By Robbie Barker, Maximilian Bryson, and Brendan Petrili

 A volcano is an opening in the Earth’s surface through which magma rises.

 1.Most volcanoes occur at colliding boundaries.  A. less dense magma rises up through the fault.  2.Other volcanoes occur at spreading boundaries on the ocean floor.  A. calmer eruptions-lava flows onto the ocean floor.  B. a new floor is created.

 1. shield-formed from lava flows that harden.  2. cinder cone volcano-formed from explosive eruptions in which volcanic materials are thrown high in the air and pile up around the vent of volcano.  3. composite-formed from alternating lava flows and explosions.

 1. crater-deep sided depression at the top or on the side of a volcano formed during an eruption.  2. magma- molten rock inside the Earth.  3. lava- molten rock which reaches Earth’s surface.  4. caldera- crater at least 1.6 km wide.  5. geysers- groundwater heated by boiling trapped magma which erupts on the Earth’s surface. Example: Old faithful.

 6. volcanic ash- tiny bits of rock that fly into the air during an eruption, can form a thick cloud of ash and cinders.

 1. Volcanic flow can reach up to 2000 degrees Fahrenheit.  2. the less gas the less dramatic eruption.  ,000 people have died in the last 300 years due to volcanic eruptions.  4. 90% of all volcanoes are in the Ring of Fire along the edges of the Pacific Ocean.

 5. about 1900 volcanoes are likely to explode again.  6. Ash and toxic gasses can cause lung damage.  7. Volcanoes usually exist along the edges of tectonic plates.

Mount St. Helens- last eruption is in 2008 Mount Barker- last eruption in 1880 Gorda Ridge- last eruption in 1996 Northwest Rota- last eruption 2004 Kilauea- last eruption 2010 Mount Cleveland- last eruption 2008