What is magnituda?
Magnitude earthquake - the notional value that characterizes the energy that is released during an earthquake as seismic waves. Magnitude calculated on records of oscillations recorded by special devices - seismographs. First magnitude scale was proposed by an American seismologist Charles Richter in 1935, so the value is often called the magnitude on the Richter scale. Magnitude no units, so the expression "5 on the Richter scale" is incorrect. In the logarithmic scale used scale, so magnitude increase in value per unit of the increase in the amplitude 10 times and an increase in dedicated energy during an earthquake 32 times.
Example record earthquakes from Romania, magnitude 2.5.
Example record earthquakes from Romania, magnitude 5.5.
It should be noted that magnitude does not fully characterize the effects of the earthquake on the earth's surface, depending on many factors, first and foremost, the depth of the source.
What is Medvedev–Sponheuer–Karnik scale?
The intensity of the earthquake - a value that represents the degree of oscillation of the Earth's surface during an earthquake. The intensity of the reflected seismic scale scores depending on the degree of destruction of standard buildings, witnesses sensations, changes in topography of the earth's surface. The intensity of the earthquake on the surface of display depends on the depth and magnitude of the earthquake source. The intensity is greater the closer to the surface lies the source. Thus, if the source of an earthquake with a magnitude of 6, at a depth of 10 km on the surface intensity will be 8-9 points, which can cause considerable damage. At this same magnitude, but at a depth of 300 km intensity will be 2-3 points, and the earthquake will be felt by only a few people. The world several scales used to determine the intensity of the earthquake (European macroseismic scale, Mercalli Intensity Scale, the scale of the Japan Meteorological Agency, etc.), but one of the most widespread in Ukraine is a 12-point scale MSK-64 (Medvedev-Shponhoyera-Karnika).
The intensity of the vibrations is below the sensitivity of the people; shakes the earth and are recorded only seismographs.
Barely perceptible earthquake.
Vibrations felt only by individuals who are at rest indoors, especially on upper floors.
Earthquake felt few people who are inside; open air - only in favorable conditions. Vibrations similar to concussion formed by a light truck. Attentive observers notice the light fluctuations of light objects slightly stronger - on the upper floors.
Highly significant earthquake.
The earthquake is felt indoors by many people in the open - a few. People are not sleeping, but nobody is frightened. Vibrations similar to concussion formed a heavily laden vehicle. Shake windows, doors and dishes. Creaking floors and walls. Begins shake furniture. Items that are hanging loose easily; fluid in open markets varies slightly. In the cars that are in place, push noticeable.
Earthquake is felt by all people inside the building, the open - a few. Prosynayetsya many people who are asleep. Some people ran out of the room. Animals worry. Shake the building as a whole. Items that are hanging vary greatly. Pictures shifted from their seats. In some cases pendulum clocks stop. Some volatile items being transferred or shifted from their seats. Doors and windows are not closed, open and closed again. With the full open market in small quantities poured liquid. Tangible vibrations similar to vibrations formed by heavy objects falling inside the building. Possible damage to 1 degree in separate buildings type A. In some cases, changing the flow rate of the source.
Strong Earthquake moderate.
Earthquake felt by most people indoors as well as outdoors. Many people who are in the building, scared and ran out into the street. Some people lose balance. Pets runs out of space. In a few cases it may break dishes and other glassware falling books. Possible move heavy furniture to hear the bell tower. Damage to 1 degree in some areas of type B in many areas of type A. Type A separate rooms 2 degrees of damage. In the few cases in damp soil may crack width of 1 cm; in mountainous areas isolated cases of landslides. Observed changes in discharge sources and water levels in wells.
Most people are frightened and run out of space. Many efforts to keep on his feet. Fluctuations observed drivers of certain vehicles. Bells big Bells. Many buildings type B - 1 degree of damage in many buildings of type B - 2 degrees of damage. Many buildings type A - 3 degrees of damage in some areas of this kind - Damage 4 degrees. In some cases - carriageway roads landslides on steep slopes and cracks on the road. Violation pipe joints, cracks in the stone fence. On the surface water generated waves, water becomes muddy in connection with raising the sludge. Changing water levels in wells and discharge sources. In some cases, the formation of new or existing water sources disappear. Individual cases of landslides on sandy and stony riverbanks.
A strong earthquake.
