Earthquakes are one of the most powerful and destructive natural forces on Earth, capable of reshaping landscapes and impacting human lives in dramatic ways. They result from various geological processes and sometimes even human activity. While most earthquakes are caused by the shifting of tectonic plates, several other factors can contribute to their occurrence. Understanding the causes of earthquakes is essential for predicting and preparing for these natural disasters. In this article, we explore the top 10 causes of earthquakes, from natural processes to human-induced factors.
Top 10 Causes Of Earthquakes
An earthquake can be both a man-made and natural disaster. It is difficult to control the magnanimity and fierceness of such an attack when an earthquake comes. The recent earthquake example is in itself a testimony of how necessary it has become to be aware of some of the earthquake preventive measures. But before that one must know how an earthquake is caused. Read up:-
1. Seismic Waves
This is one of the major causes of an earthquake. There are several types of earthquake waves including primary waves and also secondary waves. However, Surface waves consist of several major types and are known as long waves. These waves then cause heavy disruption when they flow as they are affected by changes in the density and also the rigidity of the material through which they pass. Major examples of such an earthquake were in Assam, India (1897 and 1950).
2. Fault Lines and Crustal Stress
Fault lines are fractures in the Earth’s crust where earthquakes tend to occur. When stress builds up along these faults due to tectonic movements, the release of energy causes seismic waves.
There have been many examples of Earthquakes in Australia being caused because of the movements along faults. This could be a result of the compression in the Earth’s crust. You can determine the size or magnitude of earthquakes by measuring the actual amplitude of the seismic waves which get recorded on a seismograph.
3. Dams and reservoirs
This can be one of the major causes. The rupture in the million tons of water would have hastened the earth’s shaking. No geological process can come up with such a huge concentration of mass in such a small area except for a volcano. It is history which has proven how large reservoirs of water created by dams have caused earthquakes. Examples include Zambia to Greece to India. Example: – 2008 Sichuan, China earthquake- killed nearly 70,000 people. It is believed that it was triggered by the construction of the Zipping Dam nearby.
4. Groundwater extraction
Taking water out of the ground is another example through which earthquakes have been necessarily initiated. The act causes the water table to drop thus destabilizing an existing fault. For example: – 2011 Lorca earthquake. This 2011 earthquake in Lorca, Spain caused a huge amount of destruction for its 5.1 magnitudes as was recorded on the Richter scale. It was also because the epicentre of the mountain was located so close to the surface. Its shallow epicentre could have had a relationship with that the act of groundwater extraction near Lorca. Since 1960, water extraction has been one of the main reasons as to why the region’s water table dropped by an incredible 250 meters.
5. Big skyscrapers
Big skyscrapers and buildings can put immense pressure on the earth’s surface. It can cause the rudimentary rocks to even crack. As a study points out, Taipei 101’s especially huge mass of 770,000 tons is presently putting too much pressure on the soft sedimentary rock below. It comes because of the extra steel and concrete which is being used to make the skyscraper solid enough to withstand earthquakes. Since construction began on the building of Taipei 101, the region began to receive several micro-earthquakes and even two larger earthquakes which went directly underneath the building.
6. Tectonic plate movements of the earth
The movement of tectonic plates is the primary cause of earthquakes. The Earth’s lithosphere is divided into several plates that float on the molten rock of the mantle. When these plates collide, pull apart, or slide past one another, stress builds up and is eventually released as an earthquake.
Tectonic Earthquakes are caused when the crust becomes subjected to strain and eventually starts moving. The theory of plate tectonics explains how when the crust of the Earth is made of several plates, there are large areas of crust which float on the Mantle. Since these plates are small and are free to slowly move, they undergo a lot of movement. Many of these earthquakes which we feel may be located in the areas where these plates could collide can even slide past each other.
Example: – Due to tectonic movements, San Francisco has noticed many small shakes.
7. Volcanic Eruptions Trigger Earthquakes
Volcanic activity can lead to localized earthquakes. As magma forces its way to the surface, it can cause the surrounding rock to crack and create seismic activity.
Volcanic earthquakes are much less likely than Tectonic ones. They are triggered when there is an explosion of an explosive volcano. It depends from volcano to volcano. If they are quiet, chances are less. For example: – In the case of Mt Pele, the lava solidified before it flew down the sides of the volcano. At least 20 miles of the area around is affected when a volcano explodes. However, for a tectonic earthquake, effects may be felt around the globe.
8. Any disturbance on the surface
All earthquakes are majorly caused by disturbance of the outside crust on the ephemeral surface of the earth. Anything which will tend to destroy the perfect equilibrium or the balance of the globe will likely cause an earthquake. Each side and every part must necessarily carry the same weight. There is the perfect nature balance required which man spoils due to his removals of earth, ores, oil, rock, coal, and the building of cities, which is continually changing.
