Home – Home – Jornals – Russian Geology and Geophysics 2023 number 2

A river seismic survey technology based on using pneumatic water sources and autonomous seismic recorders, which are installed on the shore and configured for continuous seismic recording, is developed at the Geophysical Survey of the Russian Academy of Sciences (GS RAS). In recent years, several thousand kilometers of profiles have been worked out by the CDP-2D method on the rivers of East Siberia: Lena, Nizhnyaya Tunguska, and Vitim. Previously, only 6- to 10-second seismograms were used to study the structure of the upper part of the Earth’s crust. At the same time, the deep structure of the Earth’s crust in the vast territories of East Siberia remains poorly understood due to the high cost of research. The river seismic survey data are used on a profile section worked out in the lower reaches of the Lena River to demonstrate the possibility of studying the structure of the Earth’s crust to the full depth, including the Moho discontinuity. For this purpose, the archival seismic records are reprocessed the construction of montages of seismograms of increased duration (up to 23 s). The low-amplitude oscillations of reflected waves from deep boundaries are distinguished due to multiple summation, which is much larger than in conventional seismic surveys. The equipment used in this study has a sufficient dynamic range, and a high magnification is achieved by increasing the binning area. Wind noise reduces the quality of time sections of the upper part of the Earth’s crust, but does not worsen the section at great depths, so this material should not be excluded from processing. The river seismic surveys carried out using the technology developed at the GS RAS on the rivers of East Siberia within about 2700 km contain data that make it possible to build deep sections up to the Moho discontinuity, and this work needs to be done.