Hazards of Volcanicity

HAZARDS
EXAMPLE
PHOTO
Lava flows burn and bury crops.

Mount Merapi, Indonesia - More than 350 people were killed. An estimated 75,000 residents had been evacuated from the area between October to November 2010.

Ash falls ruin crops and machinery, disrupt transport, pollute the air and cause breathing difficulties.
Mount Etna, Italy - Grapes needed to be washed individually before consumption to avoid ingesting fine ash. This effectively ruined the grape crop economically, even though the fruit itself was not damaged.

Dust emissions endanger air transport and see torrential rainstorms resulting in dangerous wet ash and mud lahars.
Iceland - Airline flights to, from, and within northern Europe had been cancelled because of volcanic ash spreading from an eruption from the Eyjafjallajökull volcano in August 2010.

Flooding results from lava flows and volcanic debris blocking and diverting rivers.
Spirit Lake, Washington – the water level rose by 80 metres after the eruption of Mount St. Helens in 1980. Huge quantities of debris-avalanche material caused the river to be altered in its depth, volume and surface area.

Very violent eruptions of pyroclastic flows destroy life and property.
Soufrière Hills volcano, Montserrat - erupted and buried the capital Plymouth, in more than 12 metres of mud, destroyed its airport and docking facilities, and made the southern part of it uninhabitable and not safe for travel. It also destroyed farmland and caused forest fires.

Volcanic melting of snow creates dangerous lahars.
Mount St. Helens, Washington - The lahars were triggered by the sudden melting of snow and ice from hot volcanic rocks which mixed with snow and ice to form water and trigger avalanches,
After initial eruptions in 1980.

Volcanic dust absorbs solar energy and so lowers atmospheric temperatures.
Pinatubo, Philippines – The eruption of this volcano caused three cold winters in Europe.

Lahar – volcanic mudflow
Pyroclastic flow - a dense, destructive mass of very hot ash, lava fragments, and gases ejected explosively from a volcano and typically flowing at great speed.