Analysis of Tsunami Disaster Risk Level Using Grid-Based Method (Case Study: Coastal South Beach Blitar)

Tsunamis are one of the most frequent deadly natural disasters in Indonesia. The tsunami came suddenly and destroyed everything in their path. Reporting from the BNPB website, a tsunami consists of a series of ocean waves capable of traveling at speeds reaching more than 900 kilometers per hour or more in the middle of the sea. Tsunamis are triggered by several factors, namely earthquakes and debris on the seabed, or due to volcanic eruptions at sea. No technology can predict exactly when a tsunami will occur. Therefore the mitigation process is needed as preparation to face a disaster. The geographical position of the southern coast of Blitar Regency is recorded as a tsunami-prone area due to the shift in the Indoaustralia and Euroasia plates and directly adjacent to the Indian Ocean. In this study, an analysis of the risk level of a tsunami disaster in the coastal area of Blitar Regency will be carried out as the first step for disaster mitigation to minimize the occurrence of casualties using a grid-based analysis. The process is carried out using spatial data in the form of points, which are then interpolated so that the new points are obtained. Risk analysis is obtained by three parameters, namely hazard parameters, vulnerability parameters, and capacity parameters. The area affected by the tsunami hazard in the Blitar Regency spreads over 14 villages in Blitar Regency. The area affected by the tsunami in the 10m-height model is 655.76 hectares. The village with the largest inundation area is located in Sumbersih Village with an area of 97.52 hectares. In calculating the level of vulnerability, it is found that the level of vulnerability in the coastal area of Blitar Regency is in the medium class. Furthermore, the risk analysis shows that the area at risk of tsunami in the run-up model is 10 meters covering an area of 655.76 hectares, a low-risk area of 74.69 hectares, a moderate risk area of 211.44 hectares, and a high-risk area of 369.62 hectares. Hectares. In Bakung District, there are no areas with a high level of risk.