Crustal thickness and velocity structure of southern Peninsular Malaysia

The tectonic setting of Peninsular Malaysia can be described by three distinctive stratigraphic belts, known as Western, Central and Eastern belts. These Western and Eastern belts which were formed during the Paleo-Tethys subduction process in the Late Paleozoic are separated by the Bentong-Raub suture zone. Although there are various study had evaluated this formation process, the geological detail of the region’s crust is still unknown. The velocity and detail information of the Earth’s crust is crucial in determining the earthquake’s location and seismic hazard. Since the cost to conduct a large scale geophysical study to determine the Earth’s structure is high, a better and efficient method is by incorporating the receiver function method. The receiver function is computed from the tele-seismic earthquake waveform which involve P-wave, P-S wave and pPpS + pPsS multiple phases recorded by a three-component seismogram. In this work, the data recorded at the two broadband seismometer stations located in Kota Tinggi, Johor (KOM station) and Singapore (BTDF station) (Figure 1), were investigated for the receiver function analysis, crustal thickness estimation through H-k method and waveform inversion for 1-D velocity. There are a total of 448 (for KOM station) (Figure 2) and 73 (for BTDF station) tele-seismic earthquakes which occurred in between 2005 to 2016, were evaluated for the crustal thickness and velocity structure analysis. From the H-k thickness analysis, the Moho boundary was found at 35km (Figure 3) and 30km for region beneath KOM and BTDF