© 2023 Institute of Physics Publishing. All rights reserved.The authors have been involved with the risk assessment of cliff failures as well as mobilization of rock boulders on slopes nearby settlements and roadways in Miyagi Island in Okinawa Prefecture of Japan. The main purpose of this study is to evaluate the de-stabilization of rock boulders with regular and irregular shape due to forces resulting from earthquakes as well as groundwater. A shaking table was used to investigate the motions to cause the destabilization of rock boulders made of Ryukyu limestone on flat and sloping base made of weathered sandstone beneath limestone cliffs in Miyagijima Island. Furthermore, some analytical and numerical computations were carried out to simulate the experimental results. The outcomes of these investigations are presented and discussed in this paper.