Tectonic Plates

Tectonic Plates

Google Earth.

Go to Google Earth and in your “Layers“, open the “Gallery” folder and turn on “Volcanoes“.

You will get red volcano placemarks. When you click on the placemark you get excellent descriptions and photos for each volcano. You can also use the pan/tilt option in Google Earth and look at the satellite/aerial photos on top of the 3D mountain terrain (assuming you have the “Terrain” layer turned on).

Plate tectonics is the theory that 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.

Tectonic Plates

the rigid outer part of the earth, consisting of the crust and upper mantle.

Lithosphere

Crust and upper most solid mantle

Mantle

Core

Tectonic Plates

Structure of the Earth

The Ring of Fire is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. It has 452 volcanoes and is home to over 75% of the world's active and dormant volcanoes.[1] It is sometimes called the circum-Pacific belt.

The driving force behind plate tectonics is convection in the mantle.

Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it.

Convection above a hot surface occurs because hot air expands, becomes less dense, and rises.

This causes circulation or convection.

Volcano's around the world

Many spectacular volcanoes are found along subduction zones, such as the "Ring of Fire" that surrounds the Pacific Ocean.

Mantle convection is the slow creeping motion of Earth's solid silicate mantle caused by convection currents carrying heat from the interior of the Earth to the surface.

Processes

Hot material near the Earth's core rises, and colder mantle rock sinks.

At a divergent margin, two plates are spreading apart, as at seafloor-spreading ridges or continental rift zones such as the East Africa Rift.

At subduction zones, two tectonic plates meet and one slides beneath the other back into the mantle, the layer underneath the crust. The cold, sinking plate pulls the crust behind it downward.

Transform margins mark slip-sliding plates, such as California's San Andreas Fault, where the North America and Pacific plates grind past each other with a mostly horizontal motion.

Hot material near the Earth's core rises, and colder mantle rock sinks. "It's kind of like a pot boiling on a stove," Van der Elst said. The convection drive plates tectonics through a combination of pushing and spreading apart at mid-ocean ridges and pulling and sinking downward at subduction zones, researchers think. Scientists continue to study and debate the mechanisms that move the plates.