Flexure of the Indian plate and intraplate earthquakes

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 variati...

Full description

Saved in:
Bibliographic Details
Published in:Academy Proceedings in Earth and Planetary Sciences 2003-09, Vol.112 (3), p.315-329
Main Authors: BILHAM, Roger, BENDICK, Rebecca, WALLACE, Kali
Format: Article
Language:English
Subjects:
Current distribution
Depth perception
Distribution
Earth sciences
Earth, ocean, space
Earthquake damage
Earthquakes
Earthquakes, seismology
Engineering and environment geology. Geothermics
Exact sciences and technology
Geoid
Geoids
Geological faults
Geological hazards
Geology
Gravity anomalies
Internal geophysics
Natural hazards: prediction, damages, etc
Plates
Seismic activity
Seismic hazard
Spatial variations
Stress distribution
Tectonics. Structural geology. Plate tectonics
Wavelength
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.[PUBLICATION ABSTRACT]
ISSN:0253-4126
0973-774X
DOI:10.1007/BF02709259