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Earthquake detectors
for long-wave seismic motion

Earthquake detectors for long-wave seismic motion
Earthquake detectors for long-wave seismic motion

The “Earthquake detector” for long-wave seismic motion uses an electrostatic capacity acceleration sensor, the same as in cars, produced with semiconductor micromachining technology. This system is able to detect ground oscillation, even the longer vibration cycles (long-period seismic motion).

Long-period seismic motion is an unusual slow swaying that lasts between a few and 20 seconds. Since oil tanks and high-rise buildings etc. resonate with seismic motion, stronger swaying may cause serious damages. An “Earthquake detector” that can detect such long-period seismic motion can contribute to the prevention of earthquake damage for oil tanks, highways, railway bridges of great length, and elevators of super high-rise buildings etc.

This system will give an alarm through a buzzer or light on the display/control unit and send out a contact signal to an external device, when the long-wave SI value, occurring through arithmetic procession of seismic acceleration waveforms during earthquakes, or the acceleration value exceed the preset threshold.


  1. Usage of accelerometers that have achieved good results in automobiles(high quality, high reliability)
  2. By using the CAN Protocol for sending data the system is strong against noise, thus long cables can be used
  3. Wiring simplification by using the CAN system
  4. The oscillation detection system consists of 2 lines, thus reliability is enhanced by mutual monitoring
  5. Able to connect with a PC, change set values, display in real-time, and collect waveform data
  6. Prevention of false alarms that are not earthquakes through a shock oscillation distinction logic


Item Specifications
Oscillation detection axes 2 axes in horizontal direction
Acceleration sensor
Measurement limits: 2000gal
Voltage sensitivity:1mV/gal
Response frequency: DC ~ 30Hz (-3dB)
Data transmission method CAN (Controller Area Network)
Earthquake waveform recording 5 times the data of a 5min period. Format of recorded data: CSV format
Date function Internal clock: hours/minutes/seconds/month/day/year
Input and output Non-voltage contact signal (each 1 piece)
Power supply AC 100V ±10% 50/60Hz *system drive is DC12V
Operating temperature limits -10~50℃
Dimensions (not including terminal)
Sensor unit: 140x82.2x100 (WxHxD mm), approx. 1.1kg
Body unit: 410x90x75 (WxHxD mm), approx. 2.2kg
Display & Control Unit: 445x75x50 (WxHxD mm), approx. 1.1kg

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