Principle of Design of Seismometer:

This instrument is utilized to measure the displacement. Letting expression of 'Z' given in Equation (8), if

 ω/ω_n >> 1

It means the seismometer contain very low natural frequency so that this condition is truthfully followed for operating lower value of ω. Generally the value of 'ω' is greater than '2.5 ω_n'. This is evident from the Figure 4 that the range of frequency for displacement 'y' might be approximated by 'z' is maximum for j = 0.707. Hence, in definite transducer also damping factor is kept close this value. In order to convince the essential condition the natural frequency must be very low, therefore mass must be fairly heavy and springs must be of very low stiffness. Hence, seismometer is a heavy transducer and might cause loading of the system whose displacement is to be determined. Because of this cause seismometer is not utilized mechanical applications.