![]() ![]() Will cause moderate to heavy damage to sturdy or earthquake-resistant buildings. Major damage to buildings, and structures likely to be destroyed. ![]() Felt across great distances with major damage mostly limited to 250 km from the epicenter. Well-designed structures are likely to receive damage. Strong to violent shaking in the epicentral area.Ĭauses damage to most buildings, some to partially or completely collapse or receive severe damage. Felt in wider areas up to hundreds of kilometers from the epicenter. Poorly designed structures receive moderate to severe damage. Earthquake-resistant structures survive with slight to moderate damage. Felt by everyone.ĭamage to a moderate number of well-built structures in populated areas. Zero to slight damage to all other buildings. Some objects may fall off shelves or be knocked over.Ĭan cause damage of varying severity to poorly constructed buildings. Moderate to significant damage is very unlikely. Felt by most people in the affected area. Noticeable shaking of indoor objects and rattling noises. Shaking of indoor objects can be noticeable. Often felt by people, but very rarely causes damage. Typical maximum Modified Mercalli Intensity Īverage frequency of occurrence globally (estimated) They should be taken with extreme caution since intensity and thus ground effects depend not only on the magnitude but also on the distance to the epicenter, the depth of the earthquake's focus beneath the epicenter, the location of the epicenter, and geological conditions. The following describes the typical effects of earthquakes of various magnitudes near the epicenter. ![]() īecause of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude in terms of energy, each whole number increase corresponds to an increase of about 31.6 times the amount of energy released, and each increase of 0.2 corresponds to approximately a doubling of the energy released.Įvents with magnitudes greater than 4.5 are strong enough to be recorded by a seismograph anywhere in the world, so long as its sensors are not located in the earthquake's shadow. In practice, readings from all observing stations are averaged after adjustment with station-specific corrections to obtain the M L value. Due to the variance in earthquakes, it is essential to understand the Richter scale uses logarithms simply to make the measurements manageable (i.e., a magnitude 3 quake factors 10³ while a magnitude 5 quake is 100 times stronger than that). All magnitude scales retain the logarithmic character of the original and are scaled to have roughly comparable numeric values (typically in the middle of the scale). īecause of various shortcomings of the original M L scale, most seismological authorities now use other similar scales such as the moment magnitude scale (M w ) to report earthquake magnitudes, but much of the news media still erroneously refers to these as "Richter" magnitudes. This was later revised and renamed the local magnitude scale, denoted as ML or M L . The moment magnitude (Mw) scale, based on the concept of seismic moment, is uniformly applicable to all sizes of earthquakes but is more difficult to compute than the other types.The Richter scale ( / ˈ r ɪ k t ər/), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Francis Richter and presented in his landmark 1935 paper, where he called it the "magnitude scale". Scales 1-3 have limited range and applicability and do not satisfactorily measure the size of the largest earthquakes. Several scales have been defined, but the most commonly used are (1) local magnitude (ML), commonly referred to as “Richter magnitude”, (2) surface-wave magnitude (Ms), (3) body-wave magnitude (Mb), and (4) moment magnitude (Mw). Magnitude is based on measurement of the maximum motion recorded by a seismograph. Reference Definition by : The Magnitude is a number that characterizes the relative size of an earthquake. Thus, a magnitude 7 earthquake has 32 times more energy than a magnitude 6 and almost 1,000 times more energy than a magnitude 5 earthquake). The energy released in the earthquake but the energy goes up with magnitude faster than the ground velocity, by a factor of 32. Magnitude is 1) the large size or great importance 2) a measure of the brightness of a star as it appears from earth 3) used to describe the overall strength or size of an earthquake (Seismic Magnitude Scale.
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