5 Effects of Earthquakes
Earthquakes can have quite a lot of harmful
effects, some obvious, some more subtle. Earthquakes of the same magnitude
occurring in two totally different places can cause very different amounts of
damage, relying on such variables as the nature of the local geology,
whether the area affected is near the coast, and whether the terrain is steep
or flat. Here are 5 effects of earthquakes that are damaging.
1. Ground Motion
The main effect of the earthquake is ground
motion. Movement alongside the fault is an obvious hazard. The offset between
rocks on opposite sides of the fault can break power lines, pipelines,
buildings, roads, bridges, and other buildings that actually cross the fault.
Planning and considerate design can minimize the dangers. For instance, power
lines and pipelines can be constructed with extra slack where they cross a
fault zone or they can be designed with other features to allow some “give” as
the fault slips and stretches them.
Additionally, it is essential to consider
not only how structures are built, but what they're constructed on. Buildings
constructed on solid rock (bedrock) seem to undergo far much less damage
than those constructed on deep soil. The characteristics of the earthquakes in
a particular region also have to be taken into consideration. For instance,
severe earthquakes are generally followed by many aftershocks, earthquakes that
are weaker than the principal tremor. The main shock often causes the most
harm, however, when aftershocks are many and are almost as strong as the
mainshock, they might also cause serious destruction.
The duration of an earthquake also
affects how properly a building survives it. In reinforced concrete,
floor-shaking results in the formation of hairline cracks, which then widen and
develop further as long as the shaking continues. A concrete building that may
withstand a one-minute mainshock might collapse in an earthquake by which the
mainshock lasts three minutes.
Thus, anyone living or buying a property in an area where earthquakes are a significant concern would be well-advised to pin down just what level of earthquake resistance is promised in a construction’s design.
2. Landslides
One of the 5 effects of earthquakes are landslides.
Landslides can be a severe secondary earthquake hazard in hilly areas.
Earthquakes are one of the major events that set off slides on unstable slopes.
The perfect solution is to not construct in such areas. Even if a whole area is
hilly, detailed engineering research of rock and soil properties and
slope stability may make it possible to avoid the most harmful sites. Visible
evidence of past landslides is another indication of, particularly harmful
areas.
3. Liquefaction
Liquefaction is one of the 5 effects of earthquakes
discussed. Ground shaking could trigger an additional problem in areas where
the ground is very wet—in filled land near the coast or in places with a high-water
table. This drawback is liquefaction. When wet soil is shaken by an
earthquake, the soil particles may be jarred apart, permitting water to seep in
between them, tremendously decreasing the friction between soil particles that
provides the soil strength and causing the ground to become somewhat like
quicksand. When this happens, buildings can just topple over or partially sink
into the liquefied soil; the soil has no strength to support them.
4. Tsunamis and Coastal Effects
Coastal areas, especially around the Pacific Ocean basin
where so many large earthquakes occur, might also be vulnerable to tsunamis.
The tsunami could come ashore as a very high, very fast-moving wall of water
that acts like a high tide run (perhaps the origin of the misnomer “tidal
wave”), or it might turn into large breaking waves, simply as ordinary
ocean waves change into breakers as the undulating waters “touch bottom”
near shore. Tsunamis, nonetheless, can easily be over 15 meters high within the
case of larger earthquakes. Several such waves or water surges may wash over
the coast in succession; between waves, the water may be pulled swiftly
seaward, emptying a harbor or bay, and perhaps pulling unwary onlookers along.
Tsunamis can also travel long distances in the open ocean.
Even in the absence of tsunamis, there is
the possibility of coastal flooding from sudden subsidence as plates
shift during an earthquake. Areas that had been formerly dry land may be
completely submerged and become uninhabitable.
5. Fire
A secondary hazard of earthquakes in cities
is the fire, which can be more devastating than ground movement. Fires happen
because fuel lines and tanks and power lines are damaged, touching off
flames and fueling them. At the same time, water lines also are broken,
leaving no method to fight the fires effectively, and streets filled with
rubble, blocking fire-fighting tools.
Putting numerous valves in all water and
fuel pipeline techniques help to combat these problems as a result of breaks
in pipes can then be isolated before too much pressure or liquid is lost.
These explained 5 effects of earthquakes
are irreversible. One cannot do anything to stop them. The only thing one can do
is to prevent himself by taking necessary measures.
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