Initial Field Tests Of ISP-1 And ISP-2 - Systems That Extend The Technology Of Instrumented Seabed Penetrators

Until May 1982, the use of instrumented penetrators to obtain in situ measurements of marine sediment properties had been limited to maximum depths into the sediment on the order of 10 m. This paper describes the initial field tests of two gun-launched, instrumented, seabed penetrator systems (ISP-1 and ISP-2). These tests have extended the technology of instrumented seabed penetrators by demonstrating the feasibility of obtaining in situ measurements from depths into sediment greater than 30 m. While the primary objective of these tests was to demonstrate feasibility, a secondary objective was to obtain useful information about the gas-bearing sediments in a region of the Gulf of Mexico currently being actively investigated by several organizations. This paper describes the ISP-1 and ISP-2 and discusses the results of the data from these tests. These data produced estimates of the speed and attenuation of sound in the gassy sediments as well as a sediment shear-strength profile that was computed from a penetrator acceleration profile using techniques described by R. M. Beard at Oceans 81. This paper concludes by discussing several new geotechnical instruments that could be developed to exploit the capabilities demonstrated by these tests.