Compare the use of the Mercalli scale and the Richter scale to measure the size of an earthquake.?

Question

What are the advantages and disadvantages of using each scale?

Answer 1

Wikipedia has good summaries. Here are a few excerpts:

A seismic scale is used to measure and compare the relative severity of earthquakes.

Two fundamentally different but equally important types of scales are commonly used by seismologists to describe earthquakes. The original force or energy of an earthquake is measured on a magnitude scale, while the intensity of shaking occurring at any given point on the Earth's surface is measured on an intensity scale.


The Mercalli intensity scale is a scale used for measuring the intensity of an earthquake. The scale quantifies the effects of an earthquake on the Earth's surface, humans, objects of nature, and man-made structures on a scale of 1 through 12, with 1 denoting a weak earthquake and 12 one that causes almost complete destruction.

The Richter magnitude test scale (or more correctly local magnitude ML scale) assigns a single number to quantify the size of an earthquake. It is a base-10 logarithmic scale obtained by calculating the logarithm of the combined horizontal amplitude of the largest displacement from zero on a seismometer output. Measurements have no limits and can be either positive or negative.

The major problem with Richter magnitude is that it is not easily related to physical characteristics of the earthquake source. Furthermore, there is a saturation effect near 6.3-6.5, owing to the scaling law of earthquake spectra, that causes traditional magnitude methods (such as MS) to yield the same magnitude estimate for events that are clearly of different size.

A problem with the Mercalli (or any intensity scale: Any given earthquake can be described by only one magnitude, but many intensities since the earthquake effects vary with circumstances such as distance from the epicenter and local soil conditions.

Answer 2

This is long... sorry EQ = earthquake MS = Mercalli Scale RS = richter scale Mercalli scale measure the intensity and is more descriptive than the Richter Scale that measures the magnitude. The modified Mercalli Scale ranges from I to XII with XII being the most severe. The Mercalli Scale provides a measure of environmental damage usually measured from VI and above e.g. Intensity Description 1 not felt 4 windows rattle. Crockery disturbed 8 sand and mud ejected 12 total damage. waves seen on ground surface The Richter Scale measures the magnitude of the earthquake. Magnitude is logarithmemic. Measures how strong waves are. Advantages of RS - tells us the extact magnitude of EQ Advantage of MS - tells us environmental effect Diadvantages of RS- does not tell us effect on environment Disadvantages of MS- different magnitudes of EQ have different environemntal effects e.g. Newcastle RQ 1989 was (i think - cant find it in book) 5.6 on the RS but there was a lot of environmental damage. Therefore the MS is not a accurate as the Richter scale if information on environemtnal damage is needed then you use the MS. However, if you want the magnitude of the earthquake to compare it to other EQ, you use the RS i hope that helps you

Answer 3

The Richter scale gives the energy released during earthquakes.The shaking is in ten fold and the energy released is in 32 fold.The unit of measurement will not vary from place to place for a same earthquake. The seismographic instrument is used to measure the Richter scale. It is an open ended scale. There is no upper limit for it. But so far we have experienced only up to 9.5 on Richter scale. Mercalli scale needs no instrument to measure. It gives you the meaning full intensity of earthquake.The upper limit is XII. This is decided by the observation of people living in those places and news papers report.so it will vary from place to place for the same earthquake If possible please visit my web. You will be able to see the details
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