| Abstract Submission No. | ABS-3.1-0193 |
| Title of Abstract | Subduction zone Mw 8.8 2025 Great Kamchatka Earthquake ¿ Tectonic Implications |
| Authors | Ajit Kumar *, Prosanta Kumar Khan, Lavudya Rajender, Digvijay Bhatia |
| Organisation | Department of Applied Geophysics, IIT(ISM) Dhanbad, Jharkhand |
| Address | Aquamarine Hostel, IIT ISM Dhanbad Dhanbad, Jharkhand, India Pincode: 826004 E-mail: 21je0068@iitism.ac.in |
| Country | India |
| Presentation | Poster |
| Abstract | This study presents an analysis of Global Centroid Moment Tensor (CMT) parameters of 551 events occurred between 1977 and 2025 in the area lying between latitude 50.5°N and 55.5°N and longitude 155.5°E and 164.5°E of the Kamchatka Peninsula. A central component of this research is the reconstruction of a comprehensive seismotectonic map using GMT scripting, which visualizes the spatial distribution of earthquakes, demarcating the major tectonic boundaries and slab geometry. In addition, a trench-orthogonal Benioff Zone was identified along the subduction zone, highlighting seismicity clustering at different depth-levels. Stress inversion was performed using MATLAB using rigorous statistical analysis and multiple noise realizations to resolve principal stress orientations, integrating focal mechanism data, iterative randomization, and parameter sensitivity analysis for robust uncertainty quantification and stability of stress solutions. Results reveal distinct spatial and depth-dependent trends in the ambient stress field, closely associated with tectonic segmentation and slab-mantle coupling in the Kamchatka subduction zone. The seismotectonic map successfully illustrates the linkage between clusters of seismicity, magnitude occurrences, and underlying plate boundaries, while the depth section provides insights into changes in earthquake distribution with increasing depth and proximity to the subduction zone flexing. Stress inversion outputs including detailed plots of shape ratios, stress orientations, and Mohr circles illuminate variability in stress regimes across different depths and lithospheric sections. These findings substantiate the dynamic interplay between tectonic configuration and ambient stress, shaping both the seismic hazard landscape and the ongoing tectonic evolution of Kamchatka region. The analysis shows that the bending portion of the subducting plate was the nodal domain for stress accumulation and triggering great earthquakes. The study can also be extended for basin modelling along the subduction margin globally. |
| Keywords | Kamchatka, subduction zone, focal mechanism, stress inversion, seismicity map, depth section, ambient stress, tectonic structure. |