Secondary Effects To Earthquakes Flashcards
(19 cards)
What are secondary hazards of earthquakes?
They are side effects of an earthquake, such as liquefaction and landslides, that can be just as damaging as the primary shaking.
What is soil liquefaction?
It is when water-saturated soil temporarily loses strength and behaves like a liquid due to strong ground shaking.
Where is soil liquefaction most likely to occur?
In lowland areas with saturated soils, especially where loose sediment is present.
What are some consequences of liquefaction during earthquakes?
Buildings can tilt or collapse, and infrastructure such as roads, bridges, and utility lines may be severely damaged.
What is a recorded extreme impact of liquefaction in past earthquakes?
Buildings have tilted up to 60 degrees in places like Japan and Christchurch due to liquefaction.
How does liquefaction affect emergency response and recovery?
It can delay aid delivery, hamper search and rescue, and significantly increase the cost and time required for rebuilding.
How do landslides occur as a result of earthquakes?
Seismic waves loosen rocks and unconsolidated material on steep slopes, causing them to slide downhill under gravity.
In what type of areas are earthquake-induced landslides most common?
In hilly or mountainous regions.
What risks do landslides pose to communities during an earthquake?
They can destroy roads, railways, and settlements, making rescue efforts and aid delivery very difficult.
What is a real-world example of earthquake-induced landslides causing major disruption?
The 2005 Kashmir earthquake caused deadly landslides that hindered rescue and relief efforts.
What type of secondary hazard can result from an undersea earthquake?
A tsunami, which can cause widespread and destructive impacts far from the earthquake epicenter.
Why are tsunamis considered major secondary hazards?
Due to their ability to cause massive destruction over vast areas and long distances from the source.
How are tsunamis formed by tectonic activity?
By sudden vertical movement of the seabed (upward or downward) that displaces large volumes of water.
What other event, besides earthquakes, can trigger tsunamis?
Explosive volcanic eruptions, especially on or near volcanic islands.
Why are tsunamis hard to detect in deep water?
Because they have long wavelengths and low amplitude, making them almost unnoticeable on the surface.
What happens to a tsunami wave as it enters shallow water?
It slows down, the wavelength shortens, and the wave height increases—sometimes becoming up to 20 times higher.
What made the 2004 Indian Ocean tsunami particularly significant?
It demonstrated the vast spatial impact a tsunami can have, causing devastation across multiple countries.
How did the Pacific Ocean affect the Tohoku tsunami in 2011?
The tsunami’s travel path was altered by islands, landmasses, and ocean bathymetry, taking 22 hours to cross the ocean.
What is the tsunami intensity scale called and who created it?
The Soloviev scale, developed in 1978, measures the intensity of tsunami events.
