Morphology of the subducted Indian plate in the Indo-Burmese convergence zone

  • S. S. Rai
  • D. Srinagesh
  • P. V. S. S. Rajagopala Sarma


Earthquake hypocenters and travel time residuals have been analysed to constrain the geometry and physical state of the subducted Indian plate in the Indo-Burmese convergence zone. A critical analysis of earthquake hypocenters reveals the existence of a non-uniform Benioff zone, progressively shortening from north to south. The deepest level of seismicity is observed beneath the Naga hills (160 km) followed by that under the Chin hills (120 km) and Arakan-Yoma ranges (80 km). The region seems to be devoid of moderate sized shallow (< 40 km) earthquakes. Differential travel time residuals from pairs of shallow and intermediate depth earthquakes recorded at teleseismic distances show significantly faster travel time (up to l.2s) in the north-northeast and south-southwest azimuths, whilst slower arrivals (1.2 to 1.5 s) are recorded in the transverse direction. This observation points to the presence of a high velocity slab possibly linked to the subduction of the Indian oceanic lithosphere.


Benioff zone hypocenter subduction travel time residual Indo-Burmese range 


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Copyright information

© Indian Academy of Sciences 1996

Authors and Affiliations

  • S. S. Rai
    • 1
  • D. Srinagesh
    • 1
  • P. V. S. S. Rajagopala Sarma
    • 1
  1. 1.National Geophysical Research InstituteHyderabadIndia

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