Studying the Earth layer with Earthquake Data

So far, we’ve been introduced to some of the layers of the earth. When we first learn geography in high school, the reader must have seen the earth split and appear multiple layers. When looking at the layers of the earth, it would appear the questions in our minds about “how geoscience experts know the thickness of the layer of earth and physical properties (liquid or solid) layer of the earth”.

¬†Since time immemorial, humans continue to try to learn the layers of the earth by means of drilling lining but very limited drilling method therein. The deepest drilling ever perpetrated by man to date is 12 Km in Russia (cmiiw). The drilling was hampered by very hot temperatures under the surface and it is not possible to drill up to a depth exceeding 12 Km. If “ngebor” wrote only up12 Km, how the experts can be certain terrestrial muplikasi core layer of the earth to the Earth? Answers to these questions on the use of seismic methods (vibration / earthquake waves) that has long been used by geophysicists.
Layer of earth

Seismic Method and Earth Layers

Methods Seismic is one method of measurement Geophysical most widely used by experts Geophysics in studying the earth and looking for natural resources (oil, natural gas, etc.), even though there are still many many geophysical methods such as methods Geolistrik, geomagnetic, gravity (gravity), EM (electromagnetic) are also frequently used. The basic principle is to study the seismic method seismic wave propagation (seismic) by creating an artificial wave sources (hammers, vibrators, explosives, etc.).

Waves from an artificial source will spread below the surface and the response was captured on the surface using geophones (seismometers). Time and wave propagation pattern would indicate subsurface conditions. as shown in Figure 1 below. Gampar 1 is a seismic refraction method of measuring process with the vibration source 5 Kg hammer that struck to Plate (yellow) for presenting so the vibration source. This picture was taken when the author (brown camouflage pants) and Tim are measuring seismic refraction in Kajang, Malaysia.

Figure 1. Seismic Measurement Bias for both shallow (Asrillah, 2010)

If we may assume, a geophysics is like a “doctor of the earth”. They studied the conditions in the Earth by measuring on the surface of the earth. Measurements were carried out based on physical properties (physical) earth like elastic (seismic methods), density (method Graviti), electricity (geoelectric method), susceptibility (geomagnetic method) and others. Now the question is, mampukan geophysical methods used to study the layers of the earth to the earth’s core?

Earthquake Data Bum View Layers To Earth

Seismic measurements relying on artificial vibration source such as hammers, vibrators, explosives and others reach only superficial layers of the earth, is less than 1 Km. To study the condition of the earth to the earth’s core needed source of vibrations and earthquakes are a natural vibration sources that can be used to study the layers of the earth.

When there is an earthquake , the earthquake will be transmitting body and surface waves. Body wave consisting of primary waves (P) and secondary waves (S) will penetrate into the subsurface of the earth. Between P and S waves there is the uniqueness of each where the P waves can penetrate the solid and liquid layers while S waves can only pass through a dense layer only. P and S wave propagation passing through the layers of the earth can be seen in the figure that the generated by IRIS below.

Of seismic waves traveling through the earth layers are then detected by seismometers installed worldwide. The data is analyzed to didapatlah thickness and properties than each layer of earth. As in Figure 2, the S and P waves just past the mantle nature and dense and chewy. On the outer core layer of earth only P waves are detected, this means the earth’s outer core layer and the liquid nature of the S wave can not pass. Although all the things that happen in figure 2 is not as simple as I have described, but try to understand this simple.

Currently, throughout the world have a lot of equipment installed seismometer to study the layers of the earth by earthquake waves emitted. It was not always an earthquake to bring harm and there is wisdom behind every earthquake. Let us deepen knowledge of natural disasters so that we know every meaning of the natural disaster.

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