Weak mantle in NW India probed by geodetic measurements following the 2001 Bhuj earthquake

Chandrasekhar, D. V.; Bürgmann, Roland; Reddy, C. D.; Sunil, P. S.; Schmidt, D. A.

doi:10.1016/j.epsl.2009.01.039

Cited by 36 publications

(30 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mandal and Pandey () also proposed a thin lithosphere (∼70 km) beneath the KSZ and suggested that this might have resulted from the lithosphere and Deccan/Reunion plume interaction at 65 Ma. Further, Chandrasekhar et al () supported the idea of thermal weakening beneath the KSZ on the basis of geodetic measurements and explained the low viscous strength of the mantle in terms of interaction of the Indian plate with the mantle plume. Hence, it is possible that the plume head material would reach the surface wherever the lithosphere is thin, which may be significantly displaced from the center.…”

Section: Discussionmentioning

confidence: 96%

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

et al. 2018

View full text Add to dashboard Cite

The interaction of the Indian continental lithosphere with the Reunion plume resulted in massive outpouring of basalts manifested in the Deccan Volcanic Province. Although it is postulated that preexisting weak rift zones facilitated the eruption, deeper signatures of the plume remain contentious. In this study, we investigate the shear wave velocity (Vs) structure of the crust and upper mantle by inverting regionalized group velocity dispersion data in the period range of 6 to 100 s, down to 220 km depth, using the genetic algorithm technique. We used 1,286 dispersion curves derived from waveforms of 77 regional earthquakes recorded at 38 broadband stations. Our results reveal distinct intracrustal layers, Moho, mantle lid, and asthenospheric low‐velocity layer. Signatures of magmatic underplating are recognized in terms of high Vs and a thick crust beneath the Kutch seismic zone and Western Ghats. The lithospheric thickness varies from 80 to 124 km, being thinnest at the junction of Cambay and Narmada rifts, which could be the source zone of volcanic eruption. A thin lithosphere has also been observed beneath the Kutch seismic zone. A low‐velocity zone at depths ~80 km can be related with upwarping of the asthenosphere and/or presence of partial melts. A predominant low‐velocity zone beneath the Cambay, Saurashtra, and adjoining regions may be due to the effect of a residual thermal anomaly. A thin lithosphere beneath northwestern Deccan Volcanic Province could be the result of weakening due to plume‐lithosphere interaction, which facilitated volcanism through preexisting rift zones.

show abstract

Section: Discussionmentioning

confidence: 96%

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

et al. 2018

View full text Add to dashboard Cite

show abstract

“…In order to estimate what proportion of the slip deficit has been recovered we need to estimate the amount of shallow afterslip that occurred between the main shock in February 2006 and the start of ALOS data acquisition in December 2006. One method of making this estimate is to make assumptions regarding the functional form of the surface deformation [e.g., Fialko , 2004; Chandrasekhar et al , 2009]. The Envisat data shows that the average rate of deformation between 74 and 109 days after the main shock (0.6 mm/day) was considerably faster than the roughly linear rate of 0.05 mm/day seen in the ALOS data.…”

Section: Postseismic Deformationmentioning

confidence: 99%

Constraints on fault and lithosphere rheology from the coseismic slip and postseismic afterslip of the 2006 M_w7.0 Mozambique earthquake

