Contemprorary State of the Elbrus Volcanic Center (the Northern Caucasus).

The Elbrus volcanic center is located on the northern slope of the main ridge of the Greater Caucasus. It includes Mount Elbrus, a double-top stratovolcano, and a number of small volcanoes concentrated on its western and eastern flanks. According to present understanding, the Elbrus volcano falls into the category of the so-called dormant volcanoes that become reactivated. It is a typical volcano of a continental type.

Analysis of lithosphere deformations recorded by the wide-band Baksan laser interferometer-strainmeter with a 75-m armlength which is installed in the vicinity of the Elbrus volcanic center, has allowed to develop the effective method to control the state of the Elbrus volcano. The method is based on evaluation of parameters of resonant modes, “reemitted” by the resonant structure (the volcanic chamber) in response to the excitation of the seismic impact from a sufficiently powerful earthquake.

Another method used to study the state of the Elbrus volcanic center based on low-frequency microseismic sounding. This method allows to determine the deep structure of complicated geological objects on the base of monitoring the background microseismic field.

The complex geological-geophysical study has identified several magmatic structures related to the Elbrus volcanic center. Directly under the Elbrus edifice there are a shallow magma chamber with a characteristic size of about 9 km and containing gas-saturated (30-70%) magmatic fluid, and a magma source which is located at depths of 30-40 km. 40 km east apart from the mount Elbrus it was discovered a hidden large magma apparatus, containing the magma chamber and the magmatic source, is comparable to the apparatus of Elbrus, but significantly colder at the present time. Finally 20 km south-east apart from the mount Elbrus, it was found one more shallow camera  of a small size (2-3 km), containing also gas-saturated magma.

Currently the Elbrus volcano is in a phase of a deep “seismic lull”, which may be due to the local extension of the lithosphere in a volcanic area. The extension reduces seismic activity and increases volcanic one, opening channels for the receipt of mantle material. In this regard, we can assume that Elbrus is in a state of intensified magmatic processes.