Seismic hazards Flashcards
What are the earthquakes formations?
Earthquakes are formed when two tectonic plates are moving against each other causing friction. They are at which energy is created is called the focus which is directly below the hypocenter which is where the energy is released.
What are the tsunamis formations?
A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event.
What is liquefaction?
When the ground shaking weakens the saturated soils, strength is weakened causing the water inside to rise and for anything with a mass to fall below.
Types of waves?
Primary/pressure waves are waves that travel side to side at a deep depth beneath the surface. In the mantle it can travel 6km/s and in the core, it can travel 13km/s. It is also the first to reach the surface.
Secondary/shear waves are waves going up and down around 650-700km deep and travel in the mantle at 3.5km/s. These have a high frequency.
Surface waves travel in rotations and occur from the surface that travels o.35km/s in the mantle and can be very destructive.
