| 利用三重震相探测中国东部海域410 km深度低速层 |
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| 引用本文： | 眭怡,周元泽.利用三重震相探测中国东部海域410 km深度低速层[J].地震学报,2015,37(1):1-14. |
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| 作者姓名： | 眭怡 周元泽 |
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| 作者单位： | 1) 中国北京100049中国科学院计算地球动力学重点实验室2) 中国北京100049中国科学院大学地球科学学院 |
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| 摘 要： | 基于中国数字地震台网记录的日本本州地区2009年发生的一次震源深度为167.2 km、 震级为mb6.0地震的宽频带波形资料，利用二维射线追踪方法给出P波三重震相的理论时 距曲线，并采用试错法构建出与观测时 距曲线拟合效果最优的低速异常模型，发现在中国东部海域下方410 km间断面上、下均存在局部的P波低速异常:300—410 km深度范围内低速异常为4%—5%，而410—460/470 km深度范围内的低速异常则达到4%—7%．结合前人地震层析成像结果，发现该区域不存在明确外源热流，因而，本文认为该低速异常与俯冲板片脱水引起的部分熔融有关．
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| 关 键 词： | style="font-size:14px font-family:'Times New PRoman'">P style="font-size:14px 波三重震相" target="_blank">font-family:宋体">波三重震相 style="font-size:14px font-family:'Times New 410" target="_blank">Roman'">410 km style="font-size:14px 低速层" target="_blank">font-family:宋体">低速层 中国东部海域 |
Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications |
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| Sui Yi,Zhou Yuanze.Low-velocity anomaly around 410 km beneath the Yellow and East China Seas with P wave triplications[J].Acta Seismologica Sinica,2015,37(1):1-14. |
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| Authors: | Sui Yi Zhou Yuanze |
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| Affiliation: | 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 |
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| Abstract: | 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. |
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| Keywords: | P wave triplication low velocity anomaly Yellow and East China Seas |
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