The zones of glacially induced faults in Finland are portrayed by a number of discrete <10 km-long fault scarps, often forming multiple parallel segments and establishing longer glacially induced fault systems. A set of glacially induced fault systems further form glacially induced fault complexes, which may extend tens of kilometres cross-cutting glacial sediments. The systematic mapping has revealed 18 glacially induced fault systems forming 9 glacially induced fault complexes. The moment magnitude estimates for the earthquakes in Finnish Lapland are in the range of Mw ≈ 4.9–7.5. The detailed trenching across fault scarps provides evidence of non-stationary seismicity and occurrence of multiple slip events even before the Late Weichselian maximum.

This chapter summarizes the book with a focus on the future of glacially triggered faulting research. The concept of glacially triggered faulting is challenged by new results from Fennoscandia documenting several episodes of fault rupture within the past 14,000 years. We speculate that some of these ruptures at known (or potential) glacially induced faults may not be due to glacially triggered faulting but may contain a signature of tectonically driven intraplate seismicity. Glacially triggered faulting cannot be totally ignored though for these episodes, since the ongoing rebound of the lithosphere is continuously increasing glacially induced stresses that can eventually be released under favourable conditions. As those conditions can only be described by a complex 4-dimensional model, simple identification of glacially induced faults is hampered. Precise dating of the younger fault ruptures is especially important to produce the necessary spatiotemporal image. The intended DAFNE drilling and subsequent in situ observations of the Pärvie Fault combined with numerical modelling will contribute to an improved understanding of the fault mechanism.

Despite early studies indicating fault rupture both before and after deglaciation, it has long been hypothesized that glacially induced faults in Fennoscandia ruptured only once. The now widespread availability of high-resolution digital elevation models allows for testing this hypothesis by examining cross-cutting relationships between the scarps and both glacial and postglacial landforms. Although not widespread, such cross-cutting relationships indicate that segments of the Merasjärvi, Lainio and Pärvie faults have ruptured at least twice. The timing of the Merasjärvi ruptures is unknown; the Lainio ruptures occurred both before and after deglaciation, and at least one of the Pärvie ruptures is postglacial.

Additionally, it can be demonstrated that parallel segments of the Pärvie and Lansjärv faults ruptured at different times despite being only a few kilometres from each other. Given these results, the single rupture hypothesis must be reassessed for the high-relief scarps in northern Sweden, but it may still hold true for some of the low-relief scarps.

Glacially triggered faulting, also called glacially induced faulting or postglacial faulting, describes fault movement caused by a combination of tectonic and glacially induced isostatic stresses. Stresses induced by the advance and retreat of an ice sheet are thought to be released during or after ice melting and reactivate pre-existing faults. The most impressive fault scarps that witness such activity, are found in Northern Europe. It was assumed these features are unique. This view has changed recently as new faults were discovered – even outside the former glaciated area – and fault activity dating showed several phases of reactivation thousands of years after deglaciation ended. This book summarizes the research until the very recent findings. It reviews the theoretic aspects, i.e. the knowledge to understand the presence of glacially induced fault structures, followed by an overview of geological, geophysical, geodetic and geomorphological investigations methods, a summary of all known glacially induced faults worldwide and an outline for modelling of these stresses and faults.