An earthquake is any shake on the surface of a planet that occurs suddenly. It occurs due to the passage of seismic waves through the crust. The epicenter of an earthquake is where the shaking begins. Oscillations will spread from him in all directions, which often cause many problems to humanity.
Most earthquakes are rarely strong, but this is common. As a result, human casualties are observed, as well as property destroyed or completely destroyed. Countries and states have to spend a lot of money to rebuild damaged cities.
Types of Earthquakes
In the present and recent past (last century), seismic activity could be caused by two different reasons:
- Natural phenomena. These can be shifts of earth plates, geological faults, as well as volcanic activity. As a rule, it is impossible to predict when and where such an event will occur. Moreover, even with the most advanced technological devices. Scientists can draw conclusions only based on data on past seismic activities.
- Phenomena caused by human activities. This can be destruction in mines or mineral deposits, nuclear explosions or experiments.
You should immediately pay attention directly to the fact that natural causes are extremely rare, but of course they cannot be completely excluded. As for the activities of people, it most often affects the state of the planet, which responds to them with various disasters, including earthquakes.
Epicenter definition
Shakes of the planet occur almost every day, only they are so minimal that a person can hardly feel them. Therefore, it is often quite difficult to determine exactly where the epicenter of the earthquake is located. This is done on the basis of data obtained from seismographs installed at three different stations. Or these devices can be used within the framework of one scientific enterprise.
In fact, all existing seismic belts are known to modern scientists. That is why they can arrange the stations so that there is always the opportunity to quickly determine the epicenter. It is easy to cope with such a task only if the earthquake is strong and touches a vast territory.
Accurate determination of epicenters is an important task for seismographs. This is due to the fact that they are repeated from time to time. Therefore, the more accurately the data are obtained, the better it will be possible to calculate the probability of the following fluctuations.
Earthquake strength
In order to determine the vibrational power of the plates of the planet, two quantities are required:
- Magnitude
- Intensity.
The magnitude of an earthquake is determined by a seismograph. It is found out, relying on the energy with which the plates oscillate, and the amplitude. The strength of the earthquake will depend on the second indicator. Other parameters also affect damage or destruction, but to a lesser extent.
The intensity of the earthquake is the shaking of the soil directly on the surface. That is, the epicenter can be located deep beneath the crust. And when the vibrations break out, they can lose their power. Thus, the source of the earthquake can be strong, but it will decrease until it reaches the place of residence of mankind.
As for strength, there is a scale of 12 points. The first is not felt by anyone. Starting from 4 points, a person not only feels shaking, but various objects, such as dishes or glass, are damaged. And the 11-12 level is felt strongly, since everything that people have ever built is destroyed.
How to find the epicenter
Since the epicenter of an earthquake is the beginning of shaking and vibrations, it is not always possible to find it quickly. Everything will depend on how modern the seismograph is installed at the station. He is engaged in fixing activity. First, waves P are captured, followed by S. The last to be recorded are L. These waves play a decisive role in the level of damage. Accordingly, the more sensitive the seismograph, the faster it will be possible to catch the fluctuations, and probably evacuate most of the people.
Scientists are still trying to answer the question of where the next earthquake will occur. However, it is difficult to calculate, often not even possible. At least until more sensitive seismographs relative to current ones are invented.
The most devastating earthquakes of the 21st century
Unfortunately, earthquakes occur in nature, the occurrence of which carries fatal consequences. This happened in Japan in 2011. Then, on March 11, shaking of 9 points began. She not only claimed the lives of thousands of people, but also caused an accident at the Fukushima-1 nuclear station. For this reason, far more people have been affected than from a similar earthquake.
A little earlier, in 2010 on the island of Haiti, there was also strong shaking (7 points). According to modern data, 200 thousand people died, and the capital was completely destroyed.
In 2008, a disaster occurred in China. Then seismographs recorded 8 points. The victims were about 70 thousand people, but only because the shaking began in the province. If it were a large city, then much more people would die.
Large earthquakes are rare, not more than once a year. But small tremors are recorded by extremely sensitive seismographs almost every day.
Conclusion
Thus, the epicenter of an earthquake is the point that gives rise to seismic vibrations. Modern devices allow you to quickly find the place in question. The collection of such information will be required so that subsequently seismograph scientists can determine the occurrence of earthquakes. Accordingly, these data will allow timely warning of people, take measures to minimize human and property losses.