POSTED BY BHAWNA BHARDWAJ

1. What is an Earthquake?
According to WHO,
An earthquake can be defined as the shaking of the earth caused by waves
moving on and below the earth’s surface and causing: surface faulting, tremors
vibration, liquefaction, landslides, aftershocks and/or tsunamis.
An earthquake is caused by a sudden slip on a fault. An earthquake is the
sudden release of strain energy in the Earth’s crust, resulting in waves of
shaking that radiate outwards from the earthquake source. When stresses in
the crust exceed the strength of the rock, it breaks along lines of weakness,
either a pre-existing or new fault plane.
The point where an earthquake starts is termed the focus or hypocentre and
maybe many kilometres deep within the earth. The point at the surface directly
above the focus is called the earthquake epicentre. Earthquakes are the result
of pressure specifically pressure caused by extreme stress in the Earth’s
crust. That stress can be caused by volcanic activity or even man-made
activities in certain areas.
The movement of tectonic plates causes the majority of earthquakes that
produce stress. Tectonic plates are constantly and slowly moving against,
along, or beneath one other, yet their edges can sometimes grab and
stick. Continue to move, or at the very least try to avoid the attempted
movement. Fields around the edges stay together, exerting enormous
pressure until the edges give way and the plates slip.
When the stress on the edge overcomes the friction, a powerful and rapid
release of energy occurs, breaking the earth’s crust. This breaking sends
shock waves through the ground, causing powerful vibrations or quakes. In
fact, the world’s most earthquake-prone places are where geological plates
collide.
Seismographs record earthquakes and other seismic events. The
seismographs oscillate when the earth shakes, generating a jagged line to
indicate the movement. The recorded motions are then utilized to measure the
strength or magnitude of the jagged the higher the height of the jagged.
While there are various magnitude scales to choose from, seismologists prefer
the moment magnitude scale. It has no upper limit and logarithmically
measures earthquakes. This means that, unlike the now-rarely used Richter
scale, each magnitude on the moment magnitude scale is ten times higher
than the one before it. The moment magnitude scale may be applied globally
and can quantify quakes of the highest magnitude.

2. In 1960, the strongest earthquake ever recorded happened near Bolivia,
Chile. The Valdivia earthquake, which occurred within the circum-pacific belt,
was the most powerful of a series of quakes that shook the region, with a
magnitude of roughly 9.5.
In addition to creating land vibrations, the earth unleashed a catastrophic
tsunami that reached heights of up to 80 feet. The tsunami swept across the
Pacific, wreaking havoc on countries as wide apart as the Philippines and
Japan. The shock waves released by the Valdivia earthquake, in fact,
continued to rock the entire planet for days, according to seismographs.
When an earthquake strikes, some communities have devised various
methods to protect their communal structures, and bridges are built to wobble
rather than break. The public is taught how to protect themselves in the event
of a seismic catastrophe, and government authorities conduct exercises to
guarantee that their citizens are safe.
Earthquakes cause enormous havoc, but they have also created magnificent
features, each of which adds to the planet’s unique character.
Types of Earthquakes
There are four different types of earthquakes and they include
o Tectonic Earthquakes
o Volcanic Earthquakes
o Collapse Earthquakes
o Induced or Explosion Earthquakes
1. Tectonic Earthquakes
A tectonic earthquake occurs when the earth’s crust fractures due to
geological forces acting on rocks and plates adjacent to it, causing physical
and chemical changes. Tectonic quakes are earthquakes induced by plate
tectonics.
They are responsible for the majority of earthquakes around the planet, and
they typically occur around tectonic plate boundaries. Its size could be tiny or
enormous. The majority of the planet’s mass destruction has been produced
by tectonic earthquakes. Tremors caused by tectonic earthquakes are always
violent, and if their magnitude is large enough, they can bring a metropolis to
its knees in seconds.
2. Volcanic Earthquakes

