Prediction of volcanic activities:
These predictions are very hard, and sometimes are false, and they are based on two principles, one principle is volcano geological knowledge and other one is the setting of one control station at volcano area.
Given the geological studies and age determination of one volcano, we can know it's activities type, number of eruptions, order and rule of eruptions and sleep time of volcano.
The setting of the control station at volcanos that it is possible their activity, is useful. In these stations, seismographs and soil movement test device are installed which they are named as tilt meter.
The penetration of magma from depth to the surface is caused to break stones under volcano, that these fractures cause the shakings. By continuing the fractures and rising the magma upward, the rised magma will eject finally.