Determining the Viability of Recent Storms as Modern Analogues for North-Central Gulf of Mexico Paleotempestology Through Sedimentary Analysis and Storm Surge Reconstruction

Author

Joshua Caleb Bregy, University of Southern MississippiFollow

Date of Award

Summer 8-2016

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Marine Science

Committee Chair

Davin Wallace

Committee Chair Department

Marine Science

Committee Member 2

Vernon Asper

Committee Member 2 Department

Marine Science

Committee Member 3

Grant Harley

Committee Member 3 Department

Geography and Geology

Abstract

The northern Gulf of Mexico has been devastated by recent intense storms. Camille (1969) and Katrina (2005) are two notable hurricanes that made landfall in virtually the same location in Mississippi. However, fully understanding the risks and processes associated with hurricane impacts is impeded by a short and fragmented instrumental record. Paleotempestology could potentially use modern analogues from intense storms in this region to extend the hurricane record back to pre-observational time. Existing empirically based models can back-calculate surge heights over coastal systems as a function of transport distance, particle settling velocity, and gravitational acceleration. We collected cores in a pond (3) and adjacent beach (1) in Hancock County, Mississippi. Loss-on-ignition and grain-size analyses were conducted on cores in the context of a Bayesian statistical age model using ¹³⁷Cs and ¹⁴C dating. Using Camille/Katrina to calibrate the archive, similar coarse-grained deposits were identified, and inverse sediment transport models calculated paleosurge intensities similar in magnitude to Camille over the 2500 year record. However, these are conservative estimates, as the shoreline was further seaward from its modern location approximately 700 yr BP. Our multi-millennial annual average landfall probability (0.48%) closely matches previously published studies from the Gulf of Mexico, indicating that intense hurricanes have not varied over these timescales. Over centennial timescales, active intervals occurred between 900 to 600 and 2200 to 1900 yr BP, and quiescence between 1900 to 900 yr BP. Comparison with previously published sites suggests southerly shifts in the Loop Current may be responsible for regional variability.

ORCID ID

orcid.org/0000-0002-3483-595X

Copyright

2016, Joshua Caleb Bregy

Recommended Citation

Bregy, Joshua Caleb, "Determining the Viability of Recent Storms as Modern Analogues for North-Central Gulf of Mexico Paleotempestology Through Sedimentary Analysis and Storm Surge Reconstruction" (2016). Master's Theses. 198.
https://aquila.usm.edu/masters_theses/198