Group 1 Flashcards
(17 cards)
sudden release of stored energy in the Earth’s crust that creates seismic waves
Earthquake
Usually not felt, but can be recorded by a seismograph.
Magnitude 2.5 or less
Often felt, but only causes minor damage.
Magnitude 2.5 to 5.4
Slight damage to buildings and other structures.
Magnitude 5.5 to 6.0
May cause a lot of damage in very populated areas.
Magnitude 6.1 to 6.9
Can cause serious damage.
Magnitude 7.0 to 7.9
Can totally destroy communities near the epicenter.
Magnitude 8 or more
Perched or stacked objects may fall and injure people nearby. In major earthquakes, whole districts can be destroyed.
Ground Shaking
the visible offset of the ground when an earthquake ruptures along a fault.
Surface Rupture
What causes liquefaction
- loose, granular sediment or fill
- saturation by groundwater
- strong shaking
Where is liquefaction most likely to occur
- most likely to happen in reclaimed land
- Areas with shallow water tables and close to the sea or rivers
How do you prevent liquefaction
- avoid the construction of structures on the soil susceptible to liquefaction process
- adjust the structure foundations to the type of soil susceptible to liquefaction
- improve or replace the soil susceptible to liquefaction before construction of the structure
lowering of the ground surface
Subsidence
occurs when the sloping ground starts to move downhill, causing cracks to open up that are often seen along hillcrest and river banks
Lateral spreading
are long wavelength oceanic waves generated by the sudden displacement of seawater by shallow earthquake, volcanic eruption, or submarine landslide
Tsunamis
defined as the movement of a mass of rock, debris, or earth down a slope
Landslide
Natural Signs of an Impending Tsunami
- Animal Behavior
- Drawback
- Ground Shaking
