3D crustal resistivity structure beneath the Wagad aftershock zone of the 2001 Bhuj earthquake, Kutch, India: Heterogeneous resistivity structure controlled by widespread fluid infiltration and clues to aftershocks pattern

2018 ◽  
Vol 747-748 ◽  
pp. 54-67 ◽  
Author(s):  
K.K. Abdul Azeez ◽  
Kapil Mohan ◽  
K. Veeraswamy ◽  
B.K. Rastogi ◽  
Arvind K. Gupta ◽  
...  
Keyword(s):  
Bhuj Earthquake ◽  
Resistivity Structure ◽  
Fluid Infiltration

Lithospheric resistivity structure of the 2001 Bhuj earthquake aftershock zone

2020 ◽  
Vol 224 (3) ◽  
pp. 1980-2000
Author(s):  
K K Abdul Azeez ◽  
Kapil Mohan ◽  
K Veeraswamy ◽  
B K Rastogi ◽  
Arvind K Gupta ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Critical Stress ◽  
Stress Conditions ◽  
Western India ◽  
Seismic Zone ◽  
Bhuj Earthquake ◽  
Resistivity Structure ◽  
Aftershock Activity ◽  
Stress Regime ◽  
Upward Migration

SUMMARY The Bhuj area, in the Kutch region of western India, is a unique intraplate seismic zone in the world where aftershock activity associated with a large magnitude earthquake (7.7 Mw Bhuj earthquake on 26 January 2001) has persisted over a decade and up till today. We studied the lithospheric resistivity structure of the Bhuj earthquake aftershock zone to gain more insight into the structure and processes influencing the generation of intraplate seismicity in broad and, in particular, to detect the deep origin and upward migration channels of fluids linked to the crustal seismicity in the area. A lithospheric resistivity model deduced from 2-D and 3-D inversions of long-period magnetotelluric (MT) data shows low resistive lithospheric mantle, which can be best explained by a combination of a small amount of interconnected melts and aqueous fluid in the upper mantle. The MT model also shows a subvertical modestly conductive channel, spatially coinciding with the Kutch Mainland Fault, which we interpret to transport fluids from the deep lithosphere to shallow crust. We infer that pore pressure buildup aids to achieve the critical stress conditions for rock failure in the weak zones, which are pre-stressed by the compressive stress regime generated by ongoing India–Eurasia collision. The fluidized zone in the upper mantle beneath the area perhaps provides continuous fluid supply, which is required to maintain the critical stress conditions within the seismogenic crust for continued seismicity.

Evaluating drilling fluid infiltration in porous media – Comparing NMR, gravimetric, and X-ray CT scan methods

2021 ◽  
Vol 198 ◽  
pp. 108242
Author(s):  
Badr S. Bageri ◽  
Abdulrauf R. Adebayo ◽  
Jaber Al Jaberi ◽  
Shirish Patil ◽  
Rahul B. Salin
Keyword(s):  
Porous Media ◽  
Ct Scan ◽  
Drilling Fluid ◽  
X Ray ◽  
Fluid Infiltration

scholarly journals Meteoric fluid infiltration in crustal-scale normal fault systems as indicated by δ18O and δ2H geochemistry and40Ar/39Ar dating of neoformed clays in brittle fault rocks

Lithosphere ◽  
2016 ◽  
Vol 8 (6) ◽  
pp. 587-600 ◽  
Author(s):  
Samuel Haines ◽  
Erin Lynch ◽  
Andreas Mulch ◽  
John W. Valley ◽  
Ben van der Pluijm
Keyword(s):  
Normal Fault ◽  
Fault Rocks ◽  
Fault Systems ◽  
Fluid Infiltration

scholarly journals Correcting for Static Shift of Magnetotelluric Data with Airborne Electromagnetic Measurements: A Case Study from Rathlin Basin, Northern Ireland

2016 ◽  
Author(s):  
Robert Delhaye ◽  
Volker Rath ◽  
Alan G. Jones ◽  
Mark R. Muller ◽  
Derek Reay
Keyword(s):  
Distortion Correction ◽  
Vertical Scaling ◽  
Spatial Density ◽  
Target Area ◽  
Resistivity Structure ◽  
Static Shift ◽  
Magnetotelluric Data ◽  
Archie’S Law ◽  
Order Of Magnitude ◽  
Resistivity Variation

Abstract. Galvanic distortions of magnetotelluric (MT) data, such as the static shift effect, are a known problem that can lead to incorrect estimation of resistivities and erroneous modelling of geometries with resulting misinterpretation of subsurface electrical resistivity structure. A wide variety of approaches have been proposed to account for these galvanic distortions, some depending on the target area, with varying degrees of success. The natural laboratory for our study is a hydraulically permeable volume of conductive sediment at depth, the internal resistivity structure of which can be used to estimate reservoir viability for geothermal purposes, however static shift correction is required in order to ensure robust and precise modelling accuracy. We propose a method employing frequency–domain electromagnetic data for static shift correction, which in our case are regionally available with high spatial density. The spatial distributions of the derived static shift corrections are analysed and applied to the uncorrected MT data prior to inversion. Two comparative inversion models are derived, one with and one without static shift corrections, with instructive results. As expected from the one–dimensional analogy of static shift correction, at shallow model depths, where the structure is controlled by a single local MT site, the correction of static shift effects leads to vertical scaling of resistivity-thickness products in the model, with the corrected model showing improved correlation to existing borehole wireline resistivity data. In turn, as these vertical scalings are effectively independent of adjacent sites, lateral resistivity distributions are also affected, with up to half a decade of resistivity variation between the models estimated at depths down to 2000 m. Simple estimation of differences in bulk porosity, derived using Archie’s Law, between the two models reinforces our conclusion that the sub–order of magnitude resistivity contrasts induced by correction of static shifts correspond to similar contrasts in estimated porosities, and hence, for purposes of reservoir investigation or similar cases requiring accurate absolute resistivity estimates, galvanic distortion correction, especially static shift correction, is essential.

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