Regional Wave Propagation Characteristics in China and Southern Asia,
NEW MEXICO STATE UNIV LAS CRUCES DEPT OF PHYSICS
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Regional wave propagation studies are currently an important focus of research because of concerns over proliferation of nuclear weapons. Regional studies serve a twofold purpose 1 regional data can provide stable yield estimates for underground nuclear explosions, and 2 regional data can discriminate between explosions and earthquakes. Yield and discrimination studies have often used the Sn and Lg regional phases. However, discriminants based on these types of regional data are generally not transportable and must be individually calibrated for a particular region. For China and Southern Asia the problem has been a lack of recorded local and regional events. The first step to alleviate this problem is to increase the database of regional seismic data and their associated ground truth information. To achieve this goal we have documented the regional waveform characteristics of bandpassed 0.5 - 5 Hz digital data collected by the Chinese Digital Seismic Network CDSN. Our current work has concentrated mostly on mapping Sn and Lg propagation efficiencies, especially beneath the continental plateaus. The northern Tibet Plateau seems to attenuate most Sn, but southern and eastern Tibet often have weak, but visible, Sn propagation. Sn also does not propagate efficiently beneath the Mongolian Plateau, southeast China, the Balkal Rift, the east China Rift, and Indochina. Events occurring on the Pacific Rim also lack the Sn phase. Paths of efficient Sn propagation exist in central China, in northeast China, and within the Tarim Basin and the Tien Shan. With some notable exceptions, we observe, then, that Sn seems to be attenuated for most tectonically active regions Tibet, Mongolia, Indochina, the east China Rift, and the west Pacific, while it is not attenuated within the more stable regions of eastern China.
- Government and Political Science
- Seismic Detection and Detectors
- Nuclear Weapons