Volcanic activity monitoring by unique LIDAR based on a diode laser

Abstract

For the first time, we monitored the Elbrus volcano activity detecting volcanic gases emanating through pores using an unique eye-safe LIDAR system. A highly sensitive eye-safe LIDAR system was developed for monitoring the fracture-emitted aerosol, which is transported by volcanic gases inside a hot tunnel near the Elbrus Mountain. The developed LIDAR is based on a diode laser (transmitter, 910 nm, 3 ns, <1 µJ cm−2) and a single-photon avalanche photodiode (detector). From August to October 2019, within the first months of the LIDAR monitoring, we have detected a two-fold decrease in the fracture-emitted aerosol emanation, while other parameters in the tunnel remained relatively stable (radon concentration, air temperature and humidity changed less than by 1%). A significant correlation between the LIDAR signal of volcanic aerosol and the Earth’s crust deformation measured by the laser strainmeter located nearby was found. Based on our preliminary experiments we consider the new LIDAR system as a sensitive, economical and robust instrument for Earth’s crust deformation and volcanic activity monitoring and eruption precursor observation.