Data for: Permafrost and Structural Controls on Holocene Bedrock Landslide Occurrence in Northern Iceland

Document Type

Dataset

Publication Date

2024

Abstract

Rapid, transient, landscape-scale changes associated with deglaciation can condition slopes for failure and trigger bedrock landslides. However, the mechanisms leading to paleo rock slope failures following the last glacial period are challenging to infer because observations of how both landsliding and potential driving factors were distributed in space and time are limited. Here, we map and analyze the spatiotemporal pattern of 676 post-glacial bedrock landslides in north-central Iceland using 2-m resolution digital elevation data generated from optical stereo satellite imagery. Frequency-ratio analysis demonstrates that after controlling for slope, landslides are significantly overrepresented near major Tertiary bedrock structures and at land surface elevations similar to or lower than those of a modeled lower limit to permafrost. Surface roughness analysis of landslide deposits, made possible by the high-resolution topographic data, indicates that peak landslide frequency of at least 0.2 landslides yr-1 in the 5579 km2 study area lagged deglaciation by several thousand years. This timing aligns well with that of rapid permafrost degradation from the Younger Dryas (12.9-11.7 cal ky BP) through the Holocene Thermal Maximum (~10-7 cal ky BP). Landslide frequency has averaged about 0.014 yr-1 since the Holocene Thermal Maximum when climate has generally been cooler and permafrost more extensive. However, present day warming is likely reducing permafrost extent and increasing the potential for bedrock landslides in north-central Iceland, as has already been observed for several recent shallower landslides in regolith.

Description

This data set is a landslide inventory analyzed for a manuscript in review for Journal of Geophysical Research-Earth Surface. The file berghlaup_amb.zip contains two ArcGIS shapefiles: one of landslide head scarp polygons (scarps_amb.shp and associated files) and the other of landslide deposits (deposits_amb.shp and associated files). Each shapefile has an attribute table with the following ancillary data for each landslide:

FID: Unique identifier.

Shape: All are polygon.

Confidence: high, medium, or low as described in manuscript.

Type: scarp or deposit.

Notes: AMB’s unstructured comments on interesting or unusual characteristics relevant to the interpretation of the mapped features.

reactivate: y if feature is a reactivation of a previous landslide.

long_ridge: y if deposit has clear longitudinal ridges.

truncated: y if downslope extent of deposit appears truncated.

POLY_AREA: area of polygon in square meters.

CENTROID_X: x-coordinate of center of polygon in WGS 1984 Complex UTM Zone 27N coordinate system.

CENTROID_Y: y-coordinate of center of polygon in WGS 1984 Complex UTM Zone 27N coordinate system.

Rights

This work is marked with CC0 1.0 Universal

DOI

10.15760/geology-data.07

Persistent Identifier

https://archives.pdx.edu/ds/psu/42643

berghlaup_amb.zip (485 kB)
16 data files

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