Plate Tectonics: Home

Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth’s subterranean movements. The theory, which solidified in the 1960s, transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes.

Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth's lithosphere—split apart from each other.

Earth’s tectonic plates fit together in a jigsaw puzzle of plate boundaries.

The lithosphere is the solid, outer part of Earth, including the brittle upper portion of the mantle and the crust.

A gallery of map illustrations showing the positions of tectonic plates in the geologic past.

Tectonic plates are 62 miles thick and are made up of the continental crust and the oceanic crust.
Slab pull is the most relevant force that affects the movement of tectonic plates.
Convection refers to specific cells within the Earth’s mantle that create heat. The heat makes the solid rocks move upwards while the colder rocks move downwards.

There are four types of boundaries between tectonic plates that are defined by the movement of the plates: divergent and convergent boundaries, transform fault boundaries, and plate boundary zones.

Plate tectonics has revolutionized virtually every discipline of the Earth sciences since the late 1960s and early 1970s. It has served as a unifying model or paradigm for explaining geologic phenomena that were formerly considered in unrelated fashion. Plate tectonics describes seismic activity, volcanism, mountain building, and various other Earth processes in terms of the structure and mechanical behaviour of a small number of enormous rigid plates thought to constitute the outer part of the planet (i.e., the lithosphere). This all-encompassing theory grew out of observations and ideas about continental drift and seafloor spreading.

For billions of years, Earth has been remodeling itself. Huge masses of molten rock rise from deep inside Earth, cool into a solid, travel along our planet’s surface and then sink back down. The process is known as plate tectonics.

The Earth is an ever-changing landscape. At the heart of these processes are tectonic plates, which are massive slabs of the Earth’s crust and upper mantle that float on the hotter, more fluid layer below. Understanding tectonic plates is crucial for grasping how mountains rise, why earthquakes shake the ground, and what powers volcanic eruptions.

You will need a username and password for this article, see your teacher. When you load this Britannica article, click on the 1 above the article for that Reading Level. "In an earthquake, huge masses of rock move beneath the Earth’s surface and cause the ground to shake. Earthquakes occur constantly around the world. Often they are too small for people to feel at all. Sometimes, however, earthquakes cause great losses of life and property ... "

Sometimes the Earth's crust can shift beneath us and cause hazards such as earthquakes, volcanoes and tsunamis. Geomorphology is the study of these movements. It investigates how they form the physical features we see on the Earth's surface, such as mountains, ridges and valleys.

Shona from Geoscience Australia explains to us the role of tectonic plates in causing these movements and hazards. Tectonic plates have been moving for billions of years — colliding, separating or sliding against each other. The boundaries of these tectonic plates are where we find most geo-hazards occurring, in particular along the Ring of Fire, which is around the edge of much of the Pacific Ocean.

Will scientists ever be able to accurately predict the timing of an earthquake?
Imagine the number of lives that could be saved if this were possible.

Dr Maryanne Demasi joins a group of researchers drilling into one of the most earthquake-prone regions on Earth as they try to improve earthquake prediction to add precious seconds to earthquake warning times.

"An earthquake is a sudden, rapid shaking of the earth caused by the shifting of rock beneath the earth’s surface. They strike without warning, at any time of year, day or night. "

Earth is a dynamic place, with moving tectonic plates, environmental processes and human actions shaping its features.

You will need a username and password for this article, see your teacher. When you load the article, click on the 1 above the article for that Reading Level. "A volcano is an opening in Earth’s crust. When a volcano erupts, hot gases and melted rock from deep within Earth find their way up to the surface ... "

"Imagine living in the shadow of a volcano? Well, millions of people do in Naples, Italy, where a massive volcano called Vesuvius exists. This clip explores the dangers posed by volcanoes and investigates some recent and ancient eruptions. Find out some misconceptions about volcanoes and discover how science is helping prevent future catastrophes."

"An erupting volcano can blast ash, lava, solid rocks and gases into the air, creating hazards that can kill people, disrupt air travel and destroy property many miles away. "