Recording of anomalous shear energy in the teleseismic P-wave coda at Long Valley Caldera, California, on a small aperture array
- Lawrence Livermore National Lab., CA (USA)
- California Univ., Santa Barbara, CA (USA). Dept. of Geology
Anomalous energy in the coda of teleseismic P-waves at Long Valley caldera has been suggested to be a P to S converted arrival, perhaps with the conversion occurring at the boundaries of magma bodies beneath the caldera. We have collected new data with a small-aperture, three-component array located in the northwestern quadrant of the caldera with the purpose of testing this hypothesis. An examination of three teleseismic events using array and particle motion techniques shows that converted P- to S-waves comprise a significant fraction of the early arriving anomalous energy. In volcanic areas such as Long Valley, the scattered energy could originate at a high velocity contrast feature such as magma body interface. In addition, later arriving energy was detected with slow phase velocity and is tentatively identified as body wave to surface wave scattering. Our interpretation is illustrated with waveforms of two earthquakes from the Kuril Islands and one in northern Peru. Our results show that a small-aperture, three-component array can be used to perform detailed analysis of the coda. 12 refs., 8 figs., 1 tab.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- DOE/DP
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7024307
- Report Number(s):
- UCRL-ID-103499; ON: DE90008189
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
LONG VALLEY
SEISMIC DETECTION
CALDERAS
EARTHQUAKES
KURILE ISLANDS
MAGMA
SEISMIC ARRAYS
SEISMIC EVENTS
SEISMIC P WAVES
SEISMIC S WAVES
SHEAR
WAVE PROPAGATION
ASIA
CALIFORNIA
DETECTION
EASTERN EUROPE
EUROPE
FEDERAL REGION IX
ISLANDS
MEASURING INSTRUMENTS
NORTH AMERICA
SEISMIC WAVES
USA
USSR
580000* - Geosciences