# Seismic Transducer

Definition: The seismic transducer is used for measuring the vibration of the ground. The spring mass damper element and the displacement transducer are the two main component of the seismic transducer.

The mass that connected to the damper element and spring without any other support is known as spring mass damper element. And the displacement transducer converts the displacement into the electrical quantity. The seismic transducer is used for measuring the earth vibration, volcanic eruption and other vibrations etc.

## Construction of Seismic Transducer

The systematic diagram of the seismic transducer is shown in the figure below. The mass is connected by the help of the damper and spring to the housing. The housing frame is connected to the source whose vibrations need to be measured.

The arrangement is kept in such a way so that the position of the mass remains same in the space. Such type of arrangement is kept for causing the relative motion between the housing frame and the mass. The term relative motion means one of the objects remains stationary, and the other is in motion concerning the first one. The displacement that occurs between the two is sensed and represented by the transducer.

### Mode of Transducer

The seismic transducer works in two different modes.

• Displacement Mode
• Acceleration Mode

The selection of the mode depends on the combinations of the mass, spring and damper combinations. The large mass and soft spring are used for the displacement mode measurement while the combination of the small mass and stiff spring is used for the acceleration mode.

## Types of Seismic Transducer

Vibrometer and the accelerometer are the two type of the seismic transducer.

1. Vibrometer – The vibrometer or low-frequency meter is used for measuring the displacement of the body. It also measures the high frequency of the vibrating body. Their frequency range depends on the natural frequency and the damping system.

2. Accelerometer – The accelerometer measures the acceleration of the measuring body. The acceleration shows the total force acting on the object.