HOW DO EARTHQUAKES ORIGINATE? - GEOGRAPHY - 2025

The earthquakes will originate and that the plates inside the Earth must re-adjust and release energy. Additionally, earthquakes can also be caused by volcanic eruptions. To be considered an earthquake, the energy wave must have a natural origin.

An earthquake is a tremor on the Earth's surface, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes or earthquakes can vary in size; some are so weak that they are not felt by the terrestrial population, while others are so violent that they destroy cities.

The seismic activity of an area refers to the frequency, type and size of earthquakes experienced in that location over a period of time. On the earth's surface, earthquakes are manifested by shaking and sometimes in the displacement of the ground.

Beneath the earth's surface, the asthenosphere is located, the upper part of the mantle made up of liquid rocks.

The plates of the Earth's crust essentially float on top of this layer and can be forced to move when the molten material below moves. Rocks and magma within volcanoes can also trigger earthquakes.

In all cases, large sections of the crust can fracture and move to dissipate the released energy. This tremor is the situation felt during an earthquake.

How do earthquakes originate?

Earthquakes occur all the time around the world, both at plate edges and at fault lines.

Earth has four main layers: the inner core, the outer core, the mantle, and the crust. The crust and cusp of the mantle make up a thin skin on the planet's surface.

But this skin is not in one piece, it is made up of many pieces like a puzzle covering the entire surface of the Earth.

These puzzle pieces, called tectonic plates, keep moving around slowly, sliding past each other and colliding with each other.

The edges of tectonic plates are called plate boundaries. Plate boundaries are made up of many faults or defects, and most earthquakes around the world occur from these faults.

Since the edges of the plates are rough, they get stuck while the rest of the plate continues to move.

Finally when the plate has moved far enough, the edges peel off at one of these faults and an earthquake occurs.

Natural earthquakes

Tectonic earthquakes can occur anywhere on Earth where there is enough stored elastic energy to drive fracture propagation in a fault.

The edges of a fault move with each other smoothly and asysmically only if there are no irregularities or rough edges that increase frictional resistance on the fault surface.

Most fault surfaces do have such roughness and this leads to the formation of a shaking behavior.

Once the fault has been blocked, a relatively continuous movement between the plates leads to an increase in stress and, therefore, to the tension energy stored in the volume around the surface of the fault.

This continues until the stress has increased enough to break through the roughness, allowing it to suddenly travel over the blocked portion of the fault; in this way the stored energy is released.

This energy is released as a combination of seismic waves of elastic radiation stress, frictional heating of the fault surface, and rock breakdown. Therefore, these factors cause an earthquake.

It is estimated that only 10% or less of the total energy of an earthquake is radiated as seismic energy.

Most of the earthquake energy is used to power the growth of the earthquake fracture or is converted into heat generated by friction.

Therefore, earthquakes decrease the elastic potential of available energy of the Earth and increase its temperature.

However, these changes are insignificant compared to the conductive and connective heat flux emanating from the deep interior of the Earth. The elastic rebound theory applies to these earthquakes.

Earthquakes caused by volcanoes

Volcanic earthquakes are much less common than natural plate tectonic earthquakes. They are triggered by the explosive eruption of a volcano.

When a volcano explodes, the effects of associated earthquakes are usually confined to an area of ​​16 to 32 km around its base.

The volcanoes that are much more likely to explode violently are those that produce acidic lava. Lava cools and sets very quickly when it comes into contact with air.

This chokes the volcano vent and blocks the pressure escape. The only way this blockage can be removed is by blasting out all the stored pressure.

The volcano will explode in the direction of its weakest point, so it doesn't always happen upwards.

Extraordinary pressure levels can also produce an earthquake of considerable magnitude. For example, it is known that some shock waves can produce a series of tsunamis at times.

Relationship between volcanoes and earthquakes

Earthquakes often occur in volcanic regions and are caused there, sometimes by tectonic faults and the movement of magma in volcanoes.

Some earthquakes can serve as an early warning for volcanic eruptions, as did the 1980 Mount St. Helens eruption.

Earthquake swarms can serve as markers for the location of magma flowing through volcanoes.

These swarms can be recorded by earthquake meters and microseismic monitoring equipment to be used as sensors and prevent impending or future eruptions.

References

1. Earthquake. Recovered from wikipedia.org.
2. What causes earthquakes? (2010) Recovered from universetoday.com.
3. Cutaway of Earth's layers. Recovered from earth.rice.edu.
4. How does an earthquake occur? Recovered from funvisis.gob.ve.
5. The science of earthquakes. Recovered from earthquake.usgs.gov.
6. Where do earthquakes happen? Recovered from geo.mtu.edu.