Option D.1.2

Question 1

When do Sheild volcanoes build up?`

Answer 1

When there is no explosive actvity, therefore no ejected fragments.

Question 2

What type of lava are shield volcanoes formed from?

Answer 2

Very hot, runny basaltic lava.

Question 3

What does the hot lava allow for?

Answer 3

Because it is hot the lava can flow great distances.
It builds up shield volcanoes which have gently sloping sides, a shallow crater and a large circumference

Question 4

How are composite volcanoes formed?

Answer 4

Formed by alternating eruptions of fragmental material followed by lava outflows

Question 5

What are these volcanoes characterized by?

Answer 5

Slopes of 3° near the summit and 5° near the base - very steep.

Question 6

How are cinder volcanos formed

Answer 6

By fragments of solid material which accumulate as a steep conical hill around the vent

Question 7

What are these volcanoes characterized by

Answer 7

Concave shape because the material spreads out near the base
Steep angle of 30 degrees
Violent eruptions

Question 8

Lava eruptions

Answer 8

• Silica rich
• Lava released where the oceans meet the continents absorbs silica rich sediments
• This causes lava to become more viscous and block the vents until enough pressure had built up to break them open.

Question 9

Lava eruptions - Icelandic

Answer 9

Characterized by the persistent fissure eruption.
Large quantities of balsaltic lava may build up vast horizontal plains

Question 10

Lava eruptions - Hawaiian

Answer 10

Hawaiian eruptions involve a central vent. Runny balsatic lava flows down the sides of the volcano and gases easily escape.

Question 11

Pyroclastic eruptions - Strombolian

Answer 11

Explosive eruptiona that produce pyroclasitc rock
Eruptions are commonly marked by a white clousd of steam emitted from the crater.
Frequant gas explosions blast quantities of runny lava into the air, and when these settle and cool they form the cone

Question 12

Pyroclastic eruptions - Vulcanian

Answer 12

Violent eruptions and occur when the pressure of trapped gases in viscous magma becomes sufficient to blow off the overlying crust of solidified lava.
Often the eruption clears a blocked vnt and spews large quantities of volcanic ash intp the atmosphere
Plugs of sticky or cooled lava. Fragments buil dup the cone of ash and pumice