"Plate tectonics is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates which have been slowly moving since about 3.4 billion years ago."
Study of the Earth's lithosphere and its movement over the underlying asthenosphere. Understanding plate tectonics is important to understand volcanism because most volcanoes are found near plate boundaries.
The Theory of Plate Tectonics: A scientific theory that explains how the Earth's lithosphere (outer layer) is divided into several large and small plates that move around the Earth's surface.
Types of Plate Boundaries: The three types of plate boundaries: Divergent, convergent, and transform - which describe the movement of plates and their interactions with one another.
Volcanoes: The different types of volcanoes, how they form, and where they are found.
Magma: The molten rock beneath the Earth's surface that erupts as lava during volcanic activity.
Earthquakes: The movement of tectonic plates along fault lines that can trigger seismic activity.
Plate Motions: The direction and speed of movement of the Earth's tectonic plates.
Hotspots: Areas of the Earth's surface where magma rises from the mantle, creating volcanic activity.
Subduction Zones: Areas where tectonic plates collide and one plate is pushed beneath the other, often resulting in volcanic activity.
Seafloor Spreading: The process by which new oceanic crust is created at the mid-ocean ridges.
Geological Time: The different geological eras and periods in which plate tectonics has shaped the Earth's surface.
Divergent Plate Boundary: This is where two plates are moving away from each other. This creates a gap in between the two plates which magma from the mantle can flow through, causing volcanic eruptions. The magma cools and solidifies, forming new crust on the ocean floor.
Convergent Plate Boundary: This is where two plates are moving towards each other. Depending on the type of plates that are colliding, there are three types of convergent boundary: Oceanic-Oceanic, Oceanic-Continental and Continental-Continental. When two plates collide, one will usually be forced under the other in a process called subduction. The pressure and heat created by subduction can cause volcanic eruptions.
Transform Plate Boundary: This is where two plates are sliding past each other in opposite directions. As they move, they can get stuck and then suddenly release, causing earthquakes. Transform boundaries do not usually result in volcanic eruptions, but the movement of magma underneath the surface can cause small eruptions.
"The model builds on the concept of continental drift, an idea developed during the first decades of the 20th century."
"Plate tectonics came to be accepted by geoscientists after seafloor spreading was validated in the mid-to-late 1960s."
"Earth's lithosphere is broken into seven or eight major plates."
"Where the plates meet, their relative motion determines the type of plate boundary: convergent, divergent, or transform."
"Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries."
"The relative movement of the plates typically ranges from zero to 10 cm annually."
"Tectonic plates are composed of the oceanic lithosphere and the thicker continental lithosphere, each topped by its own kind of crust."
"Along convergent plate boundaries, the process of subduction, or of one plate moving under another, carries the edge of one plate down under the other plate and into the mantle."
"The lost surface is balanced by the formation of new oceanic crust along divergent margins by seafloor spreading."
"This process of plate tectonics is also referred to as the conveyor belt principle."
"Tectonic plates are able to move because Earth's lithosphere has greater mechanical strength than the underlying asthenosphere."
"Plate movement is driven by a combination of the motion of the seafloor away from spreading ridges due to variations in topography and density changes in the crust."
"At subduction zones, the relatively cold, dense oceanic crust sinks down into the mantle forming the downward convecting limb of a mantle cell. This is the strongest driver of the plates."
"The relative importance of other proposed factors such as active convection, upwelling and flow inside the mantle, and tidal drag of the moon, and their relationship to each other is still the subject of debate."