scholarly journals Ground motion observations from the 14 November 2016 Mw7.8 Kaikoura, New Zealand earthquake and insights from broadband simulations

2017 ◽  
Author(s):  
Brendon Archie Bradley
Keyword(s):  
Ground Motion ◽  
Vertical Direction ◽  
Strong Motion ◽  
Response Spectra ◽  
Site Effect ◽  
Topographic Effects ◽  
Specific Detail ◽  
Reclaimed Soil ◽  
Ground Motion Records ◽  
Kaikoura Earthquake

This paper provide insights into the observed ground motion records from the 14 November 2016 $M_w7.8$ Kaikoura earthquake. Specific detail is given to examining observations in the near-source and those in the urban Wellington / Lower Hutt regions through a combination of time series and response spectra to understand salient source, path and site effects.Several ground motions exceeding 1.0g horizontal are recorded, as well as up to 2.7g in the vertical direction at one location.The complexity associated with multi-fault rupture is clearly evident in several strong motion stations in the near-source region.Significant site effect case histories from sedimentary and reclaimed soil deposits and topographic effects are observed in the Wellington and Lower Hutt regions.To provide further insights, predictions from preliminary broadband ground motion simulations are examined to more directly interpret the observations.

scholarly journals An Empirical Model to Account for Spectral Amplification of Pulse-Like Ground Motion Records

Geosciences ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Sara Sgobba ◽  
Giovanni Lanzano ◽  
Francesca Pacor ◽  
Chiara Felicetta
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Strong Motion ◽  
Response Spectra ◽  
Flat File ◽  
Source Effects ◽  
Near Fault ◽  
Ground Motion Model ◽  
Displacement Response Spectra ◽  
Ground Motion Records

Near-source effects can amplify seismic ground motion, causing large demand to structures and thus their identification and characterization is fundamental for engineering applications. Among the most relevant features, forward-directivity effects may generate near-fault records characterized by a large velocity pulse and unusual response spectral shape amplified in a narrow frequency-band. In this paper, we explore the main statistical features of acceleration and displacement response spectra of a suite of 230 pulse-like signals (impulsive waveforms) contained in the NESS1 (NEar Source Strong-motion) flat-file. These collected pulse-like signals are analyzed in terms of pulse period and pulse azimuthal orientation. We highlight the most relevant differences of the pulse-like spectra compared to the ordinary (i.e., no-pulse) ones, and quantify the contribution of the pulse through a corrective factor of the spectral ordinates. Results show that the proposed empirical factors are able to capture the amplification effect induced by near-fault directivity, and thus they could be usefully included in the framework of probabilistic seismic hazard analysis to adjust ground-motion model (GMM) predictions.

scholarly journals Strong ground motion observations of engineering interest from the 14 November 2016 Mw7.8 Kaikōura, New Zealand earthquake

2017 ◽  
Vol 50 (2) ◽  
pp. 85-93 ◽  
Author(s):  
Brendon A. Bradley ◽  
Hoby N.T. Razafindrakoto ◽  
M. Ahsan Nazer
Keyword(s):  
New Zealand ◽  
Ground Motion ◽  
Strong Ground Motion ◽  
Ground Motions ◽  
Source Region ◽  
Vertical Direction ◽  
Response Spectra ◽  
Ground Motion Modelling ◽  
Kaikoura Earthquake ◽  
Strong Ground

This paper provides a brief discussion of observed strong ground motions from the 14 November 2016 Mw7.8 Kaikōura earthquake. Specific attention is given to examining observations in the near-source region where several ground motions exceeding 1.0g horizontal are recorded, as well as up to 2.7g in the vertical direction at one location. Ground motion response spectra in the near-source, North Canterbury, Marlborough and Wellington regions are also examined and compared with design levels. Observed spectral amplitudes are also compared with predictions from empirical and physics-based ground motion modelling.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

Concurrent Design Forces in Structures under Three-Component Orthotropic Seismic Excitation

2002 ◽  
Vol 18 (1) ◽  
pp. 1-17 ◽  
Author(s):  
K. Anastassiadis ◽  
I. E. Avramidis ◽  
P. Panetsos
Keyword(s):  
Ground Motion ◽  
Design Procedure ◽  
Strong Motion ◽  
Response Spectra ◽  
Concurrent Design ◽  
Motion Model ◽  
Specific Point ◽  
Extreme Stress ◽  
Seismic Motion

According to the model of Penzien and Watabe, the three translational ground motion components on a specific point of the ground are statistically noncorrelated along a well-defined orthogonal system of axes p, w, and v, whose orientation remains reasonably stable over time during the strong motion phase of an earthquake. This orthotropic ground motion is described by three generally independent response spectra Sa, Sb, and Sc, respectively. The paper presents an antiseismic design procedure for structures according to the above seismic motion model. This design includes a) determination of the critical orientation of the seismic input, i.e., the orientation that gives the largest response, b) calculation of the maximum and the minimum values of any response quantity, and c) application of either the Extreme Stress Method or the Extreme Force Method for determining the most unfavorable combinations of several stress resultants (or sectional forces) acting concurrently at a specified section of a structural member.

