Miriam (Mimi) Fearn, Ph.D.
Assistant Professor

Department of Geology and Geography
mfearn@usouthal.edu
(334) 460-6381  office
(334) 461-1487  fax

 

Hurricane Research:
..... This project started when I was a graduate student at Louisiana State University. My major professor, Kam-biu Liu, was talking to me about lakes on the Canadian Shield that had dark, humic water. I told him about Lake Shelby in Alabama's Gulf State Park. Lake Shelby has fresh tea-colored water and is within a quarter mile of the Gulf. In talking, we realized that Lake Shelby's unique ecology and location made it a potential site for reconstructing a long term sedimentary record of hurricanes. We hypothesized that during a hurricane, sand would be washed over the narrow barrier beach and deposited in the lake. By dating the sand layers, we could determine the frequency and possibly the intensity of past hurricanes. The National Science Foundation funded first a pilot study and later a project which included sites from Galveston, Texas, to Panama City, Florida. I worked on the pilot study as a student and on the larger study as a research associate at LSU. The Risk Prediction Initiative of the Bermuda Biological Station for Research currently funds this work, and I continue to work with Dr. Liu on the project. My primary responsibility is analyzing diatoms from the sediment cores to determine past ecological conditions at the study sites.
 
Kam-biu Liu, Hong Lie Qiu, and Mimi Fearn taking the first core from Lake Shelby, summer, 1989. Dr. Kam-biu Liu supervises while Shen Caiming, Zuju Yao, and Jud Englett core in Western Lake, Grayton Beach State Park, Florida, summer 1996.
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Publications on hurricanes include:
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Liu, K.B. and Fearn, M.L. 2000. Reconstruction of prehistoric landfall frequencies of catastrophic hurricanes in northwestern Florida from lake sediment records. Quaternary Research 54:238-45.

ABSTRACT
Sediment cores from Western Lake provide a 7000-yr record of coastal environmental changes and catastrophic hurricane land-falls along the Gulf Coast of the Florida Panhandle. Using Hurricane Opal as a modern analog, we infer that overwash sand layers occurring near the center of the lake were caused by catastrophic hurricanes of category 4 or 5 intensity. Few catastrophic hurricanes struck the Western Lake area during two quiescent
periods 3400-5000 and 0-1000 "C yr B.P. The landfall probabilities increased dramatically to ca. 0.5% per yr during an "hyperactive" period from 1000-3400 "C yr B.P., especially in the first millennium A.D. The millennial-scale variability in catastrophic hurricane landfalls along the Gulf Coast is probably controlled by shifts in the position of the jet stream and the Bermuda High. 
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Liu, K.B. and Fearn, M.L. 2000. Holocene history of catastrophic hurricane landfalls along the Gulf of Mexico coast reconstructed from coastal lake and marsh sediments. In: Ning, Z.H. and Abdollahi, K.K. (eds.) Current Stresses and Potential Vulnerabilities: Implications of Global Climatic Change for the Gulf of Mexico Region of the United States, Franklin Press, Inc., Baton Rouge, Louisiana, pp. 38-47.

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Liu, K.B. and Fearn, M.L. 1997. Lake sediment records of Hurricane Opal and prehistoric hurricanes from the Florida Panhandle. Preprint volume, American Meteorological Society, 22nd Conference on Hurricanes and Tropical Meteorology, Fort Collins, Colorado, May 19-23, 1997, pp. 397-398.

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Liu, K.B. and M.L. Fearn. 1993. Lake sediment record of late Holocene hurricane activities from coastal Alabama. Geology 21(9): 793-796.

ABSTRACT
Coastal lake sediments contain a stratigraphically and chronologically distinct record of major hurricane strikes during late Holocene time. Frederic - a category 3 hurricane that struck the Alabama coast on the Gulf of Mexico in 1979 - left a distinct sand layer in the nearshore sediments of Lake Shelby as a result of storm-tide overwash of beaches and dunes. Sediment cores taken from the center of Lake Shelby contain multiple sand layers, suggesting that major hurricanes of category 4 or 5 intensity directly struck the Alabama coast at ca. 3.2.-3.0, 2.6, 2.2, 1.4, and 0.8 ka (14C yr), with an average recurrence interval of ~600 yr. The Alabama coast is likely to be struck by a category 4 or 5 hurricane within the next century.

Geological Society of America
P.O. Box 9140, Boulder, CO
80301-9140 USA 
http://www.geosociety.org

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See also: Presentations with Published Abstracts
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Mimi Fearn Home Page
University of South Alabama
Last modified: 11/14/01