scholarly journals Development of a country-wide seismic site-response zonation map for the Netherlands

2021 ◽  
Author(s):  
Janneke van Ginkel ◽  
Elmer Ruigrok ◽  
Jan Stafleu ◽  
Rien Herber
Keyword(s):  
The Netherlands ◽  
Seismic Hazard ◽  
Site Response ◽  
Empirical Relationship ◽  
Ambient Vibration ◽  
Ratio Method ◽  
Small Magnitude ◽  
Near Surface ◽  
Zonation Map ◽  
Moderate Seismicity

Abstract. Earthquake site-response is an essential part of seismic hazard assessment, especially in densely populated areas. The shallow geology of the Netherlands consists of a very heterogeneous soft sediment cover, which has a strong effect on seismic wave propagation and in particular on the amplitude of ground shaking, resulting in significant damage on structures despite the fact that the events are of small magnitude. Even though it is a low-to-moderate seismicity area, the seismic risk cannot be neglected, in particular, because shallow induced earthquakes occur. The aim of this study is to establish a nationwide site-response zonation by using the lithostratigraphy, earthquake- and ambient vibration recordings. In the first step, we constrain the parameters (velocity contrast and shear-wave velocity) that are indicative of ground-motion amplification in the Groningen area. For this, we combine ambient vibration and earthquake recordings using resp. the horizontal-to-vertical spectral ratio method (HVSR), borehole empirical transfer functions (ETFs) and amplification factors (AFs). This enables us to define an empirical relationship between measured earthquake amplification from the ETF and AF, and amplification estimated with the HVSR derived from the ambient seismic field. Therewith, we show that the HVSR can be used as a first proxy for amplification. Subsequently, HVSR curves throughout the Netherlands are estimated. The resulting peak amplitudes largely coincide with the in-situ lithostratigraphic sequences and the presence of a strong velocity contrast in the near-surface. Next, sediment profiles representing the Dutch shallow subsurface are categorized into five classes, where each class is representing a level of expected amplification. The mean amplification for each class, and its variability, is quantified using 66 sites with measured earthquake amplification (ETF and AF) and 115 sites with HVSR curves. The site-response (amplification) zonation map for the Netherlands is designed by transforming published geological 3D grid cell models into the five classes and an AF is assigned to most of the classes. This presented site-response assessment on a national scale is important for a first identification of regions with increased seismic hazard potential, for example at locations with mining or geothermal energy activities.

scholarly journals Development of a seismic site-response zonation map for the Netherlands

2022 ◽  
Vol 22 (1) ◽  
pp. 41-63
Author(s):  
Janneke van Ginkel ◽  
Elmer Ruigrok ◽  
Jan Stafleu ◽  
Rien Herber
Keyword(s):  
The Netherlands ◽  
Seismic Hazard ◽  
Transfer Functions ◽  
Site Response ◽  
Empirical Relationship ◽  
Ambient Vibration ◽  
Induced Earthquakes ◽  
Near Surface ◽  
Zonation Map ◽  
Moderate Seismicity

Abstract. Earthquake site response is an essential part of seismic hazard assessment, especially in densely populated areas. The shallow geology of the Netherlands consists of a very heterogeneous soft sediment cover, which has a strong effect on the amplitude of ground shaking. Even though the Netherlands is a low- to moderate-seismicity area, the seismic risk cannot be neglected, in particular, because shallow induced earthquakes occur. The aim of this study is to establish a nationwide site-response zonation by combining 3D lithostratigraphic models and earthquake and ambient vibration recordings. As a first step, we constrain the parameters (velocity contrast and shear-wave velocity) that are indicative of ground motion amplification in the Groningen area. For this, we compare ambient vibration and earthquake recordings using the horizontal-to-vertical spectral ratio (HVSR) method, borehole empirical transfer functions (ETFs), and amplification factors (AFs). This enables us to define an empirical relationship between the amplification measured from earthquakes by using the ETF and AF and the amplification estimated from ambient vibrations by using the HVSR. With this, we show that the HVSR can be used as a first proxy for site response. Subsequently, HVSR curves throughout the Netherlands are estimated. The HVSR amplitude characteristics largely coincide with the in situ lithostratigraphic sequences and the presence of a strong velocity contrast in the near surface. Next, sediment profiles representing the Dutch shallow subsurface are categorised into five classes, where each class represents a level of expected amplification. The mean amplification for each class, and its variability, is quantified using 66 sites with measured earthquake amplification (ETF and AF) and 115 sites with HVSR curves. The site-response (amplification) zonation map for the Netherlands is designed by transforming geological 3D grid cell models into the five classes, and an AF is assigned to most of the classes. This site-response assessment, presented on a nationwide scale, is important for a first identification of regions with increased seismic hazard potential, for example at locations with mining or geothermal energy activities.

