Liquefaction Potential of Volcanic Deposits During Lombok Earthquake in 2018

Abstract

AbstractThe Lombok earthquake and the Palu earthquake in 2018 were earthquakes that caused major damage in the two referenced areas. The Lombok earthquake occurred over a longer period than the Palu earthquake, but the Palu earthquake was able to cause enormous liquefaction. This study aimed to determine the behavior of the volcanic deposits of Mount Samalas during the corresponding earthquake. The research included a physical properties test, SEM photos, a shear strength test, a shaking table test, and grading tests before and after the soil samples were given cyclic loads. The results of the grading test after the shaking table test showed that there was the addition of fine grains before and after the shaking table test. This indicates that the pumice particles are scoured on the surface, resulting in the small grains becoming locked between the larger particles. This condition caused the shear strength to increase and the pore pressure to decrease significantly. The cavity in the pumice particles is thought to reduce the seismic waves during an earthquake. For the large particles, although the gradation curve has liquefaction potential, the pore water pressure did not increase significantly. However, pumice has a diameter of less than 0.075 mm because it does not have a cavity, therefore that it has the potential to experience liquefaction such as sand boiling.KeywordsLombok earthquakePumice sandLiquefaction