The formation and evolution of the Qiaojia pull-apart basin, North Xiaojiang Fault Zone, Southwest China

2016 ◽  
Vol 13 (6) ◽  
pp. 1096-1106 ◽  
Author(s):  
Tian-tao Li ◽  
Xiang-jun Pei ◽  
Run-qiu Huang ◽  
Long-de Jin
Keyword(s):  
Fault Zone ◽  
Southwest China ◽  
Pull Apart Basin ◽  
Formation And Evolution ◽  
Xiaojiang Fault

scholarly journals Microseismicity along Xiaojiang Fault Zone (China) and the Characterization of Interseismic Fault Behavior

2021 ◽  
Author(s):  
Yijian Zhou ◽  
Han Yue ◽  
Shiyong Zhou ◽  
Lihua Fang ◽  
Yun Zhou ◽  
...  
Keyword(s):  
Fault Zone ◽  
Fault Behavior ◽  
Xiaojiang Fault

New insight into the 24 January 2020, Mw 6.8 Elazığ earthquake (Turkey): An evidence for rupture-parallel pull-apart basin activation along the East Anatolian Fault Zone constrained by Geodetic and Seismological data

2021 ◽  
Vol 64 (4) ◽  
pp. SE439
Author(s):  
T Serkan Irmak ◽  
Mustafa Toker ◽  
Evrim Yavuz ◽  
Erman Şentürk ◽  
Muhammed Ali Güvenaltın
Keyword(s):  
Fault Zone ◽  
Surface Deformation ◽  
Waveform Inversion ◽  
Strike Slip ◽  
Focal Mechanisms ◽  
Deformation Pattern ◽  
Pull Apart Basin ◽  
Insight Into ◽  
East Anatolian Fault Zone ◽  
East Anatolian Fault

In this study, we investigated the main features of the causative fault of the 24 January 2020, Mw 6.8 Elazığ earthquake (Turkey) using seismological and geodetic data sets to provide new insight into the East Anatolian Fault Zone (EAFZ). We first constrained the co-seismic surface deformation and the rupture geometry of the causative fault segment using Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1A/B satellites) and teleseismic waveform inversion, respectively. Also, we determined the centroid moment tensor (CMT) solutions of focal mechanisms of the 27 aftershocks using the regional waveform inversion method. Finally, we evaluated the co-seismic slip distribution and the CMT solutions of the causative fault as well as of adjacent segments using the 27 focal solutions of the aftershocks, superimposed on the surface deformation pattern. The CMT solution of the 24 January 2020Elazığ earthquake reveals a pure strike-slip focal mechanism, consistent with the structural pattern and left-lateral motion of the EAFZ. The rupture process of the Elazığ event indicated that the rupture is started at 12 km around the hypocenter, and then propagated bilaterally along the NE-SW but mainly toward the southwest. The rupture slip has initially propagated toward the southwest (first 10 s) and northeast (4 s), and again toward the southwest (9 s). Maximum displacement is calculated as 1.3 m about 20 km southwest of the hypocenter at 6 km depth (centroid depth). The rupture stopped to down-dip around 20 km depth toward the southwest. The distribution of the slip vectors indicates that the rupture continued mostly through a normal oblique movement. Most of the moment release was released SW of the hypocenter and the rupture reached up to around 50 km. The focal mechanisms of analyzed 27 aftershocks show strike-slip, but mostly normal and normal oblique-slip faulting with an orientation of the tensional axes (NNE-SSW), indicating a normal oblique-slip, “transtensional” stress regime, parallel-subparallel to the strike of the EAFZ, consistent with SW-rupture directivity and co- seismic deformation pattern. Finally, based on the co-seismic surface deformation compatible with the distributional pattern of normal focal solutions, normal and normal oblique-slip focals of the aftershocks evidence the rupture-parallel pull-apart basin activation as a segment boundary of the left-lateral strike-slip movement of the EAFZ.

Newly-generated Daliangshan fault zone — Shortcutting on the central section of Xianshuihe-Xiaojiang fault system

2008 ◽  
Vol 51 (9) ◽  
pp. 1248-1258 ◽  
Author(s):  
HongLin He ◽  
Yasutaka Ikeda ◽  
YuLin He ◽  
Masayoshi Togo ◽  
Jie Chen ◽  
...  
Keyword(s):  
Fault Zone ◽  
Fault System ◽  
Central Section ◽  
Xiaojiang Fault

Stress State and Fault Strength Variation along Xiaojiang Fault Zone Revealed by Seismicity

2020 ◽  
Author(s):  
Yijian Zhou ◽  
Shiyong Zhou ◽  
Hao Zhang ◽  
Yu Hou ◽  
Weilai Pei ◽  
...  
Keyword(s):  
Fault Zone ◽  
Large Scale ◽  
Velocity Structure ◽  
Broad Band ◽  
High Stress ◽  
Head Wave ◽  
The Tibetan Plateau ◽  
Fault Geometry ◽  
Seismicity Pattern ◽  
Xiaojiang Fault

