Flexure of the Indian plate and intraplate earthquakes |
| |
| Authors: | Roger Bilham Rebecca Bendick Kali Wallace |
| |
| Institution: | (1) CIRES and Department of Geological Sciences, University of Colorado, 80309-0399 Boulder, CO |
| |
| Abstract: | The flexural bulge in central India resulting from India's collision with Tibet has a wavelength of approximately 670 km.
It is manifest topographically and in the free-air gravity anomaly and the geoid. Calculations of the stress distribution
within a flexed Indian plate reveal spatial variations throughout the depth of the plate and also a function of distance from
the Himalaya. The wavelength (and therefore local gradient) of stress variation is a function of the effective elastic thickness
of the plate, estimates of which have been proposed to lie in the range 40–120 km. The imposition of this stress field on
the northward moving Indian plate appears fundamental to explaining the current distribution of intraplate earthquakes and
their mechanisms. The current study highlights an outer trough south of the flexural bulge in central India where surface
stresses are double the contiguous compressional stresses to the north and south. The Bhuj, Latur and Koyna earthquakes and
numerous other recent reverse faulting events occurred in this compressional setting. The N/S spatial gradient of stress exceeds
2 bars/km near the flexural bulge. The overall flexural stress distribution provides a physical basis for earthquake hazard
mapping and suggests that areas of central India where no historic earthquakes are recorded may yet be the locus of future
damaging events. |
| |
| Keywords: | Mid-plate seismicity flexure continental earthquakes continental erosion flexural bulge India |
| 本文献已被 SpringerLink 等数据库收录！ |
