Understanding the Definition and Causes of Earthquakes

An earthquake is a natural disaster that can have an impact on the environment or on the community itself. However, do you already know the causes of earthquakes? So, on this occasion, we will discuss about earthquakes, from the definition to the causes.

Definition of Earthquake

An earthquake is a vibration that occurs in the earth due to the movement of tectonic plates. Earthquakes can occur on the surface of the earth or inside the earth. When an earthquake occurs, the movement of tectonic plates can cause faults or cracks in the ground, which can result in landslides or damage to building structures. Earthquakes can also cause tsunamis if they occur at sea.

According to experts, an earthquake is a vibration that occurs in the earth due to the movement of tectonic plates. Earthquakes can occur on the surface of the earth or inside the earth and can cause damage to building structures and other natural disasters. In addition, experts also state that earthquakes can occur suddenly and can have varying intensities, depending on factors such as the depth of the earthquake source, the type and condition of the tectonic plates, and the geological conditions in the affected area.

A seismograph is a tool used to detect and measure earthquakes. John Milne was an English geologist known for inventing the seismograph, an instrument used to detect the earth’s vibrations. He was born in 1850 in Liverpool, England, and spent most of his life in Japan, where he developed seismograph technology and helped study earthquakes. He died in 1913.

He found a way to measure ground vibrations using a device called a casing galvanometer. The casing consists of a freely movable ball in a ring mounted on a shaft. This ball will move in the same direction as the ground vibrations, so it can help us measure the intensity of an earthquake.

A seismograph is a tool used to detect earthquake vibrations and record the amplitude and frequency of these vibrations. A seismograph consists of two main parts, namely a seismic sensor and a recorder. The seismic sensor is part of the seismograph that captures earthquake vibrations and converts them into electrical signals. The electrical signal is then forwarded to the recorder, which is part of the seismograph whose function is to record the electrical signal.

The history of earthquakes dates back to ancient times and has caused tremendous damage and destruction throughout human history. The first recorded earthquake in history was one that occurred in Egypt in 1375 BC. This earthquake is mentioned in a hieroglyphic in the Pyramid of Saqqara, which shows that this earthquake caused extensive damage throughout Egypt.

The largest earthquake ever to have occurred was the Valdivia earthquake which occurred in Chile on May 22, 1960. This earthquake had a magnitude of 9.5 on the Richter scale, which is the largest magnitude ever recorded in history.

The largest earthquake that has occurred in modern times after the invention of seismographs is the Valdivia earthquake that occurred in Chile on May 22, 1960. This earthquake had a magnitude of 9.5 on the Richter scale, which is the largest magnitude ever recorded in history.

In addition, this earthquake caused extensive damage throughout Chile, and also generated a tsunami that spread throughout the region around the Pacific Ocean. As a result of this earthquake, more than 1,655 people died, and hundreds of thousands of others were injured or lost their homes. This earthquake also had a global effect, with most countries around the world feeling the tremors it caused.

Meanwhile, the largest earthquake that ever occurred in Indonesia was the earthquake that occurred in Aceh on December 26, 2004. This earthquake had a magnitude of 9.1 on the Richter scale, and is one of the largest earthquakes ever recorded in history. This earthquake caused widespread damage throughout the Aceh region, and also generated a tsunami that spread throughout the area around the Indian Ocean.

As a result of this earthquake, more than 230,000 people died, and hundreds of thousands of others were injured or lost their homes. This earthquake also had a global effect, with most countries around the world feeling the tremors it caused.

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Earthquake Types

There are several types of earthquakes, including tectonic earthquakes, volcanic earthquakes, volcanic eruption earthquakes, and local tectonic earthquakes. Tectonic earthquakes are caused by the movement of tectonic plates under the earth’s surface, while volcanic earthquakes are caused by volcanic eruptions. Local tectonic earthquakes occur in areas that have low tectonic activity.

1. Tectonic earthquake

Tectonic earthquakes are earthquakes caused by the movement of tectonic plates beneath the Earth’s surface. These earthquakes are usually caused by plate tectonic activity, such as when two plates move against each other and collide or separate from each other. Tectonic earthquakes can cause great damage around the area where the earthquake occurred.

2. Volcanic earthquake

Volcanic earthquakes are earthquakes caused by volcanic activity. These earthquakes usually occur near volcanoes or areas that have volcanic activity. In volcanic earthquakes, the movement of magma or lava within the volcano can cause earthquakes. Volcanic earthquakes are usually not as big as tectonic earthquakes, but they can cause damage to buildings around the volcano.

3. Earthquake volcanic eruption

Earthquakes resulting from volcanic eruptions are earthquakes that occur due to movements from within the earth that cause volcanoes to erupt. These earthquakes are usually caused by pressure that accumulates in the magma that is inside the mountain, which eventually erupts and produces an earthquake. Earthquakes resulting from volcanic eruptions are usually very large in strength and can cause extensive damage to buildings and infrastructure around the volcano.

4. Local earthquake

Local earthquakes are earthquakes that are not felt by the people around the place where the earthquake occurred, but can be detected by seismographs. Local earthquakes are usually caused by tectonic activity within the Earth, such as the movement of tectonic plates or faults within the lithosphere. Local earthquakes usually don’t cause major damage, but they can cause vibrations that can be felt by those around them.

