Geological investigations in the last decade increased the number of locations with evidence or indications for glacially triggered faulting in northern central and northeastern Europe, i.e. in the countries of Denmark, Germany, Poland, Belarus, Lithuania, Latvia, Estonia and parts of western Russia. These locations are at the periphery, the edge or even outside of the former ice margin. They are summarized in the following sections.

Geophysical methods have the potential to delineate and map the geometry of glacially induced faults (GIFs) in the hard rock environment of the Baltic Shield. Relevant geophysical methods include seismic, geoelectric, electromagnetic, magnetic and gravity ones. However, seismic methods have the greatest potential for determining the geometry at depth due to their higher resolving power. Seismic methods have even been used to identify a previously unknown GIF within the Pärvie Fault system. The other geophysical methods are usually employed to image the near-surface structure of GIFs. We provide a brief review of geophysical principles and how they apply to imaging of GIFs in the hard rock environment. The advantages and challenges associated with various geophysical methods are discussed through several case histories. Results to date show that it is possible to map GIFs dipping at 35–65° from the near-surface down to depths of 7–8 km. It is not clear if the limiting factor in their mapping at depth is the nature of the faults or the limitations in the seismic acquisition parameters since the mapping capacity is highly dependent upon the acquisition geometry and source type used.

Recent studies have shown that the low seismicity of northern Germany is characterized by fault activity caused by the decay of the Late Pleistocene (Weichselian) ice sheet. Several faults and fault systems show evidence of neotectonic activity, all of which are oriented parallel to the margin of the Pleistocene ice sheets. The timing of fault movements implies that the seismicity in northern Germany is likely induced by varying lithospheric stress conditions related to glacial isostatic adjustment, and the faults thus can be classified as glacially induced faults. For the Osning, Harz Boundary and Schaabe faults, this is supported by numerical simulation of glacial isostatic adjustment-related stress field changes. Glacial isostatic adjustment is also a likely driver for the historical and parts of the recent fault activity. Glacial isostatic adjustment is also described for the Alps, but it is difficult to clearly distinguish between reactivation of faults in the foreland of the Alps due to the Alpine collision and glacial isostatic adjustment.

This chapter reviews the results of studies of late- and postglacial faults in the Russian part of the Fennoscandian Shield (Kola Peninsula, Karelia, Sankt-Petersburg region). It provides a brief overview and description from north to south of the main seismic lineaments (Murmansk and Kandalaksha) as well as results from a study of some secondary lineaments, individual late- and postglacial faults and seismic dislocations. The obtained data allowed defining a decrease in seismic activity from the Late Glaciation to the present times. It is due to the fading glacial isostatic uplift of the shield and the change of the leading role from the vertically directed forces of glacial isostasy to horizontal compressive strains. Glacial isostasy as a factor giving rise to stresses has nearly exhausted itself by the present time, while the tectonic factor continues to be felt.

Southern Alaska provides an ideal setting to assess how surface mass changes can influence crustal deformation and seismicity amidst rapid tectonic deformation. Since the end of the Little Ice Age, the glaciers of southern Alaska have undergone extensive wastage, retreating by kilometres and thinning by hundreds of metres. Superimposed on this are seasonal mass fluctuations due to snow accumulation and rainfall of up to metres of equivalent water height in fall and winter, followed by melting of gigatons of snow and ice in spring and summer and changes in permafrost. These processes produce stress changes in the solid Earth that modulate seismicity and promote failure on upper-crustal faults. Here we quantify and review these effects and how they combine with tectonic loading to influence faulting in the southeast, St. Elias and southwest regions of mainland Alaska.

The following sections introduce geological, geodetic and geophysical methods and techniques that specifically help in the identification of glacially induced faults. In addition, a summary of methods for dating of fault (re-)activation is presented, and the forthcoming drilling project into the Pärvie fault is introduced.

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.

Regions affected by glacial isostatic adjustment experience stress changes. The stress will be released either by slow aseismic movements along faults or by sudden stress release in form of earthquakes. Location and source mechanism of those earthquakes can play a major role in understanding past and ongoing geodynamic processes in a glacial isostatic adjustment-affected region. On the one hand, alignments of earthquake hypocentres may act as an indicator for active faults that might not be known from geology before. On the other hand, calculation and interpretation of earthquake focal mechanisms, represent a key to stress and stress changes. We present an overview of seismological methods and tools to retrieve fault geometry and motion.

