Earthquake measuring instrument (Seismograph and Seismogram). Understand difference between Seismograph and Seismogram.

[Seismograph and Seismogram]

If you want to know that how earthquake is measured then, In this Article I am going to tell about the Earthquake measuring Instruments(Seismograph, seismogram, accelerographs) used for recording the Earthquake and seismic waves.

Seismograph and accelerographs is a instrument mostly used for recording the motion of earth while occurring of earthquake and seismogram is way of presenting the collected data from seismograph.

Seismograph:- 

This is very sensitive instrument used to record the motion of ground and arrival and transmission of several kinds of seismic waves releases during the earthquake. Seismographs records different seismic vibrations and surface displacements. 

Seismograph prepare and present chart on the basis of record of motion of ground, seismic waves etc. and this presentation is called seismogram.

Now lets understand the working principle of Seismograph:- 

 Components of seismograph are listed below:-

1) Sensor

2) Timer

3) Pendulum mass with attached Pen

4) Magnet

5) Chart paper

6) Recording drum

Sensor is used to sense the the seismic vibrations. pendulum is supported by horizontal beam and vertical support and string position is maintained with the help of magnet so that is won't deflect from its position. The timer represent the motor that rotates the drum which is wrapped by chart paper at a constant speed.

As you can see in above picture, A seismograph with its vertical support is fixed in ground and a string is attached to the horizontal beam and a pen is also attached to the tip of the string. Whenever there will be any kind of vibration on the earth surface the vertical support and the rotating drum, being rigidly fixed on the ground move simultaneously. The pendulum bob tied to the horizontal beam record the vibrations, which swings freely against the vertical support.

Magnet basically control the amplitude of oscillation and the pen records the horizontal component of vibration on chart paper.

One such instrument is also required in orthogonal direction( Perpendicular to previous direction) to measure the vertical oscillation. For recording the vertical component of seismic vibrations, the string pendulum is replaced with a spring pendulum.

Seismograph is suitable to record the feeble and weak vibrations, for recoding strong vibrations of high intensity accelerographs is used.

Seismogram:-

The records of seismic vibrations prepared and presented by earthquake measuring instrument like seismographs and accelerographs are called 'seismograms'. In a seismogram, the seismic waves are recorded in the order in which they arrive at the recording station. 

As you can see in below graph P and S waves( Body waves) are the first to be recorded whereas surface waves travel slowly and reach at the last. Surface wave like love and Rayleigh waves are the slowest to travel and last to be recorded and these surface waves are responsible for most of the destruction occur at earth surface. 

P waves are the fastest to travel therefore they arrive earliest among all waves. S waves are the second  waves to get recorded at the station

• Tweet
• Share
• Share
• Share
• Share

About Admin MC3

This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.

Related Post