Estimation of effective elastic thickness from gravity and topography dataunder the Deccan Volcanic Province, India

Effective elastic thickness (EET) under the Deccan Volcanic Province is est imated based on admittance and coherence between the gravity field and the topography. The observed admittance function shows a good fit for the regio nal compensation model with an EET of 10 +/- 2 km. The effect of a long-wav elength (geoidal) gravity anomaly on the computation of EET has been invest igated and found not to significantly influence the value of EET although a considerable change in compensation depth was noticed. The estimated EET i s less than the thickness of the seismically active layer in this region. T hese results are consistent with observations in other parts of the world t hat EET should be smaller than the depth of the 350 +/- 100 degrees C isoth erm. (C) 1999 Elsevier Science B.V. All rights reserved.