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”.
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.
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.
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.