Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake
The Himalayan mountain range has been the locus of some of the largest continental earthquakes, including the 2015 magnitude 7.8 Gorkha earthquake. Competing hypotheses suggest that Himalayan topography is sustained and plate convergence is accommodated either predominantly on the main plate boundary fault, or more broadly across multiple smaller thrust faults. Here we use geodetic measurements of surface displacement to show that the Gorkha earthquake ruptured the Main Himalayan Thrust fault. The earthquake generated about 1 m of uplift in the Kathmandu Basin, yet caused the high Himalaya farther north to subside by about 0.6 m. We use the geodetic data, combined with geologic, geomorphological and geophysical analyses, to constrain the geometry of the Main Himalayan Thrust in the Kathmandu area. Structural analyses together with interseismic and coseismic displacements are best explained by a steep, shallow thrust fault flattening at depth between 5 and 15 km and connecting to a mid-crustal, steeper thrust. We suggest that present-day convergence across the Himalaya is mostly accommodated by this fault—no significant motion on smaller thrust faults is required. Furthermore, given that the Gorkha earthquake caused the high Himalayan mountains to subside and that our fault geometry explains measured interseismic displacements, we propose that growth of Himalayan topography may largely occur during the ongoing post-seismic phase.
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Springer Nature
2016-09-01
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Subjects: | Geology, Seismology, Seismology Structural geology, Tectonics, |
Online Access: | http://hdl.handle.net/10261/214203 http://dx.doi.org/10.13039/501100000270 |
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dig-ipna-es-10261-2142032020-06-13T01:22:22Z Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake Elliott, J. R. Jolivet, Romain González, Pablo J. Avouac, J-P Hollingsworth, James Searle, M. P. Stevens, V. L. Natural Environment Research Council (UK) Geology Seismology Seismology Structural geology Tectonics The Himalayan mountain range has been the locus of some of the largest continental earthquakes, including the 2015 magnitude 7.8 Gorkha earthquake. Competing hypotheses suggest that Himalayan topography is sustained and plate convergence is accommodated either predominantly on the main plate boundary fault, or more broadly across multiple smaller thrust faults. Here we use geodetic measurements of surface displacement to show that the Gorkha earthquake ruptured the Main Himalayan Thrust fault. The earthquake generated about 1 m of uplift in the Kathmandu Basin, yet caused the high Himalaya farther north to subside by about 0.6 m. We use the geodetic data, combined with geologic, geomorphological and geophysical analyses, to constrain the geometry of the Main Himalayan Thrust in the Kathmandu area. Structural analyses together with interseismic and coseismic displacements are best explained by a steep, shallow thrust fault flattening at depth between 5 and 15 km and connecting to a mid-crustal, steeper thrust. We suggest that present-day convergence across the Himalaya is mostly accommodated by this fault—no significant motion on smaller thrust faults is required. Furthermore, given that the Gorkha earthquake caused the high Himalayan mountains to subside and that our fault geometry explains measured interseismic displacements, we propose that growth of Himalayan topography may largely occur during the ongoing post-seismic phase. This work was supported by the UK Natural Environmental Research Council (NERC) through the Looking Inside the Continents (LiCS) project (NE/K011006/1), the Earthquake without Frontiers (EwF) project (EwF_NE/J02001X/1_1), and the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET, GA/13/M/031, http://comet.nerc.ac.uk). The Sentinel-1A interferograms presented are a derived work of Copernicus data, subject to the ESA use and distribution conditions. R.J. is supported by the Marie Curie FP7 Initial Training Network iTECC (investigating Tectonic Erosion Climate Couplings). Peer reviewed 2020-06-12T10:21:43Z 2020-06-12T10:21:43Z 2016-09-01 artículo http://purl.org/coar/resource_type/c_6501 Nature Geoscience 9: 174–180 (2016) 1752-0894 http://hdl.handle.net/10261/214203 10.1038/ngeo2623 1752-0908 http://dx.doi.org/10.13039/501100000270 en Publisher's version https://doi.org/10.1038/ngeo2623 No none Springer Nature |
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Geology Seismology Seismology Structural geology Tectonics Geology Seismology Seismology Structural geology Tectonics Elliott, J. R. Jolivet, Romain González, Pablo J. Avouac, J-P Hollingsworth, James Searle, M. P. Stevens, V. L. Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
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The Himalayan mountain range has been the locus of some of the largest continental earthquakes, including the 2015 magnitude 7.8 Gorkha earthquake. Competing hypotheses suggest that Himalayan topography is sustained and plate convergence is accommodated either predominantly on the main plate boundary fault, or more broadly across multiple smaller thrust faults. Here we use geodetic measurements of surface displacement to show that the Gorkha earthquake ruptured the Main Himalayan Thrust fault. The earthquake generated about 1 m of uplift in the Kathmandu Basin, yet caused the high Himalaya farther north to subside by about 0.6 m. We use the geodetic data, combined with geologic, geomorphological and geophysical analyses, to constrain the geometry of the Main Himalayan Thrust in the Kathmandu area. Structural analyses together with interseismic and coseismic displacements are best explained by a steep, shallow thrust fault flattening at depth between 5 and 15 km and connecting to a mid-crustal, steeper thrust. We suggest that present-day convergence across the Himalaya is mostly accommodated by this fault—no significant motion on smaller thrust faults is required. Furthermore, given that the Gorkha earthquake caused the high Himalayan mountains to subside and that our fault geometry explains measured interseismic displacements, we propose that growth of Himalayan topography may largely occur during the ongoing post-seismic phase. |
author2 |
Natural Environment Research Council (UK) |
author_facet |
Natural Environment Research Council (UK) Elliott, J. R. Jolivet, Romain González, Pablo J. Avouac, J-P Hollingsworth, James Searle, M. P. Stevens, V. L. |
format |
artículo |
topic_facet |
Geology Seismology Seismology Structural geology Tectonics |
author |
Elliott, J. R. Jolivet, Romain González, Pablo J. Avouac, J-P Hollingsworth, James Searle, M. P. Stevens, V. L. |
author_sort |
Elliott, J. R. |
title |
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
title_short |
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
title_full |
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
title_fullStr |
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
title_full_unstemmed |
Himalayan megathrust geometry and relation to topography revealed by the Gorkha earthquake |
title_sort |
himalayan megathrust geometry and relation to topography revealed by the gorkha earthquake |
publisher |
Springer Nature |
publishDate |
2016-09-01 |
url |
http://hdl.handle.net/10261/214203 http://dx.doi.org/10.13039/501100000270 |
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