2. Earthquake
An earthquake is the motion or
trembling of the ground
produced by sudden
displacement of rock in the
Earth's crust. Earthquakes
result from crustal strain,
volcanoes, landslides, and
collapse of caverns.
3. The effects of earthquakes include, but are
not limited to, the following:
Shaking and ground rupture
Landslides
Fires
Soil liquefaction
Tsunami
Floods
Human impacts
14. Soil liquefaction describes a
phenomenon whereby a saturated soil
substantially loses strength and
stiffness in response to an applied
stress, usually earthquake shaking or
other sudden change in stress
condition, causing it to behave like a
liquid.
Liquefaction
15. Liquefaction occurrence:
Liquefaction is more likely to occur
in loose to moderately saturated
granular soils with poor drainage,
such as silty sands or sands and
gravels capped or containing seams
of impermeable sediments.
16.
17.
18. Earthquake liquefaction:
The pressures generated during large
earthquakes with many cycles of
shaking can cause the liquefied sand
and excess water to force its way to the
ground surface from several meters
below the ground.
19.
20. Effects:
The effects of soil liquefaction on the
built environment can be extremely
damaging. Buildings whose foundations
bear directly on sand which liquefies will
experience a sudden loss of support,
which will result in drastic and irregular
21. settlement of the building causing
structural damage, including cracking of
foundations and damage to the building
structure itself, or may leave the structure
unserviceable afterwards, even without
structural damage.
