Earthquake-induced liquefaction has been known as a complex and challenging topic in the field of geotechnical engineering. The phenomenon could bring catastrophic damage as has been seen from the past with severe damage seen on the ground and various structures such as buildings, earth structures, and lifelines. The occurrence of liquefaction is caused by the loss of strength and stiffness of the cohesionless saturated soils due to the rapid dynamic loads from the earthquake. The loss of strength and stiffness of the soil could lead to the failure of the foundation ground and structures placed above it. In order to analyze and observed the earthquake-induced liquefaction phenomena, physical modelling subjected to geotechnical centrifuge was conducted in this study. Embankment lies on liquefiable foundation ground was modelled by the means of physical modelling and subjected to the earthquake motion of The 2011 Tohoku Earthquake retrieved from K-Net Mito stations. Geotechnical centrifuge test with 50 g of centrifugal acceleration was conducted in order to create the actual fields conditions. The behaviour of the model was observed using sensors for acceleration, pore pressure, and displacement. The study aims to understand the liquefaction phenomena, mechanism and consequences through physical modelling and laboratory testing. The test shows that the liquefaction-induced damages to the foundation ground and the embankment as shown from the visual assessment and data obtained from the test. Liquefaction manifestation could be seen from the rapid development of excess pore water pressure on the foundation ground, lateral spreading, and settlement and deformation of the embankment.

Landslides are a recurring phenomenon that disrupts the natural environment and causes yearly property damage, economic losses, and fatalities. The damage is expected to increase due to deforestation rates, population growth, agriculture, slope-building infrastructure expansion, and global climate change. This study assesses the susceptibility to landslides through Weight of Evidence (WoE) and Frequency Ratio (FR) methods in the Temanggung Regency, Central Java Province, Indonesia, that located on the slopes of two active volcanoes. Initially, a landslide record and the input parameters of the landslide controlling factors were prepared from field surveys, remote sensing data, and secondary data and processed by a geographic information system (GIS). Six landslide parameters in thematic layer maps were selected to develop landslide susceptibility: slope, lithology type, geological structure density, land cover, and rainfall. According to the WoE and FR models, a landslide susceptibility zoning map was classified into four landslide-prone zones from low to very high. Finally, the success and predictive rate curves method confirmed the landslide susceptibility maps to check the model accuracy. The results showed that the landslide susceptibility map using the WoE method had better accuracy than the FR method, with a success rate of 78.48% and a prediction rate of 81.1%. In comparison, the FR method was 74.53% for the success rate and 78.48% for the prediction rate. These landslide susceptibility maps can be used as a guideline to develop land-use planning and landslide disaster mitigation.

Liquefaction is one of the causes of ground and structural damages during the earthquake. The occurrence of liquefaction during the earthquake is caused by the contractive behavior of loose sands subjected to cyclic loading. Due to this phenomenon, the soil deposits will lose its strength, causing deformation and settlement. In this study, the seismic response of the road embankment with proposed countermeasures is analyzed by conducting a centrifuge model test. The model was subjected to a gravitational acceleration of 50g to replicate the prototype scale's actual conditions of stress and strain. Two types of proposed countermeasures, gravel mat and gravel mat with geogrid, were used in this study. The study aims to observe the behavior and mechanism of the model subjected to liquefaction. The results show that the proposed countermeasures helped prevent structural failure by reducing the excess pore water pressure development and its dissipation time and reducing the settlement. It also reduces the lateral spreading of the foundation ground based on visual observations.