3. Volcanic earthquakes are less common than tectonic earthquakes. Any
earthquake that occurs as a result of tectonic forces associated with the
volcanic activity is referred to as a volcanic earthquake. They usually happen
before or after a volcanic eruption. Long-period volcanic earthquakes and
volcano-tectonic earthquakes are two types of volcanic earthquakes. After a
volcanic eruption, volcano-tectonic earthquakes are common.
Magma bursts from within the earth’s crust during an earthquake, leaving a
void behind. After a magma explosion, the empty area must be filled. As rocks
rush towards the space to fill it, violent earthquakes occur.
During volcanic activity, magma has blocked the vents several times. This
indicates that excessive pressure is not being released. The pressure builds
up to the point that it can no longer be tolerated, and it explodes in a huge
explosion. A devastating earthquake occurs as a result of the tremendous
explosion.
After a volcanic eruption, however, a long period of volcanic earthquake
occurs. The magma inside the earth’s crust sees dramatic variations in
temperatures a few days before the huge explosion. Seismic waves are
triggered by a change in temperature, resulting in an earthquake.
3. Collapse Earthquakes
Small earthquakes triggered by seismic waves created by the explosion of
rock on the surface cause collapse earthquakes in underground tunnels and
mines. They are sometimes referred to as mine bursts.
The pressure generated within the rocks as a result of subsidence can trigger
collapse quakes, which are especially common in karst areas or near mining
activities. This type of earthquake causes the mine’s ceiling to fall, causing
further tremors. Small cities with underground mines experience a lot of
collapse earthquakes.
4. Induced or Explosion Earthquakes
An earthquake that is caused by the detonation of a nuclear or chemical bomb
is known as an induced earthquake. Human activity, such as tunnel
construction, reservoir filling, and geothermal or fracking projects, causes
induced quakes.
Causes of Earthquakes
The main causes of earthquakes fall into five categories:
o Volcanic Eruptions

4. o Tectonic Movements
o Geological Faults
o Man-Made
o Minor Causes
1. Volcanic Eruptions
Volcanic eruptions are the primary source of earthquakes. Such earthquakes
are common in places where volcanic activity is common. When boiling lava
attempts to break through the earth’s surface, the increased pressure of gases
causes various movements in the crust.
Lava movement beneath the earth’s surface can potentially cause some
disruptions. This causes harm by sending shockwaves into the earth. These
tremors are minor. They have a limited range as well. There have been certain
outliers, such as when volcanic earthquakes wreak havoc and kill thousands
of people.
2. Tectonic Movements
The upper mantle is made up of plates that make up the earth’s surface.
These plates are constantly shifting, causing the earth’s crust to shift. There
are three types of movements: constructive, destructive, and conservative.
Constructive earthquakes occur when two plates move away from each other,
and they are mild earthquakes. Destructive plate boundaries occur when two
plates move towards each other and clash. This is quite harmful. Conservative
refers to the crossing of crust plates. This type of earthquake has a range of
magnitudes.
3. Geological Faults
The displacement of plates from their original plane is known as a geological
fault. It doesn’t matter if the plane is horizontal or vertical. These planes do not
emerge out of anywhere, but rather grow over time. Tectonic earthquakes are
caused by the movement of rocks along these planes.
The action of geological forces causes these faults to form. The fracturing of
rocks is caused by plate movement, which releases a lot of energy. This type
of earthquake has the potential to be devastating.
4. Man-Made
Man’s involvement with nature may potentially be a contributing factor in the
earthquake. Earthquakes can occur when the crustal balance is disrupted by
heavy water clubbing in dams. Nuclear weapons can cause specific types of
shockwaves to travel across the earth’s surface, disrupting tectonic plate

