Volcano Effects Flashcards
Primary Effects
Lava flows
Pyroclastic flows / nuees ardente
Tephra
Volcanic gases
Secondary Effects
Landslides Tsunamis Lahars Flooding Climate Change
Lava Flows
More of a threat to property than human life
Basalt fissure eruptions - dangerous, reach speeds of over 50km/h, spread far
Andesitic and Rhyolitic - moves slowly, doesn’t spread far
Destroys anything in its path
Pyroclastic Flows
A mixture of hot rock fragments, lava particles and ash powered by gas
Temperatures average 100-700 degrees Celcius
Average speeds of 60mph but can reach 430mph
Tephra
Solid material varying in size from volcanic bombs to ash, that’s ejected into the air
Ash infiltrates machinery, makes it dangerous for air travel
Volcanic Gases
Gases emitted by volcanoes
CO2, CO, Hydrogen Sulphide
Basaltic lavas emit fluoride gas
122 million tonnes of sulphur dioxide released - turned into sulphuric acid aerosols that remained in the air for 2 years
Lead to death of humans, wildlife and vegetation
Lahars
Volcanic ash mixes with water causing mud flows
Can travel up to 50km/h
Water can be derived from snow and ice melt, heavy rainfall or the collapse of a crater lake
Landslides
Collapse of volcano side/structure as the eruption takes place
Mt Saint Helens, 1980, largest landslide
Tsunamis
Collapse of the volcano or earthquakes from eruption lead to formation of large waves
Flooding
Melting snow, ice and glaciers results in the release of large volumes of water in short periods of time
Climate Change
Ash can block sunlight and reduce global temperatures
Gases like CO2 add to the greenhouse effect trapping heat and increasing global temperatures (contributes a low proportion of CO2 to carbon cycle)
Changes in global temperatures and crop yields
