Crustal Extension and Graben Formation by Fault Slip-Associated Pore Opening, Kyushu, Japan
文献类型：期刊论文
| 作者 | Wang, Zhi; Fukao, Yoshio2; Miyakawa, Ayumu3; Hasegawa, Akira4; Takei, Yasuko1 |
| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
 |
| 出版日期 | 2019 |
| 卷号 | 124期号:5页码:4879 |
| ISSN号 | 2169-9313 |
| 关键词 | crustal extension graben poroelasticity Bouguer anomaly seismic tomography |
| DOI | 10.1029/2018JB016649 |
| 英文摘要 | Crustal extension in graben takes place by normal (+strike-slip) faulting, yet the physical processes involved are poorly understood. A series of shallow large earthquakes struck the Kumamoto area of Kyushu, Japan, in 2016. The M(w)7.0 main shock was a slip along the southern boundary of the Beppu-Shimabara Graben, where NS-extensional crustal deformation is now taking place. We conducted a tomographic inversion for crustal P and S velocities and Poisson's ratio (V-p, V-s, and sigma) in Kyushu. The most outstanding feature in this region is a Beppu-Shimabara Graben-parallel belt of low V-p and V-s anomalies at depths of the upper crust. We find that within the belt dV(s)/V-s approximate to dV(p)/V-p (<0) in marked contrast to relations in other low-velocity regions where |dV(s)/V-s|>|dV(p)/V-p|. This observation can be interpreted as due to water-saturated, oblate-spheroid pores with either of two very different geometries: one almost round pore and the other very flat pore. We calculate 3-D density anomaly distributions and 2-D gravity anomaly profiles for these two pore models. The gravity anomaly map calculated for spherical pores shows a significant negative anomaly belt that spatially agrees with observed Bouguer anomaly map. The spatial agreement is very poor if pores are modeled as flat. This and extensive seismicity within Beppu-Shimabara Graben imply significance of fault-associated round pore formation in the process of graben opening. Seismic tomography combined with gravity and poroeasticty analyses can constrain the crack/pore state of extensionally deforming crust. |
| 源URL | [http://ir.scsio.ac.cn/handle/344004/17960]  |
| 专题 | 南海海洋研究所_中科院边缘海地质重点实验室 |
| 作者单位 | 1.Tohoku Univ, Dept Geophys, Sendai, Miyagi, Japan 2.Chinese Acad Sci, South China Sea Inst Oceanol, CAS Key Lab Ocean & Marginal Sea Geol, Guangzhou, Guangdong, Peoples R China 3.Japan Agcy Marine Earth Sci & Technol, CEAT, Yokohama, Kanagawa, Japan 4.Geol Survey Japan, AIST, Tsukuba, Ibaraki, Japan 5.Univ Tokyo, Earthquake Res Inst, Tokyo, Japan |
| 推荐引用方式 GB/T 7714 | Wang, Zhi,Fukao, Yoshio,Miyakawa, Ayumu,et al. Crustal Extension and Graben Formation by Fault Slip-Associated Pore Opening, Kyushu, Japan[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,2019,124(5):4879, 4894. |
| APA | Wang, Zhi,Fukao, Yoshio,Miyakawa, Ayumu,Hasegawa, Akira,&Takei, Yasuko.(2019).Crustal Extension and Graben Formation by Fault Slip-Associated Pore Opening, Kyushu, Japan.JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH,124(5),4879. |
| MLA | Wang, Zhi,et al."Crustal Extension and Graben Formation by Fault Slip-Associated Pore Opening, Kyushu, Japan".JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 124.5(2019):4879. |
入库方式： OAI收割
来源：南海海洋研究所
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