Focal mechanisms and seismogenic structures of the Ms5.7 and Ms4.8 Jiujiang-Ruichang earthquakes of Nov. 26, 2005

Jian Lü, Yong Zheng, Si Dao Ni, Jian Hua Gao

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Based on the records of 6 stations in Jiangxi regional seismic network and CSN, we obtained the focal mechanisms of the Ms 5.7 Jiujiang-Ruichang earthquake and its Ms 4.8 aftershock of Nov.26, 2005 with the "Cut and Paste" (CAP) method, and analyzed the seismogenic structure combining with relocation of the aftershock sequence and the geologic settings in the region. Our result shows that the best double couple solution of the Ms 5.7 event is 324°, 55°and 18° for strike, dip and rake angles respectively, the other nodal plane is 223°, 75° and 144°; for the Ms 4.8 aftershock the solution is 54°, 71°, - 160° respectively with the other nodal plane of 317°, 71° and - 20°. Complexities can be found from aftershock distribution and source depth of the sequence. After the occurrence of the Ms 5.7 main shock, aftershocks occurred and propagated from SE to NW and from shallower to deeper crust, then they probably encountered an asperity and triggered the Ms 4.8 strong aftershock. This complexity and the different focal mechanisms imply that the two earthquakes may not occur on the same fault, we infer that the Ms 5.7 main shock is caused by the NW striking Yangjishan-Wushan-Tongjiangling fault buried in Ruichang basin and the Ms 4.8 aftershock occurred on the NE striking Dingjiashan-Guilinqiao-Wuning fault in the northwest margin of the basin.

Translated title of the contributionFocal mechanisms and seismogenic structures of the Ms5.7 and Ms4.8 Jiujiang-Ruichang earthquakes of Nov. 26, 2005
LanguageChinese
Pages158-164
Number of pages7
JournalChinese Journal of Geophysics
Volume51
Issue number1
Publication statusPublished - Jan 2008
Externally publishedYes

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focal mechanism
aftershock
Earthquakes
earthquakes
shock
rakes
earthquake
relocation
Relocation
Ointments
margins
crusts
stations
occurrences
asperity
basin
dip
crust

Keywords

  • CAP method
  • Focal mechanism
  • Jiujiang-Ruichang earthquake
  • Seismogenic structure

Cite this

Lü, Jian ; Zheng, Yong ; Ni, Si Dao ; Gao, Jian Hua. / 2005年11月26日九江-瑞昌Ms5.7、Ms4.8地震的震源机制解与发震构造研究. In: Chinese Journal of Geophysics. 2008 ; Vol. 51, No. 1. pp. 158-164.
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abstract = "Based on the records of 6 stations in Jiangxi regional seismic network and CSN, we obtained the focal mechanisms of the Ms 5.7 Jiujiang-Ruichang earthquake and its Ms 4.8 aftershock of Nov.26, 2005 with the {"}Cut and Paste{"} (CAP) method, and analyzed the seismogenic structure combining with relocation of the aftershock sequence and the geologic settings in the region. Our result shows that the best double couple solution of the Ms 5.7 event is 324°, 55°and 18° for strike, dip and rake angles respectively, the other nodal plane is 223°, 75° and 144°; for the Ms 4.8 aftershock the solution is 54°, 71°, - 160° respectively with the other nodal plane of 317°, 71° and - 20°. Complexities can be found from aftershock distribution and source depth of the sequence. After the occurrence of the Ms 5.7 main shock, aftershocks occurred and propagated from SE to NW and from shallower to deeper crust, then they probably encountered an asperity and triggered the Ms 4.8 strong aftershock. This complexity and the different focal mechanisms imply that the two earthquakes may not occur on the same fault, we infer that the Ms 5.7 main shock is caused by the NW striking Yangjishan-Wushan-Tongjiangling fault buried in Ruichang basin and the Ms 4.8 aftershock occurred on the NE striking Dingjiashan-Guilinqiao-Wuning fault in the northwest margin of the basin.",
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2005年11月26日九江-瑞昌Ms5.7、Ms4.8地震的震源机制解与发震构造研究. / Lü, Jian; Zheng, Yong; Ni, Si Dao; Gao, Jian Hua.

In: Chinese Journal of Geophysics, Vol. 51, No. 1, 01.2008, p. 158-164.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - 2005年11月26日九江-瑞昌Ms5.7、Ms4.8地震的震源机制解与发震构造研究

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AU - Zheng, Yong

AU - Ni, Si Dao

AU - Gao, Jian Hua

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AB - Based on the records of 6 stations in Jiangxi regional seismic network and CSN, we obtained the focal mechanisms of the Ms 5.7 Jiujiang-Ruichang earthquake and its Ms 4.8 aftershock of Nov.26, 2005 with the "Cut and Paste" (CAP) method, and analyzed the seismogenic structure combining with relocation of the aftershock sequence and the geologic settings in the region. Our result shows that the best double couple solution of the Ms 5.7 event is 324°, 55°and 18° for strike, dip and rake angles respectively, the other nodal plane is 223°, 75° and 144°; for the Ms 4.8 aftershock the solution is 54°, 71°, - 160° respectively with the other nodal plane of 317°, 71° and - 20°. Complexities can be found from aftershock distribution and source depth of the sequence. After the occurrence of the Ms 5.7 main shock, aftershocks occurred and propagated from SE to NW and from shallower to deeper crust, then they probably encountered an asperity and triggered the Ms 4.8 strong aftershock. This complexity and the different focal mechanisms imply that the two earthquakes may not occur on the same fault, we infer that the Ms 5.7 main shock is caused by the NW striking Yangjishan-Wushan-Tongjiangling fault buried in Ruichang basin and the Ms 4.8 aftershock occurred on the NE striking Dingjiashan-Guilinqiao-Wuning fault in the northwest margin of the basin.

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