Saturday, April 24, 2010

Also known as composite volcano, a stratovolcano is a tall, conical volcano with many layers of hardened lava, tephra, volcanic ash, and a crater, or craters, at the summit. They are characterized by a steep profile and periodic, explosive eruptions. A stratovolcano is composed of intermixed layers of lava flows and poorly consolidated volcanic material such as ash and cinders. Stratovolcanos are typically located on continental crust above subducting plates and are easily recognized by their often beautiful symmetrically-shaped cones.

Stratovolcanoes erupt explosively as they are usually found at a destructive plate margin. They have also been responsible for the largest, most destructive historic eruptions due to retention and build-up of volatile gases within the volcanos and their magmas during their pre-eruptive phases. During any given year, a few dozen stratovolcanos are active, and around 500 have erupted during historic times.

Stratovolcanoes are also called "composite volcanoes" because of their composite layered structure built up from sequential outpourings of eruptive materials. They are among the most common types of volcanoes, in contrast to the less common shield volcanoes. A famous stratovolcano is Krakatoa, best known for the eruption in 1883.

Cross Section of Stratovolcano

Composite Volcano on an Aleutian Island

Stratovolcano video