Anomalous wave propagation across the South Caspian Basin

Conference · Wed Oct 01 04:00:00 EDT 1997

OSTI ID:626467

Priestly, K ^[1]; Patton, H J ^[2]; Schultz, C ^[3]

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1. Cambridge Univ. (United Kingdom)
2. Los Alamos National Lab., NM (United States)
3. Lawrence Livermore National Lab., CA (United States)

The Caspian basin blocks the propagation of the regional seismic phase Lg and this has importance consequences for seismic discrimination in the Middle East. Intermediate period surface waves propagating across the basin are also severely affected. In a separate study we have developed a crustal model of the south Caspian basin and the surrounding region. The crust of the basin consists of 15-25 km of low velocity, highly attenuating sediments lying on high velocity crystalline crust. The Moho beneath the basin is at a depth of about 30 km as compared to about 50 km in the surrounding region. In this study we used an idealized rendition of this crustal model to compute hybrid normal mode finite difference synthetic seismograms to identify the features of the Caspian basin which lead to the seismic blockage. Of the various features of the basin, the thickness and attenuation of the sediments appear to be the dominant blocking mechanism.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 626467
• Report Number(s): LA-UR--97-2777; CONF-970967--; ON: DE98000828
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CASPIAN SEA
EARTH CRUST
SEDIMENTS
SEISMIC WAVES
SEISMOGRAPHS
WAVE PROPAGATION