Volcano Research Paper Intro: define volcano & define tectonic plate boundaries. *many volcanoes form on plate boundaries *a few processes cause rock to melt, forming magma *because magma is not as dense as the rock around it, it moves up & erupts to form a volcano What is a volcano? A crack in the Earth’s surface where melted rock (lava/magma) and gases pass.

Where Volcanoes Form Divergent Boundary Boundary between two tectonic plates that are pulling away from each-other. Molten rock also forms submarine volcanoes The denser plates forms to make a trench Fissures form Mid-ocean ridges are formed Molten rock flows through the fissures onto the ocean floor. Divergent boundaries under water chains known as mid-ocean ridges.

Where Volcanoes Form Cont. Convergent Boundary A boundary when plates collide and it gets denser and bends One plate moves under the other (this is called subduction) As a plate moves down it gets greater heat & pressure Plates release fluid which causes surrounding rock to melt When subduction occurs, the denser plate moves underneath the lighter plate---creating a trench As the plates subduct, the rock receives greater pressure / this pressure causes the plate to give off fluid.

Where Volcanoes Form Cont. Hot Spots Places that experience a great deal of volcanic activity, but do not lie on plate boundaries Sit over columns of hot rock that come up that come up through the Earth’s mantle The columns do not move and are called mantle plumes The plate slips over this column of hot rock, and as the magma comes up, it creates a chain of volcanic islands. The Hawaiian Islands are an example of this

How Magma Forms Magma is made deep in the Earth’s crust and in the upper sections of the mantle Temperature is high and there is a great deal of pressure When temperature /pressure change, magma forms. Specifically temp. up and pressure down---makes rock melt Water can also make the melting temp. of rock lover, causing it to melt Temperature causes some minerals to melt and form magma When pressure on rock goes down, it creates space around rock. The rock then expands & melts, creating magma adding fluids In the lithosphere of oceanic plates, there is sediment and volcanic rock that holds water and other fluids When an oceanic plate subducts, the fluids come into contact with the surrounding rock When fluids enter, the melting temp. decreases and rock begins to melt.