Assessment of the Dynamic Properties of Holocene Peat

Zwanenburg, C.; Konstadinou, M.; Meijers, Piet; Goudarzy, Meisam; König, Diethard; Dyvik, Rune; Carlton, Brian; Elk, Jan van; Doornhof, Dirk; Korff, Mandy

doi:10.1061/(asce)gt.1943-5606.0002259

Cited by 11 publications

(6 citation statements)

References 23 publications

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“…The Modulus Reduction and Damping (MRD) curves are defined by Darendeli (2001) for clays, Menq (2003) for sand and Zwanenburg et al (2020) for Groningen peat. The parameters for the descriptive curves are included in Kruiver et al (2018).…”

Section: Site Response Methodologymentioning

confidence: 99%

Capturing spatial variability in the regional Ground Motion Model of Groningen, the Netherlands

Kruiver

Pefkos²,

Rodríguez-Marek³

et al. 2022

Netherlands Journal of Geosciences

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Long-term exploration of the Groningen gas field in the Netherlands led to induced seismicity. Over the past nine years, an increasingly sophisticated Ground Motion Model (GMM) has been developed to assess the site response and the related seismic hazard. The GMM output strongly depends on the shear-wave velocity (V S ), among other input parameters. To date, V S model data from soil profiles (Kruiver et al., Bulletin of Earthquake Engineering, 15(9): 3555–3580, 2017; Netherlands Journal of Geosciences, 96(5): s215–s233, 2017) have been used in the GMM. Recently, new V S profiles above the Groningen gas field were constructed using ambient noise surface wave tomography. These so-called field V S data, even though spatially limited, provide an independent source of V S to check whether the level of spatial variability in the GMM is sufficient. Here, we compared amplification factors (AF) for two sites (Borgsweer and Loppersum) calculated with the model V S and the field V S (Chmiel et al., Geophysical Journal International, 218(3), 1781–1795, 2019 and new data). Our AF results over periods relevant for seismic risk (0.01–1.0 s) show that model and field V S profiles agree within the uncertainty range generally accepted in geo-engineering. In addition, we compared modelled spectral accelerations using either field V S or model V S in Loppersum to the recordings of an earthquake that occurred during the monitoring period (ML 3.4 Zeerijp on 8 January 2018). The modelled spectral accelerations at the surface for both field V S and model V S are coherent with the earthquake data for the resonance periods representative of most buildings in Groningen (T = 0.2 and 0.3 s). These results confirm that the currently used V S model in the GMM captures spatial variability in the site response and represents reliable input for the site response calculations.

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Section: Site Response Methodologymentioning

confidence: 99%

Capturing spatial variability in the regional Ground Motion Model of Groningen, the Netherlands

Kruiver

Pefkos²,

Rodríguez-Marek³

et al. 2022

Netherlands Journal of Geosciences

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“…These angles of incidence results in 86-96% of the P-wave mapping to the vertical component. For S-waves, angles of incidence are even smaller in the near-surface due to very low velocities, down to about 35 m/s (Zwanenburg et al, 2020). And hence, not much S-wave energy can be recorded on the vertical component, as can be seen in Figure 3.…”

Section: Wave Propagation and Incidencementioning

confidence: 97%

Amplification Behaviour of Compressional Waves in Unconsolidated Sediments

et al. 2022

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Similar to horizontal earthquake motions, vertical motions are amplified depedent on the local site conditions which can be critical for the safety of certain structures. Production of natural gas in Groningen, the Netherlands, results in reservoir compaction causing low magnitude, shallow earthquakes which are recorded with a borehole seismic network. These recordings form an excellent data set to understand how shallow unconsolidated subsurface geology influences the amplification behaviour of compressional waves (P-waves). First, we present borehole and single-station techniques (amplification factors, empirical transfer functions (ETF) and V/H spectral ratio implementations) to quantify vertical amplification. We show that vertical-wave incidence is a reasonable assumption. All techniques are capable of emphasising the sites with strong amplification of vertical ground motion during an earthquake. Subsequently, we compare ETF with single-station methods with the aim to develop proxies for vertical site-response using spectral ratios. In a second step, we link vertical site-response with shallow subsurface conditions, like the P-wave velocity and peat content. To better understand the amplification mechanisms, we analytically simulate P-wave propagation. In the simulations, we compute synthetic transfer functions using realistic subsurface conditions and make a comparison with the ETF. The simulations support the hypothesis that thin layers of shallow gas, originating from the Holocene peat, result in wave amplification. We observe strong vertical site-response in particular in the eastern part of Groningen, with industrial facilities and pipeline infrastructure in the region. Here, if high vertical amplifications are persistent at large earthquake magnitudes, appreciable levels of vertical loading may be expected. This study demonstrates that vertical motions should be assessed separately from horizontal motions, given that the amplification behaviour of P-waves is affected by distinctive mechanisms.

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“…The construction of the profiles is described in Kruiver et al (2017a, b), with some minor modifications and refinements that have been made subsequently. The modulus damping and reduction (MRD) curves of Darendeli (2001) and Menq (2003) are selected for clays and sands, respectively, whereas the MRD curves derived by Zwanenburg et al (2020) from tests of local soil samples are applied to the Holland peat; for older and more consolidated deposits at depths greater than ~ 350 m (the Lower North Sea formation), a linear response is assumed. While this is perhaps an unusually large depth over which to assume a nonlinear response, the soft nature of the Groningen soils means that large strains are possible for some cases, even at considerable depths.…”

Section: Site Response Modelmentioning

confidence: 99%

Ground-motion prediction models for induced earthquakes in the Groningen gas field, the Netherlands

et al. 2022

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Small-magnitude earthquakes induced by gas production in the Groningen field in the Netherlands have prompted the development of seismic risk models that serve both to estimate the impact of these events and to explore the efficacy of different risk mitigation strategies. A core element of the risk modelling is ground-motion prediction models (GMPM) derived from an extensive database of recordings obtained from a dense network of accelerographs installed in the field. For the verification of damage claims, an empirical GMPM for peak ground velocity (PGV) has been developed, which predicts horizontal PGV as a function of local magnitude, ML; hypocentral distance, Rhyp; and the time-averaged shear-wave velocity over the upper 30 m, VS30. For modelling the risk due to potential induced and triggered earthquakes of larger magnitude, a GMPM for response spectral accelerations has been developed from regressions on the outputs from finite-rupture simulations of motions at a deeply buried rock horizon. The GMPM for rock motions is coupled with a zonation map defining frequency-dependent non-linear amplification factors to obtain estimates of surface motions in the region of thick deposits of soft soils. The GMPM for spectral accelerations is formulated within a logic-tree framework to capture the epistemic uncertainty associated with extrapolation from recordings of events of ML ≤ 3.6 to much larger magnitudes.

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Assessment of the Dynamic Properties of Holocene Peat

Cited by 11 publications

References 23 publications

Capturing spatial variability in the regional Ground Motion Model of Groningen, the Netherlands

Capturing spatial variability in the regional Ground Motion Model of Groningen, the Netherlands

Amplification Behaviour of Compressional Waves in Unconsolidated Sediments

Ground-motion prediction models for induced earthquakes in the Groningen gas field, the Netherlands

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