Fear and panic, feel the excitement even car drivers. Something where broken tree branches. Trembling and sometimes thrown hard furniture. Some fixtures are hanging damaged. Many buildings type B - 2 degrees of damage in some buildings this group - 3 degrees of damage in some - 4 degrees. Many buildings type A - 4 degrees of injury, in some - 5 degrees. Individual cases of breaking joints of pipelines. Monuments and statues of zsovuyutsya place. Gravestone upset. Stone fence destroyed. Small landslides on steep slant pits and embankments of roads, cracks in the soil up to several centimeters. Formation of new reservoirs. Some parched wells filled with water and wells that exist dry. In many cases, changing the flow rate of the sources and the water level in wells.
A destructive earthquake.
Total panic, large damage to the furniture. Animals running around and screaming. In many buildings of type b - damage 3 degree and in some - 4 degrees. In many buildings of type B damage 4 degrees, in some - 5 degrees. In many buildings of type A - damage 5 degree. Monuments and columns remain upright. Considerable damage to reservoirs; tearing parts of underground pipelines. In some cases, bent rails, damaged carriageways roads. On the plains, which are flooded frequently noticeable deposition of sand and silt. Cracks in the soil reach a width of 10 cm, on slopes and river banks more than 10 cm; furthermore a large number of thin cracks in the soil. The rocks fall away, frequent landslides and sloughing of the soil. On the surface of water waves.
A devastating earthquake.
Many buildings type B - 4 degree of damage, and in some - 5 degrees. Many buildings of type B - 5 degrees of damage, most buildings type A - 5 degrees of damage. Hazardous damage to dams, bridges severely damaged. Light curvature railways. Gaps or curvature of underground pipelines. Asphalt pavement and create a wave-like surface. Cracks in the soil several decimeters wide and in some cases up to 1 m. Along the rivers there are extensive flooding. Shedding loose rocks on steep slopes. There are big shifts on the river banks and steep coast. In coastal areas moving sand masses and masses of mud, water spilling over of canals, lakes, rivers and so on. The formation of new lakes.
The devastating catastrophic earthquake.
Serious damage even building stable construction, bridges, dams, railways, roads become unusable; damage to underground pipelines. Significant deformation of the soil in the form of extensive cracking, breaking and moving in the vertical and horizontal directions, many mountain landslides. Determination of shaking intensity requires special study.
Catastrophe. Change of relief.
Severe damage and violation of virtually all surface and underground facilities. A radical change in the earth's surface. There are significant cracks in the soil with box vertical and horizontal movements, landslides and mountain landslides on riverbanks large areas. Formed lakes, waterfalls, altered mouth year. Determination of shaking intensity (balnosti) requires special study.
Notes: the classification adopted in the scale;
Types of structures (buildings built without the required earthquake-proof).
Type A - building of the crushed stone, rural structures, buildings of raw brick, mud-brick houses.
Type B - ordinary brick building, buildings of large block and prefabricated types, high-rise buildings, buildings made of natural cut stone.
Type С - frame reinforced concrete building, wooden house sustainable building.
Quantitative characteristics: Separate - about 5%. A - about 50 %. Most - біля75%
Classification of damages:
I degree. Light damage: fine cracks in plaster and spalling of small pieces of plaster.
II degree. Moderate damage: small cracks in walls, breaking off fairly large pieces of plaster, falling of roof tiles, cracks in chimneys, falling pieces of chimneys.
III degree. Heavy damage: large and deep cracks in walls, fall of chimneys.
IV degree of Destruction: collapse of the inner walls, through cracks and gaps in walls, collapse of parts of the building, damaging the connection between the individual parts of the building.
V degree. Falls: full damage to the building. Grouping characteristics of the scale: a) people and their environment; b) structures; C) natural phenomena.
What is the estimated intense earthquake?
The estimated intensity of earthquake - intensity value, calculated using the appropriate mathematical apparatus.
Leading seismological service only determine earthquake magnitude and intensity values measured by the nature of the damage directly to the place of its origin. Assessing the impact of the earthquake may take a long time required for examination specialists in the region where the earthquake was felt, determining the degree of damage to buildings, changes in the earth's surface topography, survey eyewitnesses and others.
An example of the devastating earthquake intensity of 9 points (on a scale MSK-64) 24 August 2016, Italy (Amatriche)
To assess the possible effects of the earthquake are formulas intensity of the source and the distance from it. It must be remembered that the value of the estimated intensity at a particular location may differ from the real, depending on the types of plants, propagation of seismic waves conditions, soil types and so on.