Engineering observations on ground motion at the Van Norman Complex after the 1994 Northridge earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S333-S349 ◽  
Author(s):  
J. P. Bardet ◽  
C. Davis
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Low Frequency ◽  
Strong Motion ◽  
Response Spectra ◽  
Vertical Acceleration ◽  
Northridge Earthquake ◽  
Peak Acceleration ◽  
Geotechnical Earthquake Engineering ◽  
1994 Northridge Earthquake

Abstract During the 1994 Northridge earthquake, the Van Norman Complex yielded an unprecedented number of recordings with high acceleration, in the close proximity of the fault rupture. These strong-motion recordings exhibited the pulses of the main event. One station recorded the largest velocity ever instrumentally recorded (177 cm/sec), resulting from a 0.86 g peak acceleration with a low frequency. Throughout the complex, the horizontal accelerations reached peak values ranging from 0.56 to 1.0 g, except for the complex center, where the peak acceleration did not exceed 0.43 g. The vertical acceleration reached maximum peak values comparable with those of the horizontal acceleration. The acceleration response spectra in the longitudinal and transverse directions were significantly different. Such a difference, which is not yet well documented in the field of geotechnical earthquake engineering, indicates that the amplitude and frequency content of the ground motion was directionally dependent in the Van Norman Complex.

scholarly journals A Procedure to Select Earthquake Time Histories for Deterministic Seismic Hazard Analysis: Case Studies of Major Cities in Taiwan

2017 ◽  
Author(s):  
Duruo Huang ◽  
Wenqi Du
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Surface ◽  
Strong Motion ◽  
Response Spectra ◽  
Dynamic Responses ◽  
Motion Time ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Deterministic Seismic Hazard

Abstract. In performance-based seismic design, ground-motion time histories are needed for analyzing dynamic responses of nonlinear structural systems. However, the number of strong-motion data at design level is often limited. In order to analyze seismic performance of structures, ground-motion time histories need to be either selected from recorded strong-motion database, or numerically simulated using stochastic approaches. In this paper, a detailed procedure to select proper acceleration time histories from the Next Generation Attenuation (NGA) database for several cities in Taiwan is presented. Target response spectra are initially determined based on a local ground motion prediction equation under representative deterministic seismic hazard analyses. Then several suites of ground motions are selected for these cities using the Design Ground Motion Library (DGML), a recently proposed interactive ground-motion selection tool. The selected time histories are representatives of the regional seismic hazard, and should be beneficial to earthquake studies when comprehensive seismic hazard assessments and site investigations are yet available. Note that this method is also applicable to site-specific motion selections with the target spectra near the ground surface considering the site effect.

Spatial Variability of Source and Attenuation Characteristics in Large Ground-Motion Datasets

2020 ◽  
Author(s):  
Sreeram Reddy Kotha ◽  
Graeme Weatherill ◽  
Dino Bindi ◽  
Fabrice Cotton
Keyword(s):  
Spatial Variability ◽  
Ground Motion ◽  
Ground Motions ◽  
Low Frequency ◽  
Strong Motion ◽  
Response Spectra ◽  
Large Datasets ◽  
Earthquake Scenarios ◽  
Crustal Earthquakes ◽  
Geographical Regions

<p>Ground-Motion Models (GMMs) characterize the random distributions of ground-motions for a combination of earthquake source, wave travel-path, and the effected site’s geological properties. Typically, GMMs are regressed over a compendium of strong ground-motion recordings collected from several earthquakes recorded at multiple sites scattered across a variety of geographical regions. The necessity of compiling such large datasets is to expand the range of magnitude, distance, and site-types; in order to regress a GMM capable of predicting realistic ground-motions for rare earthquake scenarios, e.g. large magnitudes at short distances from a reference rock site. The European Strong-Motion (ESM) dataset is one such compendium of observations from a few hundred shallow crustal earthquakes recorded at a several hundred seismic stations in Europe and Middle-East.</p><p>We developed new GMMs from the ESM dataset, capable of predicting both the response spectra and Fourier spectra in a broadband of periods and frequencies, respectively. However, given the clear tectonic and geological diversity of the data, possible regional and site-specific differences in observed ground-motions needed to be quantified; whilst also considering the possible contamination of data from outliers. Quantified regional differences indicate that high-frequency ground-motions attenuate faster with distance in Italy compared to the rest of Europe, as well as systematically weaker ground-motions from central Italian earthquakes. In addition, residual analyses evidence anisotropic attenuation of low frequency ground-motions, imitating the pattern of shear-wave energy radiation. With increasing spatial variability of ground-motion data, the GMM prediction variability apparently increases. Hence, robust mixed-effects regressions and residual analyses are employed to relax the ergodic assumption.</p><p>Large datasets, such as the ESM, NGA-West2, and from KiK-Net, provide ample opportunity to identify and evaluate the previously hypothesized event-to-event, region-to-region, and site-to-site differences in ground-motions. With the appropriate statistical methods, these variabilities can be quantified and applied in seismic hazard and risk predictions. We intend to present the new GMMs: their development, performance and applicability, prospective improvements and research needs.</p>

