Ground motions variability in Israel from 3-D simulations of M 6 and M 7 earthquakes

Abstract. In Israel, due to low seismicity rates and sparse seismic network, the temporal and spatial coverage of ground motion data is insufficient to estimate the variability of moderate-strong (M > 6) ground motions required to construct a local ground motion model (GMM). To fill this data gap and to study the ground motions variability of M > 6 events, we performed a series of 3-D numerical simulations of M 6 and M 7 earthquakes. Based on the results of the simulations, we developed a statistical attenuation model (AM) and studied the residuals between simulated and AM PGVs and the single station variability. We also compared the simulated ground motions with a global GMM in terms of peak ground velocity (PGV) and significant duration (Ds 595). Our results suggest that the AM was unable to fully capture the simulated ground motions variability, mainly due to the incorporation of super-shear rupture and effects of local sedimentary structures. We also show that an imported GMM considerably deviates from simulated ground motions. This work sets the basis for future development of a comprehensive GMM for Israel, accounting for local sources, path, and site effects.

A Far-Field Ground-Motion Model for the North Australian Craton from Plate-Margin Earthquakes

10.1785/0120210191 ◽

2021 ◽

Author(s):

Trevor I. Allen

Keyword(s):

Ground Motion ◽

Ground Motions ◽

Peak Ground Velocity ◽

Far Field ◽

Motion Model ◽

Ground Acceleration ◽

Depth Dependence ◽

Ground Motion Model ◽

Plate Margin ◽

Short Period

ABSTRACT The Australian territory is just over 400 km from an active convergent plate margin with the collision of the Sunda–Banda Arc with the Precambrian and Palaeozoic Australian continental crust. Seismic energy from earthquakes in the northern Australian plate-margin region are channeled efficiently through the low-attenuation North Australian craton (NAC), with moderate-sized (Mw≥5.0) earthquakes in the Banda Sea commonly felt in northern Australia. A far-field ground-motion model (GMM) has been developed for use in seismic hazard studies for sites located within the NAC. The model is applicable for hypocentral distances of approximately 500–1500 km and magnitudes up to Mw 8.0. The GMM provides coefficients for peak ground acceleration, peak ground velocity, and 5%-damped pseudospectral acceleration at 20 oscillator periods from 0.1 to 10 s. A strong hypocentral depth dependence is observed in empirical data, with earthquakes occurring at depths of 100–200 km demonstrating larger amplitudes for short-period ground motions than events with shallower hypocenters. The depth dependence of ground motion diminishes with longer spectral periods, suggesting that the relatively larger ground motions for deeper earthquake hypocenters may be due to more compact ruptures producing higher stress drops at depth. Compared with the mean Next Generation Attenuation-East GMM developed for the central and eastern United States (which is applicable for a similar distance range), the NAC GMM demonstrates significantly higher short-period ground motion for Banda Sea events, transitioning to lower relative accelerations for longer period ground motions.

The ShakeOut Earthquake Source and Ground Motion Simulations

Earthquake Spectra ◽

10.1193/1.3570677 ◽

2011 ◽

Vol 27 (2) ◽

pp. 273-291 ◽

Cited By ~ 30

Author(s):

Robert W. Graves ◽

Brad T. Aagaard ◽

Kenneth W. Hudnut

Keyword(s):

Ground Motion ◽

Ground Motions ◽

Strong Motion ◽

Peak Ground Velocity ◽

Motion Modeling ◽

Ground Acceleration ◽

San Andreas ◽

Basin Effects ◽

Simulated Ground Motions ◽

D Model

The ShakeOut Scenario is premised upon the detailed description of a hypothetical Mw 7.8 earthquake on the southern San Andreas Fault and the associated simulated ground motions. The main features of the scenario, such as its endpoints, magnitude, and gross slip distribution, were defined through expert opinion and incorporated information from many previous studies. Slip at smaller length scales, rupture speed, and rise time were constrained using empirical relationships and experience gained from previous strong-motion modeling. Using this rupture description and a 3-D model of the crust, broadband ground motions were computed over a large region of Southern California. The largest simulated peak ground acceleration (PGA) and peak ground velocity (PGV) generally range from 0.5 to 1.0 g and 100 to 250 cm/s, respectively, with the waveforms exhibiting strong directivity and basin effects. Use of a slip-predictable model results in a high static stress drop event and produces ground motions somewhat higher than median level predictions from NGA ground motion prediction equations (GMPEs).

