ESTIMATING THE DEPTH OF THE MOHO DISCONTINUITY LAYER BENEATH MOUNT RINJANI, LOMBOK, USING RECEIVER FUNCTION

• Main Author: Romadhoni, Nurlailatul
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85794
• Institution: Institut Teknologi Bandung

Mount Rinjani is one of the stratovolcanoes in Indonesia that is still active to this day and is located on Lombok Island which is tectonically active. This condition affects the variation of the subsurface structure, that are the variation of the depth of the Moho discontinuity and the shear wave velocity. The function of the receiver method is used to study the depth of the Moho and estimate the value of the shear wave velocity. This method is able to describe the heterogeneity structure vertically and lateral variations with good resolution. This study uses teleseismic events data recorded from August 1, 2018 to September 9, 2018 with the distance between 30 ° - 90 ° and 6 - 9 Mw by using 4 temporary seismographs. Identification of the arrival time of the P, Ps waves, and their multiple phases is carried out with a windowing range of 5 seconds before Tp and 25 seconds after Tp using the iterative time domain deconvolution method. The Moho layer depth and ????????????????? ratio were estimated using the H-k stacking technique. The Moho layer depth and ????????????????? ratio beneath the 4 seismic stations used showed that the Moho depth was obtained at a depth of 30 km – 37.4 km and the ????????????????? ratio was 1.70 – 1.764. The high ????????????????? ratio indicates a zone with high fluid content, high temperature, or the presence of cracks below the surface. The S-wave velocity distribution profile was obtained using the least-square inversion method and weak velocity zones were obtained at depths of ~17 km – 19 km and ~25,5 km – 31 km.