This chapterreviews the development of “conventional” towed streamer marine seismic work from 2D through 3D, its shortcomings, and its continuing development into so-called “broadband” seismic. It describes and explains the recent trend towards ocean-bottom recording, currently mostly executed using nodes (OBN), whose market share has expanded from around 10% in 2013 to an estimated 25% in 2020. It covers the increasing requirement for higher quality seismic data to enable imaging of the very problematic subsurface structures such as subsalt plays, which require more extensive shooting geometries and extra low-frequency bandwidths. “Blended” sources are bringing costs down, and practical research includes the use of autonomous underwater vehicles (AUVs), possibly even deployed as intelligent “swarms.” Cost comparisons of the current techniques are included.

This book demonstrates that there are other approaches that when used alone, or in conjunction with seismic, can considerably reduce the uncertainty and risk of a given opportunity.Non-seismic technologies have a risk reduction role throughout the exploration value chain, from frontier basin entry exploration through to development and production and on into carbon capture and storage.

Integration is a theme running through our commentary alongside designing the survey with an understanding of the geological model you plan to validate.This is particularly the case with gravity/magnetics and Full Tensor Gradiometry (FTG) techniques for which there are non-unique outcomes for a given gravity response.Hence their best application is when using in combination with either refraction seismic or conventional reflection seismic.

As well as providing direct imaging in their own right, gravity and refraction seismic add significant value in helping to greatly improve the migration of seismic data.This is particularly the case when seismic data quality is compromised due to the presence of difficult lithologies in the overburden (e.g. salt, basalt and chalk) or to increase the resolution at depth.We review of marine electromagnetic methods, in which we explain that if correctly applied, in the right geological conditions, marine electromagnetic has an important role to plan in prospect de-risking and reservoir management.

The 90-km long Stuoragurra Fault Complex, part of the approximately 4–5-km wide Precambrian Mierojávri–Sværholt Shear Zone, constitutes the Norwegian part of the larger Lapland province of postglacial faults. It consists of three separate fault systems being 6–12 km apart. The faults dip 30–75° to the SE and can be traced to about 500 m depth. Deep seismic profiling shows that the shear zone dips at an angle of about 43° to the southeast and can be traced to about 3 km depth. A total of approximately 80 earthquakes were registered here between 1991 and 2019. Most of them occurred to the southeast of the fault scarps. The maximum moment magnitude was 4.0. The formation of postglacial faults in northern Fennoscandia has previously been associated with the deglaciation of the last inland ice. Dating of fault reactivation reveals, however, a late Holocene age (between around 700 and 4000 a BP). The reverse displacement of around 9 m and fault system lengths of 14 and 21 km of the two southernmost fault systems indicate a moment magnitude of about 7. The results from this study indicate that the expected maximum magnitude of future earthquakes in Fennoscandia is about 7.

Marine electromagnetic (EM) methods can be used to determine the resistivity of the subsurface, which can in turn be used to investigate bothstructure and properties of the subsurface.Natural source magnetotelluric (MT) and controlled source electromagnetic (CSEM) methods have been applied to a range of exploration and exploitation problems. In areas of complex geology where seismic can struggle to produce a clear subsurface image, both CSEM and MT have been applied to improve velocity model building and hence improve the final migrated image.In reservoir characterisation problems, CSEM derived resistivity provides a valuable complement to seismically derived acoustic and elastic properties, and has been shown to reduce interpretation ambiguity, particularly in the case of hydrocarbon saturation uncertainty.In all cases, a careful multiphysics approach, in which marine EM methods are integrated with seismic and other geophysical methods, provides the most robust result.

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.