Monitoring magmatic activity of the elbrus volcanic center’s small chamber utilizing an aerosol lidar

We present the results of magmatic aerosol concentration monitoring carried out utilizing an aerosol lidar. The monitoring was performed in a hot dead-end tunnel of the Baksan Neutrino Observatory (BNO) of the Institute for Nuclear Research located above the Elbrus volcanic center’s small magma chamber. An abrupt 3-fold increase of the aerosol concentration was detected by the lidar on October 28, 2019, 22: 30 UTC in the hot tunnel of BNO. The lidar data were analyzed along with the data of radon volume radioactivity, air temperature and relative humidity sensors. Synchronous changes in the air temperature, relative humidity and aerosol concentration have been observed, as well as the correlation of these signals with Earth’s crust deformation measured by a strainmeter installed in BNO. However, neither one of these signals reflected the detected 3-fold aerosol concentration growth. The acquired data confirms the existence of a hot magma chamber found earlier under the Andyrchi mountain by the small-aperture seismometer group. A possible explanation of the 3-fold aerosol concentration growth is discussed: emanation of gases from the magma chamber could trigger this growth without influencing other measured parameters.