Portable Infrasound Monitoring Device with Multiple MEMS Pressure Sensors
* Presenting author
MEMS sensors are mass-product and therefore expected to be available to produce a low cost device for infrasound monitoring. A low cost device is useful in constructing a sensor network with various scales from a small to large number of sensors. To test its feasibility, we developed a device consisting of 32 MEMS pressure sensors. A laboratory experiment showed that internal noise increases as signal frequency goes high but the noise can be reduced by simple averaging. Based on this fact, we stacked eight MEMS pressure sensors on a single board to assemble an infrasound monitoring device which enable to detect a signal with amplitude of more than approximately 5 Pa. A field test was carried out, deploying them in the surrounding area of an active volcano, Sakurajima in Japan. Signals associated with explosive eruptions were clearly observed in the frequency region between 0.1 Hz to 5 Hz. The source position was also estimated using the signals observed at four different points. The estimated source position showed in general a good agreement with that of the crater of the volcano. It was also implied that signals around the acoustic cut-off frequency can also be observed.