The document discusses the causes and effects of earthquakes. It explains that earthquakes are caused by a sudden release of energy in the Earth's crust that creates seismic waves. Major effects of earthquakes include shaking and ground ruptures that can damage buildings, landslides and avalanches, fires caused by damage to power lines or gas lines, and tsunamis generated by undersea earthquakes or landslides. While fully predicting earthquakes is not yet possible, the probability of fault movement can be estimated, and some earthquake warning systems can now provide regional alerts before shaking occurs.