Earthquakes are among the hidden forces that threaten human life and the future of civilization. Earthquakes can result in landslides, ground shaking, fires, fissures, structural damage to buildings, tsunamis and damage to highways and bridges. The extent of destruction and suffering caused by an earthquake depends on: duration, magnitude, and intensity. And with the technological progress and studies in space sciences, the Earth did not receive the attention of studies and researches, especially that related to pre-earthquakes prediction. This paper presents a brief study of some modern methods for pre-earthquakes prediction through study of physical changes in the Earth's atmosphere, especially in the ionosphere.