An Empirical Method for Estimating Source Vicinity Ground-Motion Levels on Hard Bedrock and Annual Exceedance Probabilities for Inland Crustal Earthquakes with Sources Difficult to Identify in Advance

2021 ◽  
Vol 111 (5) ◽  
pp. 2408-2425 ◽  
Author(s):  
Reiko Tajima ◽  
Hiroto Tanaka ◽  
Changjiang Wu
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Strong Motion ◽  
Specific Area ◽  
Response Spectra ◽  
Empirical Method ◽  
Fault Rupture ◽  
Vertical Array ◽  
Uniform Hazard Spectra ◽  
Crustal Earthquakes

ABSTRACT The locations and scales of the seismic sources of inland crustal earthquakes without surface fault traces (Mw≲6.5 in Japan) are difficult to identify in advance, even by conducting detailed surveys, and in such a case, it seems rational to uniformly evaluate ground-motion levels in the regions with similar seismogenic conditions. For such earthquakes, we first developed a technique to estimate ground-motion levels in a specific area by calculating the response spectra corresponding to nonexceedance probabilities (NEPs) based on probability density functions derived using strong-motion records. These records were used in the analysis after adjustments to the condition of being and on hard bedrock (VS≈2000–3000  m/s) in the source vicinity. Next, we developed an empirical method to estimate the correspondence between the NEP spectrum levels and their annual exceedance probabilities (AEPs) by considering annual occurrence frequencies for the target event group. Moreover, we showed an example that applied our approach to all over Japan, where a large number of downhole records on stiff baserock (VS≈700–3000  m/s) have been obtained by the KiK-net, a dense nationwide network of vertical array stations (pairs of surface and downhole recordings). In the example, we demonstrated that the empirical AEP spectral levels using our method are consistent with AEP response spectra, that is, uniform hazard spectra, derived from the probabilistic seismic hazard analysis using the kinematic fault rupture modeling method in a previous study.

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>

scholarly journals Development of synthetic ground motion at a specific site in Yogyakarta town, Indonesia utilizing the PSHA Method

2020 ◽  
Vol 156 ◽  
pp. 02011
Author(s):  
Widodo Pawirodikromo ◽  
Lalu Makrup ◽  
Mochamad Teguh ◽  
Bambang Suryo
Keyword(s):  
Pilot Study ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Ground Motions ◽  
Time History ◽  
Building Structures ◽  
Uniform Hazard Spectra ◽  
Crustal Earthquakes ◽  
History Analysis ◽  
Dynamic Time

This paper presents the development of synthetic ground motion at specific sites in Yogyakarta town. In the 2019 Indonesian Seismic Code [1] provides an alternative method in the analysis of building structures by applying the dynamic time history analysis. At least 11-pairs of earthquake recordings must be used in the analysis. Synthetic ground motion utilizing the Method of Probability Seismic Hazard Analysis (PSHA) was used in this study. A selected site in Yogyakarta town was chosen as a pilot study considering that there were many fatalities and building damage caused by the 2006 Yogyakarta earthquake. The Uniform Hazard Spectra (UHS) based on the shallow crustal earthquake source is higher than the Megathrust. The risk targeted spectrum demand MCEr has been considered, which on average 12.3% greater than the UHS. The synthetic ground motions (SGM) are accordingly based on the shallow crustal earthquakes. The dominant magnitude and distance are MD = 6.5 and RD = 14.5 km. They show that the contribution of the Opak River fault to the hazard in Yogyakarta town is very dominant because the distance is very close. Based on the obtained MD and RD, spectral matching, and testing significant duration D595, the 12-synthetic ground motions were successfully developed.

Performance of response spectral models against New Zealand data

2017 ◽  
Vol 50 (1) ◽  
pp. 21-38 ◽  
Author(s):  
Chris Van Houtte
Keyword(s):  
New Zealand ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Hazard Analysis ◽  
Strong Motion ◽  
Seismic Hazard Assessment ◽  
Crustal Earthquakes ◽  
Spectral Models ◽  
Strong Motion Database

An important component of seismic hazard assessment is the prediction of the potential ground motion generated by a given earthquake source. In New Zealand seismic hazard studies, it is commonplace for analysts to only adopt one or two models for predicting the ground motion, which does not capture the epistemic uncertainty associated with the prediction. This study analyses a suite of New Zealand and international models against the New Zealand Strong Motion Database, both for New Zealand crustal earthquakes and earthquakes in the Hikurangi subduction zone. It is found that, in general, the foreign models perform similarly or better with respect to recorded New Zealand data than the models specifically derived for New Zealand application. Justification is given for using global models in future seismic hazard analysis in New Zealand. Although this article does not provide definitive model weights for future hazard analysis, some recommendations and guidance are provided.

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 NGA-West2 Empirical Fourier and Duration Models to Generate Adjustable Response Spectra

2019 ◽  
Vol 35 (1) ◽  
pp. 61-93 ◽  
Author(s):  
Sanjay Singh Bora ◽  
Fabrice Cotton ◽  
Frank Scherbaum
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Amplitude Spectrum ◽  
Response Spectra ◽  
Duration Model ◽  
Fourier Amplitude ◽  
Crustal Earthquakes ◽  
Active Tectonic ◽  
Random Vibration Theory ◽  
Fourier Amplitude Spectrum

Adjustment of median ground motion prediction equations (GMPEs) from one region to another region is one of the major challenges within the current practice of seismic hazard analysis. In our approach of generating response spectra, we derive two separate empirical models for a) Fourier amplitude spectrum (FAS) and b) duration of ground motion. To calculate response spectra, the two models are combined within the random vibration theory (RVT) framework. The models are calibrated on recordings obtained from shallow crustal earthquakes in active tectonic regions. We use a subset of NGA-West2 database with M3.2–7.9 earthquakes at distances 0–300 km. The NGA-West2 database expanded over a wide magnitude and distance range facilitates a better constraint over derived models. A frequency-dependent duration model is derived to obtain adjustable response spectral ordinates. Excellent comparison of our approach with other NGA-West2 models implies that it can also be used as a stand-alone model.

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.

An NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra

2008 ◽  
Vol 24 (1) ◽  
pp. 173-215 ◽  
Author(s):  
BrianS-J. Chiou ◽  
Robert R. Youngs
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Hanging Wall ◽  
Response Spectra ◽  
Horizontal Component ◽  
Smooth Functions ◽  
Soil Response ◽  
New Model ◽  
Crustal Earthquakes ◽  
Aleatory Variability

We present a model for estimating horizontal ground motion amplitudes caused by shallow crustal earthquakes occurring in active tectonic environments. The model provides predictive relationships for the orientation-independent average horizontal component of ground motions. Relationships are provided for peak acceleration, peak velocity, and 5-percent damped pseudo-spectral acceleration for spectral periods of 0.01 to 10 seconds. The model represents an update of the relationships developed by Sadigh et. al. (1997) and incorporates improved magnitude and distance scaling forms as well as hanging-wall effects. Site effects are represented by smooth functions of average shear wave velocity of the upper 30 m ( VS30) and sediment depth. The new model predicts median ground motion that is similar to Sadigh et. al. (1997) at short spectral period, but lower ground motions at longer periods. The new model produces slightly lower ground motions in the distance range of 10 to 50 km and larger ground motions at larger distances. The aleatory variability in ground motion amplitude was found to depend upon earthquake magnitude and on the degree of nonlinear soil response, For large magnitude earthquakes, the aleatory variability is larger than found by Sadigh et. al. (1997).

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.

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