Neotectonism - An offshore evidence from eastern continental shelf off Visakhapatnam

Show simple item record Subrahmanyam, A.S. Venkateswarlu, K. Murthy, K.S.R. Rao, M.M.M. Rao, K.M. Raju, Y.S.N. 2009-01-10T10:20:27Z 2009-01-10T10:20:27Z 1999
dc.identifier.citation Current Science, Vol.76; 1251-1255p.
dc.description.abstract A minor tremor measuring 4.5 on the Richter scale occurred around 4.58 p.m. on 18 December 1995, with its epicentre located in the Bay of Bengal, nearly 30 km east of Vizianagaram on the Andhra Pradesh coast. The location of the epicentre is around 18 degrees 42 degrees E. It is significant that the epicentre falls in the innershelf off Vizianagaram, where a suite of rocks (Santapalle Rocks) outcrop at a water depth of around 30 m. Bathymetry and magnetic data were collected over this region along closely spaced, coast parallel profiles covering the shelf regions. Observed magnetic anomalies are of short wavelength and high amplitude of the order of 600 to 700 nT. Two-dimensional modelling of these anomalies with conventional as well as inversion methods indicated a severly faulted and folded basement of the order of 1 to 6 km. Three closely spaced river channels (Nagavali, Vamsadhra Nelimarla) trending NW-SE are associated with the faulted and folded basement. Faulting associated with the Nelimarla river channel extending into the offshore zone may be the possible cause of the tremor. Strong magnetic anomalies, complex basement structure exposed rock outcrops in the innershelf (20 m) in the vicinity of the epicentre of Vizianagaram earth tremor provide evidence of Neo-tectonic activity in this regio. The epicentral region falls in a shallow marine environment ideal for generating a geophysical database for stable continental region earthquakes.
dc.language.iso en
dc.publisher Current Science Association, Bangalore, India
dc.rights Copyright [1999]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
dc.subject tectonics
dc.subject seismic activity
dc.subject continental shelves
dc.subject earthquakes
dc.subject bathymetric data
dc.subject magnetic data
dc.subject magnetic data
dc.subject fault zones
dc.subject magnetic anomalies
dc.subject basement rock
dc.title Neotectonism - An offshore evidence from eastern continental shelf off Visakhapatnam
dc.type Journal Article

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