Comparison of Soil Surface Seismic Hazard Maps as Basic Disaster Mitigation Based Spatial Planning in Riau Province

Abstract

Spatial planning has an important role in disaster mitigation efforts. The availability of earthquake maps is very useful in spatial planning. The need for spatial planning today is micro spatial planning. Therefore, the 2017 national earthquake map needs to be detailed into a micro zonation map at the district or city scale. The ground acceleration presented in the national earthquake map was the acceleration at bedrock, while in spatial planning it is the necessary acceleration at the surface. Therefore, the purpose of this research was to obtain a map of the earthquake at the surface with a micro-scale. Determination of the acceleration value at the surface was carried out by two models. Model-1, the surface acceleration was obtained by multiplying the results of the PSHA analysis at bedrock by the amplification factor based on SNI-1726. While Model-2, the acceleration value at the surface was directly obtained from the results of PSHA analysis using the average surface shear wave velocity (Vs30) based on data from the USGS. The result of this study showed that from the 2 analytical models used, Model-2 has a higher surface acceleration value than Model-1. Riau Province has 12 districts. in general, the 12 districts were included in the low to moderate risk index class, but there was one district that was close to the high index class, namely Rokan Hulu district.