An approach to construct a Netherlands-wide ground-motion amplification model

2021 ◽  
Author(s):  
Janneke van Ginkel ◽  
Elmer Ruigrok ◽  
Rien Herber
Keyword(s):  
The Netherlands ◽  
Ground Motion ◽  
Seismic Wave ◽  
Transfer Functions ◽  
Site Response ◽  
Data Availability ◽  
Earthquake Ground Motion ◽  
Sediment Layer ◽  
Small Magnitude ◽  
Near Surface

<p>Local site conditions can strongly influence the level of amplification of ground-motion at the surface during an earthquake. Especially near-surface low velocity sediments overlying stiffer seismic bedrock modify earthquake ground motions in terms of amplitudes and frequency content, the so-called site response. Earthquake ground-motion site response is of great concern because it can lead to amplified surface shaking resulting in significant damage on structures despite small magnitude events. The Netherlands has tectonically related seismic activity in the southern region with magnitudes up to 5.8 measured so far. In addition, gas extraction in the Groningen field in the northern part of the Netherlands, is regularly causing shallow (3 km), low magnitude (Mw max= 3.6), induced earthquakes. The shallow geology of the Netherlands consists of a very heterogeneous soft sediment cover, which has a strong effect on seismic wave propagation and in particular on the amplitude of ground shaking.</p><p> </p><p>The ambient seismic field and local earthquakes recorded over 69 borehole stations in Groningen are used to define relationships between the subsurface lithological composition, measured shear-wave velocity profiles, horizontal-to-vertical spectral ratios (HVSR) and empirical transfer functions (ETF). For the Groningen region we show that the HVSR matches the ETF well and conclude that the HVSR can be used as a first proxy for earthquake site-response. In addition, based on the ETFs we observe that most of the seismic wave amplification occurs in the top 50 m of the much thicker sediment layer. Here, a velocity contrast is present between the very soft Holocene clays and peat on top of the stiffer Pleistocene sands.</p><p> </p><p>Based on the learnings from Groningen we first constructed sediment type classes for the Dutch subsurface, each class representing a level of expected amplification. Secondly, the HVSR curves are estimated for all surface seismometers in the Netherlands seismic network and a sediment class is assigned to each location. Highest HVSR peak amplitudes are measured at sites with the highest level of amplification of the sediment classification. Based on this correlation and the presence of a detailed shallow geological model at most sites in the Netherlands, a simplistic approach is presented to predict amplification at any location with sufficient lithologic information. With this approach based on the shallow sediment composition, we can obtain constraints on the seismic hazard in areas that have limited data availability but have potential risk of seismicity, for example due to geothermal energy extraction.</p>

scholarly journals A methodological approach to update Ground Motion Prediction Models using Bayesian Inference

2021 ◽  
Author(s):  
Saran Srikanth Bo ◽  
Merlin Keller ◽  
Abhinav Gupta ◽  
Gloria Senfaute
Keyword(s):  
Bayesian Inference ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Methodological Approach ◽  
Strong Motion ◽  
Motion Prediction ◽  
Data Sets ◽  
Ground Motion Prediction ◽  
Small Magnitude ◽  
Moderate Seismicity

Abstract In recent decades, prediction of ground motion at a specific site or a region is of primary interest in probabilistic seismic hazard assessment (PSHA). Historically, several ground motion prediction equation (GMPE) models with different functional forms have been published using strong ground motion records available from NGA-West and European databases. However, low-to-moderate seismicity regions, such as Central & Eastern United States and western Europe, is characterized by limited strong-motion records in the magnitude-distance range of interest for PSHA. In these regions, the available data for the development of empirical GMPEs is very scarce and limited to small magnitude events. For these regions, the general practice in PSHA is to consider a set of GMPEs developed from data sets collected in other regions with high seismicity. This practice generates an overestimation of the seismic hazard for the low seismicity regions. There are two potential solutions to overcome this problem: (i) a new GMPE model can be developed; however, development of such a model can require significant amount of data which is not usually available, and (ii) the existing GMPE models can be recalibrated based on the data sets collected in the new region rather than developing a new GMPE model. In this paper, we propose a methodological approach to recalibrate the coefficients in a GMPE model using different algorithms to perform Bayesian inference. The coefficients are recalibrated for a subset of European Strong-Motion (ESM) database that corresponds to low-to-moderate seismicity records. In this study, different statistical models are compared based on the functional form given by the chosen GMPE, and the best model and algorithm are recommended using the concept of information criteria.