2012

View full text Add to dashboard Cite

[1] The 2006 M w 7.0 Mozambique (Machaze) normal-faulting earthquake ruptured an unusually steeply dipping fault plane ($75°). The amount of slip in the earthquake decreased from depths of $10 km toward the surface, and this shallow slip deficit was at least partly recovered by postseismic afterslip on the shallow part of the fault plane. An adjacent normal fault segment slipped postseismically (and possibly also co-seismically) at shallow depths with a large strike-slip component, in response to the stresses generated by slip on the main earthquake fault plane. Our observations suggest that the fault zone behaves in a stick-slip manner in the crystalline basement, and that where it cuts the sedimentary layer the coseismic rupture was partially arrested and there was significant postseismic creep. We discuss the effects of such behavior on the large-scale tectonics of continental regions, and on the assessment of seismic hazard on similar fault systems. The steep dip of the fault suggests the re-activation of a preexisting structure with a coefficient of friction at least $25-45% lower than that on optimally oriented planes, and analysis of the deformation following an aftershock indicates that the value of the parameter 'a' that describes the rate-dependence of fault friction lies in the range 1 Â 10 À3 -2 Â 10 À2 . The lack of long-wavelength postseismic relaxation suggests viscosities in the ductile lithosphere of greater than $2 Â 10 19 Pa s, and an examination of the tectonic geomorphology in the region identifies ways in which similar fault systems can be identified before they rupture in future earthquakes.

show abstract

“…But there are a few researchers (e.g. Likhar et al 2006, Chandrasekhar et al 2009) who have used GPS and European Remote Sensing Satellite (ERS)-SAR data sets, but of different time periods (2001-2003 and 2002-2004, respectively) and of different locations, which do not match with our ENVISAT-ASAR data time periods (2003-2004 and 2004-2005) and location. Therefore, comparisons of post-seismic ground deformation could not be compared with the published results.…”

Section: The Insar Data Set and Processingmentioning

confidence: 80%

SAR interferometry in post-seismic ground deformation detection related to the 2001 Bhuj earthquake, India

Saraf

Das

Biswas

et al. 2011

International Journal of Remote Sensing

View full text Add to dashboard Cite

The 2001 Bhuj earthquake, which occurred due to rupturing of a hidden reverse fault, caused large-scale ground deformation. The ground deformations in the Bhuj earthquake-affected region have been analysed using two interferometric synthetic aperture radar (InSAR) data sets. The data sets belong to the years 2003-2004 and 2004-2005, covering an area east of Bhuj falling on near-flat terrain north of Kutch Mainland Fault (KMF). Two interferograms have been generated successfully displaying the interference fringes in the study area, enabling us to draw interesting observational inferences. The 2003-2004 interferogram image exhibits upliftment of about 8 cm (surface motion towards the satellite) around Kunjisar village and also upliftment of 25 and 5 cm in the other two areas north of Kunjisar, whereas the interferogram image belonging to the year 2004-2005 reveals subsidence of about 17 cm (surface motion away from the satellite) in Kunjisar area along with subsidence of about 28 and 5 cm in the two areas north and northwest of Kunjisar, respectively. Hence, between the years 2003 and 2005, two different episodes of upliftment and subsidence have been observed in the study area. The ground upliftment during 2003-2004 probably indicates that the last phase of ground deformation in the earthquake-affected region has been followed by the onset of subsidence during 2004-2005 as the rock volume involved in stress-strain processes began to experience a relaxation phase.

show abstract

Weak mantle in NW India probed by geodetic measurements following the 2001 Bhuj earthquake

Cited by 36 publications

References 24 publications

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

Constraints on fault and lithosphere rheology from the coseismic slip and postseismic afterslip of the 2006 M_w7.0 Mozambique earthquake

SAR interferometry in post-seismic ground deformation detection related to the 2001 Bhuj earthquake, India

Contact Info

Product

Resources

About

Weak mantle in NW India probed by geodetic measurements following the 2001 Bhuj earthquake

Cited by 36 publications

References 24 publications

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

Seismic Imprints of Plume‐Lithosphere Interaction Beneath the Northwestern Deccan Volcanic Province

Constraints on fault and lithosphere rheology from the coseismic slip and postseismic afterslip of the 2006 Mw7.0 Mozambique earthquake

SAR interferometry in post-seismic ground deformation detection related to the 2001 Bhuj earthquake, India

Contact Info

Product

Resources

About

Constraints on fault and lithosphere rheology from the coseismic slip and postseismic afterslip of the 2006 M_w7.0 Mozambique earthquake