Can T phases be used to map blockage?
The placement of stations in a CTBT hydroacoustic monitoring network is controlled, in large part, by the presence of bathymetric features or land masses that block propagation. In the absence of blocking features, propagation is very efficient in the SOFAR channel, allowing surveillance over large basins with hydrophone networks that are sparse compared to seismic networks. Blockage can be estimated from theoretical calculations of acoustic attenuation. While calibration of attenuation with controlled sources is best, it is also prohibitively expensive. The T phases generated by undersea earthquakes are known to be sensitive to interruptions of the SOFAR channel. Earthquakes along ridges may illuminate regions of interest to define blockage areas. Our initial examination of T phase amplitudes suggests that T phases can be used to map blockage or other strong path attenuation. The principal difficulty to be surmounted is the ambiguity between source coupling and path attenuation. We are attempting to quantify coupling with a probabilistic model, which would permit us to estimate attenuation and to quantify the reliability of the estimate.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 79755
- Report Number(s):
- UCRL-JC-120952; CONF-9505222-1; ON: DE95013309
- Resource Relation:
- Conference: 1995 monitoring technologies conference, Chantilly, VA (United States), 15-18 May 1995; Other Information: PBD: May 1995
- Country of Publication:
- United States
- Language:
- English
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