A geologic event causes changes to the physical makeup of a particular place and occurs slowly.
Geological events are what causes numerous changes and phenomena on the Earth's surface. Examples of these events include cliff erosion, volcanic eruption, or sedimentation at a mouth of a river.
Geological processes are extremely slow. However, because of the immense lengths of time involved, huge physical changes do occur - mountains are created and destroyed, continents form, break up and move over the surface of the Earth, coastlines change and rivers and glaciers erode huge valleys.
Geological events are both classified as internal and external. This means that these events occur both in the Earth's surface and interior.