[SSS14-04] Earthquake potential evaluation in the Himalayan Frontal Zone using space geodetic technique
Keywords:Nepal, Earthquake, GNSS
We collect all available GNSS data in Nepal through UNAVCO DAI v2 and process them with NERDiM data using PPP-AR method of GIPSY/OASIS II ver.6.4. Preliminary result shows that the north-south contraction in Nepal is as large as 10-15 mm/yr, equivalent to a strain rate of 0.1 ppm/yr, implying that about 30-40% of the relative Indian-Eurasian plate motion (36-37 mm/yr) is taken up in crustal shortening of the Himalayan Frontal Zone due to strong coupling on the plate boundary. The NERDiM GNSS stations clearly contribute to improve spatial resolution especially near the Indian border, that agrees roughly with the updip limit of the plate boundary. Occurrence of the 2015 Gorkha earthquake disturbs deformation field around the source region in central Nepal but does not seem to affect further west. It means that large amount of accumulated strain has remained unreleased in “Central Seismic Gap”. As the next step, we are preparing estimation of plate locking distribution using the latest plate boundary model (Hubbard et al., 2016). Strain build-up monitored by our system, in conjunction with data from other pre-existing GNSS stations in and around Nepal, will provide fundamental and important information for evaluating earthquake generation potential in the near future.