Medvedev scale

from Wikipedia, the free encyclopedia

The Medvedev scale is an intensity scale for earthquakes developed by Sergei Wassiljewitsch Medvedev . On this basis, the 12-part GEOFIAN scale , which was valid for a long time in the USSR , was developed in 1950 .

Unlike magnitude scales, for example the frequently cited Richter scale , intensity scales such as the JMA scale , the EMS scale or the Mercalli scale describe the effects of an earthquake on the surface and can therefore show different strengths for a single earthquake in different locations.

In contrast to many of today's intensity scales, the Medvedev scale has nine levels. Since the scale describes the intensity of an earthquake on the basis of damage to buildings, the first five levels are empty.

The individual levels of the Medvedev scale are described below. The abbreviation D is derived from the English word displacement and describes the reaction of a damped oscillator with a period of 0.25 seconds. V means the maximum speed reached on the earth's surface, MB means “ maximum acceleration ” and indicates the acceleration generated by earthquake waves and acting on the earth's surface. For the damaging effect of an earthquake, the horizontal forces acting parallel to the earth's surface are of particular importance, since buildings are normally constructed in such a way that they can absorb vertically acting forces.

intensity D (mm) V (cm / s) MB (cm / s 2 ) Structural damage to buildings Geotechnical damage

Degree of damage		 Type a Type B Type c
VI 1.5-3 3-6 30-60 1 50% 10% Occasionally landslides , especially in the mountains, cracks in the earth become visible with widths of up to one centimeter. In some springs and wells, the water level and spring discharge can change.
2 10%
VII 3-6 6.1-12 61-120 1 50% Occasional landslides and road damage on steep slopes and embankments made of loose material such as sand or gravel. Pipe connections in the underground can break. Sources can dry up or arise again, the water level in wells changes.
2 50% 10%
3 50% 10%
4th 10%
VIII 6-12 12.1-24 121-240 1 Small landslides occur on steep slopes, for example in road cuts and embankments. Fissures in the earth form with widths of several centimeters. Formation of new water bodies and strong changes in spring discharge and in the groundwater level in wells. Wells falling dry, in some cases also renewed water supply in wells that were previously dry.
2 50%
3 50% 10%
4th 50% 10%
5 10%
Monuments and columns are moved, gravestones and garden walls topple
IX 12-24 24.1-28 241-280 1 50% Considerable damage to the banks of reservoirs and water reservoirs. Breaking underground lines, occasional bending of railroad tracks and damage to roads. Flooding of valleys and frequent washing up of sand and silt. Fissures in the earth can gape up to 10 centimeters, and more on slopes and banks. Landslides are common and entire mountain slopes are in motion.
2 50% 10%
3 50% 10%
Monuments and columns topple over

Remarks

  1. ↑
    1. Light. Small cracks in the walls, flaking of plaster and stucco
    2. Moderate. Small cracks in walls and on the joints of facade cladding, larger areas of plaster and stucco flaking off, falling roof tiles, cracks in chimneys, destruction of some chimneys
    3. Heavy. Large and continuous cracks in walls and facade cladding, destruction of chimneys
    4. Destructive. Destruction of interior and filling walls, wall breaks, partial destruction of buildings and load-bearing structures
    5. Devastation. Complete destruction of buildings
  2. ↑ Air-brick structures and those made of uncut natural stone
  3. ↑ Brick masonry, structures made of large blocks of natural stone or concrete blocks as well as buildings with smaller, regularly cut natural stones
  4. ↑ Buildings with reinforced concrete or steel frames as well as equally reinforced structure, well-built wooden house structures

literature