Seismic hazard due to small-magnitude, shallow-source, induced earthquakes in The Netherlands

2006 ◽  
Vol 87 (1-2) ◽  
pp. 105-121 ◽  
Author(s):  
Torild van Eck ◽  
Femke Goutbeek ◽  
Hein Haak ◽  
Bernard Dost
Keyword(s):  
The Netherlands ◽  
Seismic Hazard ◽  
Induced Earthquakes ◽  
Small Magnitude

A Comparison of Site Response Techniques Using Weak-Motion Earthquakes and Microtremors

2006 ◽  
Vol 22 (1) ◽  
pp. 169-188 ◽  
Author(s):  
Sheri Molnar ◽  
John F. Cassidy
Keyword(s):  
Site Response ◽  
Strong Motion ◽  
Spectral Ratio ◽  
Ratio Method ◽  
Near Surface ◽  
Fundamental Frequencies ◽  
Standard Spectral Ratio ◽  
Impedance Contrast ◽  
Spectral Ratio Method ◽  
Geologic Setting

The applicability of the microtremor spectral ratio method is examined by comparing microtremor and weak-motion earthquake site responses at seven permanent strong-motion sites in Victoria, British Columbia. For each site, a weak-motion earthquake standard spectral ratio (bedrock reference), the average horizontal-to-vertical spectral ratio of up to five weak-motion earthquakes, and the average microtremor (Nakamura method) spectral ratio are compared. The geologic setting of Victoria is ideal for site response studies with a near-surface high impedance contrast between thin geologic layers of Victoria clay (about 11 m maximum in this study) and Pleistocene till or bedrock. Regardless of excitation source (weak-motion earthquakes or microtremors) and spectral ratio method, similar peak amplitudes and fundamental frequencies were found. Thicker material (>10 m) sites displayed higher peak amplitudes (up to six times amplification) at frequencies of 2–5 Hz compared to sites with a thin lens of material (<3 m) over bedrock that showed peak amplitudes at frequencies of >8 Hz.

Scenario shakemaps for Montreal

2015 ◽  
Vol 42 (7) ◽  
pp. 463-476 ◽  
Author(s):  
Hadi Ghofrani ◽  
Gail M. Atkinson ◽  
Luc Chouinard ◽  
Philippe Rosset ◽  
Kristy F. Tiampo
Keyword(s):  
Seismic Risk ◽  
Site Response ◽  
Distribution Patterns ◽  
Site Amplification ◽  
Near Surface ◽  
Ground Shaking ◽  
Moderate Seismicity ◽  
Event Location ◽  
Surface Geology ◽  
The Impact

Montreal has significant seismic risk due to the combination of moderate seismicity, high population density, and vulnerable infrastructure. An important tool in damage and risk assessment is a scenario shakemap, which shows the expected ground shaking intensity distribution patterns. In this study, we use regional ground motion and site response evaluations to generate scenario shakemaps for Montreal. The impact of event location on expected ground motions and intensities was tested by considering the occurrence of a scenario (a given magnitude event) at various locations, where the scenarios are defined based on an analysis of the most likely future event locations. Variability in near surface geology plays an important role in earthquake ground shaking; we use microzonation information from Montreal to assess the expected site amplification effects. The results of this study may be used as input to seismic risk studies for Montreal.

scholarly journals Calibrating a new attenuation curve for the Dead Sea region using surface wave dispersion surveys in sites damaged by the 1927 Jericho earthquake

Solid Earth ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 379-390 ◽  
Author(s):  
Yaniv Darvasi ◽  
Amotz Agnon
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Dead Sea ◽  
Attenuation Curve ◽  
Surface Wave Dispersion ◽  
Near Surface ◽  
Moderate Seismicity ◽  
Local Point ◽  
The Dead

