Secondary earthquake disaster refers to all kinds of
disasters, such as landslides, mud rocks, floods
that can threat existence of human and livestock
caused by strong earthquakes.
The secondary earthquake disaster can be divided into
two broad categories:
One is the social level, such as road leads to the formation
of a traffic paralysis, fire disasters caused by the fracture
of gas pipes, drinking water contamination caused by the damage
of wewage, interruption of communicaiton cuased by the damage
of telecommunication facilities and plague, gas pollutions,
bacteria pollution and radioactive pollution and so on.
The second is the natural level, such as landslide, collapse
and fall of rocks, debris flow, ground crack, ground surface
subsidence, sand liquefaction and other secondary and geographical
disasters. If the earthquake occures in deep ocean,
it may cause a tsunami.
The main consequence is the faults and cracks in the ground.
The surface faults of large earthquake often stretch
for tens to hundreds of kilometers, often with obvious vertical
and horizontal dip seperation, which can reflect the tectonic
movement features at the source point. However, not all surface
faults are directly related to the movement o the source
because they can also be the secondary influence caused by
earthquake wave, especially the area that has thicker sediments,
slope edge, river and road cracks. This is often the result of
terrain factors, which loose and split under the condition of
shaking due to lacking relying on the side of the rock surface soil.
The shaking of the earthquake causes the sinking of topsoil
and shallow groundwater rose to the surface ground along
ground fissures, which formed sandblasting phenomenon.
Large earthquake can transform local tepography, or rise,
or settle and caused the cracking of roads, the twisting
of railway and the breaking of bridges.