…What are Tectonic Plates?
Plate tectonics is a scientific theory that describes the large-scale motion of Earth’s lithosphere. The model builds on the concept of continental drift which was developed during the first few decades of the 20th century.
The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates.
Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.
TL:DR – This diver is swimming between things that move frequently!