What Is an Earthquake? An earthquake is an intense shaking of Earth’s surface. The shaking is caused by movements in Earth’s outermost layer. Why Do Earthquakes Happen? Although the Earth looks like a pretty solid place from the surface, it’s actually extremely active just below the surface. The Earth is made of four basic layers: a solid crust, a hot, nearly solid mantle, a liquid outer core and a solid inner core. The solid crust and top, stiff layer of the mantle make up a region called the lithosphere. The lithosphere isn’t a continuous piece that wraps around the whole Earth like an eggshell. It’s actually made up of giant puzzle pieces called tectonic plates. Tectonic plates are constantly shifting as they drift around on the viscous, or slowly flowing, mantle layer below. #earthquake #terremoto #earthquakes #gempabumi #sismo #tsunami #seismic #quake #nature #earth #deprem #tremor #potres #fault #tectonic #erdbeben #tremblementdeterre #faultline #epicenter #aardbeving #plateboundary #earthtremor #platetectonic #livingearth #movingearth #shake #disaster #engineering #geology #science