Earth Hazards

1
Earth Hazards

• A hazard is anything which can cause harm to
  people.
• Earth Hazards are processes in the earth or on
  its surface which can cause harm.
• Three hazards are volcanoes, earthquakes and soil
  erosion.

2
4C Revision Cone, Crater, Lava Flow

• A Cone is the shape of the volcano (a mountain
  with a circular base and a pointed top
• A Crater is a bowl shaped hollow at the top of
  the volcano
• A Lava Flow is the overflow path of molten magma,
  coming down the side of the cone from the crater.
  

Crater
Cone
Lava Flow
3
4B Revision Four things thrown out of a volcano
Fine dust will blow on winds for 1000s of miles
Invisible, poisonous gas is blown out of the
vent

• Volcanoes are places where the earths magma
  comes out at the earths surface.
• When a volcano erupts gas, and lava are ejected,
  plus rock from the crust. This rock can be fine
  dust or stones and boulders called ash.

Bits of molten lava rocket into the air and
fall back as volcanic bombs.
Rocks of the broken crust are called ash. They
fall back near the vent to build up as a cone.
4
4b Revision (as 4c plus )
This volcano is on Hawaii. It is caused because
two plates are moving apart and so let magma rush
up from below the crust.

• When two tectonic plates move together or
  apart the effects are that
• Earthquakes
• and
• Volcanoes
• are created.

When the magma flows out it is called lava.
As the earth moves, earthquakes shake Hawaii
5
4a revision (as 4c and 4b plus ..)

• Four effects of an earthquake are
• Roads are torn apart
• Buildings are shaken and may fall
• Gas and sewerage pipes may break
• Fires may break out

6
Earthquake animation web sites

• http//www.pbs.org/wnet/savageearth/animations/ear
  thquakes/main.html
• http//www.crustal.ucsb.edu/ics/understanding/glob
  e/globe.html
• http//www.thirteen.org/savageearth/earthquakes/
• Task
• Find these sites and review them to say which
  helped you understand the topic best and why.

7
Homework

• Write a neat 50 word review of what you have
  found out for yourself in this lesson from web
  sites.
• A. Hazards
• B. Earthquakes
• C. Volcanoes