Triggered/migrated seismicity due to the 2001 M w7.7 Bhuj earthquake, Western India

Rastogi, B. K.; Aggrawal, Sandeep Kumar; Rao, N. Madhava; Choudhury, Pallabee

doi:10.1007/s11069-011-0083-3

Cited by 27 publications

(7 citation statements)

References 37 publications

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“…As these basins are in an inversion phase, the complex nature of the fault system in Kachchh basin enables the region to uplift at a more rapid pace compared to the Cambay and Narmada basins [ Biswas and Khattri , ]. This is also supported by highest seismicity in the Kachchh region compared to the Cambay and Narmada regions [ Chamyal et al , ; Rastogi et al , ]. Our results of crustal parameters corroborate with the evolution model proposed by Biswas , [, ] for this region.…”

Section: Discussionmentioning

confidence: 99%

Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

2015

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The northwestern Deccan Volcanic Province of India and its pericratonic rift basins were reactivated during different stages after the breakup of India from the Gondwanaland and collision with the Asian plate. In this study, we present results of crustal thickness and average crustal V p /V s ratios beneath this plume-affected region using common conversion point imaging and H-k stacking analysis of 6893 receiver functions using data from a network comprising 58 broadband seismic stations sited on diverse tectonic terrains. We find large variations in crustal thickness, with the Moho depths varying from 28 to 43 km in the Kachchh rift, 28 to 38 km in the Cambay rift, 39.5-41.5 km in the north and eastern parts of the Cambay rift, and 29 to 39 km in the Saurashtra region and South Gujarat. A Moho upwarp of 6 to 7 km in the Saurashtra region can be attributed to positive buoyancy and uplift due to thermal influx affected by the Reunion plume. High crustal V p /V s ratios beneath the Kachchh rift (1.8 to 2.05), coastal areas of Saurashtra (1.75 to 2.06), and North Gujarat (1.81 to 1.85) indicate dominance of a mafic/ultramafic crust. High regional heat flow, high electrical conductivity, large intracrustal S wave velocity reduction, and high average crustal Poisson's ratios are consistent with partial melt related to the process of magmatic underplating in the lower crust. At other stations, the crust appears to be felsic with V p /V s ratios in the range of 1.57 to 1.76.

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Section: Discussionmentioning

confidence: 99%

Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

2015

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“…The major structural features of the region are bounded by the southdipping NPF and the north-dipping North Kathiawar Fault (NKF) (figure 1). Other major faults in this region are the Allah Bund Fault (ABF), Kachchh Mainland Fault (KMF), Katrol Hill Fault (KHF), Banni fault (BF), Vigodi fault (VF), South Wagad Fault (SWF), Gedi fault (GF) and North Wagad Fault (NWF) (Biswas and Khattri 2002;Rastogi et al 2013;Mandal et al 2004). These fault zones are the source of many moderate to large intraplate earthquakes in this region.…”

Section: Geology and Tectonic Setting Of The Kachchh Basinmentioning

confidence: 99%

“…These MT studies are mainly carried out in and around the Bhuj epicentral region aimed to understand the seismogenises of the region and crustal structure. Since the recent geophysical studies infer the accumulation of the large strain in eastern part of the Kachchh and migration of seismicity from the Bhuj epicentral zone (Rastogi et al 2013) necessitate detailed studies in eastern Kachchh basin mainly in the Wagad region. In addition, the tectonic evolution and seismic phenomenon of Kachchh region is due to differential movement along the major E-W trending faults (Biswas and Khattri 2002).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the tectonic evolution and seismic phenomenon of Kachchh region is due to differential movement along the major E-W trending faults (Biswas and Khattri 2002). However, couple of NW-SE to NE-SW transverse faults which cuts across the E-W tectonic setting of the region are also present in the region (Rastogi 2004;Biswas and Khattri 2002;Rastogi et al 2013;Rajendran and Rajendran 2001). These faults are suggested to be reactivated after the 2001 Bhuj earthquake (Rajendran and Rajendran 2001;Rastogi et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…However, couple of NW-SE to NE-SW transverse faults which cuts across the E-W tectonic setting of the region are also present in the region (Rastogi 2004;Biswas and Khattri 2002;Rastogi et al 2013;Rajendran and Rajendran 2001). These faults are suggested to be reactivated after the 2001 Bhuj earthquake (Rajendran and Rajendran 2001;Rastogi et al 2013). It is inferred that a part of the stresses being accumulated on the major faults is being possibly transmitted to these transverse faults, which may account for the present seismic phenomenon in the Kachchh (Maurya et al 2005).…”

