Hazard distribution - why WORLD AT RISK

WHY? Looking at geophysical hazards, why do they only occur in very specific locations? The Earth is made up of several layers, geophysical hazards are concerned the movement of the lithosphere.

Different types of plate margin

Types of plate boundary There are 4 different plate boundaries DESTRUCTIVE 2. CONSTRUCTIVE 3. COLLISON 4.TRANSFORM What geophysical hazards to we associate with each boundary?

Plate boundaries Divergent Extensional or Constructive Plates are moving apart from each other Earthquakes are usually shallow and have a magnitude of less than 8.0 They are found beneath oceans, where magma from the lithosphere can well up into the void created and lead to the formation of underwater volcanoes

Plate boundaries Convergent Compressional or Destructive Plates are moving towards each other Results in the formation of ocean trenches, volcanic mountain ranges, earthquakes and volcanic island arcs

Plate boundaries Collision Collision plate boundaries occur when the two plates moving together are both continental crust. As continental crust cannot sink or be destroyed then the land between them is buckled and pushed upwards to form high fold mountains.

Plate boundaries Transform Occur where two plates are sliding past each other The location of some of the world’s largest earthquakes

Why?

Hazard hotspots From the World Banks analysis they discovered that more than ½ the worlds population live in an area that could be affected by at least one hazard. But some places live in danger of more than one

Exam question Explain why volcanic hazards are common in the Philippines but not on the Californian coast. (5 marks)

Exam question