Before the landslide slides, there will be various abnormal phenomena and signs (precursors) of sliding. To sum up, the common ones are as follows:
(1) Before the landslide occurred, at the toe of the front slope of the landslide, the spring water that had been blocked for many years revived, or the spring water (well) suddenly dried up, the water level of the well (hole) suddenly changed and other similar abnormal phenomena appeared.
(2) Transverse and longitudinal radial cracks appear in the middle and front of the landslide. It reflects that the landslide body has been pushed forward and has entered the state of imminent sliding.
(3) Before the landslide, soil uplift (uplift) occurred at the toe of the landslide front. This is a clear sign that the landslide is moving forward.
(4) Before the landslide, there was a sound of rock breaking or being squeezed by shear. This sign reflects deep deformation and rupture. Animals are very sensitive to this and have abnormal reactions.
(5) Before the landslide, the rock mass (soil) around the landslide will collapse and relax on a small scale.
(6) If there are long-term observation data of landslide, the horizontal displacement and vertical displacement have the trend of accelerating change before large sliding. This is a clear sign of decline.
(7) The cracks at the trailing edge of the landslide expand rapidly, and hot air (or cold air) gushes out from the cracks.
(8) Animals are abnormal in panic and plants are abnormal. Such as pigs, dogs and cows, are restless and don't sleep. The mouse runs around and doesn't go into the hole. Trees wither or skew, etc.
How to save yourself when landslide happens?
When you are in the landslide area, first of all, keep calm and don't panic. Look around quickly and evacuate to a safer place. Generally, except for high-speed landslides, as long as you move quickly, you may escape from the dangerous area. When you escape, the best direction is to run to both sides of the landslide. Don't panic when you encounter an unavoidable high-speed landslide. Under certain conditions, such as the landslide as a whole, it is an effective self-help measure to keep still or hold on to trees.