OCCURRENCE OF SCOUR PITS ON THE INNER CONTINENTAL SHELF OF MATAGORDA PENINSULA, TEXAS, FOLLOWING THE LANDFALL OF HURRICANE CLAUDETTE, JULY 15, 2003

Hurricane Claudette made landfall on the inner continental shelf of Matagorda Peninsula, Texas, as a Category I hurricane with sustained winds of 41 m/s and a central pressure of 982 mB. A sidescan and mulitbeam bathymetry sonar survey was conducted two weeks after the storm at the landfall site. This survey revealed a large field of scour pits on the inner continental shelf. The scour pits occurred offshore of a break in slope in 7 to 9 m water depth. The pits ranged in area from 2 to 7624 m2 and many were greater then 50 cm deep. The Holocene mud and sand layer was completely removed from the interior of the pits, exposing Pleistocene clay. A follow-up survey conducted six months after the storm showed that the scour pits were quickly filled with muddy sand. A third survey conducted one year later showed there was no longer any bathymetric expression of the pits and the sidescan sonar data revealed a mottled pattern on the seafloor where the former scour pits had been. A similar mottled seafloor has been identified in other sidescan sonar data collected from similar regions along the Texas coast. This suggests that the formation of scour pits during tropical cyclone impacts may be a common occurrence along the Texas coast.