Estimates of motion and strain rates across active faults in the frontal part of eastern Himalayas in North Bengal from GPS measurements

Within the 2500 km stretch of the Himalayas, a narrow window between longitudes 88.185°E and 88.936°E in the frontal Himalayas in North Bengal, crisscrossed by several active fault traces, presents an interesting region for crustal deformation study. We have estimated velocities of 8 GPS stations located in this area and the accumulating strain rate by two different methods. A total shortening of 11.1 ±1.5 mm yr−1 is occurring across a set of four E–W running faults: Gorubathan, Matiali, Chalsa and Baradighi. The strain rate becomes higher in the NE part of the network, reaching −(0.25 ± 0.12) μstrain yr−1 with azimuth 21°. A statistically significant extension of 10.9 ± 1.6 mm yr−1 is estimated across the Gish transverse fault with a maximum strain rate of 0.36 ± 0.08 μstrain yr−1 with azimuth 103°. The accumulating strain will be probably released through future earthquakes.

[1]  Augusto Gansser-Biaggi.  The Geology of the Himalayas , 1892, Nature.

[2]  T. Nakata.  Geomorphic History and Crustal Movements of the Foot-Hills of the Himalayas , 1972 .

[3]  Timothy P. Loomis,et al.  Tertiary mantle diapirism, orogeny, and plate tectonics east of the Strait of Gibraltar , 1975 .

[4]  P. Molnar,et al.  Active tectonics of Tibet , 1978 .

[5]  James Ni,et al.  Seismotectonics of the Himalayan Collision Zone: Geometry of the underthrusting Indian Plate beneath the Himalaya , 1984 .

[6]  P. Molnar.  The Geologic History and Structure of the Himalaya , 1986 .

[7]  R. Armijo,et al.  Quaternary extension in southern Tibet: Field observations and tectonic implications , 1986 .

[8]  T. Nakata,et al.  Active faults of the Himalaya of India and Nepal , 1989 .

[9]  Walter H. F. Smith,et al.  New version of the generic mapping tools , 1995 .

[10]  David D. Jackson,et al.  Crustal deformation across and beyond the Los Angeles basin from geodetic measurements , 1996 .

[11]  J. Freymueller,et al.  GPS measurements of present-day convergence across the Nepal Himalaya , 1997, Nature.

[12]  Robert W. King,et al.  Estimating regional deformation from a combination of space and terrestrial geodetic data , 1998 .

[13]  S. Wesnousky,et al.  Uplift and convergence along the Himalayan Frontal Thrust of India , 1999 .

[14]  J. Avouac,et al.  Oblique convergence in the Himalayas of western Nepal deduced from preliminary results of GPS measurements , 1999 .

[15]  R. Bürgmann,et al.  Kinematics of the India-Eurasia collision zone from GPS measurements , 1999 .

[16]  David A. Seal,et al.  The Shuttle Radar Topography Mission , 2007 .

[17]  Robert W. King,et al.  Global Positioning System measurements from eastern Tibet and their implications for India/Eurasia intercontinental deformation , 2000 .

[18]  Jérôme Lavé,et al.  Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal , 2000 .

[19]  S. K. Acharyya,et al.  Seismotectonic atlas of India and its environs , 2000 .

[20]  K. Hodges.  Tectonics of the Himalaya and southern Tibet from two perspectives , 2000 .

[21]  S. Wesnousky,et al.  Earthquake Recurrence and Rupture Dynamics of Himalayan Frontal Thrust, India , 2001, Science.

[22]  Thomas A. Hennig,et al.  The Shuttle Radar Topography Mission , 2001, Digital Earth Moving.

[23]  Roland Bürgmann,et al.  Convergence across the northwest Himalaya from GPS measurements , 2002 .

[24]  Grazia Pietrantonio,et al.  Three-dimensional strain tensor estimation by GPS observations: methodological aspects and geophysical applications , 2004 .

[25]  J. Kayal,et al.  Seismic activity at the MCT in Sikkim Himalaya , 2004 .

[26]  S. Jade,et al.  Estimates of plate velocity and crustal deformation in the Indian subcontinent using GPS geodesy , 2004 .

[27]  Peter Molnar,et al.  GPS measurements from the Ladakh Himalaya, India: Preliminary tests of plate-like or continuous deformation in Tibet , 2004 .

[28]  Brendan J. Meade,et al.  Present-day kinematics at the India-Asia collision zone , 2007 .

[29]  Richard W. Allmendinger,et al.  Strain and rotation rate from GPS in Tibet, Anatolia, and the Altiplano , 2007 .

[30]  N. Cardozo,et al.  SSPX: A program to compute strain from displacement/velocity data , 2009, Comput. Geosci..