Development of Spectral Hazard Map for Indonesia with a Return Period of 2500 Years using Probabilistic Method

Abstract

This study is performed to develop spectral hazard map for Indonesia with a Return Period of 2500 years earthquake. It will be proposed for revision of the Indonesian hazard map in SNI-03-1726-2002 as response to the meeting organized by the Department of Public Works on 27-October-2008 in Jakarta. The meeting has decided to revise the Indonesia hazard map by referring to IBC-2006 where spectral acceleration values at Peak Ground Acceleration/PGA, 0.2 and 1.0 second with a return period of 2500 year will be applied for general buildings. The spectral hazard map was analyzed using total probability method and three dimensional (3-D) source models with recent seismotectonic parameters. Four source models were used in this analysis, namely: shallow background, deep background, fault, and subduction source models. Generally, the results of analysis show the values of PGA with a return period of 2500 years relatively higher 1.2-3.0 times than in SNI-03-1726-2002.

An update to seismic hazard levels and PSHA for Lombok and surrounding islands after earthquakes in 2018

“…The earthquake catalogues for the period of 1922-2018 were derived from the United State Geological Survey (USGS) [18], the International Seismological Centre (ISC) [19], and the Indonesian Centre for Meteorology, Climate and Geophysics (BMKG) [1]. The earthquakes were recorded in various magnitude types of over 3.0 at depths of <400 km, which were then modified into moment magnitudes (Mw) according to [20,21].…”

“…A number of empirical attenuation relations have been suggested by many researchers, each with different characteristics, which depend on typical earthquake patterns of the location being investigated [25]. For Indonesia, six different attenuation relations have been suggested for three different earthquake sources: subduction, fault and shallow background, and deep background [21]. The Joyner-Boore relation [26] was applied for moderate to shallow sources; whereas, the Boore-Atkinson relation [27] might be applied for a shallow reverse fault, such that located at the back arc of Lombok Island [28].…”

“…Three main seismic sources were applied to analyze the seismicity of Lombok and surrounding islands: subduction, background, and back arc shallow fault [21]. Background sources were particularly divided into five depth intervals [29].…”

“…A number of empirical attenuation equations have been developed by many researchers for different tectonic characteristics [25]. Two of them, Joyner-Boore [26] and Boore-Atkinson [27], have already been recognised to be suitable for the tectonic characteristics of Indonesia [21], particularly Lombok Island [28].…”

“…The Joyner-Boore equation indicates the influence of magnitude, distance, and site characterization, which was suitable for Lombok Island [28]. However, the shallow FT was observed to have a dominant influence on current seismic occurrences [12], and the closed distance of the FT to the island seemed to play a crucial role in the ground motion for the island; accordingly, the Boore-Atkinson relation was appropriate for these tectonic sources [21]. Results can be seen in Table 2, compared with that observed by Ardian et al…”