Optimum design of Ocean bottom seismometers |
| |
Authors: | George H Sutton Frederick K Duennebier |
| |
Institution: | (1) Rondout Associates, Inc., P.O. Box 224, 12484 Stone Ridge, NY, U.S.A.;(2) Hawaii Institute of Geophysics, University of Hawaii, 2525 Correa Road, 96822 Honolulu, HI, U.S.A. |
| |
Abstract: | Ocean bottom seismometers (OBS) have been widely used during the past decade to collect seismic data for determination of the structure of the oceanic lithosphere, stress patterns in regions of earthquake activity, and geoacoustic parameters of the ocean floor. Data quality from these experiments has often been disappointing because of poor signal quality and high noise levels. Many of these problems result from motion of the OBS package that is decoupled from motion of the ocean floor. These coupling problems are more serious in the ocean than on land because of the low shear strengths of most ocean sediments. In this paper we continue to develop the theory of coupling of OBSs to soft sediments and arrive at results suggesting that OBS packages should be designed with: (1) the minimum mass possible, (2) radius of area in contact with the sediment proportional to the cube root of the mass, and the maximum radius less than 1/4 of the shear wavelength, (3) density of the OBS approximately that of the sediment, (4) a low profile and a small vertical cross section with water, and (5) low density gradients, and maximum symmetry about the vertical axis. Agreement of the theory with test data is good; most deviations are reasonable, given limitations of the theory and experiments. The theory also suggests that the coupling frequency, the frequency above which the OBS does not follow the motion of the sediment, is directly proportional to the sediment shear velocity. |
| |
Keywords: | ocean bottom seismometer optimization |
本文献已被 SpringerLink 等数据库收录! |
|