VolcanoesVolcanoes

General ScienceGeneral Science

What is a VolcanoWhat is a Volcano

a crack in the earth's a crack in the earth's crust through which crust through which molten lava and molten lava and gases eruptgases erupt

Formation of a VolcanoFormation of a Volcano

The process begins The process begins deep within the earthdeep within the earth

Small amounts of mantle Small amounts of mantle rock melts, forming liquid rock melts, forming liquid magmamagma

Gaseous pressure builds Gaseous pressure builds up up

Magma forces up and Magma forces up and outout

Volcano ComparisonVolcano Comparison

The process is similar The process is similar to shaking can of popto shaking can of pop

Pressure from Pressure from carbonated gas buildscarbonated gas builds

Forcing the liquid right Forcing the liquid right out the topout the top

What Causes An EruptionWhat Causes An Eruption

Structure of a VolcanoStructure of a Volcano

Magma Chamber- Pool Magma Chamber- Pool of magma, that fills and of magma, that fills and builds up pressure builds up pressure

Vent- Opening in the Vent- Opening in the ground where magma ground where magma escapesescapes

Crater- Bowel shaped Crater- Bowel shaped pit at the toppit at the top

Two Eruptions TypesTwo Eruptions Types

A Quiet EruptionA Quiet Eruption

An Explosive EruptionAn Explosive Eruption

Quite EruptionQuite Eruption

Quiet Eruptions lava Quiet Eruptions lava flows in streams and flows in streams and can travel over can travel over many kilometers many kilometers

The vent is not The vent is not clogged, no excess clogged, no excess gas build upgas build up

Explosive Eruptions Explosive Eruptions

Thick magma can Thick magma can clog the vent causing clog the vent causing pressure build up.pressure build up.

Lava and gas are Lava and gas are hurled outward high hurled outward high into the skyinto the sky

Lava Lava

Lava:Lava: Magma which has reached the surface Magma which has reached the surface through a volcanic eruption. through a volcanic eruption.

Lava Flow:Lava Flow: An outpouring of lava onto the land An outpouring of lava onto the land surface from a vent, flows like a riversurface from a vent, flows like a river

Lava Fountain:Lava Fountain: A rhythmic vertical fountainlike A rhythmic vertical fountainlike eruption of lava. Lava eruption of lava. Lava

Locations of VolcanoesLocations of Volcanoes

Most Volcanoes Most Volcanoes occur along plate occur along plate boundariesboundaries

Types of VolcanoesTypes of Volcanoes

1.1. ShieldShield

2.2. Cinder conesCinder cones

3.3. Composite Composite volcanoesvolcanoes

Shield VolcanoesShield Volcanoes

Shield volcanoes are Shield volcanoes are wide, and short wide, and short

Lava flows a long Lava flows a long distance before it distance before it solidifiessolidifies

Cinder Cone VolcanoCinder Cone Volcano

A Small Volcano with A Small Volcano with steep sidessteep sides

They form from the They form from the ash and cinders that ash and cinders that are ejected into the are ejected into the air and back into the air and back into the volcanovolcano

One ventOne vent

Composite VolcanoComposite Volcano

Tall with steep sidesTall with steep sides Built from layers of Built from layers of

lava and ashlava and ash Often have secondary Often have secondary

ventsvents

Hot SpotHot Spot

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

Are Volcanoes Erupting TodayAre Volcanoes Erupting Today

KILAUEA, HAWAII

Location: 19.452 N, 155.292 WLast Update: March 2, 2004

How was Hawaii Formed?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

                                                                       

LoihiLoihi A new small islandA new small island Growing nowGrowing now Scientists plan to monitor Scientists plan to monitor

eruptions, collapses and eruptions, collapses and earthquakes as Loihi grows. earthquakes as Loihi grows.

But despite its dramatic and But despite its dramatic and visible growth, Loihi will not visible growth, Loihi will not break the ocean's surface for break the ocean's surface for about 50,000 years. about 50,000 years.