A subset of CyberShake ground-motion time series for response-history analysis

Earthquake Spectra ◽

10.1177/8755293020981970 ◽

2021 ◽

pp. 875529302098197

Author(s):

Jack W Baker ◽

Sanaz Rezaeian ◽

Christine A Goulet ◽

Nicolas Luco ◽

Ganyu Teng

Keyword(s):

Time Series ◽

Los Angeles ◽

Seismic Hazard ◽

Ground Motion ◽

Ground Motions ◽

Response Spectra ◽

Motion Time ◽

History Analysis ◽

Response History Analysis ◽

This manuscript describes a subset of CyberShake numerically simulated ground motions that were selected and vetted for use in engineering response-history analyses. Ground motions were selected that have seismological properties and response spectra representative of conditions in the Los Angeles area, based on disaggregation of seismic hazard. Ground motions were selected from millions of available time series and were reviewed to confirm their suitability for response-history analysis. The processes used to select the time series, the characteristics of the resulting data, and the provided documentation are described in this article. The resulting data and documentation are available electronically.

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

Bulletin of Earthquake Engineering ◽

10.1007/s10518-021-01077-1 ◽

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.

Simulation of response spectrum-compatible ground motions using wavelet-based multi-resolution analysis

Measurement and Control ◽

10.1177/00202940211013057 ◽

2021 ◽

pp. 002029402110130

Author(s):

Guan Chen ◽

Zhiren Zhu ◽

Jun Hu

Keyword(s):

Ground Motion ◽

Response Spectrum ◽

Ground Motions ◽

Power Spectra ◽

Simulation Method ◽

Eurocode 8 ◽

Effective Response ◽

Multi Resolution Analysis ◽

Resolution Analysis ◽

This study proposed a simple and effective response spectrum-compatible ground motions simulation method to mitigate the scarcity of ground motions on seismic hazard analysis base on wavelet-based multi-resolution analysis. The feasibility of the proposed method is illustrated with two recorded ground motions in El Mayor-Cucapah earthquake. The results show that the proposed method enriches the ground motions exponentially. The simulated ground motions agree well with the attenuation characteristics of seismic ground motion without modulating process. Moreover, the pseudo-acceleration response spectrum error between the recorded ground motion and the average of the simulated ground motions is 5.2%, which fulfills the requirement prescribed in Eurocode 8 for artificially simulated ground motions. Besides, the cumulative power spectra between the simulated and recorded ground motions agree well on both high- and low-frequency regions. Therefore, the proposed method offers a feasible alternative in enriching response spectrum-compatible ground motions, especially on the regions with insufficient ground motions.

The 30 October 2020 Samos (Eastern Aegean Sea) Earthquake: effects of source rupture, path and local-site conditions on the observed and simulated ground motions

10.21203/rs.3.rs-215817/v1 ◽

2021 ◽

Author(s):

Aybige Akinci ◽

Daniele Cheloni ◽

AHMET ANIL DINDAR

Keyword(s):

Ground Motion ◽

Structural Damage ◽

Ground Motions ◽

Aegean Sea ◽

Peak Ground Velocity ◽

Ground Shaking ◽

Local Site ◽

Eastern Aegean ◽

Motion Characteristics ◽

Eastern Aegean Sea

Abstract On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately 70 km from the epicenter. In this study, we provide a detailed description of the Samos earthquake, starting from the fault rupture to the ground motion characteristics. We first use Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data to constrain the source mechanisms. Then, we utilize this information to analyze the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and spectral pseudo-accelerations. Modelling of geodetic data shows that the Samos earthquake ruptured a NNE-dipping normal fault located offshore north of Samos, with up to 2.5-3 m of slip and an estimated geodetic moment of 3.3 ⨯ 1019 Nm (MW 7.0). Although low PGA were induced by the earthquake, the ground shaking was strongly amplified in Izmir throughout the alluvial sediments. Structural damage observed in Izmir reveals the potential of seismic risk due to the local site effects. To better understand the earthquake characteristics, we generated and compared stochastic strong ground motions with the observed ground motion parameters as well as the ground motion prediction equations (GMPEs), exploring also the efficacy of the region-specific parameters which may be improved to better predict the expected ground shaking from future large earthquakes in the region.

