Earthquake

Geographic

2022

We explain what earthquakes are and what types of earthquakes exist. What are its causes and consequences. Tidal waves.

They cause the fall of buildings, collapse of houses and other urban accidents.

What is an earthquake?

It's called an earthquake (from the Latin earth: “earth”, and motus: "movement") or also earthquake, earthquake, tremor or telluric movement, to an episode of violent and temporary shaking of the Earth crust, the result of the sudden release of Energy (seismic wave) in the subsoil, where certain geological phenomena occur, such as faults, volcanoes or friction between tectonic plates.

An earthquake has an underground focus or point of origin, known as hypocenter, and a point on the surface directly above the focus, called the epicenter, where the greatest intensity of the flash usually occurs. movement. In almost all cases, earthquakes of much lesser intensity, known as earthquakes, are produced after the tremor. replicas.

The magnitude of the force of motion is usually measured according to the Richter scale, a record of local earthquake magnitude ranging from 2.0 (imperceptible daily micro tremors) to 10 (never recorded).

These types of seismic events occur recurrently, on a cyclical basis, according to the movement over the centuries of the subsurface tectonic plates, and to the processes of change of the earth's crust. Seismologists are dedicated to the study of earthquakes and the calculation of their repetition probabilities in the weather.

Earthquakes have occurred since time immemorial and have always transmitted to the human being an impression of the gigantic forces of the nature, to the extent that they have caused tragedies and generated secondary catastrophes.

types of earthquake

Intermediate earthquakes range between 70 and 300 kilometers deep.

Three different types of earthquake are usually considered, according to the region of the crust in which its hypocenter is located:

  • Superficial. They have a focus not less than 70 kilometers deep, thus having a greater impact on the surface. This makes them the most devastating of earthquakes.
  • Intermediates. Its focus ranges between 70 and 300 kilometers deep.
  • deep. Events that occur deep within the Earth, usually outside the lithosphere, more than 300 kilometers from the surface. Called batisismos, they are usually imperceptible.

Causes of an earthquake

A tremor can respond to various causes, natural and human:

  • geological processes. The tectonic plates of the Land move under the surface, over the magma, and often collide with each other, generating waves earthquakes that reverberate towards the surface. This can also occur in the presence of volcanic activity.
  • Geothermal installations. Tremors can also be accidentally caused by the human hand, such as microseisms that often occur when injecting Water cold in geothermal deposits, where the heat of the earth makes the liquid boil and produces geysers.
  • Fracking. There is debate about the possibility that methods hydraulic fracturing or fracking, consisting of the injection of water and chemical materials into hydrocarbon wells to increase or promote the extraction of valuable matter, may increase the seismic instability of the area and cause earthquakes.
  • Nuclear tests. Atomic weapons tests are so destructive that they must be done far from human and wildlife, so they are often conducted underground.These explosions are so strong that they can impact tectonic plates and transmit vibrations that cause small earthquakes.

Consequences of an earthquake

On many occasions the population is not prepared or educated in seismic matters.

Earthquakes can have various consequences, such as:

  • urban destruction. The fall of buildings, the collapse of houses and other urban accidents usually accompany the vibratory movement of tremors, and usually exact a high price in human lives, especially if the population is not prepared and educated in seismic matters.
  • Ground slides. Elevations such as hills, hills, and mountains they can yield to the force of earthquakes and thus generate landslides or avalanches capable of burying entire populations
  • Fires. The fall of urban or industrial installations often causes electrical failures or the release of flammable chemicals, which often start fires.
  • Soil liquefaction. The seismic waves are so strong that they can force the material of the I usually to release the contained water, losing solidity and becoming muddy, which is lethal for the stability of houses and buildings.
  • Tsunamis. Large earthquakes can transmit their vibrations to the water of the oceans, thus generating an artificial agitation of it and then large waves known as tsunamis.

Seaquake

It is known as a tidal wave tsunami to the effect of the transmission of seismic waves from an earthquake to the water of the oceans, producing an initial withdrawal and then a gigantic wave that can travel several kilometers and crash on the coast, depending on how much energy is released by the initial earthquake. It is one of the most feared and devastating effects of tremors, and the "tsunami alert" is usually after the end of large earthquakes.

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