Sui Yi1,2) Zhou Yuanze1,2). 2015: Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications. Acta Seismologica Sinica, 37(1): 1-14. DOI: 10.11939/jass.2015.01.001
Citation:
Sui Yi1,2) Zhou Yuanze1,2). 2015: Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications. Acta Seismologica Sinica, 37(1): 1-14. DOI: 10.11939/jass.2015.01.001
Sui Yi1,2) Zhou Yuanze1,2). 2015: Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications. Acta Seismologica Sinica, 37(1): 1-14. DOI: 10.11939/jass.2015.01.001
Citation:
Sui Yi1,2) Zhou Yuanze1,2). 2015: Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications. Acta Seismologica Sinica, 37(1): 1-14. DOI: 10.11939/jass.2015.01.001
1) Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049,China2) College of Earth Sciences, University of Chinese Academy of Sciences, Beijing 100049,China
Broadband waveform data for one mb6.0 earthquake beneath Honshu,Japan, with focal depth of 167.2 km, recorded by China Digital Seismic Network (CDSN) were retrieved. Through trial-and-error method, the anomalous models beneath the Yellow and East China Seas for the six sub-regions were obtained by matching the theoretical travel-time curves of the P triplications from the modified models for the six sub-regions by using 2-D ray tracing with the observed ones. The local lower velocity anomaly appears around the 410 km discontinuity. Above the discontinuity, the P wave velocity decreases by 4%—5% from 300 km to 410 km and below the discontinuty, the velocity decreases by 4%—7% from 410 km to 460/470 km. Because thermal flow was not observed by former seismic tomographic results, the local low velocity anomaly should be due to the partial-melting caused by the dehydrated water from subducting slab.