Modeling Gravity Anomalies in Subduction Zones and Their Response in Gravity Gradient Tensor

Abstract

Subduction zones are complex tectonic regions that often exhibit significant gravity anomalies. This study aims to model gravity anomalies in subduction zones and evaluate their responses in the form of gravity gradient tensors (GGT). Modeling is carried out using a Matlab-based numerical approach, by dividing the subduction zone into small cubic elements, each of which has a certain density contrast to the surrounding medium. From the model configuration, the gravity field response is calculated in three dimensions. Furthermore, the obtained gravity field is spatially reduced to obtain nine components of the gravity gradient tensor, each of which reflects the spatial variation of the gravity field in a certain direction. The results show that the pattern of GTG components is very sensitive to the geometry and density variations in the subduction zone, thus providing additional information that is more detailed than conventional gravity anomalies. This approach is expected to be a tool in interpreting subsurface structures, especially in complex tectonic regions such as subduction zones.