Science: Natural Hazards Flashcards
How do earthquakes happen?
Below the surface of the earth are tectonic plates, which are always moving (very slowly). They push, pull, or slide against other plates at their edges, which causes stress along faults where the plates meet. Eventually, that stress is released, which results in earthquakes.
When do people start feeling earthquakes? When do earthquakes become hazards? Use the Modified Mercalli Intensity Scale.
Earthquakes that measure below M3.0 usually are not felt.
At M5.0, earthquakes can rattle buildings and cause minor damage.
At M6.0 above, earthquakes can become serious hazard where buildings might crumble and bridges might fall.
What causes tsunamis?
Earthquakes that rupture the ocean floor can cause tsunamis. The kinetic energy from the earthquake travels in large waves that transfer the energy when the waves crashes into land.
What causes volcano eruptions?
Volcano eruptions happen when super heated materials like magma reach the earth’s surface. This could happen because of earthquakes, or landslides that create openings on the earth’s surface for magma to be released, or when enough magma is collected in one area to create enough pressure to burst through to the surface.
What hazards could volcanoes cause?
Volcanoes release lava that might cause buildings, land and trees to burn. Volcanoes also spew clouds of hot ash that could also cause burns and hurt people and animals. Volcanoes could melt ice to create rivers of mud that could erode soil, cause pollution and destroy buildings.
What are some ways to reduce the impact of volcanoes for people that live close to them?
1) Prepare evacuation plan to move people away when there is an eruption.
2) Prevent buildings from being built in volcano danger zones.
3) Make buildings airtight so that volcanic ash cannot get in.
4) Stay indoors and close all widows and doors to avoid contact with volcanic ash.
What is a blizzard and how is it a hazard?
A blizzard is a snow storm with high winds. A blizzard could cut off electricity, and tress and buildings could cave in under the weight of a large amount of snow. It is also dangerous to drive in a blizzard.
How do hurricanes form?
Hurricanes begin over warm ocean water, as warm air rises and is replaced by cooler air which heats and also rises, forming storm clouds that carry huge amounts of water. As the storm increases in strength, wind speed and rain increase, which can cause flooding as well as fallen trees and sometimes buildings.
What are some outcomes of landslides?
Damage to buildings, roads and property. Landslides could also block rivers to form temporary dams and lakes that could lead to huge floods when they break.
True or false: natural hazards have both short term and long term impact.
True.
For example, a volcanic eruption could have devastating short impact by destroying forests. It will take years for the soil and plant life to recover in the long term.
True or false: scientists can now predict earthquakes.
False.
Despite alot of research and study, scientists are still not able to predict earthquakes.
What are some important needs that need to be met for people who suffer from natural hazards?
Shelter, food, water, medical attention, and clothing.
