Glacially induced fault identification with LiDAR, based on examples from Finland

Using information from airborne light detection and ranging (LiDAR) data has produced a breakthrough in identification of postglacial faults and earthquake-deformed Quaternary deposits. LiDAR digital elevation models (DEMs) also improve the collection of detailed information on their spatial distribution, characteristics and geometry, and provides guidance for the more costly and time-consuming field studies. In areas of weak glacial erosion, younger and older (i.e. Pre-Late Weichselian) ruptures have been discovered superimposed on the same or adjacent postglacial fault segments, as has been identified when combining the DEM information and test pit sedimentological studies. We discuss Finnish examples and identify advantages, disadvantages and limitations. Advantages include verification of previously known fault scarps, detection of new postglacial fault segments, systems and entire complexes and the ability to measure the dimensions (lengths and offset) of the fault scarps from the LiDAR DEM data. Disadvantages include that inventory of the sub- and postglacial fault scarps is only possible when linear scarps cross-cut glacial and postglacial sediments.