Why don't we see any earthquakes occurring below 650 km? temperature and prossure cause those rocks to be more plastic than rigid there is no limit to the depth at which earthquakes can occur only tounami are able to form at that depth there is no friction at that depth

The correct answer is: temperature and pressure cause those rocks to be more plastic than rigid.<br /><br />Earthquakes are caused by the sudden release of stress that has built up in the Earth's crust. This stress is usually caused by the movement of tectonic plates. The deeper into the Earth you go, the higher the temperature and pressure become. At depths below 650 km, the rocks are so hot and pressurized that they become more plastic-like, meaning they can flow and deform more easily. This reduces the amount of stress that can build up, and therefore, earthquakes are less common at these depths.