Types of earthquakes based on vibration waves

There are several types of earthquakes based on the vibration waves they cause, including:

  • P-side earthquake (Primary Wave / Longitudinal Wave) 

This type of earthquake is the first to occur and is characterized by vibrations in the direction of wave propagation. These waves can penetrate rocks and spread at a relatively faster speed compared to other waves. An earthquake is a vibration caused by the transfer of energy that occurs within the Earth. Earthquakes occur when the rocks contained in the Earth experience pressure and tension that are strong enough, causing fractures or cracks to occur in these rocks.

When an earthquake occurs, several types of seismic waves will be created, one of which is the primary wave or what is commonly referred to as the P wave. The P wave is the first wave that occurs when an earthquake occurs. The P wave is a wave that has the fastest speed among other types of seismic waves.

The P wave is also a wave that has a high frequency and has a small amplitude. Because of their fast speed, P waves are usually the first to reach a seismograph station and can be used to determine the point of origin of an earthquake.

  • S-side earthquake (Secondary Wave / Transverse Wave) 

This type of earthquake is a wave that occurs after the P-side wave. This wave is characterized by vibrations that are opposite to the direction of wave propagation and can only penetrate soft rocks. Its propagation speed is also slower than that of the P-side wave.

An earthquake is a vibration or shaking that occurs in the ground. Earthquakes can be divided into several types, one of which is a secondary earthquake. Secondary earthquakes are vibrations that occur after the main earthquake.

Secondary earthquakes can occur due to pressure concentrated on the lower part of the earth’s surface, which causes the upper part of the earth’s surface to move or vibrate. Secondary earthquakes can also occur due to changes in pressure in the ground due to the main earthquake.

  • L-side earthquake (Surface Wave / Longitudinal Wave)  

This type of earthquake is a wave that can only spread on the surface of the earth. These waves are characterized by rapid up-and-down motions and can cause considerable damage to the area they affect.

The speed of propagation is also slower than the P-side and S-side waves. Earthquake surface wave is a type of earthquake wave that moves on the surface of the earth. Surface wave earthquakes occur when earthquake waves pass through rock layers beneath the earth’s surface, and propagate to the earth’s surface.

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Surface waves usually have a lower frequency than other earthquake waves, so they can give a longer and stronger vibration. Surface wave earthquakes can affect large areas and can cause damage to building structures.

All of these types of earthquakes can occur simultaneously when an earthquake occurs. However, the types of earthquakes that occur most frequently are S-side and S-side earthquakes, while L-side earthquakes are rare.

Causes of Earthquakes

The main cause of earthquakes is plate tectonic movement. These plates can move slowly or suddenly, causing earthquakes when the Earth’s surface shifts. This movement can occur on the surface of the earth or in the ground, and can cause damage to building structures and soil. There are also several other factors that can cause earthquakes, such as volcanic activity, mining, and changes in water pressure in the ground.

There are several main causes of earthquakes, namely:

  1. Earthquakes can occur when the pressure and friction between tectonic plates increases to the point where the rocks beneath the earth’s surface can no longer withstand the pressure, resulting in faults or cracks in the rocks.
  2. Earthquakes can also occur when magma pressure inside the earth increases, resulting in the discharge of magma to the earth’s surface through cracks that occur in the rocks beneath the earth’s surface.
  3. Earthquakes can also occur when there is volcanic activity, such as a volcanic eruption or the dumping of lava.
  4. Earthquakes can also occur when tectonic plates move rapidly, such as when tectonic plates collide or slide over one another.
  5. Earthquakes can also occur due to human activities, such as when mining is too deep or the construction of buildings or bridges that are too large can affect the structure of the earth below.

Things to Do During an Earthquake 

Here are some things you can do when an earthquake occurs:

  1. If you are at home, immediately take cover under a sturdy table or chair or behind a solid wall. Avoid standing near windows or wide tables, as these objects could fall and cause injury.
  2. If you are outside, walk immediately into an open area and avoid standing near tall buildings or tall trees.
  3. If you are in a vehicle, stop immediately in a safe place and avoid standing near tall buildings or tall trees.
  4. Avoid using the elevator during an earthquake, as it can get stuck between floors.
  5. If you are near the beach, avoid standing near the beach and walk quickly to a safe place, because an earthquake can cause a tsunami.
  6. After the earthquake is over, immediately check the condition of your house and immediately evacuate if necessary. If there is a fire or open gas, immediately call the fire department.

Conclusion

An earthquake is a geological event caused by tectonic movements within the Earth. Earthquakes occur when the Earth’s crust shifts or there is a change in pressure inside the Earth, which causes strong vibrations. These vibrations can be felt on the surface of the Earth, and can cause damage and destruction in the areas they affect.

Earthquakes can occur anywhere on Earth, but they usually occur in areas of high tectonic activity, such as along continental plates or around the ring of fire (most earthquakes occur around the ring of fire). namely Indonesia.

Well, Sinaumed’s, our article about the understanding of earthquakes has been completed, after knowing what earthquakes are both in general and the opinions of experts to the causes of earthquakes.

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Author: Mutual

Reference:

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  • https://bpbd.ntbprov.go.id/pages/gempa-bumi
  • https://www.kompas.com/tren/read/2021/03/21/162900965/profil-penemu-seismograf–john-milne?page=all
  • https://www.merdeka.com/events/earthquake-large-selong-history-indonesia.html