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Earthquake Effects
Damage caused after an
earthquake is known as earthquake effects. There is five different effects
ground shaking, surface faulting, ground failure, landslides, and tsunamis. No
damage at all won't happen if the magnitude of the earthquake is not above five
and no damage won't happen if the magnitude of the earthquake is six if the
building is built right for an earthquake.
Ground Shaking
Ground shaking is caused by two shock waves, primary shock waves (P waves)
and secondary shock waves (S waves). Their frequencies
can be from .1 to 30 hertz. P waves is the shock waves that hits first traveling at 4 miles a second and has a frequencies
higher then 1 hertz. Were S waves is also called share waves is the shock waves that cause the most damage traveling at 2 miles a
second and has frequencies of lower than 1 hertz. How you can tell what wave
just hit is that P waves cause buildings to shake vertically and S waves
to shake horizontally.
Surface Faulting
Surface faulting is caused by when the tectonic plates shift creating a gap
in the earth. their is three types of movement strike-slip, normal, and reverse.
This is the least dangerous type of earthquake effect to humans, but causes a
little to a lot of damage to buildings. The size of a surface faulting can have
a width of 6 feet to 1000 feet, a length of 1 mile to 200 mile. and a
fault displacement of an inch to 20 feet. A side effect of surface faulting is
that it can cause landslides.
Landslide
Landslides are caused by the
erosion of soil and the lack of vegetation, which causes the soil to become less
compact. If the loose soil is disturbed gravity will cause it to begin to slid
down hill therefore causing a landslide.
Ground Failure
Ground failure first starts from
the liquefaction of the ground which is an effect of earthquakes. which after
their is three different types of ground failure. Lateral spreads, flow failure,
and loss of bearing strength. How liquefaction happens is that after the S wave
hits the saturated clay-free soil, sand and slits lose strength which then
distorts it's granular structure and causes some void space to collapse. soil
generated by the collapses cause transfer of ground shaking load from grain to
grain contacts in the soil layer to the pore water. The load increases pore
water pressure causing drainage to occur, but if drainage can't occur pressure
keeps rising when pressure of pore water is close to pressure of soil, the soil
will act like a liquid rather than solid causing ground failures. Lateral
spreads is later movement of large blocks of soil. This usually happens on gentle
slopes and in the subsurface layer. Flow failure is the liquefied soil intact
material riding on a layer of liquefied soil and most dangerous type of ground
failure. Loss of bearing strength is the soil becomes weak under a building
causing it to tip.
Tsunami
Another side effect of
earthquakes is Tsunamis which you can find about here.
Tsunamis
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