Structural insights from geodetic Global Positioning System measurements in the Darjiling-Sikkim Himalaya


Mukul M., Jade S., Ansari K., Matin A., Joshi V.

JOURNAL OF STRUCTURAL GEOLOGY, cilt.114, ss.346-356, 2018 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 114
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1016/j.jsg.2018.03.007
  • Dergi Adı: JOURNAL OF STRUCTURAL GEOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.346-356
  • Karadeniz Teknik Üniversitesi Adresli: Hayır

Özet

Deformation in active convergent wedges like the Himalaya occurs over different time and space scales requiring integrated datasets for holistic insights into wedge-scale deformation. A new long-time series (1998-2009) of geodetic, static Global Positioning System (GPS) dataset suggests that active deformation in the Darjiling-Sikkim Himalaya (DSH) is not confined to the Himalayan front as previously believed. Instead, the similar to 9 mm/yr N-S active convergence here is divided almost equally within the Lesser Himalayan Duplex (LHD) and the Higher Himalaya due to aseismic reverse slip of similar to 18 mm/yr on the Himalayan decollement (Main Himalayan thrust (MHT)) dipping 6 degrees -> 006 degrees and locked at similar to 16 km depth. Slip transfer along the MHT causes minor to moderate earthquakes at the brittle-ductile transition in the DSH. Measured East velocities show no systematic variation indicating that strike-slip seismicity, though dominant in the region, does not alleviate the decollement (MHT) seismic hazard. Continued slip along the MHT, therefore, will cause a great decollement earthquake in the region. Also, GPS velocities vary in the eastern and western DSH suggesting segmentation of the Himalayan arc along a transverse fault over geological to decadal time scales. Our integrated approach can provide better insight into active deformation in convergent wedges worldwide.