Northeastern part of the Indian subcontinent is seismically active region with excessive rainfall and frequent landslides, which cause disruption of the road networks for couple of months in every year. The region has...Northeastern part of the Indian subcontinent is seismically active region with excessive rainfall and frequent landslides, which cause disruption of the road networks for couple of months in every year. The region has a typical morphotectonic setup where many active thrusts and faults have affected the landforms as well as the major part of the terrain. A prominent creeping strike-slip fault, named Chrachandpur Mao Fault (CMF), trending NS, is one of the triggering factors for frequent landslides, creeping low magnitude earthquakes. The life line of Manipur, national high way NH39 traverses through this fault in Manipur, hence the traffic is disrupted during the monsoon season. Based on the GPS campaign mode studies on western and eastern sides of the CMF, it is observed that there is a change in the crustal velocities from 16 - 22 mm/yr in east to 33 - 42 mm/yr in the west. Micro-deformations are also observed;the displacements along the vertical, N-S and E-W components are –0.111 mm/yr (downward), 0.03 mm/yr (north) and –0.011 mm/yr (west). The net displacement is 0.126 mm/yr with an azimuth of N 85? and dipping 13? towards west. Neotectonic development along the CMF with the GPS measurements suggest an aseismic nature of the fault with dextral component. Fault plane solutions of the earthquakes show northerly directed principal Paxis indicating the extension (T-axis) along eastwest. The resulting creeping of micro-deformation towards the western slopes of the terrain is aligned with the principal Taxis. The creeping triggers the microseismicity as well as the landslides along the CMF.展开更多
文摘Northeastern part of the Indian subcontinent is seismically active region with excessive rainfall and frequent landslides, which cause disruption of the road networks for couple of months in every year. The region has a typical morphotectonic setup where many active thrusts and faults have affected the landforms as well as the major part of the terrain. A prominent creeping strike-slip fault, named Chrachandpur Mao Fault (CMF), trending NS, is one of the triggering factors for frequent landslides, creeping low magnitude earthquakes. The life line of Manipur, national high way NH39 traverses through this fault in Manipur, hence the traffic is disrupted during the monsoon season. Based on the GPS campaign mode studies on western and eastern sides of the CMF, it is observed that there is a change in the crustal velocities from 16 - 22 mm/yr in east to 33 - 42 mm/yr in the west. Micro-deformations are also observed;the displacements along the vertical, N-S and E-W components are –0.111 mm/yr (downward), 0.03 mm/yr (north) and –0.011 mm/yr (west). The net displacement is 0.126 mm/yr with an azimuth of N 85? and dipping 13? towards west. Neotectonic development along the CMF with the GPS measurements suggest an aseismic nature of the fault with dextral component. Fault plane solutions of the earthquakes show northerly directed principal Paxis indicating the extension (T-axis) along eastwest. The resulting creeping of micro-deformation towards the western slopes of the terrain is aligned with the principal Taxis. The creeping triggers the microseismicity as well as the landslides along the CMF.
