| Finite difference tomography of the crustal velocity structure in Tengchong, Yunnan province | |
| Cao Ling-Min1; Xu Yi2; Wu Shi-Guo1; Cao, LM | |
| 2013-04-01 | |
| 发表期刊 | CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
 |
| ISSN | 0001-5733 |
| 卷号 | 56期号:4页码:1159-1167 |
| 文章类型 | Article |
| 摘要 | This paper applies the finite difference tomography method to invert for the P-wave velocity structure in the Tengchong area using earthquake data from a temporary network and other permanent stations, and analyzes the magmatic activity of the Tengchong volcanoes and the deep tectonic genesis of Longling M7.3/M7.4 earthquakes. The results show the mean velocity in the crust with clear heterogeneity is a little lower. The lower velocities in the shallow layers are caused by unconsolidated basin deposits, Cenozoic volcanic deposits, fluid fractures and hot springs. The high-velocity zone at 5 similar to 15 km depth probably represents the cooled and solidified magmatic intrusions or the less volatile ultramafic remnants. The low-velocity structure in the deep indicates the molten or semi-molten magma. It is probable that the magmatic activity beneath the volcanoes and heat flow intrusions in the deep crust of Longling earthquake zone are from the same magmatic hearth area, which is the main area of the present magmatic activities. A strong lateral heterogeneity is observed in Longling earthquake zone. The east of the Nujiang fault belt and the west of the Long ling fault belt have the characters of high-velocity with the high strength of rock, which are the main bearing body of stress accumulation. However, the low-velocity anomaly between the two faults extends to lower crust, probably caused by magmatic intrusions in the deep crust. The magmatic activity in this area is controlled clearly by the Long ling fault and the Nujiang fault. The Long ling M7.3 and M7.4 earthquakes occurred near the velocity boundary beneath the faults. The main reasons of the strong earthquakes in the Long ling area contain the heterogeneity of stress accumulation caused by the lateral variation of the crustal medium strength, the deep magmatic aggregation and dynamic effects.; This paper applies the finite difference tomography method to invert for the P-wave velocity structure in the Tengchong area using earthquake data from a temporary network and other permanent stations, and analyzes the magmatic activity of the Tengchong volcanoes and the deep tectonic genesis of Longling M7.3/M7.4 earthquakes. The results show the mean velocity in the crust with clear heterogeneity is a little lower. The lower velocities in the shallow layers are caused by unconsolidated basin deposits, Cenozoic volcanic deposits, fluid fractures and hot springs. The high-velocity zone at 5 similar to 15 km depth probably represents the cooled and solidified magmatic intrusions or the less volatile ultramafic remnants. The low-velocity structure in the deep indicates the molten or semi-molten magma. It is probable that the magmatic activity beneath the volcanoes and heat flow intrusions in the deep crust of Longling earthquake zone are from the same magmatic hearth area, which is the main area of the present magmatic activities. A strong lateral heterogeneity is observed in Longling earthquake zone. The east of the Nujiang fault belt and the west of the Long ling fault belt have the characters of high-velocity with the high strength of rock, which are the main bearing body of stress accumulation. However, the low-velocity anomaly between the two faults extends to lower crust, probably caused by magmatic intrusions in the deep crust. The magmatic activity in this area is controlled clearly by the Long ling fault and the Nujiang fault. The Long ling M7.3 and M7.4 earthquakes occurred near the velocity boundary beneath the faults. The main reasons of the strong earthquakes in the Long ling area contain the heterogeneity of stress accumulation caused by the lateral variation of the crustal medium strength, the deep magmatic aggregation and dynamic effects. |
| 关键词 | p Wave Tomography Magmatism Longling Earthquakes Tengchong Volcanic Area |
| 学科领域 | Geochemistry & Geophysics |
| DOI | 10.6038/cjg20130411 |
| URL | 查看原文 |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS研究方向 | Geochemistry & Geophysics |
| WOS类目 | Geochemistry & Geophysics |
| WOS记录号 | WOS:000318456900011 |
| WOS关键词 | SIMULTANEOUS INVERSION ; SEISMIC TOMOGRAPHY ; TIBETAN PLATEAU ; WESTERN YUNNAN ; VOLCANIC FIELD ; TRAVEL-TIMES ; BENEATH ; CHINA ; EARTHQUAKE ; REGION |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qdio.ac.cn/handle/337002/16301 |
| 专题 | 海洋地质与环境重点实验室 |
| 通讯作者 | Cao, LM |
| 作者单位 | 1.Chinese Acad Sci, Inst Oceanol, Marine Geol & Environm Key Lab, Qingdao 266071, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Petr Resource Res, Beijing 100029, Peoples R China |
| 第一作者单位 | 中国科学院海洋研究所 |
| 推荐引用方式 GB/T 7714 | Cao Ling-Min,Xu Yi,Wu Shi-Guo,et al. Finite difference tomography of the crustal velocity structure in Tengchong, Yunnan province[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2013,56(4):1159-1167. |
| APA | Cao Ling-Min,Xu Yi,Wu Shi-Guo,&Cao, LM.(2013).Finite difference tomography of the crustal velocity structure in Tengchong, Yunnan province.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,56(4),1159-1167. |
| MLA | Cao Ling-Min,et al."Finite difference tomography of the crustal velocity structure in Tengchong, Yunnan province".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 56.4(2013):1159-1167. |
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