Strong-motion instrument spatial distribution model for Indonesia

The government of Indonesia has begun a strong-motion instrumentation program, and one of the questions raised during the implementation of this program is how to spatially distribute these instruments in a systematic way, because the planned number of instruments is relatively small for the vast country. This strong-motion instrument spatial distribution model follows the concept that requires placing most of the instruments in main cities and high-seismicity areas. The analysis unit is based on administrative areas; second-level administrative areas (cities and regencies) appear to be the most appropriate choice for the distribution model. The model is an adaptation of a risk approach, consisting of a hazard part and an exposure part. The indicator for the hazard part is the weighted-average peak ground acceleration. The exposure part is represented by a parameter that is the aggregation of the total gross regional domestic product, and it represents infrastructure exposed to seismic hazard, population, and land area. The plot of the hazard and exposure parameters is subsequently used for determining a set of priority areas for the instruments.