Volcanoes - created from Mind Map

Seite 1

Causes

Types

Effects

Chances Peak Montserrat

Magma rises through cracks in earths crust.

Pressure builds up inside the earth, when this pressure is released (e.g. plate movement) magma explodes to surface

Lava from eruption makes new crust, after several eruptions, the rock builds up and a volcano forms

Destructive boundaries

Constructive boundaries

plates moving towards each other

Plates moving away from each other causing new land to be formed

Active - still erupts frequently

Dormant - temporarily inactive but not extinct

Extinct - never likely to erupt again

Shield

Composite

Cone

Constructive boundaries

Gently sloping

Made from thin runny lava and eruptions are gentle and frequent

Alternate layers of lava and ash

Destructive boundaries

Pyroclastic flow - mixture of hot steam, ash, rock and dust at very high speeds and temperatures of over 400 C

shaped like a cone - not made from layers

Positive

Negative

Nice scenery for tourists after eruptions

Nutrients from lava good for soil

Geothermal energy

Dangerous - lost lives

Fast moving mudflows if ash and mud mixes with rain or snow - called lahars - can destroy agriculture or woodland

Destroying human and natural landscapes

Caribbean Island, volcanic area on Soufriere Hills called Chances Peak

Started showing small eruptions and earthquakes 1995

Main eruptions in 1997

Massive pyroclastic flows

Responses

11,000 people evacuated in 1995 to other Islands and UK

19 people killed

lahars destroyed vast areas, with homes and buildings destroyed including airport and roads

Evacuation and abandonment of capital city

Compensation from UK government

Unemployment

Exclusion zone around volcanic region

Growth in tourism after eruption

New airport and roads built

Services in North of island developed