A geological history of Groningen’s subsurface

Netherlands Journal of Geosciences, 2017

Kruiver, P.P., Wiersma, A., Kloosterman, F.H., De Lange, G., Korff, M., Stafleu, J., Busschers, F.S., Harting, R., Gunnink, J.L., Green, R.A., Van Elk, J. and Doornhof, D., 2017. Characterisation of the Groningen subsurface for seismic hazard and risk modelling. Netherlands Journal of Geosciences, 96: 215-233, doi:10.1017/njg.2017.11 The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (V S30 around 200 m s −1) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the 'Geological model for Site response in Groningen' (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at ∼800 m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100 m × 100 m) to which properties (V S and parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the 'Geological model for Liquefaction sensitivity in Groningen' (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40 m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5–17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth–stress reduction relationships (r d).

2015

Hydrocarbon extraction lead to compaction of the gas reservoir which is visible as subsidence on the surface. Subsidence measurements can therefore be used to better estimate reservoir parameters. Total subsidence is derived from the result of the measurement of height differences between optical benchmarks. The procedure from optical height difference measurements to absolute subsidence is an inversion, and the result is often used as an input for consequent inversions on the reservoir. We have used the difference measurements directly to invert for compaction of the Groningen gas reservoir in the Netherlands. We have used a linear inversion exercise to update an already existing reservoir compaction model of the field. This procedure yielded areas of increased and decreased levels of compaction compared to the existing compaction model in agreement with observed discrepancies in porosity and aquifer activity. Introduction The Groningen gas field is a giant onshore field that has c...

This paper presents depth maps for eight key horizons and seven thickness maps covering the onshore and offshore areas for the Late Permian to recent sedimentary section of the Netherlands. These maps, prepared in the context of a TNO regional mapping project, are supported by nine regional structural cross sections and a table summarizing the timing of tectonic activity from Carboniferous to recent. These new regional maps enable the delineation of various structural elements but also reveal the development of these elements through time with improved detail.

Kombrink, H., Doornenbal, J.C., Duin, E.J.T., Den Dulk, M., Van Gessel, S.F., Ten Veen, J.H. & Witmans, N.

Illinois State Geological Survey Circular 578, 2011

This paper corresponds to Chapter 12 of a report on the "current status of 3D geological modelling". This report was published by the Illinois and British Geological Surveys. The URL provides a link to the full report. The PDF contains the cover and Chapter 12 only. Full reference: Stafleu, J., Maljers, D., Busschers, F.S., Gunnink, J.L. and Vernes, R.W., 2011. TNO – Geological Survey of the Netherlands: 3-D Geological Modeling of the Upper 500 to 1,000 Meters of the Dutch Subsurface. In: Berg, R.C., Mathers, S.J., Kessler, H. & Keefer, D.A. (eds.): Synopsis of Current Three-dimensional Geological Mapping and Modeling in Geological Survey Organizations, Illinois State Geological Survey Circular 578, 64-68.

There is an increasing demand for detailed information on the spatial distribution of geological units and their physical and chemical properties. However, existing studies on sediment properties are scarce. The project TOPINTEGRAAL aims to build a geological model of the upper 30 to 50 meters of the subsurface and to characterize the lithological, hydraulic, geochemical and geotechnical properties of the sediments. A drilling campaign was launched in 2006 in order to obtain additional soil samples for the analyses and measurement of physical and geochemical properties. So far 157 cored wells were drilled. The results of the analysis and measurements of the samples are interpreted and published per GeoTOP-main area. In 2009 a first interpretation of the grain size and geochemical data of main area "Noord-Nederland" in the northern part of the Netherlands has been performed. The data and their interpretations will become a unique national database which will help researchers and planners to obtain better and more accurate results.