On-site Earthquake Early Warning: Predictive Models for Acceleration Response Spectra Considering Site-Effects

2020 ◽  
Author(s):  
Antonio Giovanni Iaccarino ◽  
Matteo Picozzi ◽  
Dino Bindi ◽  
Daniele Spallarossa
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Cross Validation ◽  
Prediction Models ◽  
Random Effect ◽  
Response Spectra ◽  
Site Effect ◽  
Ground Motion Prediction ◽  
Acceleration Response ◽  
Effect Regression

<p>Including site specific amplification factors in ground motion prediction models represented an advance for PSHA (Atkinson 2006; Rodríguez-Marek et al. 2013; Kotha et al. 2017) that has become nowadays a standard. However, this issue has only recently received attention by the seismological community of earthquake early warning (EEW) (Spallarossa et al., 2019; Zhao and Zhao, 2019), which applications require a real-time prediction of ground motion and the delivery of alert messages to users for mitigating their exposure to seismic risk. Indeed, all EEW systems are high-technological infrastructures devoted to the real-time and automatic detection of earthquakes, rapid assessment of the associated seismic hazard for targets and the prompt delivery of alerts trough fast telecommunication networks. Among them, the on-site approaches are based on seismic networks placed near to the target, indifferently by the location of seismic threats and they issue the alert predicting the ground motion at the target from P-wave parameter. This configuration cause that On-Site EEWS are generally highly affected by site conditions.</p><p>In this work, we calibrated ground motion prediction models for on-site EEW considering acceleration response spectra (RSA) and the P-waves EEW parameters Iv2 and Pd, and we investigated the role of site-effects. We considered a dataset of nearly 60 earthquakes belonging to the Central Italy 2016-17 sequence. The high density of stations near to the sequence has allowed us to use a non-ergodic random-effect regression approach to explore and to reduce the contribution of site-effects to the uncertainty of the On-site laws predictions. We grouped the records in two ways: by stations and by EC8 classification. Then, we validated the estimated models by the Leave One Out (L1Out) technique and applied a K-means analysis to assess the performance of the EC8 classification.</p><p>The residuals analysis proved that grouping by station provides a set of relations that improves the predictions at many stations. On the contrary, L1Out cross-validation proved that the regressions retrieved grouping by EC8 classification produce higher uncertainties on the predictions than the others. Furthermore, the cross-validation proved that Iv2 is more correlated to RSA than Pd. Finally, the analysis of the random effect vs period curves confirmed that EC8 classification is unrelated to the site effect on RSA even looking only at the trend of these curves.</p><p>In conclusion, non-ergodic random-effect regression can be used also in the EEW applications to predict site-specific ground motion. EEWS that use this approach are less dependent by site-effect and able to provide more precise and reliable alerts.</p>

Strong motion accelerograph records from the 1993 Napierville earthquake

1995 ◽  
Vol 22 (1) ◽  
pp. 190-196
Author(s):  
René Tinawi ◽  
André Filiatrault ◽  
Pierre Léger
Keyword(s):  
Ground Motion ◽  
Energy Content ◽  
Strong Motion ◽  
Response Spectra ◽  
High Energy ◽  
Period Range ◽  
Attenuation Relationships ◽  
Acceleration Time Histories ◽  
Short Period ◽  
Time Histories

An earthquake of magnitude ML = 4.3 occurred near Napierville, Quebec, on November 16, 1993. An accelerograph at the liquefaction, storage, and regasification plant of Gaz Metropolitain in Montreal, about 55 km from the epicentre, recorded the ground motion. Although the maximum accelerations and velocities from this event are small, the acceleration time histories do confirm the high energy content in the very short period range. The recorded ground motion and corresponding absolute acceleration response spectra are presented and various attenuation relationships, proposed for eastern North America, are utilized to compare the measured and predicted ground motion parameters. Key words: Napierville earthquake, attenuation relationships, acceleration spectra, strong motion records.

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