5. alignment. The large removal of rocks from various regions caused by mining
can also cause disruption.
Minor Causes
Small shockwaves can be caused by landslides, avalanches, the fall of
massive rocks, and other minor sources. Gases beneath the earth’s surface
contract and expand, causing plate motions beneath the crust. Adjustments in
rock strata in the interior of the earth’s crust generate the plutonic earthquake.
All of these characteristics are associated with mild earthquakes, but they can
also be associated with moderate earthquakes.
Positive Effect of Earthquakes
The positive effects of earthquakes include:
o Earthquakes form Natural Springs
o Earthquakes form Oases and Natural Energy Sources
o Earthquakes form Mineral Resources
o Earthquakes create Hills, Coastal Terraces and Mountain Ranges
o Earthquakes create Valleys
o Earthquake helps Monitor the inside of Earth
o Seismic Hazard Assessments
for Designing Earthquake Resistant Structures
1. Earthquakes form Natural Springs
One of the positive effects of earthquakes is that they form natural springs.
One of the most significant effects of earthquakes is the formation of faults.
The subsurface flow of water, oil, and natural gas are influenced by these
faults. When there is an earthquake, rocks are shifted.
Underground fluid conduits are created or restructured as a result of this
displacement. As a result of fault movement, liquids can either percolate
deeper into the ground or resurface as springs. Fault zones, for example, give
rise to Barton Springs in Austin, Texas.
2. Earthquakes form Oases and Natural Energy Sources
One of the positive effects of earthquakes is that they form oases and natural
energy sources. Similarly, flaws can become a part of the natural landscape.
The rock materials along these faults may degrade quicker than the earth
materials around them. As a result, if rivers and streams cut across them,
valleys may emerge over time. The Rio Grande Rift Valley, which stretches
from Colorado in the United States to Chihuahua in Mexico, is one such
example.

6. 3. Earthquakes form Mineral Resources
One of the positive effects of earthquakes is that they form mineral resources.
Earthquakes also have a beneficial effect on underground mineral extraction.
Mineral deposits frequently form underground as it is. When molten rocks
(magma) cool or minerals in underground water crystallize, they form.
As faulting occurs, mineral deposits may clump together or become exposed.
Mineral-rich fissures known as veins are important sources of precious metals
such as gold, silver, and platinum. As a result, earthquakes make these
mineral deposits relatively inexpensive to mine.
4. Earthquakes create Hills, Coastal Terraces and Mountain Ranges
One of the positive effects of earthquakes is that they create terraces and
mountain ranges. The natural landform that we observe today was produced
by earthquakes that occurred over millennia. During earthquakes, the ground
is raised, broken, and faulted. These processes result in the formation of hills,
coastal terraces, and mountain ranges. Seismic activity, for example, can be
seen in the magnificent coastal terraces of Capo Vaticano in western Calabria,
Italy.
5. Earthquakes create Valleys
One of the positive effects of earthquakes is that they create valleys. In the
same way, defects can become a natural part of the landscape. The earth
elements near these faults may decay faster than the rock materials along
with them. As a result, valleys may form over time if rivers and streams cut
through them. One such example is the Rio Grande Rift Valley, which runs
from Colorado in the United States to Chihuahua in Mexico.
6. Earthquake helps Monitor the inside of Earth
One of the positive effects of earthquakes is that they help monitor the inside
of the Earth. Earthquakes benefit us in terms of research and comprehension.
Seismic waves and faults can help us figure out what’s going on beneath the
surface. Tremors around volcanoes, for example, indicate that they are about
to erupt.
Similarly, we can map the Earth’s internal structure by measuring the time it
takes seismic waves to travel through it. Experts also look into areas on active
faults that haven’t seen an earthquake in a long time. Seismic gaps, as they
are known, have the greatest potential for future large earthquakes. As a
result, more accurate forecasting and community planning are now possible.
7. Seismic Hazard Assessments
for Designing Earthquake Resistant Structures

