Implementation of ESA-MWT method satellite gravitation data to estimate the depth of moho layer and subduction zone in Indo-Australia plate of Central Java

A study has been conducted to measure the depth of the Mohorovicic (Moho) discontinuity and the Indo-Australian Plate subduction zone in Central Java. Both of these structures have high density contrast and thus are very sensitive to gravity methods. This study uses satellite image gravity data derived from satellite Geodetic Satellite (GEOSAT) and European Remote-Sensing 1 (ERS-1). Satellite data obtained in the form of free air anomaly which then corrected Bouguer using the average density of the Parasnis method of 2.64 g/cm³ so obtained Complete Bouguer Anomaly (CBA). The identification of Moho layers and subduction zones was done using the Energy Spectrum Analysis - the Multi Window Test (ESA-MWT) method with 19 lines of South-North. ESA-MWT results get 9 layers with depths that can reach more than 100 km. The Moho layer is identified as the 4^th layer at varying depths from 28 to 63 km. The subduction zone is also identified by ESA-MWT with a depth of about 60 km and deeper to the North. The dip of slab looks sloped down at 40° at the South of Central Java. The dip of slab in the middle of mainland Central Java seen sharply sloped down into the North with a dip of about 75°. All these results are well confirmed by the seismic data of the earthquake in Central Java.