Natural hazards
7 questions tagged Natural hazards — spanning every one of the seven Ws.
Why do deserts sometimes get flash floods?
Hard ground, sparse vegetation, and intense storms let water run off very quickly. Even a short downpour can send a sudden flood through dry channels.
When was the Tsunami warning system in the Pacific first established?
In 1949, with the creation of the Pacific Tsunami Warning Center after the 1946 Aleutian Islands tsunami.
How do tsunamis travel across entire oceans?
They are very long-wavelength waves caused mainly by seafloor displacement, often from undersea earthquakes. In deep water they can travel around 700–800 km/h and grow much taller near shore.
When was the first modern tsunami warning system established?
A major modern Pacific tsunami warning system was established in 1949.
How do tsunamis form after an undersea earthquake?
A sudden seafloor movement displaces a huge volume of water, sending long waves across the ocean.
What is liquefaction in geology?
Liquefaction is when water-saturated soil temporarily loses strength and behaves like a liquid during shaking. It often happens during strong earthquakes.
When was the first tsunami scientifically studied?
Scientific tsunami study grew in the 19th and 20th centuries, with major advances after the 1755 Lisbon earthquake and later events such as the 1883 Krakatoa eruption.