KERALA PSC / PHYSICAL GEOGRAPHY / RITCHER SCALE &
SEISMOGRAPH / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE
KERALA PSC / PHYSICAL GEOGRAPHY / RITCHER SCALE & SEISMOGRAPH / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE
·
An
earthquake is measured by its Magnitude and Intensity.
·
Magnitude
is a measure of the strength of the earthquake at its source (focus). It is
assessed in Richter Scale.
·
Seismometers
are instruments that measure motions of the ground, including those of seismic
waves generated by earthquakes, nuclear explosions, and other seismic sources.
It is also used to measure the strength (intensity) and location of
earthquakes.
·
Richter
Magnitude Scale was developed in 1935 by Charles F Richter of the California
Institute of Technology as a mathematical device to compare the size of
earthquakes. The magnitude of an earthquake is determined from the logarithm of
the amplitude of waves recorded by seismographs
·
On
the Richter Scale, magnitude is expressed in whole numbers and decimal fractions.
The Richter magnitudes are based on a logarithmic scale (base 10). What this
means is that for each whole number you go up on the Richter scale, the
amplitude of the ground motion recorded by a seismograph goes up ten times.
·
The
Richter Scale has no upper limit. Recently, another scale called the Moment Magnitude
Scale has been devised for more precise study of great earthquakes.
·
Earthquakes
with magnitude of about 2.0 or less are usually called micro earthquakes; they
are not commonly felt by people. A magnitude 5.3 might be computed for a
moderate earthquake, and a strong earthquake might be rated as magnitude 6.3.
The magnitude ranging ‘7’ is severe and magnitude ranging ‘8’ is devastating.
KERALA PSC / PHYSICAL GEOGRAPHY / RITCHER SCALE & SEISMOGRAPH / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE
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