Collecting single and multichannel seismic‐reflection data in shallow water‐near Aberdeen proving ground, Chesapeake Bay, Maryland

Abstract

In August and September 1994, single- and multi-channel seismic-reflection data were collected by the U.S. Geological Survey (USGS), in cooperation with the U.S. Army and the U.S. Army Corps of Engineers (COE), to support a regional hydrogeologic framework study at Aberdeen Proving Ground (APG), Maryland. Data were collected in Chesapeake Bay, as well as in the Bush, Gunpowder, and Sassafras Rivers, which are tributaries to Chesapeake Bay. Data were collected along the shoreline in very shallow water, usually less than 1 m. Approximately 100 km of single-channel seismic-reflection data were collected using a water gun and an electromechanical plate as sound sources; about 50 percent of these data contained usable geologic information. A prominent channel in the Quaternary sediments at a depth of 61 m is clearly evident, and the depth to bedrock ranges from approximately 184 to 223 m. Approximately 14 km of multi-channel data were collected in the Gunpowder and Bush Rivers and in Chesapeake Bay; about 40 percent of these data showed subsurface reflectors, often in small, discontinuous segments. Data were processed using established processing techniques. Numerous reflectors were present in the data that were continuous over long distances. The multi-channel data contained more detail and significantlymore » less noise than the single-channel data. The quality and continuity of the single- and multi-channel data were best in shallow water (less than 1 m) where the presence of gassing organic sediments was at a minimum.« less