Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity
Abstract The Kashmir “seismic gap” in NW Himalaya is marked by hinterland‐to‐foreland reduction in GPS‐geodetic arc‐normal convergence‐velocity and increase in horizontal strain‐rate, associated with occurrence of moderate‐to‐small earthquakes. We analyze continuous waveforms from Jammu and Kashmir...
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| Format: | Article |
| Language: | English |
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Wiley
2024-11-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL110160 |
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| author | S. K. Shamim Ayon Ghosh Supriyo Mitra Keith Priestley Swati Sharma Sunil Kumar Wanchoo |
| author_facet | S. K. Shamim Ayon Ghosh Supriyo Mitra Keith Priestley Swati Sharma Sunil Kumar Wanchoo |
| author_sort | S. K. Shamim |
| collection | DOAJ |
| description | Abstract The Kashmir “seismic gap” in NW Himalaya is marked by hinterland‐to‐foreland reduction in GPS‐geodetic arc‐normal convergence‐velocity and increase in horizontal strain‐rate, associated with occurrence of moderate‐to‐small earthquakes. We analyze continuous waveforms from Jammu and Kashmir seismological network (2015–2017) to detect and preliminarily locate 1064 events, followed by probabilistic non‐linear relocation of 360 well‐located local earthquakes, with magnitudes 0.6–4.7 and hypocentral depths 0–60 km. Hypocenters shallower than 20 km lie on or above the Main Himalayan Thrust (MHT), clustered beneath the Kishtwar Higher‐Himalaya. Hinterlandward dipping seismicity‐clusters coincide with a MHT mid‐crustal frontal ramp, marking a ∼50 km wide locked‐to‐creep transition. The frictionally‐locked up‐dip MHT segment is ∼100 km wide, capable of hosting a Mw∼ 8.4 earthquake, if ruptured completely. Clustered seismicity SW of the Kishtwar Window and to its east illuminate MHT lateral‐ramps, which may limit the rupture width and/or modulate the rupture propagation. Entirely seismogenic underthrust Indian‐crust poses additional hazard from large earthquakes within it. |
| format | Article |
| id | doaj-art-daa60f8c2661406a9537c40a0bbbb114 |
| institution | DOAJ |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-daa60f8c2661406a9537c40a0bbbb1142025-08-20T03:02:07ZengWileyGeophysical Research Letters0094-82761944-80072024-11-015121n/an/a10.1029/2024GL110160Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located SeismicityS. K. Shamim0Ayon Ghosh1Supriyo Mitra2Keith Priestley3Swati Sharma4Sunil Kumar Wanchoo5Department of Earth Sciences Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal IndiaDepartment of Earth Sciences Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal IndiaDepartment of Earth Sciences Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal IndiaBullard Laboratories Department of Earth Sciences University of Cambridge Cambridge UKDepartment of Earth Sciences Indian Institute of Science Education and Research Kolkata Mohanpur West Bengal IndiaSchool of Physics Shri Mata Vaishno Devi University Katra Jammu and Kashmir IndiaAbstract The Kashmir “seismic gap” in NW Himalaya is marked by hinterland‐to‐foreland reduction in GPS‐geodetic arc‐normal convergence‐velocity and increase in horizontal strain‐rate, associated with occurrence of moderate‐to‐small earthquakes. We analyze continuous waveforms from Jammu and Kashmir seismological network (2015–2017) to detect and preliminarily locate 1064 events, followed by probabilistic non‐linear relocation of 360 well‐located local earthquakes, with magnitudes 0.6–4.7 and hypocentral depths 0–60 km. Hypocenters shallower than 20 km lie on or above the Main Himalayan Thrust (MHT), clustered beneath the Kishtwar Higher‐Himalaya. Hinterlandward dipping seismicity‐clusters coincide with a MHT mid‐crustal frontal ramp, marking a ∼50 km wide locked‐to‐creep transition. The frictionally‐locked up‐dip MHT segment is ∼100 km wide, capable of hosting a Mw∼ 8.4 earthquake, if ruptured completely. Clustered seismicity SW of the Kishtwar Window and to its east illuminate MHT lateral‐ramps, which may limit the rupture width and/or modulate the rupture propagation. Entirely seismogenic underthrust Indian‐crust poses additional hazard from large earthquakes within it.https://doi.org/10.1029/2024GL110160NW Himalayaseismicitymid‐crustal ramps |
| spellingShingle | S. K. Shamim Ayon Ghosh Supriyo Mitra Keith Priestley Swati Sharma Sunil Kumar Wanchoo Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity Geophysical Research Letters NW Himalaya seismicity mid‐crustal ramps |
| title | Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity |
| title_full | Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity |
| title_fullStr | Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity |
| title_full_unstemmed | Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity |
| title_short | Locked Frontal and Lateral Ramps on the Main Himalayan Thrust Beneath NW Himalaya Illuminated by Precisely Located Seismicity |
| title_sort | locked frontal and lateral ramps on the main himalayan thrust beneath nw himalaya illuminated by precisely located seismicity |
| topic | NW Himalaya seismicity mid‐crustal ramps |
| url | https://doi.org/10.1029/2024GL110160 |
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