Where is lava made?

Answer 1

Melting of solid rock to form magma is controlled by three physical parameters: its temperature, pressure, and composition.

TemperatureAt any given pressure and for any given composition of rock, a rise in temperature past the solidus will cause melting. Within the solid earth, the temperature of a rock is controlled by the geothermal gradient and the radioactive decay within the rock. The geothermal gradient averages about 25 °C/km with a wide range from a low of 5-10 °C/km within oceanic trenches and subduction zones to 30-80 °C/km under mid-ocean ridges and volcanic arc environments. PressureAs magma buoyantly rises it will cross the solidus-liquidus and its temperature will reduce by adiabatic cooling. At this point it will liquefy and if erupted onto the surface will form lava. Melting can also occur due to a reduction in pressure by a process known as decompression melting. CompositionIt is usually very difficult to change the bulk composition of a large mass of rock, so composition is the basic control on whether a rock will melt at any given temperature and pressure. The composition of a rock may also be considered to include volatile phases such as water and carbon dioxide.

The presence of volatile phases in a rock under pressure can stabilize a melt fraction. The presence of even 0.8% water may reduce the temperature of melting by as much as 100 °C. Conversely, the loss of water and volatiles from a magma may cause it to essentially freeze or solidify.

Also a major portion of all magma is silica, which is a compound of silicon and oxygen. Magma also contains gases, which expand as the magma rises. Magma that is high in silica resists flowing, so expanding gases are trapped in it. Pressure builds up until the gases blast out in a violent, dangerous explosion. Magma that is relatively poor in silica flows easily, so gas bubbles move up through it and escape fairly gently. Though an eruption of silica-poor magma can throw lava high into the air, forming lava fountains, visitors can usually watch safely nearby.

Magma rises toward the Earth's surface as long as it is less dense than the surrounding rock. Once magma stops rising, it can collect in areas called magma chambers. Magma can remain in a chamber until it cools, forming igneous rock, or it can erupt. Volcanic eruptions occur when, for example, a chamber is not large enough to hold additional magma that pushes in. When magma erupts, it is called lava.

Answer 2

Lava is just molten rock and it is usually made in volcanoes.

Answer 3

lava is super heated rock heated by the pressure of the earth underground.

Answer 4

At or very near the surface of erupting volcanoes.
Lava is the molten or solidified magma (rock) found where volcanic activities is taking place or had taken place in the past.

Answer 5

lava is made in volcanoes when ejected materials begin to flow. it can flow as a viscous fluid or a free flowing fluid