CSDP: The seismology of continental thermal regimes

Technical Report · Wed May 01 00:00:00 EDT 1991

DOI:https://doi.org/10.2172/6261484· OSTI ID:6261484

Aki, K

The past year continued to be extremely productive following up two major breakthroughs made in the preceding year. One of the breakthroughs was the derivation of an integral equation for time- dependent power spectra, which unified all the existing theories on seismic scattering including the radiative transfer theory for total energy and single-multiple scattering theories based on the ray approach. We successfully applied the method to the data from the USGS regional seismic arrays in central California, Long Valley and Island of Hawaii, and obtained convincing results on the scattering Q{sup {minus}1} and intrinsic Q{sup {minus}1} in these areas for the frequency range from 1 Hz to 20 Hz. The frequency dependence of scattering Q{sup {minus}1} is, then, interpreted in terms of random medium with continuous or discrete scatterers. The other breakthrough was the application of T-matrix formulation to the seismic scattering problem. We are currently working on 2-dimensional inclusions with high and low velocity contrast with the surrounding medium. In addition to the above two main lines of research, we were able to use so-called T-phase'' observed on the Island of Hawaii to map the Q value with a good spatial resolution. We found that we can eliminate remarkably well the frequency dependent recording site effect from the T-phase amplitude using the amplification factor for coda waves, further confirming the fundamental separability of source, path and site effects for coda waves, and proving the effectiveness of stochastic modeling of high-frequency seismic waves. 70 refs., 24 figs.

• Research Organization: University of Southern California, Los Angeles, CA (United States). Center for Earth Sciences
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG03-87ER13807
• OSTI ID: 6261484
• Report Number(s): DOE/ER/13807-T3; ON: DE92003392
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
GEOLOGIC STRUCTURES
MAPPING
SEISMIC SURVEYS
DATA ANALYSIS
CALCULATION METHODS
CALIFORNIA
CAVITIES
FREQUENCY DEPENDENCE
HAWAII
PROGRESS REPORT
SCATTERING
SEISMIC ARRAYS
SEISMIC WAVES
TWO-DIMENSIONAL CALCULATIONS
DEVELOPED COUNTRIES
DOCUMENT TYPES
FEDERAL REGION IX
GEOPHYSICAL SURVEYS
MEASURING INSTRUMENTS
NORTH AMERICA
SURVEYS
USA
580000* - Geosciences
990200 - Mathematics & Computers