Estimation of parameters of the flows forming sediment waves on the western slope of the middle caspian sea

By means of mathematical modeling, the parameters of flows forming sedimentary waves on the western slope of the Derbent basin were estimated. The height of these flows depends on the slope steepness and varies from 25 to 170 m to reach its maximum values at gentler slope areas. However, the flow rate is independent of the slope steepness and depends only on the concentration of sediment matter supplied by the flow. At the upper part of the slope (the flow starting), the rate amounts to 0.4–1.4 m/s, being almost halved at the depths where the sedimentary waves are damped. The present rates of near-bottom currents show pronounced seasonal differences, and their values are close to flow rates obtained by numerical modeling.     

Expected geological and geomorphological risks along the Northern Sea Route

Degradation of the underwater multiyear permafrost rocks (UMPR) together with intensification of thermal abrasion processes in the coasts are global risks on a planetary scale. Changes in the physical properties of sediments can occur after degradation of the UMPR and can lead to unpredictable consequences especially in the regions of technical development. Drifting ice bottom exaration (ice plucking of bottom sediments), which is increasing based on the data of recent expeditions, is no less dangerous. These processes are hazardous for practically all types of activity.