Studying earthquakes

To record, measure, determine the strength and location of earthquakes, scientists use a recording instrument called the seismograph. It is equipped with many sensors called seismometres. These seismometres are able to detect ground motions caused by seismic waves from earthquakes.

Seismologists measure seismic ground movements in three directions: the up-down, the north-south and the east-west directions.

A seismograph produces wavy lines that reflect the size of seismic waves passing in the ground beneath it. The record of the wave, known as a seismogram, is imprinted on paper, film or recording tape or is stored and displayed by computers. Every increase of one number in magnitude means the energy release is 32 times greater.

The most well-known gauge of earthquake intensities is the Richter Magnitude Scale, developed in 1935 by a United States seismologist Charles F. Richter. All earthquakes of various magnitudes are recorded on the Richter Scale. However, earthquakes with magnitudes greater then 7.0 are commonly recorded on the Moment Magnitude Scale, which provides more accurate descriptions.

Earthquakes are located by measuring the time it takes for body waves to arrive at the seismographs from 3 different locations. From these times, the distance of an earthquake from each seismograph can be calculated. From there, seismologists are able to pinpoint the earthquake’s focus.

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