| 中国东北地区远震S波走时层析成像研究 |
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| 引用本文： | 张风雪,吴庆举,李永华.中国东北地区远震S波走时层析成像研究[J].地球物理学报,2014,57(1):88-101. |
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| 作者姓名： | 张风雪 吴庆举 李永华 |
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| 作者单位： | 1. 中国地震局地球物理研究所 地震观测与地球物理成像重点实验室, 北京 100081;
2. 中国地震局地球物理研究所, 北京 100081 |
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| 基金项目： | 国家自然科学基金重点项目（90814013），国土资源部深部探测技术实验研究专项（SinoProbe-02-03），中国地质调查局地质调查工作项目（1212011121072），国家自然科学基金（41304066）联合资助. |
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| 摘 要： | 利用中国东北流动和固定台网的234个宽频带地震仪在2009年6月-2011年5月所记录的远震波形数据，采用波形相关方法拾取了10301个有效的S震相相对走时残差数据，进一步采用两种射线走时层析成像的方法，反演获取了研究区下方深达800 km的S波速度结构，不同射线走时层析成像方法的结果对本区的S波速度异常结构起到一定的约束作用.S波成像结果与我们先前开展的P波成像研究结果整体相似：在长白山下方发现有一个高速异常结构，这可能就是俯冲到欧亚大陆板块下方的太平洋板块，由于板块的部分下沉，使得板块的形状并没有呈现出明显的板片状.长白山、阿尔山、五大连池火山下方都有低速异常体，长白山和阿尔山下的低速异常向下延伸至地幔转换带附近，可能与其上部的火山形成有关.五大连池火山下方的低速异常向下延伸至200 km左右，不同埋深的低速异常结构可能意味着五大连池与长白山和阿尔山有着不同的成因.松辽盆地呈现以高速异常为主导、高低速异常混合分布的特性，暗示松辽盆地岩石圈地幔可能遭受了改造与破坏，可能有岩石圈拆沉的过程，盆地南部下方的低速异常与长白山和阿尔山下的低速异常有连通性，可能是下地幔热物质上涌的一个通道.S波和P波相似的成像结果从另一个角度展示了中国东北地区的上地幔速度异常结构，对我们认识此区的地下结构提供了重要的约束.
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| 关 键 词： | 中国东北 长白山 阿尔山 五大连池 层析成像 |
| 收稿时间： | 2013-07-05 |
A traveltime tomography study by teleseismic S wave data in the Northeast China area |
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| ZHANG Feng-Xue,WU Qing-Ju,LI Yong-Hua.A traveltime tomography study by teleseismic S wave data in the Northeast China area[J].Chinese Journal of Geophysics,2014,57(1):88-101. |
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| Authors: | ZHANG Feng-Xue WU Qing-Ju LI Yong-Hua |
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| Institution: | 1. Key Laboratory of Seismic Observation and Geophysical Imaging, Institute of Geophysics, China Earthquake Administration, Beijing 100081, China;
2. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China |
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| Abstract: | We picked 10301 S wave relative traveltime residuals from the teleseismic waveform data by waveform correlation method. The teleseismic waveform data were recorded by the temporary and permanent seismic networks in Northeast China from June 2009 to May 2011, the total number of the station is 234. We imaged the S-wave velocity structure beneath Northeast China down to 800 km depth by two ray traveltime tomography methods. The S-wave velocity anomaly structures are partly restricted by the two different tomography results in this area. Most parts of the S wave results are similar to the previous P wave results: There is a high-velocity anomaly beneath the Changbaishan volcano, maybe this anomaly is the Pacific Plate, which subducted under the Eurasian Plate. Because of the local depressing of the plate, the shape of the plate doesn't appear as an obvious slab. There are low-velocity anomalies beneath the Changbaishan volcano, A'ershan volcano and Wudalianchi volcano. The low-velocity anomalies under the Changbaishan and A'ershan volcano extend down to the near area of mantle transition zone, while the low-velocity anomaly under the Wudalianchi volcano extends down to about 200 km depth, which may indicate that Changbaishan and A'ershan volcano have some relationship with the low-velocity anomalies under them, and the different depths of the low-velocity anomalies represent the different origin of the Wudalianchi volcano. There is a mainly high-velocity zone with a mixture high- and low-velocity distribution character beneath the Songliao Basin area. The mixture character suggests that the lithospheric mantle may have suffered destruction and transformation, and lithospheric delamination may have occurred and greatly affected the Songliao Basin. The low-velocity anomaly beneath the southern part of Songliao Basin area is connected to the low-velocity anomalies beneath the Changbaishan and A'ershan volcano, which may be a upwelling material channel from the lower mantle. We show the upper mantle S wave anomaly structure of Northeast China, which is similar to the P wave result but from another perspective, and provides an important constraint on our understanding of this area. |
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| Keywords: | Northeast China Changbaishan volcano A'ershan volcano Wudalianchi volcano Tomography |
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