Van Balen et al., 2019

Paleoseismological trenching studies constrain recurrence times and magnitudes of faulting events and earthquakes on active faults. In a trench along the central part of the Peel Boundary fault zone (PBFZ), southeastern Netherlands, evidence was found for such a large faulting event that occurred around 14 ka. The event caused a fault scarp in unconsolidated sediments of ~1 m height. A colluvial wedge was formed next to the scarp. A second faulting event offsets this colluvial wedge by 0.2e0.1 m. This event can be tentatively dated at ~13 ka. During or immediately after the second event, a large clastic dyke intruded along the fault plane. The dyke is not faulted, but its emplacement did cause some minor thrust faulting around the injection. The sudden character of the main faulting event, the brittle deformation style of loam layers, the lack of growth faulting in the colluvial wedge, the clastic dykes and the flame structures demonstrate that the main faulting event was a surface rupturing earthquake. Based on the scarp height, the estimated moment magnitude is about 6.8 ± 0.3. Similar observations in a previous trench site suggest that the length of the surface rupture was at least 32 km. The earthquake took place during the Weichselian (Würmian) Late Glacial. This timing corresponds to the start of the glacio-isostatic forebulge collapse in the Netherlands. Glacio-isostatic movements have been invoked before to explain earthquake events in the Roer Valley Rift System in which the PBFZ is situated, and in northern Germany and Denmark. If these earthquakes can indeed be attributed to a collapsing forebulge, their ages should show a decrease in the direction of ice-sheet retreat. This might indeed be the case, as the ages decrease from 14 ka and 13 ka in this trench via 13e16 ka at the Osning Thrust Zone, NW Germany, to 12e14 ka in northern Denmark.

Netherlands Journal of Geosciences, 2003

In northwest Europe the pattern of earthquake distribution is correlated with known Quaternary faults. Excavation of fault scarps revealed that these fault zones have been active during the Late Pleistocene. In this paper we present the results of an exploratory trenching study across the Geleen Fault, part of the Feldbiss Fault Zone, the Netherlands. Middle Saalian fluvial deposits of the Meuse, overlain by local slope deposits, were excavated. The Geleen Fault has displaced the fluvial deposits by at least 5 meters. The upper layers of local slope deposits could be correlated across the fault and were all dated at approximately 15 ka B.P. This gives the opportunity to reconstruct the sequence of events that occurred about 15 ka ago. Liquefactions provide evidence for an earthquake event. However, the main offset along the Geleen Fault is not stratigraphically related to the liquefactions. The liquefactions and the fault offset are stratigraphically separated by a period of erosion...

Global and Planetary Change, 2000

The pattern of fault reactivation, basin deformation and concentration of seismicity along the main trans-Netherlands fault zone, located NW-SE across the centre of the Netherlands, indicates that this zone is a major zone of weakness. Gravity modelling reveals after back-stripping of the sedimentary succession a distinctive continuous positive anomaly that can be explained by lithospheric sources. This zone of weakness is therefore likely to have a major influence on the tectonic processes currently active in the Netherlands region. We give a review of the tectonic history of the Netherlands and then present the results of a quantitative study of the reactivation of basin boundary faults and the influence on the surrounding basin. Well-data, balanced and back-stripped cross-sections are used to constrain the lithosphere rheology. The lithosphere rheology modelling results show a weak coupling between upper crustal deformation and the subcrustal lithosphere. A finite element modelling approach focussing on the upper crust is carried out in which the basin boundary faults are assigned various dips. The modelling results indicate that, for continuous reactivation of basin boundary faults, the presence of both a pre-existing weakness and a reduced friction angle is required. The latter implies that large displacements accommodated by primary faults cannot be directly attributed to the relative weakness of these faults compared to the secondary faults, which is in close accordance with inferences from trenching. A reduced friction angle has a significant effect on lithospheric strength and appears to be the major controlling factor in the reactivation of basin boundary faults. q

This paper presents depth maps for eight key horizons and seven thickness maps covering the onshore and offshore areas for the Late Permian to recent sedimentary section of the Netherlands. These maps, prepared in the context of a TNO regional mapping project, are supported by nine regional structural cross sections and a table summarizing the timing of tectonic activity from Carboniferous to recent. These new regional maps enable the delineation of various structural elements but also reveal the development of these elements through time with improved detail. Since the latest Carboniferous the tectonic setting of the Netherlands changed repeatedly. During successive tectonic phases several pre-existing structural elements were reactivated and new elements appeared. The various identified regional structural elements are grouped into six tectonically active periods: Late Carboniferous, Permian, Triassic, Late Jurassic, Late Cretaceous and Cenozoic. This study demonstrates that many ...