Terminology » Measurements » Seismic Sensors for Earthquake Detection

Seismic Sensors for Earthquake Detection

seismic sensor
earthquake detector
sensor
measurement
transducer

This page describes the basic workings of a seismic sensor used in an earthquake detector.

The seismic sensor, or earthquake detector, is used as an alarm for forecasting earthquake disasters. It operates by incorporating one of the following types of transducers:

  • Resistive
  • Capacitive
  • Piezoelectric
  • Optical (i.e., interferometers, encoders)
  • Inductive (combination of coil and magnet)
  • Eddy current based
  • LVDT (Linear Variable Differential Transformer)

Based on the output voltage’s dependability, seismic sensors are classified as follows:

  • Displacement
  • Velocity (Geophones, feedback geophones known as seismometers)
  • Acceleration (Accelerometers, Force Balanced Accelerometers)

seismic sensor in earthquake detector

The following specifications are considered for seismic sensors:

  • Velocity Output Bandwidth in Hz
  • Velocity Output Sensitivity in V/m/s
  • Peak Output
  • Lowest Spurious Resonance in Hz
  • Linearity in dB
  • Cross Axis Rejection in dB
  • Electronic Noise Level
  • Dynamic Range - Max/Min measurable value
  • Active/Passive Type (i.e., whether it needs a power supply or not)

Seismic sensors are widely used as earthquake detectors, as depicted in the figure above.

Understanding Sensor Sensitivity

Sensor sensitivity determines how well a sensor responds to changes in the quantity it's measuring. It impacts the resolution and precision of measurements.

sensor
sensitivity
measurement