A brief historical review of the development of crustal seismic studies is presented including the importance of the Mohorovičić (Moho) Discontinuity and the basic composition of the earth's crust. The essential elements of Wide-Aperture Reflection and Refraction Seismics (WARRS) using wide-angle reflection and refracted diving waves are discussed with an explanation of how they can provide both P and S wave velocity models of the crust.

A discussion of the instrumentation used for collecting crustal seismic data both on- and off-shore is followed by four case studies from different environments. These demonstrate how crustal seismic data can be used to provide a regional understanding of the physical properties of the crust and the regional geology of the basin and its importance in the early exploration stage of the exploration and production process. The importance of integrating the crustal seismic data with other geophysical data to obtain an optimum geophysical model is stressed. This leads to a better understanding of the key geological processes that assists the exploration strategy. A brief discussion of the costs involved in acquiring crustal seismic data is presented.

In this chapter we present examples of earthquake-induced geomorphology in Northern Europe ranging from the readily visible surface expression to more subtle and complex landforms.

Stress changes in the subsurface created by loading and unloading of the ice sheets can result in reactivation of deep-seated faults. Glacially induced faulting can happen during the glaciation in a proglacial or subglacial setting, in a distal setting away from the ice margin or in a postglacial setting after the ice sheet has melted away. Thus, the timing and the location of the tectonic event is important for the resulting landform creation or landform change. Identification of earthquake-induced landforms can be used in interpretations of palaeoseismic events, for location of previously unrecognized fault zones and in evaluations of the likelihood of future seismic events. Interpretations of earthquake-induced landforms in and around former glaciated areas can therefore add important information to interpretations of both the Quaternary geology and the deep structural framework.

Poland is in an intraplate area characterized almost everywhere by low recent tectonic activity. This does not imply, however, that earthquakes have not affected it, even in the – geologically speaking – recent geological past. This is due to Pleistocene glaciations, which left traces in the form of earthquake-induced deformed layers. The strongly deformed layers (seismites) as well as some fault zones with significant offsets crossing also Quaternary sediments can indicate fault (re-)activation due to glacial isostatic adjustment. We inventory and describe the five sites/areas in the intraplate northern and central parts of Poland where traces of glacial isostatic adjustment occur. We do not deal, however, with the mountain areas of southern Poland, because Alpine pressure and glacial isostatic adjustment may each, possibly jointly, have acted there as a trigger; distinguishing between traces left by them is not yet viable.

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.

The Danish area is divided by the Fennoscandian Border Zone into a north-eastern part, which is generally tectonically stable with low seismicity marginally related to well-known fault zones, and close to no seismicity in the south-western non-shield part. Stress measurements show that lithospheric plate motion is generally responsible for the modern stress pattern. However, stress changes induced by the weight-relief from the ice sheets during the Pleistocene appears to have created tectonic instability with maximum intensity at the time of deglaciation. The Danish area is generally covered by thick successions of unconsolidated sediments, and therefore it is often difficult to observe unambiguous examples of glacially induced faults. Nevertheless, a number of examples indicate that faults in major fault zones appear to have experienced short periods of reactivation in Lateglacial and early postglacial times. In this chapter, we present an updated map of the historic earthquakes in the Danish area, selected examples of Quaternary deformation of the terrain and near-surface sediments, and suggestions for intensified future monitoring, investigations and research.

This section presents a detailed overview of soft-sediment deformation structures of possibly seismic origin in the Eastern Baltic Region. Recent studies of soft-sediment deformation structures discovered in Estonia, Latvia, Lithuania, Belarus and the Kaliningrad District of Russia demonstrated that their formation could have been caused by fluidization and liquefaction of sediments possibly triggered by palaeoearthquakes; thus, they could be interpreted as seismites. An identification of corresponding seismogenic faults is complicated though due to the rather small scale of the tectonic dislocations in the intracratonic area with up to 2.5-km thick Phanerozoic sedimentary cover. Nevertheless, a part of soft-sediment deformation structures can be interpreted as seismites and attributed to the seismic events triggered by glacial isostatic adjustment of the lithosphere during the Last (Weichselian) glacial advance and subsequent deglaciation.