7. One of the positive effects of earthquakes is that they can be used for
designing earthquake-resistant structures. Earthquakes benefit us in terms of
research and comprehension. Seismic waves and faults can help us figure out
what’s going on beneath the surface. Tremors around volcanoes, for example,
indicate that they are about to erupt.
Similarly, we can map the Earth’s internal structure by measuring the time it
takes seismic waves to travel through it. Experts also look into areas on active
faults that haven’t seen an earthquake in a long time. The places with the
greatest risk of producing large earthquakes in the future are known as
seismic gaps. As a result, more accurate forecasting and community planning
are now possible.
Negative Effect of Earthquakes
The negative effects of earthquakes include:
o Damage to Buildings
o Damage to Infrastructure
o Landslides and Rockslides
o Floods
o Tsunamis
o Fires
o Liquefaction
o Earthquakes can lead to other Hazards
o Earthquakes Impact on the Economy
o Loss of Lives and Social Disruption
o Ground Shaking
o Surface Rupture
1. Damage to Buildings
One of the negative effects of earthquakes is that they can damage buildings.
High-magnitude earthquakes can utterly demolish structures. Because the
falling effects of massive, heavy things can be harmful to humans, the major
hazard during an earthquake is debris from crumbling structures. In high-
magnitude earthquakes, mirrors and windows are shattered, putting people in
danger.
2. Damage to Infrastructure
One of the negative effects of earthquakes is that they can damage
infrastructures. Earthquakes have the potential to take down power lines. Live
wires that are exposed are hazardous because they can electrocute people or
cause fires. Major earthquakes can destroy roads, gas lines, and water pipes.
A broken gas pipe might cause gas to leak.

8. Escaped gas can cause explosions and fires that are difficult to put out.
Severe shaking, on the other hand, has the potential to cause major damage
to the built environment. In the same way as seismic waves
3. Landslides and Rockslides
One of the negative effects of earthquakes is that they can cause landslides
and rockslides. Large rocks and pieces of earth located uphill can be
dislodged during an earthquake, causing them to roll fast down into valleys.
People living downstream can be harmed or killed by landslides and
rockslides.
Furthermore, earthquake vibrations compact granular soils (sand, gravel, and
silt), resulting in the sinking. When the terrain is dry, slightly saturated, or
saturated with high permeability, this type of ground movement is common.
Flooding occurs along the sea, lakes, and river banks, posing a hazard to
ports, roadways, and services. Land uplift combined with flooding can
sometimes result in the formation of artificial waterfalls.
4. Floods
One of the negative effects of earthquakes is that they can cause floods. High-
magnitude earthquakes can cause dam walls to break and eventually
collapse. This would cause major flooding by releasing raging waters into
nearby places.
5. Tsunamis
One of the negative effects of earthquakes is that they can cause tsunamis. A
tsunami is a series of long, strong sea earthquakes caused by an earthquake
or underwater volcanic explosions. A tsunami is a sequence of very lengthy
waves caused by an earthquake that occurs deep under the Pacific Ocean’s
surface. Large tsunamis that rise from the ocean floor are hazardous to
people’s health, property, and infrastructure.
Tsunami destruction has long-term consequences that can be felt well beyond
the coast. A tsunami has the potential to wipe out the whole population of a
coastal area. A recent example is an earthquake and tsunami that devastated
Japan’s shoreline on March 11, 2011, killing more than 18,000 people.
6. Fires
One of the negative effects of earthquakes is that they can cause fire
outbreaks. Earthquake damage facts show fires caused by earthquakes are
the second most common hazard. Earthquake fires start when electrical and
gas lines are dislodged due to the earth’s shaking. Gas is set free as gas lines
are broken and a spark will start a firestorm.

