Climate-induced landsliding within the larch dominant permafrost zone of central Siberia

Abstract

Climate impact on landslide occurrence and spatial patterns were analyzed within the larch-dominant communities associated with continuous permafrost areas of Central Siberia. We used high resolution satellite imagery (i.e. QuickBird, WorldView) to identify landslide scars over an area of 62000 km. Landslide occurrence was analyzed with respect to climate variables (air temperature, precipitation, drought index SPEI), and GRACE satellite derived equivalent of water thickness anomalies (EWTA). Landslides were found only on southward facing slopes, and the occurrence of landslides increased exponentially with increasing slope steepness. Lengths of landslides correlated positively with slope steepness. The observed upper elevation limit of landslides tended to coincide with the tree line. Observations revealed landslides occurrence was also found to be strongly correlated with August precipitation (r = 0.81) and drought index (r = 0.7), with June-July-August soil water anomalies (i.e., EWTA, r = 0.68-0.7), and number of thawing days (i.e., a number of days with t > 0°C; r = 0.67). A significant increase in the variance of soil water anomalies was observed, indicating that occurrence of landslides may increase even with a stable mean precipitation level. The key-findings of this study are (1) landslides occurrence increased within the permafrost zone of Central Siberia in the beginning of the 21st century; (2) the main cause of increased landslides occurrence are extremes in precipitation and soil water anomalies; and (3) landslides occurrence are strongly dependent on relief features such as southward facing steep slopes.

Monitoring the Degradation of Island Permafrost Using Time-Series InSAR Technique: A Case Study of Heihe, China

“…The surface deformation caused by island permafrost degradation is localized, which is different from the surface deformation (usually the overall uplift or subsidence) caused by permafrost degradation. Additionally, the degradation of island permafrost has a great impact on the local environment, leading to phenomena such as landslides [3], solifluction, and partial expressway collapse and destruction. With the increase of construction projects, understanding the distribution of surface deformation in the island permafrost area is the key to disaster warning and prevention.…”

Permafrost landslides promote soil CO2 emission and hinder C accumulation

“…In the beginning of XXI century, one another driver become essential to provoke permafrost degradation. These are landslide processes (e.g., solifluctions) which are increased its occurrence in permafrost zone of central Siberia (Abaimov et al, 2002, Geertsema and Schwab 2004, Kharuk et al 2016, and mostly attributed to south-exposed river slopes (Prokushkin et al 2010). Landslide are more disturbing factor for forest ecosystem and permafrost than wildfires or clear-cuttings since solifluction eliminates entire ecosystem including vegetation and productive soil (Shishov et al 1999;Prokushkin et al 2010) and radically alter wildlife habitat.…”

“…Soil landslides usually occur on the thickest soil active layer (e.g., south and west slopes), and can be provoked by biotic (pathogen and insects outbreaks) and abiotic disturbance (wildfires, logging) agents or local climate anomalies such as overwetting of seasonally thawed layer due to climate change (as a result of combination of high air and soil temperatures and excessive precipitation in summer, or intensive nival thawing) (Kharuk et al 2016). Thus, new ecosystem succession starts on parent material.…”

“…So, during the landslide event, an active layer of soil (together with vegetation) slides down on a rupture surface of permafrost and can be accumulated at river terraces (coastal sediments), and in that way soil carbon can be preserved or stabilized over long time period. Last decades, the formation and consequences of landslides, as well as soil-vegetation regeneration patterns in high latitudes are attracting little attention, though an increasing regularity of landslides in permafrost areas is one of the challenging concerns of global change (Bugaenko et al 2005;Prokushkin et al 2010;Kharuk et al 2016). For example in 2001, within 100 kilometers along the middle stream of Nizhnyaya Tunguska River (Siberia) 72 solifluction areas were observed (Abaimov et al, 2002).…”

“…For the period of 2000-2012, Kharuk et al (2016) found 145 landslides at the territory of 62000 km 2 located just on the north of Tura with using analysis of satellite imagery. In British Columbia a half of all watersheds located at NE part is covered by landslides (Swanson et al 1992).…”