Potential Economic Losses due to Earthquakes Induced Building Damages in Ambon-Indonesia: An Event Based Probabilistic Seismic Hazards Assessment Approach

¹ Tsunami and Disaster Mitigation Research Center (TDMRC), Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia
² Civil Engineering Department, Faculty of Engineering, Universitas Syiah Kuala, Banda Aceh, 23111, Indonesia
³ Faculty of Agriculture, Universitas Pattimura, Ambon, 97234, Indonesia
⁴ International Research Institute of Disaster Science (IRIDeS), Tohoku University, Sendai, Miyagi Prefecture, 9800845, Japan
⁵ Civil Engineering Department, Faculty of Engineering, Universitas Teuku Umar, Meulaboh-Aceh, 23651, Indonesia

^* Corresponding author: syamsidik@usk.ac.id

Abstract

Ambon, in the eastern part of Indonesia, has historical records of damaging earthquake events. In the last ten years, at least there were two times of earthquakes that caused severe damages on the city. This research was aimed at estimating potential economic losses due to earthquake induced building damages in Ambon. There were over 80,000 buildings included in the analysis based on a series of surveys conducted in 2023 and in 2024. The earthquake hazards were calculated using Event based Probabilistic Seismic Hazards Analysis (PSHA). The damage ratios were computed using Global Earthquake Model (GEM)’s vulnerability curves. A stochastic event set method which later produce Event Loss Table was introduced to calculate Probable Maximum Losses (PML) and Average Annual Losses (AAL) of buildings in Ambon. The sources of the seismic hazards were taken from two segments, namely North Banda Segment and South Banda Segment. There were 16,910 earthquake events ranging from 6.55 Mw until 9.05 Mw included in the analysis. The intensity values for the buildings were computed based on Peak Ground Acceleration (PGA) and Spectral Acceleration (SA). This study found that the average annual losses (AAL) for the city is 249,964 USD per year due to the earthquake or about 1.56% comparing to the AAL of Maluku Province provided by GEM for latest version in 2023. The highest loss would be from residential type buildings that could reach probable maximum loss (PML) of around 87 million USD.