- What are generally considered to be the two greatest hazards to humans during a volcanic eruption?
Pyroclastic flows and lahars are generally considered to be the two greatest hazards to humans during a volcanic eruption.
- Why are lava flows usually not considered hazardous to humans during an eruption?
Lava flows very slowly, not exceeding a few kilometers (roughly 2 miles) per hour. This is slow enough for humans and animals to be able to get out of the path of lava flows.
- Are gas emissions from a volcano only a concern during an eruption? Explain.
An eruption is not always necessary in order for volcanoes to emit dangerous quantities of gas. The toxic cloud of carbon dioxide gas at Lake Nyos in Cameroon in 1986 was not preceded by an eruption.
- Why is volcanic soil so important for agriculture?
The nutrients that volcanic ash puts in to the soil make volcanic soils some of the most fertile in the world. Coffee beans, for example, thrive in volcanic soil.
- What are some industrial applications of volcanic materials?
Products such as polishes, erasers, cosmetic exfoliants, abrasive soap, and certain kinds of concrete contain volcanic materials.
- What are some indicators that scientists use to predict whether a volcano will erupt?
Scientists make use of indicators such as changes in seismic behavior, ground deformation, changes in gas composition, and past volcanic behavior to predict whether an eruption will occur.