| Abstract Submission No. | ABS-1.2-0120 |
| Title of Abstract | Seismic Imaging the Indian Ocean Geoid Low Region Using Ambient Noise Tomography |
| Authors | P. Sion Kumari*, Sanjay Singh Negi, Amit Kumar, N. Lachit Singh, Rinku Mahanta, John Kurian P. |
| Organisation | National Centre for Polar and Ocean Research |
| Address | Bhandi Street, Koraput Koraput, Odisha, India Pincode: 764020 E-mail: sion.ngri@gmail.com |
| Country | India |
| Presentation | Poster |
| Abstract | The Indian Ocean Geoid low (IOGL) is a prominent negative geoid anomaly located south of the Indian subcontinent, with a prominent magnitude of -106 m, making it the largest geoid depression observed globally. Various studies have investigated its origin, proposing different mechanisms. Some studies attribute it to the upper mantle heterogeneity, specifically low-density anomalies, while others suggest a combination of low velocity anomalies in the upper mantle and high-velocity anomalies in the lower mantle. Despite numerous geodynamic models attempting to explain its origin, a consensus remains elusive, largely due to the limited availability of high-resolution seismic imaging beneath the vast oceanic region. Recent progress has been made with the deployment of a linear array of passive ocean bottom seismometers (OBSs), which has significantly advanced the understanding of deep mantle structures beneath the Ocean. Although the IOGL is believed to be influenced by deeper mantle structures, the lithosphere and uppermost asthenosphere are crucial to understand how deeper mantle processes manifest at shallower depths. We employ ambient noise tomography (ANT) to develop three-dimensional shear wave velocity models using the Rayleigh wave dispersion data in the period range 5 ¿ 80s. The dispersion measurements are estimated from cross-correlation functions (CCFs) computed between the station pairs, which include the 17 linear stations deployed during IOGL Phase-I, and 4 nearby land-based seismic stations. The inversion shear velocity results contribute to understanding the expression in the lithospheric and upper asthenosphere structure due to the deeper mantle processes in the Indian Ocean region. |
| Keywords | Indian Ocean Geoid low (IOGL), Ocean bottom seismometers (OBSs), ambient noise tomography, and seismic imaging. |