Plant Equipment Volcanic and Geothermal area Seabed On the sea

Seismic monitoring system for harsh environment (No semiconductor devices in sensors)

Optical sensor seismic monitoring systemby phase-shifted optical interferometry

Seismic observation in harsh environments

High-precision seismic observation is possible under the harsh environment, places where power cannot be supplied, high temperature where electronic devices do not operate and oil and gas field where explosion proof devices are required.


The phase-shifted optical interferometry enables highly accurate* seismic observation without power supply to the sensor.

Optical circuit

* In a comparison of microtremor observation conducted in a quiet place, the same high sensitivity and low noise as the electric broadband seismometer were confirmed.

Phase-shifted optical interferometry

Optical interferometer can measure a very small distance change. However usual interferometer has only a half (1/2) wavelength of measurement range. Our patented phase shifted optical interferometer extends the range of up to thousands of wavelengths.

Observation results