Displacement measurements of three slow moving landslides at Almenningar, north Iceland. A feature tracking application.

In 1968 the Siglufjarðarvegur road was built in north Iceland, serving as the only whole year road connecting the remote town of Siglufjörður with the capital city of Reykjavík. This road cuts through the area of Almenningar where three active slow moving landslides are situated, these are the Tjarnadalir, Þúfnavellir and Hraun landslides. The constant activity of these landslides affect a 5-6 km long stretch of the road that has been a problem both for the road authorities as well as travellers in terms of safety and maintenance. All three landslides have been mapped and studied before and the northernmost area of Tjarnadalir has gained the most attention as rate of movement is considered to be up to 1 m/yr for some periods. This is also the case for the southernmost Hraun landslide (0.83 m/yr) but the Þúfnavellir landslide in the middle is moving much slower with an estimated rate of 0.17 m/yr. The movement rate is constant with shorter periods of increased activity and there is strong evidence that the rate of movement is directly linked with weather patterns as more water in the landslide systems seems to cause increased activity. Ever since the year 1977, the road authorities have conducted GPS displacement measurements on a yearly basis with a limited number of points that are all situated along the road. Little is known about the different movement rates within the landslide bodies themselves but this study extends these displacement measurements through the application of remote sensing. Aerial photogrammetry comparison will be conducted with the feature tracking method in order to estimate the rate of movement throughout the entirity of all three landslide bodies. Available data extends back to the year 1954 to present day, giving an unprecedented insight into the temporal and spatial dynamics of the landslides.