Abstract. Instrumental strong motion data are not common around the Dead Sea region. Therefore, calibrating a new attenuation equation is a considerable challenge. However, the Holy Land has a remarkable historical archive, attesting to numerous regional and local earthquakes. Combining the historical record with new seismic measurements will improve the regional equation. On 11 July 1927, a rupture, in the crust in proximity to the northern Dead Sea, generated a moderate 6.2 ML earthquake. Up to 500 people were killed, and extensive destruction was recorded, even as far as 150 km from the focus. We consider local near-surface properties, in particular, the shear-wave velocity, as an amplification factor. Where the shear-wave velocity is low, the seismic intensity far from the focus would likely be greater than expected from a standard attenuation curve. In this work, we used the multichannel analysis of surface waves (MASW) method to estimate seismic wave velocity at anomalous sites in Israel in order to calibrate a new attenuation equation for the Dead Sea region. Our new attenuation equation contains a term which quantifies only lithological effects, while factors such as building quality, foundation depth, topography, earthquake directivity, type of fault, etc. remain out of our scope. Nonetheless, about 60 % of the measured anomalous sites fit expectations; therefore, this new ground-motion prediction equation (GMPE) is statistically better than the old ones. From our local point of view, this is the first time that integration of the 1927 historical data and modern shear-wave velocity profile measurements improved the attenuation equation (sometimes referred to as the attenuation relation) for the Dead Sea region. In the wider context, regions of low-to-moderate seismicity should use macroseismic earthquake data, together with modern measurements, in order to better estimate the peak ground acceleration or the seismic intensities to be caused by future earthquakes. This integration will conceivably lead to a better mitigation of damage from future earthquakes and should improve maps of seismic hazard.

Framework for a Ground-Motion Model for Induced Seismic Hazard and Risk Analysis in the Groningen Gas Field, The Netherlands

2017 ◽  
Vol 33 (2) ◽  
pp. 481-498 ◽  
Author(s):  
Julian J. Bommer ◽  
Peter J. Stafford ◽  
Benjamin Edwards ◽  
Bernard Dost ◽  
Ewoud van Dedem ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Quantitative Estimation ◽  
Epistemic Uncertainty ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Small Magnitude ◽  
Ground Motion Model ◽  
Hazard And Risk ◽  
Groningen Gas Field

The potential for building damage and personal injury due to induced earthquakes in the Groningen gas field is being modeled in order to inform risk management decisions. To facilitate the quantitative estimation of the induced seismic hazard and risk, a ground motion prediction model has been developed for response spectral accelerations and duration due to these earthquakes that originate within the reservoir at 3 km depth. The model is consistent with the motions recorded from small-magnitude events and captures the epistemic uncertainty associated with extrapolation to larger magnitudes. In order to reflect the conditions in the field, the model first predicts accelerations at a rock horizon some 800 m below the surface and then convolves these motions with frequency-dependent nonlinear amplification factors assigned to zones across the study area. The variability of the ground motions is modeled in all of its constituent parts at the rock and surface levels.

scholarly journals A hybrid model for mapping simplified seismic response via a GIS-metamodel approach

2014 ◽  
Vol 14 (7) ◽  
pp. 1703-1718 ◽  
Author(s):  
G. Grelle ◽  
L. Bonito ◽  
P. Revellino ◽  
L. Guerriero ◽  
F. M. Guadagno
Keyword(s):  
Seismic Hazard ◽  
Seismic Response ◽  
Hybrid Model ◽  
Computational Models ◽  
Site Response ◽  
Seismic Hazard Assessment ◽  
Physical Parameters ◽  
Seismic Zone ◽  
Acceleration Response ◽  
Good Correspondence

Abstract. In earthquake-prone areas, site seismic response due to lithostratigraphic sequence plays a key role in seismic hazard assessment. A hybrid model, consisting of GIS and metamodel (model of model) procedures, was introduced aimed at estimating the 1-D spatial seismic site response in accordance with spatial variability of sediment parameters. Inputs and outputs are provided and processed by means of an appropriate GIS model, named GIS Cubic Model (GCM). This consists of a block-layered parametric structure aimed at resolving a predicted metamodel by means of pixel to pixel vertical computing. The metamodel, opportunely calibrated, is able to emulate the classic shape of the spectral acceleration response in relation to the main physical parameters that characterize the spectrum itself. Therefore, via the GCM structure and the metamodel, the hybrid model provides maps of normalized acceleration response spectra. The hybrid model was applied and tested on the built-up area of the San Giorgio del Sannio village, located in a high-risk seismic zone of southern Italy. Efficiency tests showed a good correspondence between the spectral values resulting from the proposed approach and the 1-D physical computational models. Supported by lithology and geophysical data and corresponding accurate interpretation regarding modelling, the hybrid model can be an efficient tool in assessing urban planning seismic hazard/risk.

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