Question

explain the theory of tectonic plates

Answer 1

Plate tectonics (from the Late Latintectonicus, from the Greek: τεκτονικός"pertaining to building")[1] is a scientific theorydescribing the large-scale motion of seven large plates and the movements of a larger number of smaller plates of the Earth'slithosphere, since tectonic processes began on Earth between 3 and 3.5 billion years ago. The model builds on the concept ofcontinental drift, an idea developed during the first decades of the 20th century. Thegeoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s and early 1960s.

The lithosphere, which is the rigid outermost shell of a planet (the crust and upper mantle), is broken into tectonic plates. The Earth's lithosphere is composed of seven or eight major plates (depending on how they are defined) and many minor plates. Where the plates meet, their relative motion determines the type of boundary: convergent, divergent, ortransform. Earthquakes, volcanic activity,mountain-building, and oceanic trenchformation occur along these plate boundaries (or faults). The relative movement of the plates typically ranges from zero to 100 mm annually.[2]

Answer 2

Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth's mantle. This strong outer layer is called the lithosphere, which is 100 km (60 miles) thick, lithosphere includes the crust and outer part of the mantle. Below the lithosphere is the asthenosphere, which is malleable or partially malleable, allowing the lithosphere to move around.