Suture Zones, Seismic Wave Propagation and Tectonics of Central Asia

摘要

Research was conducted in the following areas of interest: (1) A paper entitled 'Intra-Plate Seismicity, Reactivation of Pre-Existing Zones of Weakness, Alkaline Magnetism, and Other Tectonism Post-Dating Continental Fragmentation'; In one portion of the paper the tectonics of the French test site in Algeria are investigated. The study shows that the test site is not in the middle of a shield area. Other authors have shown that tectonic setting is significant in estimating yield from seismic amplitude. (2) A study is underway to investigate the possible correlation between P-residuals observed by the New York State Seismic Network and tectonic-structural features. (3) An investigation of anomalous relative residuals for P and PP arrivals from earthquakes with reflection points beneath Tibet. Some residuals are significantly larger (more positive) than those expected for a double crust. (4) Source parameters for earthquakes of relatively small magnitude are being determined using the spectra of Rayleigh waves at about 25 WWSSN stations. (5) Calculation of the reflection and transmission coefficients for Rayleigh waves inpinging upon a vertical discontinuity at oblique angles. (6) Calculation of moment and average shear stress for two earthquakes in the Aleutian subduction zone from strong-motion accelerograph records. (7) Development of more sophisticated tectonic models of the current tectonic processes in the Himalayas, Hindu Kush, Tien Shan, and Pamir Mountains. (8) An analysis of the correspondence between documented teleseismic earthquakes and mapped faults in Pakistan.