THE EMPIRICAL FORMULA DETERMINATION OF LOCAL MAGNITUDE FOR THE YOGYAKARTA EARTHQUAKE IN PERIOD OF JUNE 2006

• Main Author: Deddy Zainal, M.
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46643
• Institution: Institut Teknologi Bandung

The Indonesian archipelago is in the equatorial region where three large plates of the world meet, namely the Indo-Australian Plate, the Eurasian Plate, and the Pacific Plate. As one of its effects, Indonesia is in the 'Ring of Fire' zone. Therefore, it is not surprising that Indonesia is categorized as a region that has high volcanic and seismic activity. One of the major earthquakes in Indonesia was the Yogyakarta earthquake on May 27th, 2006. The earthquakes are in the areas of Bantul, Klaten, Gunung Kidul and Kulon Progo Regencies. The Meteorology and Geophysics Agency (BMKG) detected that the earthquake occurred at 5:53:58 at local time. One of the basic seismological parameters which associated with earthquake risk assessment is the mangnitude scale. Magnitude calculations until now is still using references from in other regions studies that are estimated to have similar conditions to Yogyakarta. In this research, the determination of the empirical local magnitude equation for the Yogyakarta area using 388 aftershock earthquake data for the period of June 2006. The research was carried out by making a database containing the parameters of the picked results of arriving P waves and S waves that have been chosen from the previous study. The obtained result will be converted in the form of magnitude, so the value of model parameters on the basic equations of magnitude can be determined by linear inversion. Then, we get ????" = log(????) + 0,8065 log(????) + 0,01003???? ? 1.8441