Publication Date:
2019
Description:
〈span〉〈div〉Abstract〈/div〉Triplicated 〈span〉P〈/span〉 waveforms related to the 410‐km discontinuity from five intermediate‐depth earthquakes in the central Philippines are clearly recorded by the Chinese Digital Seismic Network, but some branches of the 〈span〉S〈/span〉‐wave triplications are obscure. Matching the observed 〈span〉P〈/span〉‐wave triplications with synthetics through a grid‐search technique, we obtain the best‐fit 1D 〈span〉P〈/span〉‐wave velocity model near the 410‐km discontinuity beneath the northeastern South China Sea. In such a model, a low‐velocity layer (LVL) is found to reside atop the mantle transition zone, and it is characterized by a thickness of 92.5±11.5 km and a 〈span〉P〈/span〉‐wave velocity decrement of 1.5%±0.1% compared with the IASP91 model. The relatively thick and weak LVL is possibly a response of a small amount of remnant hydrous partial melts after plume‐like upwelling.〈/span〉
Print ISSN:
0037-1106
Electronic ISSN:
1943-3573
Topics:
Geosciences
,
Physics
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