Hurricanes Katrina
and Rita
focused the international spotlight on the vulnerability of the Kam-biu Liu, George
William
Barineau III Professor in LSU's Department of Oceanography and Coastal
Sciences, is the pioneer of a relatively new field of study called
paleotempestology, or the study of prehistoric hurricanes. Liu, a
long-time
resident of "People were
discussing the
probability of a Category 5 hurricane making direct impact on Currently, experts
tend to agree
that Atlantic hurricane activity fluctuates in cycles of approximately
20-30
years, alternating periods of high activity with periods of relative
calm. But
records of such events have only been kept for the last 150 years or
so. What
would happen, Liu wondered, if you looked back thousands of years?
Would larger
cycles present themselves? How does a scientist
study storms
that happened during prehistoric times? "Basically, we worked under the
assumption that the storm surge from these catastrophic hurricanes
would have
the capability to drive sand over beach barriers and into coastal
lakes,"
said Liu. "This is called an overwash event. We believed that pulling
sediment cores from coastal lakes and analyzing the sand layers might
give us
the information we needed." The same methodology can be used to find
overwash sand layers in coastal marshes. Using radiocarbon analysis and
other
dating techniques, Liu and his research team worked to develop a
chronology of
prehistoric storms in order to analyze any emerging patterns or cycles.
This methodology has
proven
successful for the group. In an article printed in the March issue of American Scientist, the magazine of
Sigma Xi, the Scientific Research Society, Liu states that evidence
from the
Gulf Coast drill sites shows that hurricanes of catastrophic magnitude
directly
hit each location only approximately 10 – 12 times in the
past 3,800 years.
"That means the chances of any particular Gulf location being hit by a
Category 4 or Category 5 hurricane in any given year is around 0.3
percent," said Liu. After spending more
that 15 years
studying dozens of lakes and marshes along the U.S. Gulf and Liu's
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