Towards a physical and chemical characterization of the shallow subsurface of the Netherlands

Vernes, Ronald W.; Bosch, Aleid J.H.A.; Harting, Ronald; Heer, Eppie de; Griffioen, Jasper

doi:10.3997/2214-4609-pdb.150.c03

Cited by 2 publications

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“…The Top Integraal database is a benchmark data set that contains lithological, hydraulic, geochemical and geotechnical measurements of the main lithofacies types in the Netherlands. The project aims to gather representative samples of the 27 geologically homologous areas identified by Vernes et al (2010), with the overall objective of building a high-resolution geological model of the top 30-50 m of the Dutch subsurface. The 4885 particle-size distributions used by this project from the database are representative of aeolian, estuarine, fluvial, glacial, marine and lagoonal depositional environments found in the Netherlands.…”

Section: The Datamentioning

confidence: 99%

Modelling particle-size distributions from operator estimates of sediment particle-size

Roberson

Weltje

2014

Netherlands Journal of Geosciences

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Link to this article: http://journals.cambridge.org/abstract_S0016774614000109How to cite this article: S. Roberson and G.J. Weltje Modelling particle-size distributions from operator estimates of sediment particle-size. AbstractEstimates of particle-size made by operators in the field and laboratory represent a vast and relatively untapped data archive. The wide spatial distribution of particle-size estimates makes them ideal for constructing geological models and soil maps. This study uses a large data set from the Netherlands (n = 4837) containing both operator estimates of particle-size and complete particle-size distributions measured by laser granulometry. Operator estimates are inaccurate and imprecise relative to measured laser data; only 16.68% of samples were successfully classified using the Dutch classification scheme for fine sediment.Operator estimates of sediment particle-size encompass the same range of percentage values as particle-size distributions measured by laser analysis. However, the distributions measured by laser analysis show that most of the sand percentage values lie between 0 and 1, so the majority of the variability in the data is lost because operator estimates are made to the nearest 1% at best, and more frequently to the nearest 5%. Operator estimates made by three technicians trained by the Geological Survey of the Netherlands are found not to be influenced by bias, rather they exhibit very similar levels of accuracy and precision. This study compares five different methods of modelling complete particle-size distributions from sparse data: (i) a four-part Pearson's probability distribution function, (i) a log-linear interpolation, (iii) a logit-linear interpolation, (iv) a logistic probability distribution function and (v) a logit constrained cubic-spline (logit-CCS) interpolation. The logit-CCS interpolation performed best across all the samples used, although the performance of all models was very similar for normal Gaussian, skewed and peaked distributions. Predictions for bimodal distributions using the Pearson's, logit-linear and logistic models are markedly less accurate than both log-linear and logit-CCS interpolation models. Although the logit-CCS interpolation model produces the best predictions of continuous particle-size distributions, the low accuracy and precision of operator estimates does not warrant the use of such a complex algorithm. Given this, it is suggested that a standard log-linear interpolation is the most effective means of modelling complete particle-size distributions from sparse data. Interpolation-based models are recommended over probability distribution functions because they allow for a greater degree of flexibility and will always honour the available input data.

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Section: The Datamentioning

confidence: 99%

Modelling particle-size distributions from operator estimates of sediment particle-size

Roberson

Weltje

2014

Netherlands Journal of Geosciences

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“…The objective is to sample all main lithofacies types represented in a total of 27 geologically homologous areas, in order to obtain regional property characteristics ( Fig. 10; Vernes et al, 2010). A total of about 325 drillings are planned as a first set of 'golden spikes'.…”

Section: Characterisation and Model Parameterisationmentioning

confidence: 99%

“…The subdivision of the Netherlands into 27 geologically homologous areas(hatched: underwater). SeeVernes et al (2010) for further explanation.…”

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3D geology in a 2D country: perspectives for geological surveying in the Netherlands

Meulen¹,

Doornenbal²,

Gunnink³

et al. 2013

Netherlands Journal of Geosciences

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ScopePursuant to a new law that will become effective in 2015, DINO, the national Dutch subsurface database operated by the Geological Survey of the Netherlands, is to become an official government register (a 'key register' / basisregistratie). In facing the responsibilities associated with this new status, the Survey is reconsidering and redesigning its operation and in that process a new, or at least sharper picture is emerging of geological surveying in the future.These developments set the final stages of a process of modernisation that geological survey organisations all over the world are currently entangled in (Allen, 2003;Jackson, 2010). Most surveys are replacing paper archives that were built in the AbstractOver the last ten to twenty years, geological surveys all over the world have been entangled in a process of digitisation. Their paper archives, built over many decades, have largely been replaced by electronic databases. The systematic production of geological map sheets is being replaced by 3D subsurface modelling, the results of which are distributed electronically. In the Netherlands, this transition is both being accelerated and concluded by a new law that will govern management and utilisation of subsurface information. Under this law, the Geological Survey of the Netherlands has been commissioned to build a key register for the subsurface: a single national database for subsurface data and information, which Dutch government bodies are obliged to use when making policies or decisions that pertain to, or can be affected by the subsurface. This requires the Survey to rethink and redesign a substantial part of its operation: from data acquisition and interpretation to delivery. It has also helped shape our view on geological surveying in the future.The key register, which is expected to start becoming operational in 2015, will contain vast quantities of subsurface data, as well as their interpretation into 3D models. The obligatory consultation of the register will raise user expectations of the reliability of all information it contains, and requires a strong focus on confidence issues. Building the necessary systems and meeting quality requirements is our biggest challenge in the upcoming years. The next step change will be towards building 4D models, which represent not only geological conditions in space, but also processes in time such as subsidence, anthropogenic effects, and those associated with global change.Keywords: Netherlands, applied geoscience, hydrogeology, geological surveying, mapping, geomodelling, geodatabase Netherlands Journal of Geosciences -Geologie en Mijnbouw | 92 -4 | 217-241 | 2013 217 course of many decades by electronic databases; many surveys started producing electronically distributed 3D subsurface models in addition to or instead of 2D geological maps that were their primary output since their establishment. For a variety of reasons explained below, the Dutch survey is among the early adapters in both respects.In this overview paper we present the Geological S...

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Towards a physical and chemical characterization of the shallow subsurface of the Netherlands

Cited by 2 publications

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Modelling particle-size distributions from operator estimates of sediment particle-size

Modelling particle-size distributions from operator estimates of sediment particle-size

3D geology in a 2D country: perspectives for geological surveying in the Netherlands

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