Eye-safe photon counting LIDAR for magmatic aerosol detection

Abstract An eye-safe photon counting light detection and ranging (LIDAR) instrument has been developed for magmatic aerosol sensing in real time. The developed LIDAR was based on a pulsed diode laser (transmitter, 910 nm, 3 ns, <1 µ J cm −2 ) and a single-photon avalanche photodiode. The instrument was designed to fit the requirements of highly sensitive sensing of aerosol dynamics at distances up to 50 meters. The accuracy of the LIDAR instrument ranging was estimated as 18 cm. Field experiments inside the Baksan Neutrino Observatory tunnel above the volcano Elbrus chamber revealed a good correlation between the magmatic aerosol dynamics and the Earth’s crust deformation due to Moon and Sun tides quantified by a tiltmeter and a laser strainmeter.