Ground-Motion Prediction Model Based on Neural Networks to Extract Site Properties from Observational Records

10.1785/0120200339 ◽

2021 ◽

Author(s):

Tomohisa Okazaki ◽

Nobuyuki Morikawa ◽

Asako Iwaki ◽

Hiroyuki Fujiwara ◽

Tomoharu Iwata ◽

...

Keyword(s):

Ground Motion ◽

Ground Acceleration ◽

Site Specific ◽

Motion Data ◽

Motion Models ◽

Proposed Model ◽

Single Station ◽

Input Variables ◽

Ground Condition ◽

Ground Motion Models

ABSTRACT Choosing the method for inputting site conditions is critical in reducing the uncertainty of empirical ground-motion models (GMMs). We apply a neural network (NN) to construct a GMM of peak ground acceleration that extracts site properties from ground-motion data instead of referring to ground condition variables given for each site. A key structure of the model is one-hot representations of the site ID, that is, specifying the collection site of each ground-motion record by preparing input variables corresponding to all observation sites. This representation makes the best use of the flexibility of NN to obtain site-specific properties while avoiding overfitting at sites where a small number of strong motions have been recorded. The proposed model exhibits accurate and robust estimations among several compared models in different aspects, including data-poor sites and strong motions from large earthquakes. This model is expected to derive a single-station sigma that evaluates the residual uncertainty under the specification of estimation sites. The proposed NN structure of one-hot representations would serve as a standard ingredient for constructing site-specific GMMs in general regions.

Deterministic 3D Ground-Motion Simulations (0–5 Hz) and Surface Topography Effects of the 30 October 2016 Mw 6.5 Norcia, Italy, Earthquake

10.1785/0120210133 ◽

2021 ◽

Author(s):

Arben Pitarka ◽

Aybige Akinci ◽

Pasquale De Gori ◽

Mauro Buttinelli

Keyword(s):

Surface Topography ◽

Ground Motion ◽

Seismic Station ◽

Ground Motions ◽

Peak Ground Velocity ◽

Earth Model ◽

Rupture Directivity ◽

Epicentral Area ◽

Near Fault ◽

Local Topography

ABSTRACT The Mw 6.5 Norcia, Italy, earthquake occurred on 30 October 2016 and caused extensive damage to buildings in the epicentral area. The earthquake was recorded by a network of strong-motion stations, including 14 stations located within a 5 km distance from the two causative faults. We used a numerical approach for generating seismic waves from two hybrid deterministic and stochastic kinematic fault rupture models propagating through a 3D Earth model derived from seismic tomography and local geology. The broadband simulations were performed in the 0–5 Hz frequency range using a physics-based deterministic approach modeling the earthquake rupture and elastic wave propagation. We used SW4, a finite-difference code that uses a conforming curvilinear mesh, designed to model surface topography with high numerical accuracy. The simulations reproduce the amplitude and duration of observed near-fault ground motions. Our results also suggest that due to the local fault-slip pattern and upward rupture directivity, the spatial pattern of the horizontal near-fault ground motion generated during the earthquake was complex and characterized by several local minima and maxima. Some of these local ground-motion maxima in the near-fault region were not observed because of the sparse station coverage. The simulated peak ground velocity (PGV) is higher than both the recorded PGV and predicted PGV based on empirical models for several areas located above the fault planes. Ground motions calculated with and without surface topography indicate that, on average, the local topography amplifies the ground-motion velocity by 30%. There is correlation between the PGV and local topography, with the PGV being higher at hilltops. In contrast, spatial variations of simulated PGA do not correlate with the surface topography. Simulated ground motions are important for seismic hazard and engineering assessments for areas that lack seismic station coverage and historical recordings from large damaging earthquakes.

