Volcano!Volcano!I don’t know where I’m gonna I don’t know where I’m gonna

go when the volcano blowsgo when the volcano blows

vocabularyvocabulary corecore crustcrust lavalava lithospherelithosphere magmamagma tectonictectonic calderacaldera conduitconduit sillsill ventvent

forming volcanoesforming volcanoes

A volcano will form if the magma reaches the surface. A volcano will form if the magma reaches the surface. When magma does reach the surface it is then called lava.When magma does reach the surface it is then called lava.

Volcanoes in the Banda Sea result from subduction of the Pacific Plate under the Eurasia Plate. Black "teeth" are on the overriding plate. Arrows show direction of movement along major transform faults.

Krakatoa creates calderaKrakatoa creates calderaKrakatau volcano lies Krakatau volcano lies in the Sunda strait in the Sunda strait between the islands between the islands of Java and Sumatra. of Java and Sumatra. In about 416 A.D., In about 416 A.D., caldera collapse caldera collapse destroyed the destroyed the volcano and formed volcano and formed a 4-mile (7-km) wide a 4-mile (7-km) wide caldera. caldera.

The eruption and The eruption and collapse of the collapse of the caldera in 1883 caldera in 1883 produced one of the produced one of the largest explosions largest explosions on Earth in on Earth in recorded time and recorded time and destroyed much of destroyed much of Krakatau island, Krakatau island, leaving only a leaving only a remnant.remnant.

earth-shaking earth-shaking explosionexplosion

ash rises ash rises over over KrakatauKrakatauIn 1960 In 1960 scientists scientists visited Anak visited Anak Krakatau to Krakatau to record its record its renewed renewed activity and to measure changes in the size and activity and to measure changes in the size and shape of the island. They observed explosive shape of the island. They observed explosive eruptions of pyroclasts from ash to boulders in eruptions of pyroclasts from ash to boulders in size. A column of ash rising above Rakata, a size. A column of ash rising above Rakata, a remnant of the volcano prior to the 1883 remnant of the volcano prior to the 1883 eruption, is in the background.eruption, is in the background.

four years of explosionsfour years of explosions

Explosive eruptions occurred at half to 10-Explosive eruptions occurred at half to 10-minute intervals. The largest explosions minute intervals. The largest explosions produced turbulent clouds of ash that rose 4,000 produced turbulent clouds of ash that rose 4,000 feet above the vent.feet above the vent.

In this photo In this photo a column of a column of ash is rising ash is rising about 1,500 about 1,500 feet (450 m) feet (450 m) above the above the crater.crater.

Sunset and one of the older islands.Sunset and one of the older islands.

Hot SpotsHot SpotsThe Hawaiian Islands, which are entirely of The Hawaiian Islands, which are entirely of volcanic origin, have formed in the middle of the volcanic origin, have formed in the middle of the Pacific Ocean more than 3,200 km from the Pacific Ocean more than 3,200 km from the nearest plate boundary.nearest plate boundary.

The vast majority of earthquakes and The vast majority of earthquakes and volcanic eruptions occur near plate volcanic eruptions occur near plate boundaries, But there are some exceptions.boundaries, But there are some exceptions.

Hawaii Hawaii eruptserupts

Artist's Artist's conception conception of the of the movement of movement of the Pacific the Pacific Plate over the Plate over the fixed Hawaiian fixed Hawaiian "Hot Spot," "Hot Spot," illustrating the formation of the Hawaiian Ridge-illustrating the formation of the Hawaiian Ridge-Emperor Seamount Chain.Emperor Seamount Chain.

HotspotsHotspots

Volcano life cycleVolcano life cycle

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