POWER CONTROL AND OPTIMIZATION: Proceedings of the 7th Global Conference on Power Control and Optimization

Conference date: 27–28 August and 2-3 December 2013

Location: Prague (Czech Republic) and Yangon (Myanmar)

ISBN: 978-983-44483-63

Editors: Ivan Zelinka, Zeya Oo and Nader Barsoum

Volume number: 2008

Published: 21 April 2013

Evaluations of the Strong Ground Motion Parameter by Emperical Stochastic Green’s Function Computing and Microtremor Array Measurement at Palu Depression Area, Central Sulawesi, Indonesia

Pyi Soe Thein, Subagyo Pramumijoyo, Kirbani Sri Brotopuspito, Junji Kiyono, Wahyu Wilopo, Agung Setianto

PCO Conf-Proc 2008 (2013), - PDF

In this study, we investigated evaluations of the strong ground motion parameter for Palu region. One of the major structures in Central Sulawesi is the Palu-Koro Fault system. Several powerful earthquakes have struck along the Palu-Koro Fault during recent years, one of the largest of which was an M 6.3 event that occurred on January 23, 2005 and caused several casualties. Following the event, we conducted a microtremor survey to estimate the shaking intensity distribution during the earthquake. From this survey we produced a map of the peak ground acceleration, velocity and displacement in Palu City. We performed single observations of microtremors at 151 sites in Palu City. The results enabled us to estimate the site-dependent shaking characteristics of earthquake ground motion. We also conducted 8-site microtremor array investigation to gain a representative determination of the soil condition of subsurface structures in Palu. . Four accelerometers were used in each array observation site. One was installed at a center of the circle with a radius, r. Other three were arranged on the circle with a shape of regular triangle. Observation duration time was 20〜30 minutes and sampling frequency was 100 Hz. Sequential observations were conducted three times by changing the array radius; r=3, 10 and 30 meters. Then, a substructure profile was identified from the dispersion curve by using the Particle Swarm Optimization. From the dispersion curve of array observations, the central business district of Palu corresponds to relatively soil condition with Vs ≤ 300 m/s, the predominant periods due to horizontal vertical ratios (HVSRs) are in the range of 0.4 to 1.8 s and the resonant frequency are in the range of 0.7 to 3.3 Hz. Strong ground motions of the Palu area were predicted based on the empirical stochastic Green’s function method. Peak ground acceleration and peak ground velocity becomes more than 400 gal and 30 kine in some areas and peak ground displacement becomes more than 17 cm in some areas, which causes severe damage for buildings in high probability.