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Topographies of seismic velocity discontinuities and penetrations of subducting slabs beneath the Sea of Okhotsk

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Chinese Science Bulletin 2002年第24期47卷 2034-2041页

作者： Zhiyong Jiang Shaoxian Zhang yuanze zhou Peking Univ Dept Geophys Beijing 100871 Peoples R China

The existence of discontinuities, the topographies of the 410 km and 660 km discontinuities, and the penetrations of subducting slabs near the 660 km discontinuities beneath the Sea of Okhotsk were studied using Nth root slant stack and digital records from networks in Germany and the western United States. Results show the obvious evidence for reflected and refractive phases associated with the 410 km and 660 km discontinuities. There may be discontinuities at other depths such as 150 km, 220 km and 520 km. The 410 km discontinuity is elevated and the 660 km discontinuity is depressed respectively, consistent with the expected thermal signature of the phase transitions. The subducting slab has penetrated into the lower mantle in the northern part of the Sea of Okhotsk, while it is stagnant on the 660 km discontinuity in the southern part.

关键词： the Sea of Okhotsk discontinuity subducting slab Nth root slant stack.

A Reappraisal of the 2005 Kashmir Earthquake in the Northwestern Himalaya Syntaxis

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Acta Geologica Sinica(English Edition) 2021年第S01期95卷 22-24页

作者： BAI Ling SU Hui zhou yuanze Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 10086China

The collision of the Indian and Eurasian plates caused a massive surface uplift and formed the *** the 2500-km long Himalaya mountain range,significant earthquake hazards have occurred either on the interface between ... 详细信息

关键词： 2005 Mw7.5 Kashmir earthquake source parameters western Himalayan syntaxis

Detection of the Lehmann discontinuity beneath Tonga with short-period waveform data from Hi-net

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Science China Earth Sciences 2014年第7期57卷 1953-1960页

作者： CHEN Jian zhou yuanze WANG HongCai College of Earth Science University of Chinese Academy of Sciences Key Laboratory of Computational Geodynamics Chinese Academy of Sciences Institute of Geomechanics Chinese Academy of Geological Sciences

The undulation and characteristics of the Lehmann discontinuity at the base of the Low Velocity Zone in the upper mantle are significant for understanding the coupling between the lithosphere and asthenosphere, and corresponding geodynamic processes. Vertical waveform data from six earthquakes with focal depths between 75 and 150 km and magnitudes Mb 5.0–6.0 since 2004 were collected from the short-period Hi-net array. Selected waveform data were processed for each event network pair using the Nth-root slant stack method to retrieve the SdP conversion phases from the possible 220 km(Lehmann) discontinuity. The conversion points related to the SdP phases show that there is a clear and flat velocity interface around 230 km, suggesting that there is a sinking of the Lehmann discontinuity beneath Tonga with no obvious undulation. The 230 km depth of the Lehmann discontinuity in this location could be explained by an hypothesis of transition in the deformation mechanism from dislocation creep to diffusion creep.

关键词： Lehmann discontinuity Nth-root slant stack Hi-net array Tonga region

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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

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Earthquake Science 2014年第2期27卷 209-215页

作者： Xuzhang Shen yuanze zhou Koki Idehara Xiuping Mei Kangsheng Xu Lanzhou Institute of Seismology China Earthquake Administration Key Lab of Computational Geodynamics of Chinese Academy of Sciences/College of Earth Science University of Chinese Academy of Sciences Earthquake Research Institute Tokyo University

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 MS6.3 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 between2,610 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.

关键词： D'' Russia-Kazakhstan border Spain deep earthquake North eastern margin of Tibet

Seismic detection of the X-discontinuity beneath the Ryukyu subduction zone from the SdP conversion phase

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Earth and Planetary Physics 2018年第3期2卷 208-219页

作者： QingHui Cui WenLan Li GuoHui Li MaiNing Ma XiaoYu Guan yuanze zhou Key Laboratory of Computational Geodynamics Chinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau ResearchChinese Academy of Sciences

The X-discontinuity,which appears at the depth of approximately 300 km,is an important seismic interface with positive velocity contrasts in the upper *** its presence and topography can be useful to understand phase transformations of relevant mantle minerals under the high-temperature and high-pressure circumstance of the Earth's *** this study,we detect the X-discontinuity beneath the Ryukyu subduction zone using five intermediate-depth events recorded by the dense Alaska Regional Network(AK).The X-discontinuity is successfully revealed from the robust slant stacking of the secondary down-going and converting Sd P *** the depth distribution of conversion points,we find that the X-discontinuity's depth ranges between 269 km and 313 km,with an average depth of 295 *** the conversion points are located beneath the down-dipping side of the Philippine Sea *** energy comparisons in vespagrams for observed and synthetic seismograms,the strong converted energy is more likely from a thin high-velocity layer,and the S-wave velocity jumps across the X-discontinuity are up to 5% to 8% with an average of 6.0%.According to previous petrological and seismological studies,the X-discontinuity we detected can be interpreted as the phase transformation of coesite to stishovite in eclogitic materials within the oceanic crust.