<p>Xiaojiang Fault (XJF) lies at the southeastern edge of the rhombic Sichuan-Yunnan block, and has an extent for over 400km from Qiaojia to Shanhua district. The Sichuan-Yunnan block experiences clockwise rotation and southwestward escaping from the Tibetan Plateau, producing complex fault geometry and seismicity pattern. The strong variation along fault segments provides a special opportunity to study the relationship between fault zone properties and seismicity pattern. However, the fine structure of XJF remains unknown due to the sparse observational stations.</p><p>Seismic data has its unique advantage of resolving fault zone properties at depth. We deployed 48 broad-band seismometers along XJF in order to capture detailed seismicity patterns. Our seismic network covers the northern and middle part of XJF, with an average aperture of 20km; the continuous observation from 2015 to 2019 guarantees enough data volume. We detected about 12,000 earthquakes by STA/LTA phase picking and association, and augmented the detection to over 50,000 events with template matching. The relocated catalog has lateral and vertical resolution of 500m and 1km, respectively; the magnitude of completeness (Mc) reaches ML0.3</p><p>This high-resolution catalog depicts detailed 3D fault geometry. The seismicity shows clustered lateral distribution, with the clusters’ depth extension ranging from 20km at northern to 35km at southern segments. Unmapped orthogonal faults on northern XJF are illuminated by seismicity, which matches orthogonal topography characteristics. Repeating events are detected from 8 seismicity clusters, under a threshold of 5 repeating families, indicating a creeping slip mode, while the separated low-seismicity segments exhibit a high locking rate. Taking advantage of the high detectability, we got reliable b-value estimation for different segments of XJF. The low-b regions correlate well with the margins of locking patches, which points to a high stress concentration. Velocity structure extracted from ambient noise and fault zone head wave present similar spatial variation, which further proved the seismicity pattern. The high heterogeneous characteristics of XJF may produce stress barriers, preventing future earthquake rupture from propagating to a large scale. </p>

Scenario-Based Seismic Hazard Analysis for the Xianshuihe Fault Zone, Southwest China

2017 ◽  
Vol 175 (2) ◽  
pp. 707-720 ◽  
Author(s):  
Lifang Zhang ◽  
N. Seth Carpenter ◽  
Zhenming Wang ◽  
Yuejun Lyu ◽  
Shanyou Li
Keyword(s):  
Seismic Hazard ◽  
Fault Zone ◽  
Southwest China ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Xianshuihe Fault Zone

scholarly journals Geomorphological And Sedimentary Records of Late Quaternary Activities of Qiaojia-Jinyang Segment of Lianfeng Fault Zone, Southwest China

2021 ◽  
Author(s):  
Youpeng Wang ◽  
Dewen Li
Keyword(s):  
Fault Zone ◽  
Late Pleistocene ◽  
Southwest China ◽  
Late Quaternary ◽  
Morphological Characteristics ◽  
Second Grade ◽  
Jinsha River ◽  
Middle Holocene ◽  
River Terraces ◽  
Regional Tectonic

Abstract Lianfeng Fault Zone (LFZ) in Southwest China has great significance for understanding the seismogenic environment, but its activity is still poor constrains. The Qiaojia-Jinyang segment (QJS) of LFZ intersects with Jinsha River; Here well developed river terraces provide a potential Spatiotemporal constrains for faulting. Based on investigation of the terrace deposits along river, this paper makes a detailed logging and dating of the faulting and liquefaction of QJS. Combined previous data, the spatiotemporal sequence of the Late Quaternary river terraces in the area was redetermined. It is considered that the first and second grade river terraces at QJS (~10-20m and 60-70m, respectively, above the local river level) are roughly developed in the middle Holocene and the late Late Pleistocene, indicating that the valley along QJS was strongly undercut since the Late Pleistocene. Based on the analysis of the morphological characteristics, spatial distribution, material composition and intersecting relationship between the sand veins and the layers, the cause of the ground motions is preliminarily determined, which indicates the strong seismic activity of the LFZ during the Quaternary. Combined with the faulting characteristics within the profiles of terrace deposits and the dating data of the overlying strata, it is considered that the LFZ is active at least at QJS, and the latest active time is not earlier than the early-middle Holocene. These understandings provide a clear geological evidences for the seismicity assessment at LFZ, and help to the understanding of regional tectonic environment and the prevention of earthquake disasters.

scholarly journals Termination of a Trench-Linked Strike-Slip Fault Zone in the Sumatra–Java Forearc Basin and Accretionary Wedge Complex

2020 ◽  
Vol 21 (4) ◽  
pp. 177
Author(s):  
Maruf M Mukti ◽  
Ilham Arisbaya ◽  
Haryadi Permana
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Large Earthquake ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Accretionary Wedge ◽  
The South ◽  
Forearc Basin ◽  
Pull Apart Basin ◽  
Vertical Fault

