1 D VELOCITY AND HYPOCENTER ESTIMATION OF 2003 EARTHQUAKE IN WEST JAVA USING SIMULTANEOUS INVERSION METHOD

• Main Author: MULANA PANDAPOTAN NAINGGOLAN (NIM : 12404017), HENRY
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22424
• Institution: Institut Teknologi Bandung

Tectonic earthquake of West Java is occured by the effect of fracture releases energy suddenly from continuous deformation in subsurface of the earth. The earthquake sources came from subduction zone (interplate), caused by the interaction between Eurasia with Indo&#8208;Australian plate and the faults in a plate (intraplate). There are many active faults in intraplate, the major faults are Lembang, Cimandiri and Baribis fault. During 2003, the signals are recorded by seismogram in the seismic station at Ciparay, Soreang, and Lembang with the complex waveform. From the observed <br /> <br /> <br /> <br /> <br /> seismogram, the P and S wave phases can be determined by using S&#8208;Transform method, corectly. To calculate origin time, we use Wadati method, then the hypocenter can be <br /> <br /> <br /> <br /> <br /> determined by graphic and gridsearch method. The hypocenter and seismic wave velocity which propagated alongside the discrete trajectory of seismic raypath must both be treated as unknown parameters. These parameters can be estimated by using arrival or observed <br /> <br /> <br /> <br /> <br /> traveltime. By the linier approach, the solutions can be obtained simultaneously by using damped least square inverse technique. The estimation is processed iteratively, which consist of forward modelling by ray tracing and inverse modelling step. The objective of this research at intraplate and interplate of West Java is to estimate the hypocenter compatibility with 1 D velocity model by simultaneous inversion. The simultaneous inversion obtained the hypocenter location which narrower as well as located for the faulting area than the hypocenter location which obtained by gridsearch method.