POST-HURRICANE CLAUDETTE SURVEY OF THE INNER CONTINENTAL SHELF NEAR MATAGORDA PENINSULA, TEXAS

Following the passage of Hurricane Claudette over the Texas coast, 15 July, 2003, a geophysical survey was conducted from 27 July to 1 August, 2003 of the inner continental shelf north of where the storm made landfall. The survey will be used as a baseline for comparison with subsequent surveys to monitor the recovery of the system in the months following the storm. Sidescan sonar, Chirp subbottom seismic, and multibeam sonar data were collected along with surface sediment and core samples. The survey area extended from the shoreface of Matagorda Peninsula to 3 km offshore in nearly 10 m of water depth. X-radiographs of the sediment cores show a storm layer located near the surface of many of the gravity cores. Below the surface storm layer the sediments are heavily bioturbated throughout most of the cores. Deep storm layers are present in some cores indicating past storm or flood events. A number of large pits in the surficial Holocene sediment were obseved in the sidescan sonar record. The pits ranged from 10 to 100 m in diameter, 1 to 2 m deep and the base of the pits contained densely consolidated Pleistocene sediments. The pits were presumably created by strong offshore bottom currents created by the 2m storm surge. Also visible in the sidescan record were a series of shore perpendicular features on the shoreface that may have been formed in a similar manner to the pits. Follow up surveys of the area are planned for early January and Spring 2004. These surveys will incorporate sidescan, seismic, bathymetry data, and sediment samples to observe the inner shelf transition back to its fair weather configuration.