Abstract
Abstract. Seismic hazard assessments, both deterministic and probabilistic, for Peninsular Malaysia have been carried out using peak ground acceleration (PGA) data recorded between 2004 and 2016 by the Malaysian Meteorological Department using triaxial accelerometers placed at 19 seismic stations on the peninsula. Seismicity source modelling for the deterministic seismic hazard assessment (DSHA) used historical point sources whereas in the probabilistic (PSHA) approach, line and areal sources were used. The earthquake sources comprised the Sumatran subduction zone (SSZ), Sumatran fault zone (SFZ) and local intraplate (LI) faults. Gutenberg–Richter law b value for the various zones identified within the SSZ ranged between 0.56 and 1.06 (mean=0.82) and for the zones within the SFZ, between 0.57 and 1.03 (mean=0.89). Suitable ground motion prediction equations (GMPEs) for Peninsular Malaysia along with other pertinent information were used for constructing a logic tree for PSHA of the region. The DSHA “critical-worst” scenario suggests PGAs of 0.07–0.80 ms−2 (0.7–8.2 percent g), whilst the PSHA suggests mean PGAs of 0.11–0.55 ms−2 (0.5–5.4 percent g) and 0.20–1.02 ms−2 (1.9–10.1 percent g) at 10 % and 2 % probability of exceedance in 50 years, respectively. DSHA and PSHA, despite using different source models and methodologies, both conclude that the central-western cities of Peninsular Malaysia, located between 2 and 4∘ N, are most susceptible to high PGAs, due to neighbouring active Sumatran sources, SFZ and SSZ. Of the two Sumatran sources, surprisingly, the relatively less active SFZ source with low magnitude seismicity appeared as the major contributor due to its proximity. However, potential hazards due to SSZ mega-earthquakes should not be dismissed. Finally, DSHA performed using the limited LI seismic data from the Bukit Tinggi fault at a reasonable moment magnitude (Mw) value of 5.0 predicted a PGA of ∼0.40 ms−2 at Kuala Lumpur.
Highlights
Seismic hazard assessment (SHA) of a particular region can generally be defined as the estimation of hazard at a specific site due to occurrence of a hypothetically damaging earthquake originating within the geographic region
As observed for Case 1 in Fig. 9a and b, the peak ground acceleration (PGA) value varies from 0.02 to 0.34 ms−2 across the peninsula while the PGA values expectedly rise approximately 2.5 times for Case 2 in the range of 0.07–0.80 ms−2. Both figures clearly show that lower central-western area of Peninsular Malaysia is more susceptible to higher seismic hazard with PGA values decreasing from the southwest to northeast of Peninsular Malaysia
When the overall deterministic seismic hazard assessment (DSHA) map is split into the regional sources (SSZ and Sumatran fault zone (SFZ)), as shown in Fig. 10a and b, it is observed that the source that contributes to the high PGA in the cities of Kuala Lumpur (KL), Seremban and Malacca was the SFZ with the maximum possible earthquake (MPE) associated located close to the Angkola segment
Summary
Seismic hazard assessment (SHA) of a particular region can generally be defined as the estimation of hazard at a specific site due to occurrence of a hypothetically damaging earthquake originating within the geographic region. Deterministic seismic hazard assessment (DSHA) is often desirable for regions with well-defined seismotectonic models, for example, California, where DSHA dictates the design ground motion parameters for bridges and buildings (Wang, 2011) The application of this approach is straightforward and less complicated, allowing engineers to make clear-cut decisions, for consideration of other earthquake parameters unrelated to the site is seldom required. With intensifying interest in earthquake studies in Malaysia, the present work aims to contribute a detailed study of the seismic hazard faced by Peninsular Malaysia including the development of seismic zonation maps To this end, updated strong ground motion records obtained from the Malaysian Meteorological Department (MMD) for the period of 2004–2016 in conjunction with recent findings on the suitability of existing and.
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