9. Subduction Zones
Subduction zones, where one tectonic plate is forced under another, are responsible for some of the most powerful earthquakes in history. These regions are known for producing large-magnitude earthquakes and tsunamis.
Earthquakes and Tsunamis: A Deadly Pair
Underwater earthquakes can trigger massive waves known as tsunamis. When tectonic plates beneath the ocean floor shift, they displace large amounts of water, leading to destructive waves.
10. Man-Made Earthquakes: Mining, Drilling, and Dams
Human activities like mining, deep-well injections, geothermal energy extraction, and the building of large dams can sometimes induce seismic activity. Hydraulic fracturing (fracking) has also been linked to minor earthquakes.
Geothermal power plants — Salton Sea Geothermal Field and The Geysers Geothermal Field
According to a 2011 study published, it was clear that researchers at the University of California had discovered that seismic activity had increased around the Salton Sea as geothermal field operations around the area had ramped up. While these earthquakes in themselves may not be the main cause of damage but the other interaction with bigger faults like San Andreas could be one. Earthquake swarms include bursts of dozens of small quakes prevailing below magnitude 6 or so—happen regularly along the Salton Sea. Examples of such an earthquake include: – Salton Sea Geothermal Field and The Geysers Geothermal Field
Tracking and injection wells — 2011 Oklahoma earthquake
The process of hydraulic fracturing, or fracking is not the main cause of earthquakes. It is when the waste fracking liquid is injected back underneath into the deep wells that causes rupture. The fluid caused due to the extraction of liquids can seep out and also lubricate faults. This can cause them to slip more easily. For example:- 2011 Oklahoma earthquake- A study pointed out that Seismic activity in Oklahoma has shot up along with the rise of fracking. Earthquake swarms have become a regular occurrence in the region. The number of earthquakes had shot up from a dozen in 2008 to over 1,000 in 2010.
The Environmental Effects of Earthquake
Earthquakes have a profound impact not only on human societies but also on the environment. These natural events cause significant changes to the Earth’s surface, ecosystems, and atmosphere. From triggering landslides and tsunamis to altering water bodies and releasing greenhouse gases, the environmental effects of earthquakes can be long-lasting and widespread. Understanding these effects is essential in assessing the overall damage and preparing for the aftershocks that come not only in the form of tremors but also as environmental disruptions.
1. Surface Ruptures and Ground Shaking
One of the most immediate effects of an earthquake is the physical rupturing of the Earth’s surface. Fault lines crack open, and the ground may be uplifted or displaced. The intensity of ground shaking can cause widespread damage to ecosystems, destroying natural habitats and altering landforms.
2. Landslides
Earthquakes, especially in mountainous or hilly regions, often trigger landslides. The sudden shaking of the ground destabilizes loose soil and rocks, causing them to slide downhill. These landslides can bury forests, block rivers, and lead to the destruction of wildlife habitats.
3. Tsunamis
Underwater or near-shore earthquakes can displace large amounts of water, creating powerful tsunamis. These waves can travel across entire oceans, devastating coastal ecosystems and communities. Tsunamis often result in the salinization of freshwater sources, which harms both plant and animal life.
4. Liquefaction
In some areas, earthquakes cause a process known as liquefaction, where saturated soil temporarily loses its strength and behaves like a liquid. This phenomenon can lead to the sinking of buildings, destruction of infrastructure, and disruption of natural environments such as wetlands.
5. Changes to River Courses and Water Bodies
Earthquakes can alter the course of rivers, either by uplifting land or triggering landslides that block waterways. This can result in the formation of new lakes or the drying up of old ones, significantly impacting aquatic ecosystems. Flooding may also occur in areas previously unaffected.
6. Destruction of Vegetation and Wildlife
Earthquake-induced landslides, floods, and fires can devastate plant and animal life. Forests may be destroyed, and animals are often displaced from their habitats. In some cases, endangered species may lose their homes, putting their survival at further risk.
7. Release of Greenhouse Gases
Earthquakes can cause the release of gases trapped underground, such as methane and carbon dioxide. This can contribute to greenhouse gas concentrations in the atmosphere, further exacerbating climate change. Moreover, ruptured gas lines during earthquakes can lead to fires, releasing additional pollutants.
8. Soil Degradation
The shaking of the ground can disturb the topsoil, making it more susceptible to erosion by wind and water. This degradation reduces the fertility of the land, negatively impacting agriculture and natural plant life.
9. Coastal Erosion
The powerful shaking and tsunamis resulting from earthquakes can lead to significant coastal erosion. Beaches may be swept away, and shoreline ecosystems like mangroves and coral reefs can be severely damaged or destroyed.
