Environmental Science Natural Disasters and Environmental Hazards 2 ā Questions and Answers
Question 1: What is a lahar, and which natural disaster is it most directly associated with?
- A lava flow caused by shield volcanism
- A mudflow of volcanic debris and water associated with volcanic eruptions (Correct answer)
- A type of submarine landslide triggering tsunamis
- An ash plume that disrupts aviation
Correct answer: A mudflow of volcanic debris and water associated with volcanic eruptions
A lahar is a fast-moving mudflow or debris flow composed of a mixture of volcanic material and water that travels down the slopes of a volcano.
Question 2: Which region of the United States is most frequently referred to as 'Tornado Alley' due to the high frequency of tornado formation?
- The Pacific Northwest coast
- The Great Plains states from Texas to South Dakota (Correct answer)
- The Appalachian Mountain region
- The Gulf Coast from Louisiana to Florida
Correct answer: The Great Plains states from Texas to South Dakota
The Great Plains, stretching from Texas northward through South Dakota, is called Tornado Alley because the frequent collision of warm moist Gulf air with cold dry Arctic air creates ideal tornado-forming conditions.
Question 3: Which term describes the process by which saturated soil loses its strength and behaves like a liquid during an earthquake?
- Subsidence
- Liquefaction (Correct answer)
- Sinkholes
- Lateral spreading
Correct answer: Liquefaction
Liquefaction occurs when seismic shaking causes water-saturated, loosely packed sediment to temporarily act as a liquid, causing buildings and infrastructure to sink or tilt.
Question 4: The Modified Mercalli Intensity (MMI) scale differs from the Richter scale in that the MMI measures:
- The energy released at the earthquake's focus
- The frequency of seismic waves detected
- The perceived shaking and damage at a specific location (Correct answer)
- The depth of the earthquake's hypocenter
Correct answer: The perceived shaking and damage at a specific location
The MMI scale measures the intensity of shaking felt and the resulting damage at specific locations, which can vary across a region depending on distance from the epicenter and local geology.
Question 5: During a hurricane, which component is responsible for the greatest loss of life along coastlines?
- High-speed sustained winds
- Tornadoes spawned by the storm
- Storm surge flooding (Correct answer)
- Inland freshwater flooding from rainfall
Correct answer: Storm surge flooding
Storm surgeāthe abnormal rise in sea level driven by a hurricane's winds and low pressureāis historically the deadliest hurricane hazard, capable of inundating coastal areas with several meters of water.
Question 6: What is the primary environmental benefit of natural wildfire in many ecosystems?
- It permanently increases soil nitrogen concentrations
- It clears accumulated dead biomass and promotes new growth and biodiversity (Correct answer)
- It eliminates invasive animal species from the region
- It prevents all future fires by removing all fuel
Correct answer: It clears accumulated dead biomass and promotes new growth and biodiversity
Natural wildfires clear accumulated dead wood and leaf litter, recycle nutrients into the soil, and open the canopy for light-dependent plant species, ultimately promoting habitat diversity.
Question 7: Which type of drought is defined by a deficiency of precipitation over an extended period?
- Agricultural drought
- Hydrological drought
- Meteorological drought (Correct answer)
- Socioeconomic drought
Correct answer: Meteorological drought
A meteorological drought is defined purely in terms of the degree of dryness compared to normal precipitation levels over a defined period.
Environmental Science Natural Disasters and Environmental Hazards 2
What is a lahar, and which natural disaster is it most directly associated with?