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| An examination of the presence and topography of the D″ discontinuity under the Russia–Kazakhstan border region using seismic waveform data from a deep earthquake in Spain |
| Xuzhang Shen1, Yuanze Zhou2, Koki Idehara3, Xiuping Mei1, Kangsheng Xu1 |
1 Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China
2 Key Lab of Computational Geodynamics of Chinese Academy of Sciences/College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China
3 Earthquake Research Institute, Tokyo University, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan |
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Abstract The D″ layer, which is located atop the core– mantle boundary, has long been an area of focus for global seismology studies. A widely used approach to study the discontinuities in the D″ layer involves the use of the SdS phases between the S and ScS phases, which requires that certain stringent conditions be satisfied with respect to an epicentral distance and earthquake depth. Therefore, this approach is only practical for investigating the presence and topography of velocity interfaces in certain local regions around the world. The Russia–Kazakhstan border region has been a ‘‘blind spot’’ with respect to this detection method. The seismic network deployed in the northeastern margin of the Tibetan Plateau has recorded relatively clear SdS phases for the MS 6.3 earthquake that occurred in Spain on April 11, 2010, allowing this blind spot to be studied. This paper compares the observed waveforms and synthetics and uses the travel times of the relevant phases to obtain a D″ discontinuity depth between 2,610 and 2,740 km in the examined area. This study provides the first results regarding the depth of the D″ layer discontinuity for this region and represents an important addition to the global studies of the D″ layer.
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Received: 29 August 2013
Published: 14 March 2014
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| Fund:Science and Technology Development Fund of Gansu Earthquake Administration of Gansu Province (No. 2012M02) and National Natural Science Foundation of China (No. 41274093) |
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Corresponding Authors:
Yuanze Zhou
E-mail: yzzhou@ucas.ac.cn
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