10. Long-term Environmental Impacts
The environmental effects of an earthquake can last for years or even decades. Ecosystems may take a long time to recover, and some habitats may never fully regenerate. Additionally, changes to the landscape, such as new lakes or rivers, can permanently alter regional environments.
Example: – The Himachal Pradesh Earthquake in India, 2014.
Biggest Earthquakes in the World
| Date | Location | Magnitude |
| May 22, 1960 | Valdivia, Chile | 9.5 |
| March 27, 1964 | Prince William Sound, Alaska, USA | 9.2 |
| December 26, 2004 | Sumatra, Indonesia | 9.1 |
| March 11, 2011 | Tohoku, Japan | 9.1 |
| November 4, 1952 | Kamchatka, Russia | 9.0 |
| January 31, 1906 | Ecuador-Colombia | 8.8 |
| February 27, 2010 | Maule, Chile | 8.8 |
| January 13, 1906 | Valparaiso, Chile | 8.6 |
| August 15, 1950 | Assam-Tibet | 8.6 |
| March 28, 2005 | Nias, Indonesia | 8.6 |
| April 11, 2012 | Indian Ocean | 8.6 |
| October 9, 1905 | Kangra, India | 8.6 |
| February 3, 1923 | Kamchatka, Russia | 8.5 |
| November 10, 1922 | Chile-Argentina Border | 8.5 |
| December 25, 1932 | Gansu, China | 8.5 |
| August 31, 1886 | Charleston, South Carolina, USA | 8.3 |
| December 1, 1923 | Sea of Okhotsk | 8.3 |
| June 9, 1994 | Bolivia | 8.2 |
| September 20, 1935 | Taiwan | 8.2 |
| March 9, 1957 | Andreanof Islands, Alaska, USA | 8.1 |
5 strongest Earthquakes in the history
1. Valdivia, Chile (1960) – Magnitude 9.5:
The 1960 Valdivia earthquake is the most powerful earthquake ever recorded. This massive earthquake struck southern Chile, resulting in widespread destruction. It triggered tsunamis that affected countries as far away as Japan and the Philippines. Over 1,000 people lost their lives, and entire cities were leveled.
2. Prince William Sound, Alaska, USA (1964) – Magnitude 9.2
The Great Alaska Earthquake is the second most powerful earthquake in recorded history. The quake caused severe ground fissures, collapsing buildings, and tsunamis that killed 131 people. It also led to significant geological changes, including land elevations.
3. Sumatra, Indonesia (2004) – Magnitude 9.1
This undersea earthquake triggered the devastating Indian Ocean tsunami that claimed over 230,000 lives across 14 countries. Coastal communities in Indonesia, Thailand, Sri Lanka, and India were decimated, making it one of the deadliest natural disasters in history.
4. Tohoku, Japan (2011) – Magnitude 9.1
The Tohoku earthquake resulted in massive tsunamis that caused the Fukushima Daiichi nuclear disaster. Thousands of lives were lost, and the economic cost was estimated to be in the hundreds of billions of dollars, making it the costliest earthquake ever.
5. Kamchatka, Russia (1952) – Magnitude 9.0
The Kamchatka earthquake was a major event in the Soviet Union that triggered large tsunamis across the Pacific Ocean. Despite its strength, the region was sparsely populated, which minimized casualties. The resulting tsunamis caused damage as far away as Hawaii.
Conclusion
While earthquakes are a natural phenomenon, their impact on the environment is immense. From landslides to tsunamis and soil degradation, these effects can disrupt ecosystems and harm wildlife. Understanding these consequences is essential for developing strategies to mitigate the damage caused by such powerful natural events.
FAQs on Earthquake
Q. What is A Tsunami?
Ans. Underwater earthquakes can trigger massive waves known as tsunamis. When tectonic plates beneath the ocean floor shift, they displace large amounts of water, leading to destructive waves.
Q. What are Earthquake Swarms?
Ans. Earthquake swarms are sequences of seismic events that occur in a local area over a short period. They are different from aftershocks because there is no single main event. These swarms can occur due to volcanic activity or tectonic movements.
Q. What are Aftershocks?
Ans. After a large earthquake, smaller tremors, known as aftershocks, often follow. These can continue for days, weeks, or even years. They occur because the Earth’s crust is adjusting after the initial event.
Q. Can We Predict Earthquakes?
Ans. While exact predictions are not possible, scientists use various tools to study seismic activity and issue early warnings. These systems help save lives by providing a brief window of time to take protective measures.
Q. What are the meanings of magnitude and intensity related to earthquakes?
Ans. The magnitude of an earthquake refers to the energy released at its source, while intensity measures the strength of shaking at a particular location. The Richter Scale measures magnitude, while the Modified Mercalli Intensity Scale measures intensity.
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