MOHO DEPTH UNDULATIONS BELOW THE BAY OF BENGAL USING 3D INVERSION OF GRAVITY DATA

  • Srinivasarao Manchala
  • S.K. Begum Priyesh Kunnummal
Keywords: 85˚E Ridge, 90˚East Ridge, Moho undulations, Free Air Gravity Anomaly, 3D gravity inversion, Crustal thickness

Abstract

A high-resolution satellite-derived free air gravity data set has been used in the Bay of Bengal. Bullard A (Bouguer plate), Bullard B (Curvature), and Bullard C (Terrain) corrections were applied to the Indian Geoidal Low derived from the Free Air gravity data (often referred to as FAG-IOGL) data in order to create a Complete Bouguer Anomaly (CBA). The Parker Method was first employed in order to invert the CBA data and generate Moho topography. From the CBA data, the Mantle Residual Gravity Anomaly (MRGA) has been derived by removing the gravitational impacts, lithosphere- and pressure-induced anomalies created by the sediments. Moreover, the Moho undulations were produced by inverting the MRGA, and these have been used for calculating the Crustal thickness. Moho depths estimated with the MRGA and CBA are, respectively, 13 to 30 km and 10 to 26 km. The range of predicted crustal thickness is 2–28 km. Moho depths, as determined by CBA and MRGA, are shallower in the western basin between latitudes 7˚N and 15˚N, or in the direction of the 85˚E Ridge on both the western and eastern sides. However, the lowest Moho (i.e., 25 and 23 km from the CBA & MRGA) is found at latitude 14˚N underneath the 85˚E Ridge. Deeper Moho depths of 21 and 23 km are derived from the CBA and MRGA beneath 90˚East Ridge, at the southern end of the research area. In our study area, the sediment thickness increases from 1000 m at the southernmost spot to 11,000 m at the northernmost spot. In the area under study, the bathymetry fluctuates from 500 m north to 4500 m south. The thickness of the crust has increased to 8–12 km below the 85°E Ridge, but it has decreased to 2–4 km on both of the ridge's boundaries. At the extreme SSE BoB, the crustal thickness is 19 km.

Author Biographies

Srinivasarao Manchala

Department of Geophysics, Andhra University, Visakhapatnam-530003, Andhra Pradesh, India

S.K. Begum Priyesh Kunnummal

Indian Institute of Geomagnetism, Navy Mumbai, Maharashtra 410218, India

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Published
2024-08-31
How to Cite
Srinivasarao Manchala, & S.K. Begum Priyesh Kunnummal. (2024). MOHO DEPTH UNDULATIONS BELOW THE BAY OF BENGAL USING 3D INVERSION OF GRAVITY DATA. Revista Electronica De Veterinaria, 25(1), 958-975. https://doi.org/10.69980/redvet.v25i1.725
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