This paper presents a review of several published seismic reflection and seismicity data and analyzes of high-resolution bathymetry data to revise the exact location and reveal detail characteristics of a strike-slip fault zone that formed the southernmost segment of the Sumatran Fault (SF). Previous works interpreted this fault segment as a horst structure to the south of a pull-apart basin. We observe a clear linear trace of dissected seafloor parallels to SF in the high-resolution bathymetric map. This structure extends from the south of a pull-apart basin in the northwest to the Sunda accretionary wedge farther southeast. This lineament exhibits a narrow valley and a linear ridge that in the subsurface are interpreted as negative and positive flower structures, respectively. The structure exhibits a vertical fault plane and appears to have deformed the accretionary wedge sediments and basement at depth. A cluster of shallow seismicity is observed along this NW-trending fault zone, indicating the activity of this zone. Here, we proposed this strike-slip fault as the Ujung Kulon Fault that marks the southeasternmost segment of the SF zone. This segment deformed the area of the Sumatra-Java forearc basin and terminated in accretionary wedge near the trench. The accumulated strain within UKF may trigger large earthquake in the future, close to the highly populated areas in the coast of Sumatra and Java.Keywords: Strike-slip fault, Sumatra Fault, Ujung Kulon Fault, segmentation, earthquake.

scholarly journals STRUCTURAL STYLE AND DEPOSITIONAL HISTORY OF THE SEMANGKO PULL APART BASIN IN THE SOUTHEASTERN SEGMENT OF SUMATRA FAULT ZONE

2018 ◽  
Vol 28 (1) ◽  
pp. 115
Author(s):  
Maruf M Mukti
Keyword(s):  
Fault Zone ◽  
Seismic Data ◽  
Side Wall ◽  
Depositional History ◽  
Structural Style ◽  
Pull Apart Basin ◽  
History Of ◽  
Step Over ◽  
Structural High

Re-examination of published seismic data in the southeasternmost segment of the active Sumatra Fault zone (SFZ) reveals the characteristics of structural style and depositional history of Semangko pull apart basin (SPB). The SPB have been developed as a transtensional pull apart basin resulted from stepping over of the Semangko to Ujung Kulon segments of the SFZ. The geometry of SPB is of rhomboidal shape characterized by dual depocenters separated by a discrete structural high in the center of SPB. Based on the determination of pre- and syn-kinematic strata related to the formation of SPB, sedimentary units prior to deposition of Unit 3 can be regarded as pre-kinematic strata, whereas the syn-kinematic strata is represented by Unit 3. The basin sidewall faults of the SPB are likely to have been developed as en-echelon side wall faults and identified as the East Semangko Fault (ESF) and Kota Agung – South Panaitan Faults (KAF-SPF) in the western and eastern margin of the SPB, respectively. The development of discrete highs along the center of the SPB may relate to the formation of en-echelon cross-basin faults that are now overprinted by volcanic activity or magmatic intrusion.Analisa ulang data seismik yang telah dipublikasikan di daerah segmen paling tenggara dari zona sesar aktif Sumatra (SFZ) mengungkapkan karakteristik struktur dan sejarah pengendapan dari cekungan pull-apart Semangko (SPB). SPB terbentuk sebagai cekungan transtensional pull-apart yang dihasilkan dari step over segmen Semangko dan segmen Ujung Kulon. Geometri SPB adalah bentuk rhomboidal yang dicirikan oleh dua depocenter yang dipisahkan oleh struktur tinggian yang tidak menerus di bagian tengah SPB. Berdasarkan penentuan unit pre- dan syn-kinematic strata yang terkait dengan pembentukan SPB, unit sedimen yang terbentuk sebelum pengendapan Unit 3 dapat dianggap sebagai pre-kinematic strata, sedangkan syn-kinematic strata diwakili oleh Unit 3. Sesar side-wall dari SPB kemungkinan telah berkembang sebagai sesar yang bersifat en-echelon dan diidentifikasi sebagai Sesar Semangko Timur (ESF) dan Sesar Kota Agung - Panaitan Selatan (KAF-SPF) di tepian barat dan timur SPB. Pembentukan tinggian  yang tidak menerus di sepanjang bagian tengah SPB berhubungan dengan pembentukan sesar-sesar cross-basin yang bersifat en-echelon yang sekarang telah tertutupi jejaknya oleh aktivitas gunung api atau intrusi magmatik. 

Three-Dimensional P-Wave Velocity Structure Around the Xiaojiang Fault Zone and Its Tectonic Implications

2013 ◽  
Vol 56 (4) ◽  
pp. 400-410
Author(s):  
WU Jian-Ping ◽  
YANG Ting ◽  
WANG Wei-Lai ◽  
MING Yue-Hong ◽  
ZHANG Tian-Zhong
Keyword(s):  
Fault Zone ◽  
Wave Velocity ◽  
Velocity Structure ◽  
Three Dimensional ◽  
P Wave ◽  
Tectonic Implications ◽  
P Wave Velocity ◽  
Xiaojiang Fault ◽  
P Wave Velocity Structure
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