Volcanoes, Earthquakes and Tsunamis

Question 1

The Crust

Answer 1

The layer you live on. A thin skin of rock around the Earth. The lighest layer of the earth.

Question 2

The mantle

Answer 2

It forms half the Earth. It is made of heavier rock than the crust. The upper mantle is hard but the rock below is soft, like toffee. It is runny in some places.

Question 3

The core

Answer 3

It is mainly iron, mixed with a little nickel. The outer core is liquid but the inner core is solid.

Question 4

Convection Currents

Answer 4

These are currents of warmer rock, heated from below, which rise, cool and fall. A current of warmer material (soft rock) under the lithosphere.

Question 5

Earthquake

Answer 5

A shaking of the Earth’s crust, caused by a sudden rock movement.

Question 6

Lithosphere

Answer 6

The hard outer part of the Earth’s surface; it is broken into big slabs called plates. The crust and upper mantle together.

Question 7

Focus

Answer 7

The point under the surface where the earthquake starts

Question 8

Epicentre

Answer 8

The point on the surface where the earthquake starts

Question 9

Seismometer

Answer 9

Used to measure seismic activity and earthquakes

Question 10

Magnitude

Answer 10

Measurement of earthquakes. The amount of energy an earthquake gives out.

Question 11

Earth’s core is :

Answer 11

5500 degrees centigrade

Question 12

Richter Scale

Answer 12

is used to categorise earthquakes

Question 13

Continental Crust

Answer 13

Crust on Earth(above sea). Made of granite

Question 14

Oceanic Crust

Answer 14

Crust under the sea. Made of basalt

Question 15

Trench

Answer 15

Valley under the sea

Question 16

Magma

Answer 16

Molten rock in the mantle

Question 17

Lava

Answer 17

Molten rock above the surface

Question 18

Why do tectonic plates move?

Answer 18

Because of the convection currents in the mantle.

Question 19

Aftershocks

Answer 19

Smaller earthquakes after the big one

Question 20

Volcano

Answer 20

A volcano is where liquid rock or MAGMA shoots out or ERUPTS thorough the ground. Above the ground, the liquid rock is called LAVA.

Question 21

`What damage can eruptions do?

Answer 21

Mudflows can travel at 100km an hour. They sweep everything along. You drown in mud.

Lava flows destroy crops, and bury towns and villages. (They could kill you too-but you can just walk out of the way).

Volcanic gas causes acidic rain. This kills trees and plants over a wide area.

A thick layer of ash is heavy enough to make roofs collapse.

The dust from an explosive eruption may rise high in the atmosphere and block out the sun; causing tempatures around the world to fall. The dust can also cause planes to crash.

A thick blanket of ash will ruin crops.

The ash from an explosive eruption gets everywhere- in your eyes, your hair, your lungs. It can suffocate you.

Question 22

Tsunami

Answer 22

A tsunami is a series of waves, set off by an earthquake on the ocean floor. The waves spread in all directions. They can travel more than 700km an hour. They can be 30m high when they reach the shore.

Question 23

What the Earth’s crust is broken into…

Answer 23

Plates

Question 24

Short-term responses

Answer 24

Things that are done straight after a natural disaster happens

Question 25

Soil that comes from weather lava is …

Answer 25

Fertile

Question 26

Volcanologist

Answer 26

Volcano scientist

Question 27

Magma chamber

Answer 27

Where magma is stored in a volcano. The magma chamber is a collection is a collection of magma inside the Earth, below the volcano.

Question 28

Sheild Volcanoes

Answer 28

Sheild volcanoes are usually found at constructive or tensional boudaries. They are usually low with gently sloping sides. They are formed by eruptions of thin, runny lava. Eruptions tend to be frequent but relatively gentle.

Question 29

Composite Volcanoes

Answer 29

Composite volcanoes are made up of alternating layers of lava and ash (other volcanoes just consist of lava). They are usually found at destructive or compressional boundaries. The eruptions from these volcanoes may be a pyroclastic flow rather than a lava flow. A pyroclastic flow is a mixture of hot steam, ash, rock and dust. A pyroclastic flow can roll down the sides of a volcano at very high speeds and with tempatures of over 400 degrees centigrade.

Question 30

Main vent

Answer 30

The main vent is the main outlet for the magma to escape.

Question 31

Secondary vents

Answer 31

Secondary vents are smaller outlets through which magma escapes.

Question 32

Crater

Answer 32

The crater is created after an eruption blows the top off the volcano.

Question 33

Super volcanoes

Answer 33

A supervolcano is a volcano on a massive scale. It is different from a volcano because:

It erupts at least 1,000 cubic kilometres of material (a large volcano erupts around 1 cubic kilometre)

It forms a depression, called a caldera (a volcano forms a cone shape)

A supervolcano often has a ridge of higherland around it.

A supervolcano erupts less frequently - eruptions are hundreds of thousands of years apart.

Question 34

How a super volcano forms

Answer 34

1. Magma cannot escape to the surface and collects under the lower crust.
2. An ‘uplifted bulge’ begins to form under the lower crust as the magma enlarges.
3. Cracks appear on the surface. Gas and ash erupts from the magma chamber through these cracks.
4. The magma Chamber collapses and a depression is formed. This is called a caldera.

Question 35

What caused the Tsunami in the Indian Ocean, 2004?

Answer 35

The Indo-Australian plate pushed north, and dived under the Eurasian plate (eurasion plate moved South-West) in this region. So the ocean floor was under huge pressure.

Question 36

Tsunami in the Indian Ocean, 2004

Answer 36

On boxing day 2004, there was an earthquake on the floor of the Indian Ocean. It was the second largest ever recorded: 9.2 on the Richter scale.It has set off a tsunami that left 230,000people dead, and hundreds of thousands homeless. Indonesia, Sri Lanka and Thailand had sufferred the most. It had even hit the coast of Africa! But never managed to reach the Phillipies because of the land infront of it that blocked it from being damaged.

Question 37

What would happen if the Yellowstone supervolcano erupted?

Answer 37

It would cause a volcanic winter.
Cause problems for the whole world.
Famine.
Change rainfall patterns.
Wipe out large areas of the USA.
Catastrophic worldwide efffects.
World climate change

Question 38

Yellowstone super volcano

Answer 38

It has had 3 huge eruptions in the last 3 million years (its last eruption was 630,000 years ago and was 1,000 times bigger than the Mount St Helens eruption in 1980.
The large volume of material from the last Yellowstone eruption caussed the ground to collapse,creating a caldera.
It was formed because of a volcanic hotspot.
Millions of visitors come each year to see the volcano’s geysers and hot springs.

Question 39

Volcanic hotspot

Answer 39

An area of the Earth’s crust where a high amount of heat flow is causing volcanic activity.