Segmentation of the Himalayas as revealed by arc-parallel gravity anomalies
2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, 33866Article in journal (Refereed) Published
Univ Lausanne, Inst Earth Sci, Geopolis, Quartier UNIL Mouline, CH-1015 Lausanne, Switzerland.;ETH, Dept Earth Sci, Soneggstr 5, CH-8092 Zurich, Switzerland.;Ecole Normale Super, CNRS, Geol Lab, UMR 8538, 24 Rue Lhomond, F-75005 Paris, France..
Ecole Normale Super, CNRS, Geol Lab, UMR 8538, 24 Rue Lhomond, F-75005 Paris, France.;Univ Montpellier, CNRS UMR5243, Geosci Montpellier, Pl E Bataillon, F-34095 Montpellier, France..
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Geophysics.
Le Moigne, Nicolas
Univ Montpellier, CNRS UMR5243, Geosci Montpellier, Pl E Bataillon, F-34095 Montpellier, France..
Lateral variations along the Himalayan arc are suggested by an increasing number of studies and carry important information about the orogen's segmentation. Here we compile the hitherto most complete land gravity dataset in the region which enables the currently highest resolution plausible analysis. To study lateral variations in collisional structure we compute arc-parallel gravity anomalies (APaGA) by subtracting the average arc-perpendicular profile from our dataset; we compute likewise for topography (APaTA). We find no direct correlation between APaGA, APaTA and background seismicity, as suggested in oceanic subduction context. In the Himalayas APaTA mainly reflect relief and erosional effects, whereas APaGA reflect the deep structure of the orogen with clear lateral boundaries. Four segments are outlined and have disparate flexural geometry: NE India, Bhutan, Nepal & India until Dehradun, and NW India. The segment boundaries in the India plate are related to inherited structures, and the boundaries of the Shillong block are highlighted by seismic activity. We find that large earthquakes of the past millennium do not propagate across the segment boundaries defined by APaGA, therefore these seem to set limits for potential rupture of megathrust earthquakes.
Place, publisher, year, edition, pages
2016. Vol. 6, 33866
IdentifiersURN: urn:nbn:se:uu:diva-305335DOI: 10.1038/srep33866ISI: 000383577600001PubMedID: 27649782OAI: oai:DiVA.org:uu-305335DiVA: diva2:1037316