Measurement of Multichannel Analysis of Surface Wave in the South of Pangandaran as an Effort for Earthquake Hazard Mitigation

Abstract

The Regency of Pangandaran is located on the southern side of West Java, surrounded by local faults, and close to the Indo-Australia and Eurasian subduction zone, causing the area to feel the earthquake's impact often. Tasikmalaya Earthquake M 7.3, on September 2, 2009, was felt strong and has caused damage in this area. Therefore, mitigation efforts are critical to reducing the earthquake impact. This study aims to determine the classification of soil types in the southern Pangandaran based on 1D Vs up to 30 m depth (Vs30) measured by the Multichannel Analysis of Surface Wave (MASW) method. The study used the SNI 1726-2012 as the categorization of soil types based on Vs30. To clarify, the Vs profile made the cross-section from west to east part in 2D. The results show that hard and medium soils dominate the research area with Vs30 values between 210 - 627 m/s that make the area relatively safe from the potential of strong earthquake shocks. However, the southern part of Cijulang, Parigi, and Pangandaran districts have medium soil types that are relatively thick. Those parts may indicate the potential for stronger earthquake shocks.