Analisis Potensi Likuifaksi Pada Pasir Vulkanik Di Pantai Glagah Kulonprogo Berdasarkan Data N-SPT

Abstract

One of the most causes of damage to structures during an earthquake is liquefaction. Liquefaction happened in loose sand, which saturated under earthquake shaking. Earthquake shaking will cause cyclic loading to the ground's surface, which potential for the occurrence of liquefaction. The liquefaction phenomenon is a soil behavior under cyclic loads that occurs in just a few moments. Due to the short cyclic load, the soil mass suddenly changes from a solid limit to a liquid limit or has a paramount consistency, such as liquid. Liquefaction events during an earthquake can be characterized by the presence of ground movement in the horizontal direction, seepage water out from fracture of the ground, movement of sloping or descending buildings, displacement of ground advance, and landslides. This study took a case study in Glagah Beach at Kulonprogo Regency. That is beach areas, a landform alongside body water, which consists of loose particles such as sand where Yogyakarta International Airport (YIA) is located. The analysis was carried out to determine the potential of liquefaction based N-SPT data using the Seed, Martin & Lysmer (1975). Based on these data, The Cyclic Stress Ratio (CSR) value is calculated, which is the ratio between the average shear stress caused by the earthquake with the significant vertical stress in each layer and the value of the Cyclic Resistance Ratio (CRR), which is the amount of soil resistance to liquefaction. The analysis in the Kulonprogo Regency area is an area that is considered to require liquefaction. Analysis of liquefaction potential based on N-SPT data with the Seed, Martin & Lysmer (1975) method on a 6.3 magnitude earthquake. The result indicates that the liquefaction potential occurs up to a depth of 8.5 meters.

Integrated mapping of the earthquake-induced liquefaction in Wates Groundwater Basin, Kulon Progo for land use planning consideration: A preliminary study

“…Dwiyanta (2016) [4] found that the NYIA area has majorly severe and moderate susceptibility to liquefaction hazards. Anggara et al (2020) [5] and Artati et al (2020) [6] stated that majorly, the coastal area of Kulon Progo district is highly susceptible to liquefaction if there is an earthquake with more than 6.3 Mw happened in the surrounding area. The complete research is aimed at getting a detailed liquefaction potential map of the Wates Groundwater Basin area.…”