Abstract: Strong earthquakes, extreme weather conditions and human activities are among the major factors triggering landslides. These strong disturbances can change the physical properties of the landslides and the mechanical properties of the weak surfaces, which are responsible for the failure of the early warning. A new method is examined for quickly evaluating the safety of the landslides after a disturbance, such as an earthquake. The natural frequency of harmful geological structures are measured using the laser measurement technology. The measured natural frequency can quantitatively reflect the parameters of the internal structure. Using the simplified model of the landslide body, the stress loss of the slope surface due to an earthquake or heavy rain can be determined. The experimental results show that the natural frequency can be used to infer the monitoring indices such as the stress loss coefficient when the landslide subjected to a large disturbance. Rapid and remote monitoring can be effectively used to quickly evaluate a landslide. The laser vibration technology will play an important role in disaster prevention and disaster mitigation in the engineering practice.

Key words: natural frequency, landslide, laser, stability analysis, monitoring and early warning