In islands, states, and countries of the Pacific Ocean the lava flows out of the gaping jaw in the mountian. The ash that comes forth as a result of this explotion covers the surrounding ground and much that is not surrounding; smothering all life in that area.
All of this comes from one simple land form: the volcano. A volcano is an area in the Earth where magma, the liquid rock found in the mantle, comes out of the Earth and forms a cone shaped mountain. The magma, called lava once it reaches the top of the crust, does not just pour out of the volcano at random. It pours out of specific areas called vents. Thes areas often create violent explotions. When a volcano explodes, letting loose lava, it is called an eruption.
There are three different types of volcanoes. Each one has its own type of eruption.
Volcanoes that are made up of cinders and other rock particles that have settled in a mountain shape are called cinder cones. These volcanoes are usually not very high and have narrow bases and steep sides. Eruptions from cinder cones are often the most explosive.
Shield volcanoes are those composed of quiet lava flows. The lava flows over a large area and eventually forms a gently sloping dome-shaped mountain. Eruptions from these types of volcanoes are often the least explosive and can some times be diverted by spraying sea water on to the on-coming lava.
The third type of volcano is the composite volcano. These are built up of alternating layers of rock particles and lava. Composite volcanoes are formed by alternating violent and quiet eruptions.
When volcanoes erupt, sometimes larger bits of rock, called volcanic bombs, come hurling out. These pieces are molten when they leave the volcano, but harden before they reach the ground.
Scientists have discovered that volcanoes, just like earthquakes, occur most often at plate boundaries. One of these volcanic boundaries is the Ring of Fire in the Pacific Ocean. Some of the deadliest and most often erupting volcanoes are located there.