The Role of Interannual Climate Variability in Controlling Solifluction Processes, Endalen, Svalbard

ABSTRACTA continuous record is presented of active layer processes at Endalen, Svalbard, over the period 2005–08. The monitored slope has a gradient of around 7° and in 2005, active layer depth was 94 cm, but this increased by around 14 cm over the next three years. The presence of an ice‐rich transient layer proved highly significant in determining the timing and profiles of solifluction movement. Frost heaving was 4.2 cm in 2005–06, 6.6 cm in 2006–07 and 3.2 cm in 2007–08, but thaw settlement exceeded frost heave in each year, giving a net total ground surface lowering of 6.2 cm. In winter, segregation ice was concentrated within the upper and lower active layer, leaving the central parts ice‐poor. During the summers of 2006 and 2008, thawing of the transient layer was associated with artesian pore pressures at 90 cm depth and basal soil shearing, but in 2007, when the thaw front failed to reach the ice rich basal zone, pore pressures during thaw were sub‐hydrostatic and no basal shearing was observed. Solifluction shear strain during thaw settlement resulted in downslope surface displacements of 2.3 cm in 2005–06, 1.2 cm in 2006–07 and 1 cm in 2007–08. Copyright © 2011 John Wiley & Sons, Ltd.