Question

what is Marcelline scale?

Answer 1

The Mercalli intensity scale is a seismic intensity scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake. It is distinct from the moment magnitude (Mw) usually reported for an earthquake, which is a measure of the energy released (sometimes misreported as the Richter magnitude, ML). The intensity of an earthquake is not entirely determined by its magnitude. It is not based on first physical principles, but is, instead, empirically based on observed effects.[1]

The Mercalli scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale from I (not felt) to XII (total destruction).[2][3] Values depend upon the distance from the earthquake, with the highest intensities being around the epicentralarea. Data gathered from people who have experienced the quake are used to determine an intensity value for their location. The Italian volcanologist Giuseppe Mercalli revised the widely used simple ten-degree Rossi–Forel scale between 1884 and 1906, creating the Mercalli Intensity scale which is still used today.

In 1902, the ten-degree Mercalli scale was expanded to twelve degrees by Italian physicist Adolfo Cancani. It was later completely re-written by the German geophysicist August Heinrich Sieberg and became known as the Mercalli–Cancani–Sieberg (MCS) scale.

The Mercalli–Cancani–Sieberg scale was later modified by Harry O. Wood and Frank Neumann, and published in English in 1931 as the Mercalli–Wood–Neumann (MWN) scale. It was later improved by Charles Richter, the father of the Richter magnitude scale.

The scale is known today as the Modified Mercalli scale (MM) or Modified Mercalli Intensity scale (MMI).

Modified Mercalli Intensity scaleEdit

The lower degrees of the Modified Mercalli Intensity scale generally deal with the manner in which the earthquake is felt by people. The higher numbers of the scale are based on observed structural damage.

This table gives Modified Mercalli scale intensities that are typically observed at locations near the epicenter of the earthquake.[2]

I. Not feltNot felt except by very few under especially favorable conditions.II. WeakFelt only by a few people at rest, especially on upper floors of buildings.III. WeakFelt quite noticeably by people indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated.IV. LightFelt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably.V. ModerateFelt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocksmay stop.VI. StrongFelt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.VII. Very strongDamage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.VIII. SevereDamage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.IX. ViolentDamage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. Liquefaction.X. ExtremeSome well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.XI. ExtremeFew, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipe lines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.XII. ExtremeDamage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into the air.

Correlation with magnitudeEdit

MagnitudeMagnitude / intensity comparison1.0–3.0I3.0–3.9II–III4.0–4.9IV–V5.0–5.9VI–VII6.0–6.9VII–IX7.0 and higherVIII or higherMagnitude/intensity comparison, USGS

The correlation between magnitude and intensity is far from total, depending upon several factors including the depth of the hypocenter, terrain, distance from the epicenter.

Answer 2

$\large \sf{Answer}$

The Mercalli intensity scale (or more precisely the Modified Mercalli intensity scale) is a scale to measure the intensity of earthquakes. When there is little damage, the scale describes how people felt the earthquake, or how many people felt it.