An embryonic fold and thrust belt south of the Himalayan morphological front: Examples from the Central Nepal and Darjeeling piedmonts

The morphological boundary between the Himalayas and foreland plain is well expressed most often corresponds to frontal emergence of Main Himalayan Thrust (MHT). This affected by surface ruptures during very large earthquakes (Mw > 8) that regularly induce (with a recurrence order 500 1200 years) uplift foothills relative plain. However, thrust-fold system hidden beneath displayed seismic profiles oil companies in east/central Nepal H/V passive geophysical techniques Darjeeling. Its long-term kinematic evolution slow, with tectonic hanging wall lower than subsidence rate basin, is, less approximately half millimetre per year. During phases low sedimentation controlled climatic fluctuations, surfaces piedmont are incised rivers for several tens metres; therefore, structures under sediments emerge slightly an embryonic thrust belt mainly shortening 1.4 +2.5/−1.2 mm·yr−1, 2–20% entire system. Nonetheless, details deformation associated still poorly understood. Several components could affect central Darjeeling piedmonts. i) Any slow steady-state deformation, such as layer parallel (LPS) not detected Global Navigation Satellite System (GNSS) data, would therefore absorb 0.5 mm·yr−1. geodetic data suggest aseismic growth some highly controversial. ii) For rest wedge, it yet be proven whether occurs rare great affecting medium and/or post-seismic related earthquakes. amplitude this too limited significantly reduce hazard gaps belt. iii) In portions front, (India), propagates kilometres south front zone previously deformation. It induces multi-metre mean 8.5 ± 6.2 iiii) Pre-existing faults bedrock Indian craton, oblique structures, locally reactivated rates.