11. Volcanoes features of stratovolcano + formation of volcano

Question 1

features of stratovolcano

Answer 1

vent, magma, branch pipe, volcano ash

Question 2

e.g. of stratovolcano

Answer 2

Mt. St. Helens, Washington, USA, formed by Juan de Fuca and North American Plate

Question 3

formation of stratovolcano

Answer 3

magma chamber, layers of ash, layers of lava, secondary cone, lava flow, cone, vent, ash, rock fragments, crater

Question 4

1.

Answer 4

after initial eruption of pyroclasts –> subsequent eruption ejects lava –> covers pyroclasts, prevents its erosion

Question 5

2.

Answer 5

lava flows shorter distance before solidifying

Question 6

3.

Answer 6

overtime, successive eruptions build a higher volcano w/ slightly concave profile

Question 7

4.

Answer 7

secondary cones: some magma cool & solidify in main vent –> forces magma to seep into sides via secondary vents –> secondary vent cones erupt

Question 8

formation of shield volcano

Answer 8

caldera, vents, magma chamber

Question 9

1.

Answer 9

formed when basic lava ejected –> lava don’t trap much gas, eruptions not explosive –> flows longer before solidifying –> successful eruptions ↑, base of volcano ↑ in size