Volcanoes General Science

What is a Volcano a crack in the earth's crust through which molten lava and gases erupt a crack in the earth's crust through which molten lava and gases erupt

Formation of a Volcano The process begins deep within the earth The process begins deep within the earth Small amounts of mantle rock melts, forming liquid magma Small amounts of mantle rock melts, forming liquid magma Gaseous pressure builds up Gaseous pressure builds up Magma forces up and out Magma forces up and out

Volcano Comparison The process is similar to shaking can of pop The process is similar to shaking can of pop Pressure from carbonated gas builds Pressure from carbonated gas builds Forcing the liquid right out the top Forcing the liquid right out the top

What Causes An Eruption

Structure of a Volcano Magma Chamber- Pool of magma, that fills and builds up pressure Magma Chamber- Pool of magma, that fills and builds up pressure Vent- Opening in the ground where magma escapes Vent- Opening in the ground where magma escapes Crater- Bowel shaped pit at the top Crater- Bowel shaped pit at the top

Two Eruptions Types A Quiet Eruption A Quiet Eruption An Explosive Eruption An Explosive Eruption

Quite Eruption Quiet Eruptions lava flows in streams and can travel over many kilometers Quiet Eruptions lava flows in streams and can travel over many kilometers The vent is not clogged, no excess gas build up The vent is not clogged, no excess gas build up

Explosive Eruptions Thick magma can clog the vent causing pressure build up. Thick magma can clog the vent causing pressure build up. Lava and gas are hurled outward high into the sky Lava and gas are hurled outward high into the sky

Lava Lava: Magma which has reached the surface through a volcanic eruption. Lava: Magma which has reached the surface through a volcanic eruption. Lava Flow: An outpouring of lava onto the land surface from a vent, flows like a river Lava Flow: An outpouring of lava onto the land surface from a vent, flows like a river Lava Fountain: A rhythmic vertical fountainlike eruption of lava. Lava Lava Fountain: A rhythmic vertical fountainlike eruption of lava. Lava

Locations of Volcanoes Most Volcanoes occur along plate boundaries Most Volcanoes occur along plate boundaries

Types of Volcanoes 1. Shield 2. Cinder cones 3. Composite volcanoes

Shield Volcanoes Shield volcanoes are wide, and short Shield volcanoes are wide, and short Lava flows a long distance before it solidifies Lava flows a long distance before it solidifies

Cinder Cone Volcano A Small Volcano with steep sides A Small Volcano with steep sides They form from the ash and cinders that are ejected into the air and back into the volcano They form from the ash and cinders that are ejected into the air and back into the volcano One vent One vent

Composite Volcano Tall with steep sides Tall with steep sides Built from layers of lava and ash Built from layers of lava and ash Often have secondary vents Often have secondary vents

Hot Spot A hot spot is a region where hot rock extends from deep within the earth’s mantle to the surface A hot spot is a region where hot rock extends from deep within the earth’s mantle to the surface

Are Volcanoes Erupting Today KILAUEA, HAWAII Location: N, W Last Update: March 2, 2004 March 2, 2004

How was Hawaii Formed?

Hawaiian Islands sit on the Hawaiian Hotspot. The hotspot does not move. The Pacific Plate does and carries the islands After each island was formed, it was carried away from the hotspot Another island formed in its place.

Next to the 4.5 billion-year earth, the Hawaiian Islands are geologically young. 40 million years ago,

The process repeated and created a chain of similar islands. The island of Hawaii has 3 active volcanoes South of Hawaii, the seamount of Loihi is building and will become another island in 10,000 years

Loihi A new small island A new small island Growing now Growing now Scientists plan to monitor eruptions, collapses and earthquakes as Loihi grows. Scientists plan to monitor eruptions, collapses and earthquakes as Loihi grows. But despite its dramatic and visible growth, Loihi will not break the ocean's surface for about 50,000 years. But despite its dramatic and visible growth, Loihi will not break the ocean's surface for about 50,000 years.