A Preliminary Crustal Thickness Map of Sri Lanka

A variation of crustal thickness beneath Sri Lanka, where there is no deep seismic work has been carried out, is derived from its gravity anomaly map using an iterative technique of gravity data inversion and a preliminary crustal thickness map of the island is compiled. Results of the inversion show that the observed gravity anomaly can be best explained using a crustal model of average density 2840 kgm³ and average thickness 313 km. The model further shows that the crust is relatively thin beneath the central Highlands and northeastern part of the island and relatively thick beneath the Highland-Vijayan lithological boundary reaching a maximum of 37 km.