Estimation of Peak Ground Accelerations of the Malay Peninsula due to Distant Sumatra Earthquakes

Abstract

The low-seismicity Malay Peninsula has never experienced any earthquake damage. Thus, earthquake-resistant design has not been specifically required in the building codes. However, it has been realized that urban areas located rather distantly from earthquake sources may also be affected by tremors. In this article, the potential ground motion in terms of the peak ground accelerations (PGAs) due to long-distance Sumatra earthquakes is investigated for Singapore and Kuala Lumpur, following a probabilistic seismic hazard assessment approach. Earthquakes that have occurred in Sumatra in the last 37 yr are used, for which M s and M w catalogs are constructed from the available m b catalog. The analysis is then carried out using the M w catalog. Based on the PGAs of 52 recent Sumatra earthquakes recorded in Singapore, the attenuation relationship of Fukushima and Tanaka (1992) is found to correlate well with the high-rate attenuation characteristic of the region. The predicted design-basis PGAs (i.e., PGA with 10% probability of being exceeded in a 50-yr exposure time) on rock outcrop sites are 12.7 and 29.5 gal for Singapore and Kuala Lumpur, respectively. The predicted maximum credible PGAs (i.e., PGA with 2% probability of being exceeded in 50 yr) are 24.3 and 55.1 gal for the two cities. Current building design codes in the region require that buildings be capable of resisting a notional ultimate horizontal design load equal to 1.5% of the characteristic dead weight, applied at each floor simultaneously to ensure structural robustness. The base shear forces resulting from the predicted design-basis PGAs and the maximum credible PGAs at rock site in Singapore and Kuala Lumpur are therefore comparable to or higher than the capacity required by the current building codes. Manuscript received 27 February 2001.