Crustal Structure of Andaman Islands using Joint Inversion of Receiver Functions and Surface Wave Dispersion Measurements

Santosh Mishra, Srichand Prajapati


We investigate the crustal structure of Andaman Islands, central part of Burma-Sunda-Java subduction complex, through joint inver- sion of receiver functions and surface wave dispersion measurements. For this study, we used teleseismic earthquakes recorded over 13 temporary broadband seismographs operated in two different phases: pre and post 2004 Sumatra earthquake. Beneath the Andaman fore- arc region, the crustal thickness varies between ~24 and 28 km. The uppermost crust consists of ~4 to 7 km thick soft accretionary sed- iments. Average Vp/Vs ratio, between ~1.79 and 1.83, suggests accretionary hydrated oceanic crust with different level of saturation. Combining derived crustal structure with global seismicity and CMT fault plane solutions indicate a complex convergence along the arc, with transitional (continental-oceanic) type in the north to oceanic type in the south Andaman.

Full Text:




Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X