Each of us have heard about the dangers of life and health of people earthquake.Fortunately, modern seismic instruments are able to predict the possible onset of the earthquake, and the authorities have the opportunity to inform the public about the impending threat, and in some cases to evacuate him from the area of the expected disaster.But how to understand, how strong will the tremors, and what harm they cause?After all, there is an earthquake hypocenter (focus in the earth's crust), the epicenter (the point on the earth's surface, which is located at the hypocenter), in addition to the devastating earthquake affects the composition of the soil, and even seismic stability of buildings.In some cases, weaker shocks can be felt, and in some - stronger.Now to describe the strength of the soil oscillation accepted international Richter scale, and the unit of force recognized the magnitude of seismic shocks.
fairness it should be noted that Richter does not belong to the laurels of developing an international scale of earthquake intensity.It was developed by the Italian scientist Mercalli, and up to the 30s of the twentieth century and it was called - "Mercalli Intensity Scale."It consisted of 12 points (most likely, by analogy with the rating power of the wind speed and 12-point Beaufort scale).By Mercalli, the weakest push (intensity 1 point) there are only a few people who are sensitive to the shocks of the soil, and the strongest (12 points) leads to complete destruction of the buildings, and even changes in the landscape.On the Mercalli scale of earthquake more than 6 points were considered strong, and below - the weak.But Mercalli Intensity Scale, used not all countries: for example, in Japan, it was decided to measure earthquakes in a 7-point school, and in some countries enjoyed a 10-point scale of Rossi and Forel.With the advent of globalization, there was a need to develop an international scale to seismographs around the world can clearly explain the extent of the impending threat to its neighbors.This scale, which has become the standard throughout the world, became the Richter scale.
First Japanese scientist T. Welat proposed to measure the strength of earthquakes introduce logarithmic magnitude scale (in Latin magnitudo - size, value), which take into account the total vibrational energy of the earth.American seismograph Ch.Rihter proposed to measure the magnitude of earthquakes used logarithm maximum oscillation amplitude of the soil (which is calculated directly proportional to the relative deviation of the needle on a seismograph, making allowance for the distance from the epicenter).It is a scientific explanation does not, of course, the simple layman to judge correctly how the Richter scale will help it to determine the risks of the coming earthquake.
In Russia, the earthquake, which record only seismic devices, but not the people, estimated at 1 point.If the cabinet rattling dishes, and on the upper floors of tall buildings swaying chandeliers, so the earthquake is estimated at 4 points.Of course, it is only monitoring the territory, which can be removed from the epicenter of many hundreds of kilometers, and the Richter scale with these points is the same extremely rare.Yet, such a characteristic of Russian forces aftershocks has the practical advantage that it allows to work out the correct action during an earthquake.Thus, when the intensity of the tremors in the 6 points you need to leave the room (especially the panel and high-rise), and if this is not possible, stay away from windows and close to the inner walls of the structure.
way, despite the fact that the scale of Richter crashed his 12 points, the most powerful earthquake, which was observed by instruments, never exceeded a magnitude of 9 points.It was a devastating earthquake in the northeast of India, August 15, 1950.It brought the death of a thousand people, but after the earth formed the new faults and failures, and the Brahmaputra river has changed its course.