Section: Introductionmentioning

confidence: 99%

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Magnetotelluric impedance tensor analysis for identification of transverse tectonic feature in the Wagad uplift, Kachchh, northwest India

Kumar

Nagar

et al. 2017

J Earth Syst Sci

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The 2001 Bhuj earthquake (Mw 7.7) occurred in northwestern region of Indian peninsula has reactivated a couple of transverse faults to its surroundings. Intermediate to moderate magnitude earthquakes are occurring along these faults which includes recent Dholavira earthquake (Mw 5.1, 2012) suggesting distinct tectonic scenario in the region. We present the results of magnetotelluric (MT) impedance tensors analyses of 18 sites located along a profile cutting various faults in the uplifted Wagad block of the Kachchh basin. The MT time series of 4-5 days recording duration have been processed and the earth response functions are estimated in broad frequency range (0.01-1000 s). The observed impedance tensors are analyzed by using three decomposition techniques as well as by the phase tensor method constraining with the induction arrows. The analyses suggest distinct tectonic feature within the block bounded by the South Wagad Fault (SWF) and the North Wagad Fault (NWF) particularly in the period band of 1-10 s. In the south of NWF, the telluric vectors and the major axes of the phase ellipses are aligned in the NNW-SSE to NW-SE direction where as a dominant E-W strike is obtained for northern side of the NWF. The transverse geo-electric strike coincides with the prominent clustering of seismicity after the Bhuj earthquake and trend of the Manfara transverse fault is located in close vicinity of the study area. We therefore suggest the presence NNW-SSE trending transverse structural feature in the Wagad uplift of the basin appears to play significant role in the current seismicity of the active intraplate region.

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Role of deep crustal fluids in the genesis of intraplate earthquakes in the Kachchh region, northwestern India

Kumar

Mahesh

Nagar

et al. 2017

Geophysical Research Letters

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Fluids play a prominent role in the genesis of earthquakes, particularly in intraplate settings. In this study, we present evidence for a highly heterogeneous nature of electrical conductivity in the crust and uppermost mantle beneath the Kachchh rift basin of northwestern India, which is host to large, deadly intraplate earthquakes. We interpret our results of high conductive zones inferred from magnetotelluric and 3‐D local earthquake tomography investigations in terms of a fluid reservoir in the upper mantle. The South Wagad Fault (SWF) imaged as a near‐vertical north dipping low resistivity zone traversing the entire crust and an elongated south dipping conductor demarcating the North Wagad Fault (NWF) serve as conduits for fluid flow from the reservoir to the middle to lower crustal depths. Importantly, the epicentral zone of the 2001 main shock is characterized as a fluid saturated zone at the rooting of NWF onto the SWF.

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Triggered/migrated seismicity due to the 2001 M w7.7 Bhuj earthquake, Western India

Cited by 27 publications

References 37 publications

Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

Crust beneath the northwestern Deccan Volcanic Province, India: Evidence for uplift and magmatic underplating

Magnetotelluric impedance tensor analysis for identification of transverse tectonic feature in the Wagad uplift, Kachchh, northwest India

Role of deep crustal fluids in the genesis of intraplate earthquakes in the Kachchh region, northwestern India

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