Strato Volcanoes

Question 1

Features

Answer 1

Made of layers of ash and acidic lava

Have concave symmetrical profiles

Contain complex internal networks of lava flows which form dykes

Question 2

Why do these volcanoes erupt so violently?

Answer 2

The magma is quite acidic so it doesnt flow easily, this means that vents are often filled by solidified magma, preventing magma from rising freely

This causes lots of pressure to build up, causing explosive eruptions

Question 3

What are calderas, when do they form and give an example?

Answer 3

Volcanic craters which are more than 2km in diameter

If an explosive eeuption destroys a lot of the cone and the underlying magma chamber is emptied, the sides of a volcano collapse because of the absense of support from the magma

EXAMPLE: 1883 eruption of Krakatoa left a 7km caldera

Question 4

Convergent plate boundaries and explosive volcanoes

Answer 4

Give rise to chains of strato volcanoes

EXAMPLE: Indonesia has 130 active strato volcanoes along its archipelago

Question 5

Tsunamis and example

Answer 5

Massive eruptions can cause the displacement of ocean water and create tsunamis capable of travelling 600 km/h.

Rapidly increase in height as they break which transfers large amounts of potential energy and water along the shore

EXAMPLE: tsunamis generated from Krakatoa in 1883 drowned 36 000