesday for Haiti, Cuba and the Bahamas. But the likelihood of a tsunami in the Caribbean is lower because the shifting plates occurred on land, said Florida International University professor Grenville Draper, an expert in Caribbean geology.

Here's what geologists think happened:

The actual quake appears to have occurred along the Enriquillo-Plantain Garden Fault, a virtually immovable rock that runs from Montego Bay in Jamaica to the southern part of the island of Hispaniola, which Haiti shares with the Dominican Republic. That vertical fault is pushed by the Caribbean Plate, an unsettled land mass that moves about 20 millimeters east each year.

According to Paul Mann, a research scientist at the University of Texas in Austin, Texas, the plates have been pushing against the fault since a major quake in 1760. On Tuesday, the plates got the fault to move.

What the plate did to the fault is akin to a human trying to move a grand piano across a floor, Draper said. The person will push with no effect — then, the piano will suddenly slip forward.

Such movement is relatively small compared with plates moving underground in California, Draper said. The effect would be less-frequent earthquakes, but relatively large ones when they do occur.

The slip Tuesday appears to have occurred around six miles below the earth, Draper said, resulting in the large earthquake. The closer the slip is to the surface, the bigger the quake.

Ah yes, to be out of highschool 35 years and so unhip that this is my first blog post ever, so whup te do!
I hope those that can will make it back to MBA for our Reunion Weekend. It will be fun to revisit all the stuff we pulled on each other and on the few very unfortunate teachers that we drove from that noble profession...whether it was slashed coats by Waldo, industrial glass cleaner in the coffee, or just disected frogs in lunch bags, mirrors and spitwads, it still rolls me. I am glad we came along when we did...they put people in jail and the Tennessean today for far less.
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