Development of seismic map for offshore platform design in Indonesia, case study of the North Coast of Java

Abstract

Indonesia’s design of earthquake-resistant offshore platforms does not yet have specific regulations. The commonly used standard in Indonesia, API RP 2A WSD, does not explicitly state the earthquake return period for offshore structures. A more detailed procedure is described in ISO 19901-2:2004. Two methods are introduced in the standard. First, the simplified method allows the use of earthquake maps with a return period of 1000 years. Second, the detailed method requires a site-specific seismic hazard study to determine the return period of earthquakes. This paper presents the development of seismic hazard maps using a simplified method following ISO 19901-2:2004. The maps are prepared using the probabilistic method with a case study on the North Coast of Java. The results show that the study area falls into seismic zones 1 and 2. The seismic hazard maps can be used for earthquake resistance design for structures with exposure level L2 and L3 based on the seismic risk category following the ISO.