Modeling The Potential Risk Of Building Vulnerability Towards Tsunami Hazard In Ulak Karang And Pasir Jambak Sub-District, Padang

Padang was destroyed by tsunamis generated by the earthquakes in the history of Padang. As an area located in a coastal region, its buildings in Padang face major vulnerability against a tsunami. The objectives of this study are to develop the potential impact model of building vulnerability toward tsunami hazard and to compare the building damage levels based on water inundation, internal, and external factors in Ulak Karang and Pasir Jambak sub-districts. The objective of this research is also to give recommendation to government in making planning strategies for reducing and managing the tsunami risk on building vulnerability. There are three stages of modeling; first stage in this study is simulating an eartquake model for two study areas to estimate the maximum inundation. The second stage of modeling is implementing the spatial analysis of building vulnerability based on the field surveys and GIS. The third stage to conlude is developing the Relative Vulnerability Index (RVI) scores of buildings by mapping the building vulnerability toward tsunami hazard and giving several alternatives to develop a risk management plan in a coastal community. The result shows that Ulak Karang sub-district is determined to be more vulnerable than Pasir Jambak sub-district because many buildings near the coastline of Ulak Karang sub-district are made of timber and are arranged close to each other. Moreover, many buildings in Ulak Karang sub-district, especially along the river, are made of traditional brick. Although near Pasir Jambak coastline many buildings are made of timber, but the buildings are not close to each other. There are several alternatives to increase resilience of buildings in a coastal zone, namely: 1) regulation for buildings that have RVI: 4 and 5; 2) building codes; 3) vertical evacuation structures; 4) land use zones; 5) sea walls along the coastlines; 6) natural barriers and 7) early warning system.