The Traveltime Tomography Study by Teleseismic P Wave Data in the Northeast China Area
详细信息
- 责任者：Zhang Fengxue (Key Laboratory of Seismic Observation and Geophysical Imaging ; Institute of Geophysics ; China Earthquake Administration ; Beijing 100081 ; China) ; Wu Qingju
- 刊名：Chinese Journal of Geophysics
- 出版年：2013
- 卷期：56(8)
- 关键词：远震信号 ; teleseismic signals ; 速度结构 ; velocity structure ; 东北地区 ; Northeast China
- 页码：p.2690-2700
- 图表：7 illus., 31 refs.
- 分类号：0400
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
We picked the relative traveltime residuals from the teleseismic waveform data by waveform correlation method,and got 57251 usable relative traveltime residuals.The teleseismic waveform data were recorded by the temporary and permanent seismic networks in Northeast China,the total number of the station is 234.We imaged the P-wave velocity structure beneath Northeast China down to 800 km depth by the FMTT(Fast Marching Teleseismic Tomography).The results reveal that 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 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,Aershan volcano and Wudalianchi volcano.The low-velocity anomalies under the Changbaishan and Aershan volcano extend down to the 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 Aershan 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 mixed high-and low-velocity distribution character beneath the Songliao Basin area.The mixture character suggests that lithospheric delamination may have occurred and greatly affected the Songliao Basin.The low-velocity anomaly,beneath the southern part of Songliao Basin area connecting to the low-velocity anomalies beneath the Changbaishan and Aershan volcano,may be a upwelling material channel from the lower mantle.
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