The collapse and landslip processes activation within Magadan region in 21st century
Many new rockfalls, landslides and mudflows have been registered and studied by virtue of field and remote sensing methods, and using the Google Earth and SASPlanet systems in the territory of Magadan Region since the beginning of the 21st century. Slope destruction processes are reported as becoming more intense and much hazardous for the city and road infrastructures. All registered rockfalls and landslides are distinguished by their geology and geomorphology into the following types: 1a - sea coastal sequences non-resistant to sea wave’s action; 1b - sea cliffs; 2a - industrially modified slopes not subject to abrasive processes; 2b - non-industrial slopes not subject to abrasive processes. By their character, all gravitational deformations are classified as abrasive-cryogenic, cryogenic, also those caused by excessive wetting in spring and summer time, and industrial and seismic ones. Since 2002 through 2016, major coastal rockfall and landslide events reveal the following seasonal distribution: 62,5 %, 25 % and 12,5 % in fall, spring and summer time respectively (many frequent small landslides caused by heavy showers in 2014 and seismic rock falls in 2009 are not included). Proceeding from this, we can conclude that major slope processes are basically caused by seasonal freeze-and-thawing processes within the upper layers of coastal slopes, the results of which are repeated changes in slope’s size in spring and fall seasons, when soil temperatures often come from below to above zero values and vice-versa. The author presents his hypothesis to explain the drastic intensification of slope and coastal processes as due to climate warming effects. The author has made an assessment of existing shore consolidation projects for Nagaeva Bay and proposes an alternative project of an all-round protection of coastal areas and industrial facilities from slope destruction processes.