Analysis of liquefaction potential in the Malalayang beach area, North Sulawesi

Abstract

North Sulawesi Province was locating in a tectonically active area, affected by subduction of the Sulawesi Sea plate, Sangihe, and Halmahera. These plates are still active to provide an earthquake threat. Several large earthquakes that came from various plates around Manado City have been recorded. A large earthquake that shakes sandy soil can produce liquefaction events. The Malalayang beach area, located in the West of Manado City a part of Malalayang Beach Area Arrangement Work Package and the Bunaken Village Ecotourism Arrangement, was chosen as the research object to analyse the possibility of liquefaction. The research begin with collect boring testing data, lab test data, and earthquake data such as the moment of magnitude and Peak Ground Acceleration (PGA). This study also uses various methods or attenuation equations to determine the peak ground acceleration from the history of earthquakes obtained from multiple sources. Based on the data obtained from the field and laboratory tests, data processing is carried out to determine the liquefaction potential. From the results of the Liquefaction Potential Index (LPI) calculation, it was found that the Malalayang Beach Area has the potential for the occurrence of the liquefaction phenomenon.