9. 7. Liquefaction
One of the negative effects of earthquakes is that they can cause liquefaction.
The phenomenon of liquefaction occurs when the soil becomes wet and loses
its strength. When high-water-content sediments are subjected to continual
trembling, the water pressure stored in the sediment pores gradually rises.
The sediments eventually lose almost all of their cohesive strength and begin
to behave like liquids. Built on top of this liquefied earth, buildings and other
structures overturn or sink into the ground. It occurs when the pore water
pressure in the ground is too high.
Sand boils are formed when sand is expelled through holes to the ground
surface. When the vibrations stop and the pore water pressure drops, the
sand returns to being solid. The foundations of buildings and structures
become unstable, leading them to collapse or tilt.
Sea defences and wharf walls were even damaged during the Kobe
earthquake. Underground tanks, bridge pilings, and pipelines may be lifted to
the surface by liquefaction. Ground subsidence and slope failure can also
occur across broad areas.
8. Earthquakes can lead to other Hazards
One of the negative effects of earthquakes is that they can lead to other
hazards. Disease outbreaks are possible when the built human environment is
affected in this way. They occur as a result of a lack of housing, poor
sanitation, and water contamination due to a clogged sewer line.
The consequences of earthquakes on the natural environment, such as
floods, can sometimes result in the formation of wetlands. Disease-causing
organisms may be encouraged to reproduce and spread as a result of this.
9. Earthquakes Impact on the Economy
One of the negative effects of earthquakes is that they affect the economy.
Earthquakes, like all-natural disasters, disrupt business operations, ruin
assets, and injure or kill people. All of these factors, when combined,
invariably result in financial losses. During the twentieth century alone, more
than 1200 global earthquakes cost more than $10 billion in economic damage.
10. Loss of Lives and Social Disruption
One of the negative effects of earthquakes is that they can lead to loss of lives
and social disruption. Similarly, earthquakes that strike unprepared
communities might result in several casualties and deaths. This can happen

10. when buildings and structures collapse due to ground shaking, or it can
happen as a result of secondary impacts.
People may experience psychological anguish as a result of such situations.
Some people may have to live with chronic injuries for the rest of their life.
Earthquakes can cause family stress and social fabric destruction in
communities as a whole.
11. Ground Shaking
One of the negative effects of earthquakes is that they cause the ground to
shake. Earthquakes cause ground shaking as a result of their immediate
effects. When these vibrations grow strong, they can displace or even break
the Earth’s surface. Other risks, like liquefaction and landslides, are triggered
by the shaking.
Seismic waves travelling beneath houses, roads, and other structures cause
the majority of earthquake damage. As a result, a low cliff known as a fault
scarp may emerge along the fault, which may extend for a considerable
distance. Other hazards and sorts of damage, such as a house shifting off its
foundation, are frequently caused by ground shaking.
12. Surface Rupture
One of the negative effects of earthquakes is that they can cause surface
rupture. Surface rupture is the most dangerous type of earthquake
hazard. Structures, roads, railways, and pipelines can be severely damaged
by surface rupture, which can affect enormous amounts of land. An
earthquake’s vibrations can cause ground displacement and surface rupture.
Other risks, as well as damage to roads and buildings, may result from the
surface breach. The surface rupture, in this case, resulted in huge fissures
and the collapse of a paved road. This could result in injuries, death, or make
it difficult for people to get home or to work.
19 Effects of Earthquake on the Environment – FAQs
How do I know an area prone to Earthquake?
How you can know if you are in an earthquake-prone area is by checking the
maps at the old Global seismic hazard assessment program, compiled by
ETH in Zurich (index) to know if your area falls under the earthquake-prone
areas.
Also, if you are close to The Mid-Atlantic ridge (an underwater line that runs
down the Atlantic ocean), the Alpide belt (which stretches from the
Mediterranean to Southeast Asia), and the Circum-Pacific belt (which traces

11. along the edge of the pacific ocean and is where about 80% of all earthquakes
occur), you are in an earthquake-prone area.
What is the Main Cause of an Earthquake?
The main causes of an earthquake are Tectonic movement which is the
movement of tectonic plates. Tectonic plates are constantly and slowly moving
against, along, or beneath one other, yet their edges can sometimes grab and
stick. Continue to move, or at the very least try to avoid the attempted
movement. Fields around the edges stay together, exerting enormous
pressure until the edges give way and the plates slip.
When the stress on the edge overcomes the friction, a powerful and rapid
release of energy occurs, breaking the earth’s crust. This breaking sends
shock waves through the ground, causing powerful vibrations or quakes. In
fact, the world’s most earthquake-prone places are where geological plates
collide.
Can I build a structure in an area that has experienced earthquake
before?
Yes, you can but, you would have to be extra careful by making arrangements
from your building design to be able to factor in earthquakes anytime soon.
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