Earthquake swarms near eastern Himalayan Syntaxis along Jiali Fault in Tibet: A seismotectonic appraisal

Abstract

a b s t r a c tThe seismotectonic characteristics of ten repeated earthquake swarm sequence within a seismic cluster along Jiali Fault in eastern Himalayan Syntaxis (EHS) have been analysed. The swarms are spatially disposed in and around Yigong Lake (a natural lake formed by blocking of Yigong River by landslide) and are characterized by low magnitude, crustal events with low to moderate b values. Ms : mb discriminant functions though indicate anomalous nature of the earthquakes within swarm but are considered as natural events that occurred under condition of high apparent stress and stress gradients. Composite fault plane solutions of selected swarms indicate strikeeslip sense of shear on fault planes; solution parameters show low plunging compression and tensional axes along NWeSE and NEeSW respectively with causative fault plane oriented ENEeWSW, dipping steeply towards south or north. The fault plane is in excellent agreement with the disposition and tectonic movement registered by right lateral Jiali Fault. The process of pore pressure perturbation and resultant 'ret plot' with modelled diffusivity (D ¼ 0.12 m 2 / s) relates the diffusion of pore pressure to seismic sequence in a fractured poro-elastic fluid saturated medium at average crustal depth of 15e20 km. The low diffusivity depicts a highly fractured interconnected medium that is generated due to high stress activity near the eastern syntaxial bent of Himalaya. It is proposed that hydro fracturing with respect to periodic pore pressure variations is responsible for generation of swarms in the region. The fluid pressure generated due to shearing and infiltrations of surface water within dilated seismogenic fault (Jiali Fault) are causative factors.Ó 2015, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Three‐Dimensional Density Distribution and Seismic Activity along the Guxiang–Tongmai Segment of the Jiali Fault, Tibet

“…The second segment, located below 14 km in depth, has a dip direction of southwest-west (SWW) and it features a dip angle of 62°. This interpretation is consistent with previous findings (Mukhopadhyay and Dasgupta, 2015;Wang H et al, 2020;Xie et al, 2021).…”

Structural and Thermochronologic Constraints on the Cenozoic Tectonic Development of the Northern Indo‐Burma Ranges

“…The eastern Lohit Plutonic Complex belt is cut in the northeast by two northwest striking strands of the right‐slip Jiali fault zone: the Puqu fault, or the Pu‐Chu fault, in the south and the Parlung fault in the north (Figure 2) (e.g., Armijo et al, 1989 Molnar & Tapponnier, 1975). Both the Puqu fault and the Parlung fault are interpreted to be active based on local seismicity and their geomorphic expression including ~10‐km‐long, linear scarps and beheaded and right‐laterally deflected stream channels (Figure 5) (Mukhopadhyay & Dasgupta, 2015; Ni & York, 1978; Thingbaijam et al, 2008). Lee et al (2003) documented right‐slip mylonitic shear zones parallel to the brittle traces of the Puqu fault and the Parlung fault and suggested shearing initiated at ~18–12 Ma based on 40 Ar/ 39 Ar thermochronology.…”

Estimation of Seismic Landslide Hazard in the Eastern Himalayan Syntaxis Region of Tibetan Plateau

“…Having the characteristics of the right-lateral strike-slip fault and thrust fault, the Apalong fault was intensively active in late Pleistocene. Lilong fault is left-lateral strike-slip which was active in Holocene (Shao Cuiru et al, 2008;Zhang Yi et al, 2015;Mukhopadhyay and Dasgupta, 2015). Since the Quaternary period, these faults produced a series of earthquakes.…”