Seismic moment tensor solutions and geophysical settings in the Philippine Sea basin mapped by GMT

Abstract

The study is focused on mapping geophysical settings on the margins of the Philippine Sea Plate (PSP). Active volcanism and seismic situation along the margins of the Philippine Sea Basin (PSB) shows earthquake events demonstrating high seismicity of the region caused by tectonic plate subduction. The aim was to perform cartographic mapping of the earthquake events using Generic Mapping Tools (GMT) modules, to analyze seismic situation through visualization of the geophysical datasets. The data was processed by GMT using multi-source data: GEBCO, CMT and ISC seismic data. Technically, a set of GMT modules was used ('psmeca', 'psvelo', 'grdtrack', 'grdimage') for data modelling and mapping. An application of GMT functionality is presented by selected code snippets with selected code snippets for 'psmeca' and 'psvelo', 'img2grd', 'img2grd' modules. Current paper presents a report on the cartographic techniques applied for geophysical mapping. Centroid moment tensor solutions are visualized for shallow depth earthquakes of Mw <10 along the PSB margins from 1976 to 2010. Earthquakes along the tectonic plate subduction zone are shown by GMT. Data from Global Centroid-Moment-Tensor (CMT) Project. Presented and explained GMT code snippets contribute to the development of methods in geological mapping using GMT scripting toolset, for visualizing focal mechanisms.