Seismic Tomography Study of the Deccan Traps in Gujarat, India

Kukarina E.¹, Koulakov I.¹, Prajapati S.²

1 A.A. Trofimuk Institute of Petroleum Geology and Geophysics, sb ras, Novosibirsk, Russia, 2Institute of Seismological Research, Cardhinagar, Gujarat, India

E.V.Kukarina@gmail.com

Deccan Traps are a large area of igneous rock that is located on the Deccan Plateau in west-central India. They are among the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that are more than 2000 m thick and cover an area of 1.5 million square km. They have a volume of 512 000 km³. The Deccan Traps were formed at the end of the Cretaceous period (60 million years ago) and probably played a role in the Cretaceous–Tertiary extinction event, which included the extinction of the non-avian dinosaurs.

Tomographic inversion of the Gujarat region was done using the non-linear passive source tomographic code, LOTOS. We used high quality arrivals from 22 280 P and 22 040 S waves of 9242 events recorded during the period from August 2006 to May 2011 at 138 permanent and temporary stations installed in the Gujarat state of India by the Institute of Seismological Research (ISR).

The resulting high velocity anomalies are most likely related to aged massifs of magmatic rocks down to the depth of Moho (40 km), and low velocity anomalies are related to weakened zones of faults and fracturing. The low velocity anomaly in the north of the region coincides with the seismic activity zone and appears to be related to the rift system which is apparently associated with the channel of the outpouring of Deccan basalts.

The experience of studying the Deccan Traps might be translated onto the Siberian Traps where temporary seismic networks can also be installed in the future.

The relation of fault tectonic, cenozoic magmatism and seismic activity (the Japan Sea link of the West-Pacific continent-ocean transition zone)

Ogorodnii A.A.

V.I.Il`ichev Pacific Oceanological Institute, Vladivostok, Russia

Ogorodnii@poi.dvo.ru

Other - General Topic Background: Fault tectonics Japan Sea Link (JL) is determined by the fact that it is located in the of West Pacific Continent-Ocean Transition Zone, where were actively showed both ancient, and modern tectonic movements. Within JL two general systems of long-living faults √ W√E ("Asian") and NE ("Pacific") are developed. It is rather remarkable that in the Japan Sea Basin and in its Continental Frame as a result of long-term researches of geologists and geophysics of Pacific Oceanological Institute areas a Miocene-Holocene magmatites (basalts, andesites, etc.) are established. In 2004-2010 years as a result of detailed geologo-structural and geomagnetic researches in water area of the Peter Great Bay the new data allowing on others to consider communication of geology, tectonics, geodynamics and Seismically Active Zones on a joint of Continental and Marginal-marine Structures are obtained.