Deepka Kumar, G. Suresh, Mukat Lal Sharma, Subhash Chandra Gupta
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引用次数: 0
Abstract
Northern India's seismic monitoring has advanced significantly in the past with the establishment of a dense and well-distributed network of seismometers. This has greatly enhanced the ability to detect and analyze seismic events in the region and provided a high-quality dataset within the study region. We use a 20-year dataset of 413 earthquakes comprising 3,191 P-arrivals and 2,986 S-arrivals to develop a one-dimensional velocity model for the region. The dataset is meticulously curated based on the azimuthal gap, minimum station requirements, and root mean square travel-time residual. A collection of preliminary models taken from previous studies conducted in and around the central north Indian region is subjected to random perturbations and utilized in a coupled hypocenter and one-dimensional seismic velocity inversion. The model exhibiting a reduced travel time residual in comparison to its predecessors is adopted as the final 1-D velocity model. This final five-layered model up to a depth of 100 km reveals a sediment thickness of 3.5 km with a P-wave velocity of 3.9 km/s and an upper crustal layer down to 20 km with a P-wave velocity of 6.01 km/s, and Moho depth of 42 km with P-wave and S-wave velocities at the Moho of 8.18 km/s and 4.71 km/s, respectively. In defining the local magnitude scale for Central Northern India, we analyzed 166 earthquakes, ensuring each event had at least three synthetic Wood-Anderson amplitudes, with a data set comprised of 1404 maximum amplitudes of S- and Lg waves. The derived ML scale, expressed as =log A (nm) + 0.752 log R (km) + 0.00129 R (km) -1.315+S, has been validated for earthquakes with magnitudes up to 4.6(Mw) over hypocentral distances of up to 1000 km.
期刊介绍:
Annals of Geophysics is an international, peer-reviewed, open-access, online journal. Annals of Geophysics welcomes contributions on primary research on Seismology, Geodesy, Volcanology, Physics and Chemistry of the Earth, Oceanography and Climatology, Geomagnetism and Paleomagnetism, Geodynamics and Tectonophysics, Physics and Chemistry of the Atmosphere.
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Annals of Geophysics is published by Istituto Nazionale di Geofisica e Vulcanologia (INGV), nonprofit public research institution.