Home – Home – Jornals – Geography and Natural Resources 2022 number 3

A combined analysis is made of the structure of the St. Petersburg mud volcano and the lake bottom surface surrounding it by using bathymetric, seismoacoustic, backscatter and water column data. A high-precision digital elevation model with a horizontal resolution of up to 10 meters was developed for the bottom surface in the area of the volcano. By analyzing the resulting model, it was possible to update the morphometric parameters of the underwater structure under consideration and prepare its detailed morphological description. It was found that the volcanic edifice consists of several ridge-like parts located on the wings of the Gidratnyi Fault and crossing it. A canyon-shaped and curved in plan 800-m wide valley was mapped to the south-east of the fault. A graphical representation of backscatter data with separation by types of sedimentary layers was created via comparison of the intensity of the reflected signal and expected mathematical model values. Based on the results of the data analysis, it was established that the mud volcano largely consists of clay with the possible inclusion of relatively large fragments (up to 10 cm). On the bottom surface around the volcano there presumably are also large fragments; however, fine-grained fractions (sandy, clays and silts) are dominant. A three-dimensional visualization of the water column data is presented for the study area with outcrops of gas in the form of two the detected gas flares with the observed heights of 800 and 700 meters. According to a statistical sample of the values of the reflected signal amplitudes, the intensity of gas release in the flares differs by approximately 7 times. The seismoacoustic data of the chirp profiler indicate the possible presence of gas hydrates.