01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0069 |
| Title of Abstract | The imprint of tectonics on observed sea-level rise in the Indian Ocean |
| Authors | Nidheesh Gangadharan*, Sophie Coulson, Brent G. Delbridge, Grace Ertel, Aurel Moise, Matthew D. Palmer |
| Organisation | Indian National Centre for Ocean Information Services (INCOIS) |
| Address | Datri Green Ville, Bachupally, Hyderabad Choose, Telangana, India Pincode: 500090 E-mail: nidheesh.ag@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | The islands of the Maritime Continent are highly vulnerable to sea-level rise driven by a range of barystatic and sterodynamic processes. The region also sits astride a complex network of active tectonic boundaries, and deformation along these boundaries produces vertical displacements of the seafloor and gravitational field perturbations, altering sea surface height (SSH). However, the long-term impact of tectonics on SSH has not been identified in SSH observations due to the difficulty of disentangling this signal from other processes. We decompose satellite observations of SSH change during 1993-2021 into ocean sterodynamic changes, sea-level fingerprints originating from contemporary mass redistribution between ocean and land (GRD effects), and glacial isostatic adjustment (GIA), using model predictions for each component. Our results reveal a persistent SSH anomaly along the Sumatra-Andaman subduction zone that cannot be attributed to sterodynamic or GRD/GIA processes. This anomaly is coincident with long-term GRACE-derived geoid height changes near the rupture zone of the 2004 M9.1 Indian Ocean Earthquake. These findings present the first observational evidence of tectonic activity modulating regional SSH trends and highlight the necessity of integrating tectonic effects into future sea-level projections for seismically active regions. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Sea-level rise, sterodynamic changes, GRD fingerprints, Subduction tectonics, Sea-level projections |
| For Awards | no |