A tsunami is a series of waves caused by the displacement of a large volume of water, usually in an ocean. Earthquakes, volcanic eruptions, landslides, explosions, meteorite impacts and other disturbances above or below water can generate a tsunami. Unlike wind-driven waves, a tsunami is caused by the displacement of water. Most tsunamis are generated by earthquakes occurring in subduction zones along plate boundaries. Tsunamis have extremely long wavelengths, over 100 km, and travel at high speeds of 400 to 500 mph. Their long wavelengths allow tsunamis to travel great distances with little loss of energy, making them still destructive even after traveling thousands of miles.