NGA-Subduction research program

Earthquake Spectra ◽

10.1177/87552930211056081 ◽

2021 ◽

pp. 875529302110560

Author(s):

Yousef Bozorgnia ◽

Norman A Abrahamson ◽

Sean K Ahdi ◽

Timothy D Ancheta ◽

Linda Al Atik ◽

...

Keyword(s):

Ground Motion ◽

Research Program ◽

Epistemic Uncertainty ◽

Specific Model ◽

Peak Ground Velocity ◽

Ground Acceleration ◽

Motion Data ◽

Motion Models ◽

Aleatory Variability ◽

Adjustment Factors

This article summarizes the Next Generation Attenuation (NGA) Subduction (NGA-Sub) project, a major research program to develop a database and ground motion models (GMMs) for subduction regions. A comprehensive database of subduction earthquakes recorded worldwide was developed. The database includes a total of 214,020 individual records from 1,880 subduction events, which is by far the largest database of all the NGA programs. As part of the NGA-Sub program, four GMMs were developed. Three of them are global subduction GMMs with adjustment factors for up to seven worldwide regions: Alaska, Cascadia, Central America and Mexico, Japan, New Zealand, South America, and Taiwan. The fourth GMM is a new Japan-specific model. The GMMs provide median predictions, and the associated aleatory variability, of RotD50 horizontal components of peak ground acceleration, peak ground velocity, and 5%-damped pseudo-spectral acceleration (PSA) at oscillator periods ranging from 0.01 to 10 s. Three GMMs also quantified “within-model” epistemic uncertainty of the median prediction, which is important in regions with sparse ground motion data, such as Cascadia. In addition, a damping scaling model was developed to scale the predicted 5%-damped PSA of horizontal components to other damping ratios ranging from 0.5% to 30%. The NGA-Sub flatfile, which was used for the development of the NGA-Sub GMMs, and the NGA-Sub GMMs coded on various software platforms, have been posted for public use.

Evaluation of Earthquake Response Spectra Directionality Using Stochastic Simulations

10.1785/0120210101 ◽

2021 ◽

Author(s):

Alan Poulos ◽

Eduardo Miranda ◽

Jack W. Baker

Keyword(s):

Stochastic Process ◽

Ground Motion ◽

Ground Motions ◽

Gaussian White Noise ◽

Response Spectra ◽

Orientation Dependence ◽

Stochastic Simulations ◽

Earthquake Ground Motion ◽

Significant Duration ◽

ABSTRACT For earthquake-resistant design purposes, ground-motion intensity is usually characterized using response spectra. The amplitude of response spectral ordinates of horizontal components varies significantly with changes in orientation. This change in intensity with orientation is commonly known as ground-motion directionality. Although this directionality has been attributed to several factors, such as topographic irregularities, near-fault effects, and local geologic heterogeneities, the mechanism behind this phenomenon is still not well understood. This work studies the directionality characteristics of earthquake ground-motion intensity using synthetic ground motions and compares their directionality to that of recorded ground motions. The two principal components of horizontal acceleration are sampled independently using a stochastic model based on finite-duration time-modulated filtered Gaussian white-noise processes. By using the same stochastic process to sample both horizontal components of motion, the variance of horizontal ground acceleration has negligible orientation dependence. However, these simulations’ response spectral ordinates present directionality levels comparable to those found in real ground motions. It is shown that the directionality of the simulated ground motions changes for each realization of the stochastic process and is a consequence of the duration being finite. Simulated ground motions also present similar directionality trends to recorded earthquake ground motions, such as the increase of average directionality with increasing period of vibration and decrease with increasing significant duration. These results suggest that most of the orientation dependence of horizontal response spectra is primarily explained by the finite significant duration of earthquake ground motion causing inherent randomness in response spectra, rather than by some physical mechanism causing polarization of shaking.