'Earthquake Archaeology' Blends Two Histories

[Courtney Caine]

'Earthquake Archaeology' Blends Two Histories
Larry O'Hanlon, Discovery News e-mail  share bookmark  print

     
 April 17, 2008 -- Do tomorrow's archaeologists a big favor: Always carry some change in your pocket. That way if you happen to be buried alive by an earthquake, any future researchers who unearth your bones from the quake debris can easily approximate the year of the quake.

That's one way that earthquakes in parts of the ancient Roman Empire have been dated.

But usually it's not so easy, say researchers who are pioneering the new field of archaeoseismology. Their aim is to clean up the seismological record by calling on geologists, engineers and seismologists to help archaeologists make better sense of ancient disasters.

"A better term is earthquake archaeology," said Manual Sintubin, a professor of geodynamics at Katholieke Universiteit Leuven in Belgium.

Sintubin announced the kick-off of a UNESCO-backed project to push forward the new field of research on Wednesday at the annual meeting of the Seismological Society of America in Santa Fe, N.M. Earthquake seismology contrasts with the growing field of paleoseismology, which usually does not involve human artifacts, and historical seismology, which relies on documents and other historical accounts to create regional earthquake histories.

Neither approach helped archaeologists facing evidence of an unknown ancient disaster, opening the door to some error-prone circular thinking, explained geologist Tina Niemi of the University of Missouri-Kansas City.

What happens, she explained, is that an archaeologist will uncover a layer of destruction at a study site -- say, Petra, in Jordan. The researcher would then look in one of the earthquake catalogs made by historical seismologists to see which listed quake their Petra destruction layer might belong to.

Then, the historical seismologists read the archaeologist's report about the newfound ruins and add the Petra site to the list of those affected by that particular quake in the next edition of the earthquake catalog.

http://dsc.discovery.com/news/2008/04/17/earthquake-archaeology.html

[Courtney Caine]

_{Photo by Martha Cooper/National Geographic/Getty Images
 
Old Bones, New Life
A skeleton in found in the ruins of an ancient Roman market in Kourion, Cyprus.}

[Courtney Caine]

"It's gone full circle," said Niemi. "Finding primary sources is very difficult."

As a result, many ruins are assigned to the wrong earthquake. This could mean underestimating the frequency of earthquakes in many places. It has probably also skewed our historical perspective of the scope of damage caused by individual quakes.

"Often these earthquakes are taken up by these archaeologists as big catastrophic events" rather than localized disasters, said Sintubin. "There were several attempts [by earlier researchers] to link separate events into a large catastrophe."

The first step in setting things straight, say the researchers, is to make sure that a given site was, indeed, affected by an earthquake. Quake damage can leave an undeniable signature: temple columns or monuments fallen in the same direction or skeletons buried under fallen walls, said Niemi. Other clear-cut signs are aqueducts cut off and offset by a fault.

Next you have to date the quake. In Petra, coins found in the pockets of buried victims were dated to 361 A.D. Likewise, ruins in Aqaba, Jordan, show walls that were repaired in the early 4th century and coins featuring Roman emperor Constantius II (337-361 A.D.) buried under fallen walls.

Finally, archaeologists must accept the possibility that they may uncover evidence of a previously unknown earthquake.

"None of the catalogues have all the earthquakes," said Niemi. "They should be viewed as incomplete and dynamic."