Volcanic hazards Flashcards
What are lahars?
Melted snow and ice as a result of the eruption combined with volcanic ash forms mud flows that can move down the course of river valleys at high speeds.
What is pyroclastic flows?
Formed from a mixture of hot gas and tephra. After ejection from the volcano they can flow down the sides of a mountain at speeds of over 700km per hour.
What is tephra?
The solid matter ejected by a volcano into the air. It ranges from volcanic bombs to ash.
What is volcanic gases?
Carbon dioxide, carbon monoxide, hydrogen sulphide, sulphur dioxide and chlorine. This can lead to headaches, dizziness, increased heart rate and difficulty breathing.
What is flooding?
When an eruption melts glaciers and icecaps, serious flooding can result.
What are tsunamis?
Volcanic eruption can create an impulsive force that displaces the water column and generates a tsunami. The falling debris displaces the water from its equilibrium position and produces a tsunami.
What is acid rain?
Volcanoes emit gases which include sulphur. When this combines with atmosphere moisture, acid rain results. This can burn skin.
How does volcanic eruptions affect climate change.
The ejection of huge amounts of volcanic debris into the atmosphere can reduce global temperatures and is believed to have been an agent in past climatic change.
