Assessing Multi-Hazard Risk through Spatial Analysis: A Geographic Information Systems for Susceptibility Mapping in Java Island, Indonesia

Abstract The geographic location and population make Java Island a disaster-prone area with various threats, including earthquakes, floods, landslides, and volcanic eruptions. Based on historical data, these four types of disasters caused a total of US$24,303,159,688 in economic losses in the last 50 years. In regard to the big loss, it is considered important to identify potential disaster risks to avoid more sustainable economic losses in the future. By utilizing developments in Geographic Information Systems (GIS) technology, potential disaster risk mapping could be carried out. The process begins with preparing a map of the potential risk of earthquakes, floods, landslides, and volcanic eruptions by referring to the regulatory document of the head of the National Disaster Management Agency (BNPB) Number 2 of 2012 and Indonesian National Standard (SNI). Afterwards, the potential risk map for each type of disaster will be combined to determine the hazard level of each disaster in 1 square kilometer-sized pixels. The merging process uses annual economic loss data over a period of 50 years as a weighting factor. Based on the data, the results show that 11.554% (15.092 square kilometers) of the area of Java Island falls into the high hazard level class, 77.642% (101.413 square kilometers) into the moderate hazard level class, and 10.804% (14.112 square kilometers) into the low hazard level class. The resulting multi-hazard map could be further used for various specific purposes, such as creating an early warning system or estimating direct losses due to disasters.