Tectonic plates are slabs of rock that are part of the crust, or the Earth’s outermost layer. Tectonic plates helped form continents and mountains millions of years ago. Continents are still moving around the world!! This is because of tectonic plate movement. Earthquakes are also caused by tectonic plates. When the plates grind together, the make a shockwave called an earthquake. Volcanoes and earthquakes are known as tectonic disasters. This is what tectonic plates are.