MAGMA IN EARTH CRUST:

Magma is a mixture of molten rock, volatiles and solids, that is found beneath the surface of the Earth, and may also exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma often collects in magma chambers that may feed a volcano or turn into a pluton. Magma is capable of intrusion into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock.

Magma is a complex high-temperature fluid substance. Temperatures of most magmas are in the range 700 °C to 1300 °C (or 1300 °F to 2400 °F), but very rare carbonatite melts may be as cool as 600 °C, and komatiite melts may have been as hot as 1600 °C. Most are silicate mixtures.

Environments of magma formation and compositions are commonly correlated. Environments include subduction zones, continental rift zones, mid-oceanic ridges, and hotspots, some of which are interpreted as mantle plumes. Despite being found in such widespread locales, the bulk of the Earth's crust and mantle is not molten. Rather, most of the Earth takes the form of a rheid, a form of solid that can move or deform under pressure. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several kilometers of the Earth's surface.

Magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing. By definition, all igneous rock is formed from magma.

While the study of magma has historically relied on observing magma in the form of lava outflows, magma has been encountered in situ three times during drilling projects—twice in Iceland, and once in Hawaii

MOLTEN LAVA IN MIDDLE OF EARTH

Mountains that could erupt at any time forcing hot lava, gas, steam, rock, and ash out of the earth can be very dangerous, but they amazing forces of our planet earth!
Molten lava is hot! - Lava is extremely hot. Lava can reach temperatures of about 1,250° Celsius. The lava of the Hawaiian volcanoes reaches these temperatures. Normal lava temperatures reach 750° Celsius. That is still much hotter than your oven is capable of reaching.

How Volcanoes Are Formed:
A volcano is formed when there is a crack or hole in the crust, called a vent. The temperature in the deeper layers of the earth sometimes gets so hot that it melts rocks that are deep down in the earth, in the mantle and the core. Then, extremely high pressure from inside the earth builds up so much that it forces the melted rock up out of the earth through the vent, causing a volcano! Often times the vent is inside of a mountain, which means that when a volcano erupts, it shoots out of the top of the mountain. Sometimes the vent is in a flat area and the rock that erupts cools around the vent and the volcano forms its own mountain-like structure.
There can even be vents in the floor of the ocean, so sometimes volcanoes can erupt underwater. The melted rock that is pushed out of the earth is called magma. Once the magma reaches the surface of the earth and explodes out of the volcano, it is called lava. The lava flows very quickly and is very dangerous because it is burning hot! Dangerous gases, whole rocks, and ash can also shoot out of a volcano along with lava. The effects of a volcano on the land surrounding it can be very deadly. Plants and trees are often burned by the flowing hot lava or completely covered.

MANTLE

The mantle
Underlying the crust is the mantle, which is composed mainly of minerals containing magnesium, iron, silicon, and oxygen. The uppermost section of the mantle is a rigid layer. Combined with the overlying solid crust, this section is called the lithosphere, which is derived from the Greek word lithos, meaning "stone."

At the base of the lithosphere, a depth of about 40 miles (65 kilometers), there is another distinct seismic transition called the Gutenberg low velocity zone. At this level, all seismic waves appear to be absorbed more strongly than elsewhere within Earth. Scientists interpret this to mean that the layer below the lithosphere is a zone of partially melted material. This "soft" zone is called the asthenosphere, from the Greek word asthenes, meaning "weak." It extends to a depth of about 155 miles (250 kilometers).

This transition zone between the lithosphere and the asthenosphere is named after American geologist Beno Gutenberg (1889–1960).

EXPLORING EARTH CRUST

EARTH CRUST:

In geology, the crust is the outermost solid shell of a rocky planet or moon, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantles.

The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust. The boundary between the crust and mantle is conventionally placed at the Mohorovičić discontinuity, a boundary defined by a contrast in seismic velocity. Earth's crust occupies less than 1% of Earth's volume.