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Joint Modeling of Velocity Structure and Hypocentral Locations in the Seismically Active Kachchh, Saurashtra, and Narmada Regions of Western India: An Active Intraplate Region

2017; Seismological Society of America; Volume: 88; Issue: 5 Linguagem: Inglês

10.1785/0220160203

1938-2057

Vishwa Joshi, Sumer Chopra, P. Mahesh, Santosh Kumar,

Seismic Imaging and Inversion Techniques

Research Article| June 14, 2017 Joint Modeling of Velocity Structure and Hypocentral Locations in the Seismically Active Kachchh, Saurashtra, and Narmada Regions of Western India: An Active Intraplate Region Vishwa Joshi; Vishwa Joshi aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Search for other works by this author on: GSW Google Scholar Sumer Chopra; Sumer Chopra aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Search for other works by this author on: GSW Google Scholar P. Mahesh; P. Mahesh aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Search for other works by this author on: GSW Google Scholar Santosh Kumar Santosh Kumar aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Search for other works by this author on: GSW Google Scholar Author and Article Information Vishwa Joshi aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Sumer Chopra aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in P. Mahesh aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Santosh Kumar aInstitute of Seismological Research, Next to Pandit Deendayal Petroleum University, Raisan, Gandhinagar 382009, Gujarat, India, vishwajoshi@isr.res.insumerchopra@isr.res.inpmahesh@isr.res.insantoshkumar@isr.res.in Publisher: Seismological Society of America First Online: 15 Sep 2017 Online Issn: 1938-2057 Print Issn: 0895-0695 © Seismological Society of America Seismological Research Letters (2017) 88 (5): 1390–1402. https://doi.org/10.1785/0220160203 Article history First Online: 15 Sep 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Vishwa Joshi, Sumer Chopra, P. Mahesh, Santosh Kumar; Joint Modeling of Velocity Structure and Hypocentral Locations in the Seismically Active Kachchh, Saurashtra, and Narmada Regions of Western India: An Active Intraplate Region. Seismological Research Letters 2017;; 88 (5): 1390–1402. doi: https://doi.org/10.1785/0220160203 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search ABSTRACT The Kachchh, Saurashtra, and Narmada regions, located in the western part of India, are seismically active intraplate regions. After the setup of the dense network by the Institute of Seismological Research (ISR), a large number of local earthquakes were recorded. Availability of such a large data set has enabled us to obtain 1D velocity models for the three regions separately, using the earthquake data recorded at digital broadband seismic stations operating during 2006–2015. A total of 570, 114, and 225 well‐recorded earthquakes with azimuth gap of <180° (each of which had a minimum of five P‐phase and five S‐phase readings) that occurred in the three regions, respectively, are used in the analysis. The P‐ and S‐wave velocities of the resulting seven‐layer model for Kachchh (up to the depth of 34 km) vary from 3.01 to 7.88 km/s and 1.74 to 4.55 km/s⁠; of the four‐layer model for Saurashtra (up to the depth of 18 km) vary from 4.61 to 6.73 km/s and 2.66 to 3.89 km/s⁠; and of the six‐layer model for Narmada (up to the depth of 30 km) vary from 3.22 to 7.09 km/s and 2.08 to 3.92 km/s⁠, respectively. The obtained optimum 1D velocity models in this study are further used to relocate all the earthquakes recorded from 2006 to 2015. We observe that the depths of the earthquakes are better constrained although the horizontal difference in earthquake locations is small. We also find that in the Kachchh rift both the upper and lower crusts are seismically active, with earthquakes occurring up to Moho. In Saurashtra, Narmada, and Cambay regions, the upper crust is seismically active, whereas the lower crust is aseismic. These region‐specific 1D velocity models can also be used as reliable starting models to obtain 3D velocity structure of these regions in seismic tomography studies. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.