关键词： Ryukyu subduction zone X-discontinuity coesite-stishovite transformation dense network SdP conversion phase

基于三重震相方法探测日本海俯冲区地幔转换带的速度结构

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地震学报 2016年第5期38卷 659-670,813页

作者：崔辉辉周元泽中国科学院计算地球动力学重点实验室中国北京100049 中国科学院大学地球科学学院中国北京100049

本文基于中国数字地震台网记录的发生于日本北海道地区的一次中源地震的三重震相资料研究了日本海俯冲区地幔转换带的速度结构.结果表明,该区域P波速度结构与S波速度结构的一致性整体上较强.冷的西太平洋俯冲板块导致410km间断面出现了1... 详细信息

本文基于中国数字地震台网记录的发生于日本北海道地区的一次中源地震的三重震相资料研究了日本海俯冲区地幔转换带的速度结构.结果表明,该区域P波速度结构与S波速度结构的一致性整体上较强.冷的西太平洋俯冲板块导致410km间断面出现了10km的抬升,660km间断面出现了25km的下沉;410km和660km间断面之上均存在与俯冲板块相关的高速层;660km间断面下方存在厚度为65km的低速异常.纵横波波速比vP/vS值在210—400km深度范围内偏低,约为1.827,体现出海洋板块低泊松比的特征;在560—685km深度范围内,该值偏高,约为1.831,可能预示地幔转换带底部含有一定量的水.

关键词：三重震相地幔转换带日本海俯冲区波形拟合

利用三重震相探测中国东部海域410km深度低速层

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地震学报 2015年第1期37卷 1-14,204页

作者：眭怡周元泽中国科学院计算地球动力学重点实验室中国北京100049 中国科学院大学地球科学学院中国北京100049

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167.2km、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,... 详细信息

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167.2km、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%一7%.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.

关键词： P波三重震相 410 km低速层中国东部海域

New crustal thickness(H) and Vp/Vs ratio(k) images beneath the central Tien Shan revealed by the H-k-c stacking

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New crustal thickness(H) and Vp/Vs ratio(k) images beneath t...

伊豆-小笠原地区岩石圈软流圈边界地震学证据

2020年中国地球科学联合学术年会

作者： Cui Qinghui zhou yuanze Li Jiangtao Song Xiaodong Gao Yuan Key Laboratory of Earthquake Prediction Institute of Earthquake ForecastingChina Earthquake Administration Beijing Key Laboratory of Computational Geodynamics College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing Department of Geophysics School of Geodesy and Geomatics Wuhan University Wuhan Institute of Theoretical and Applied Geophysics School of Earth and Space Sciences Peking University Beijing

As an active intracontinental orogenic belt in Asia, the Tien Shan is a natural laboratory to study the mechanisms of the large-scale mountain building. The crustal shorting, intracontinental subduction or underthrusting models and some other dynamic models have been proposed to interpret the mountain building mechanisms in previous studies(e.g., Abdrakhmatov et al., 1996;Gao et al., 2013;Gilligan et al., 2014). However, the dynamics of tectonic rejuvenation of the Tien Shan have been controversial in recent decades, and still remain unclear so far.

关键词： and Vp/Vs ratio images beneath the central Tien Shan revealed by the H-k-c stacking New crustal thickness

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科学通报 2017年第7期62卷 711-720页

作者：崔辉辉高雅健周元泽中国科学院计算地球动力学重点实验室北京100049 中国科学院大学地球科学学院北京100049

岩石圈软流圈边界(lithosphere-asthenosphere boundary,LAB)是上地幔内具有负速度梯度的地震间断面.开展对俯冲带区域LAB的地震学探测有助于进一步理解岩石圈与软流圈的相互作用以及与板块俯冲相关的地球动力学过程.本文收集了2002~201... 详细信息

岩石圈软流圈边界(lithosphere-asthenosphere boundary,LAB)是上地幔内具有负速度梯度的地震间断面.开展对俯冲带区域LAB的地震学探测有助于进一步理解岩石圈与软流圈的相互作用以及与板块俯冲相关的地球动力学过程.本文收集了2002~2014年发生于伊豆-小笠原地区的3个深源地震(400~600 km)的垂向宽频带波形资料,利用线性倾斜叠加方法对波形数据进行处理后获得了相对走时-慢度域的灰度图和叠加波形图,并成功提取了s_P震相在LAB反射的前驱震相s_(LAB)P,该震相的极性与s_P相反,幅度比为0.17~0.21.基于改进的一维速度模型IASP91-IB计算获得了近源区6个s_(LAB)P震相反射点的分布.研究表明伊豆-小笠原岛弧下方LAB深度位于58~65 km,平均深度为62 km,起伏变化较小(7 km).与菲律宾海构造稳定地区研究结果相比,伊豆-小笠原岛弧地区海洋岩石圈出现了明显减薄的现象,其应与西太平洋俯冲板块在地球深部持续释放的挥发分物质导致了软流圈出现部分熔融以及弧后地幔楔内小尺度对流的强侵蚀作用密切相关.

关键词：岩石圈软流圈边界伊豆-小笠原地区俯冲带 sP前驱震相线性倾斜叠加