Abstract
This paper studied some properties of PdSwr phase related to 670 km discontinuities in detail, and theoretically processed a preliminary analysis to this phase. We discussed the relationships between the incident angle i h of PdSwr phase with its path, epicentral distance, travel-time and relative amplitude due to low velocity zone (LVZ) of upper mantle, and preliminarily pointed out the main characters of PdSwr phase recorded in seismogram. The PdSwr phase is concentrated in range of 13.5°–96.5°. When epicentral distance is greater than 33°, the start point of PdSwr phase is relatively well distinguishable and could thus be determined more easily. When the epicentral distance is between 13.5° to 33°, the triplication of PdSwr’s travel-time curve could be slightly distinguished due to the low velocity zone and 220 km seismic velocity discontinuity of upper mantle. The relevant observed PdSwr phase should be in a more complex pattern and it should be more difficult to determine its start point.
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This study is supported by the State Natural Science Foundation of China (No. 49070191 and 49734150) and National Doctoral Foundation of China (No. 157WJ0704/ 9435811).
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Wei, DP., Zhou, HL. & Wang, ZQ. Low velocity zone of upper mantle and its effect on PdSwr phase related to 670 km discontinuity. Acta Seimol. Sin. 13, 67–74 (2000). https://doi.org/10.1007/s11589-000-0083-y
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DOI: https://doi.org/10.1007/s11589-000-0083-y