Mercalli intensity scale

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The Mercalli intensity scale is a seismic scale uised for measurin the intensity o an yirdquauk. It measurs the effects o an yirdquauk, an is distinct frae the moment magnitude uisually reportit for an yirdquauk (whiles misreportit as the Richter magnitude), which is a measur o the energy released. The intensity o an yirdquauk is nae tot determined bi its magnitude. It is nae based on first pheesical principles, but is, insteid, empirically based on observed effects.[1]

Scale[eedit | eedit soorce]

I. Not felt Nae felt except bi a very few unner especially favorable condeetions.
II. Weak Felt anly bi a few persons at rest, especially on upper fluirs o biggins.
III. Weak Felt quite noticeably bi persons indoors, especially on upper fluirs o biggins. Mony fowk dae ae recognise it as an yirdquauk. Staundin motor caurs mey rock slichtly. Vibrations seemilar tae the passin o a truck. Duration estimatit.
IV. Licht Felt induirs bi mony, ootduirs bi few durin the day. At nicht, some awakened. Dishes, windaes, duirs disturbed; waws mak crackin soond. Sensation lik hivy truck strikin biggin. Staundin motor caurs rocked noticeably.
V. Moderate Felt bi nearly everyane; mony awakened. Some dishes, windaes broken. Unstable objects owerturned. Pendulum clocks mey stap.
VI. Strong Felt bi aw, mony frichtened. Some hivy furnitur moved; a few instances o fawen plaster. Damage slicht.
VII. Very Strong Damage negligible in biggins o guid design an construction; slicht tae moderate in well-biggit ordinary structurs; considerable damage in puirly biggit or badly designed structurs; some chimneys broken.
VIII. Severe Damage slicht in specially designed structurs; considerable damage in ordinary substantial biggins wi pairtial collapse. Damage great in puirly biggit structures. Faw o chimneys, factory stacks, columns, monuments, waws. Hivy furnitur owerturned.
IX. Violent Damage considerable in specially designed structurs; well-designed frame structurs thrown oot o plumb. Damage great in substantial biggins, wi pairtial collapse. Biggins shifted off foondations.
X. Extreme Some well-biggit widden structures destroyed; maist masonry an frame structurs destroyed wi foondations. Rails bent.
XI. Extreme Few, if ony (masonry), structurs remain staundin. Brigs destroyed. Broad fissures in grund. Unnergrund pipe lines completely oot o service. Yird slumps an laund slips in saft grund. Rails bent greatly.
XII. Extreme Damage tot. Waves seen on grund surfaces. Lines o sicht an level distortit. Objects thrown upward intae the air.

References[eedit | eedit soorce]

  1. "The Modified Mercalli Intensity Scale". USGS.