Conditional Ground-Motion Models for Horizontal Peak Ground Displacement for Active Crustal Regions

Author(s):  
Chih-Hsuan Sung ◽  
Norman A. Abrahamson ◽  
Jyun-Yan Huang

ABSTRACT Ground-motion models (GMMs) are developed for peak ground displacement (PGD) and for bandlimited PGD based on strong-motion data that has been filtered as part of standard processing and the total PGD that includes the tectonic deformation as well as the vibratory ground motion. For the bandlimited PGD, we develop conditional ground-motion models (CGMMs) using subsets of the Pacific Earthquake Engineering Research Center Next Generation Attenuation-West2 Project (NGA-W2) database and the National Center for Research on Earthquake Engineering Taiwan Senior Seismic Hazard Analysis Committee level 3 project database. The CGMM approach includes the observed pseudospectral acceleration (PSA(T)) as an input parameter in addition to magnitude and distance. The period of the PSA(T) is used as an input parameter; it is magnitude dependent and is based on the period for which there is the highest correlation between the ln(PGD) and ln(PSA(T)). Two CGMMs are developed: a global model based on the NGA-W2 data and a region-specific model for Taiwan. The conditional PGD models are combined with traditional GMMs for PSA(T) values to develop GMMs for both the median and standard deviation of PGD without the dependence on PSA. A second set of PGD GMMs are developed to correct for two factors: the effect of the high-pass filtering from standard record processing and the stronger large magnitude (M>6.5) scaling due to tectonic deformation. For magnitudes greater than 7, the PGD values from the total PGD GMMs are 2–5 times larger than the bandlimited PGD values based on the strong-motion data sets, but the increase is at very long periods. The appropriate PGD model to use, bandlimited PGD or total PGD, depends on the period range of interest for the specific engineering application.

2008 ◽  
Vol 24 (1) ◽  
pp. 3-21 ◽  
Author(s):  
Maurice Power ◽  
Brian Chiou ◽  
Norman Abrahamson ◽  
Yousef Bozorgnia ◽  
Thomas Shantz ◽  
...  

The “Next Generation of Ground-Motion Attenuation Models” (NGA) project is a multidisciplinary research program coordinated by the Lifelines Program of the Pacific Earthquake Engineering Research Center (PEER), in partnership with the U.S. Geological Survey and the Southern California Earthquake Center. The objective of the project is to develop new ground-motion prediction relations through a comprehensive and highly interactive research program. Five sets of ground-motion models were developed by teams working independently but interacting with one another throughout the development process. The development of ground-motion models was supported by other project components, which included (1) developing an updated and expanded PEER database of recorded ground motions, including supporting information on the strong-motion record processing, earthquake sources, travel path, and recording station site conditions; (2) conducting supporting research projects to provide guidance on the selected functional forms of the ground-motion models; and (3) conducting a program of interactions throughout the development process to provide input and reviews from both the scientific research and engineering user communities. An overview of the NGA project components, process, and products is presented in this paper.


Author(s):  
Giovanni Lanzano ◽  
Lucia Luzi ◽  
Carlo Cauzzi ◽  
Jarek Bienkowski ◽  
Dino Bindi ◽  
...  

Abstract Strong ground motion records and free open access to strong-motion data repositories are fundamental inputs to seismology, engineering seismology, soil dynamics, and earthquake engineering science and practice. This article presents the current status and outlook of the Observatories and Research Facilities for European Seismology (ORFEUS) coordinated strong-motion seismology services, namely the rapid raw strong-motion (RRSM) and the engineering strong-motion (ESM) databases and associated web interfaces and webservices. We compare and discuss the role and use of these two systems using the Mw 6.5 Norcia (Central Italy) earthquake that occurred on 30 October 2016 as an example of a well-recorded earthquake that triggered major interest in the seismological and earthquake engineering communities. The RRSM is a fully automated system for rapid dissemination of earthquake shaking information, whereas the ESM provides quality-checked, manually processed waveforms and reviewed earthquake information. The RRSM uses only data from the European Integrated Waveform Data Archive, whereas the ESM also includes offline data from other sources, such as the ITalian ACcelerometric Archive (ITACA). Advanced software tools are also included in the ESM to allow users to process strong-motion data and to select ground-motion waveform sets for seismic structural analyses. The RRSM and ESM are complementary services designed for a variety of possible stakeholders, ranging from scientists to the educated general public. The RRSM and ESM are developed, organized, and reviewed by selected members of the seismological community in Europe, including strong-motion data providers and expert users. Global access and usage of the data is encouraged. The ESM is presently the reference database for harmonized seismic hazard and risk studies in Europe. ORFEUS strong-motion data are open, “Findable, Accessible, Interoperable, and Reusable,” and accompanied by licensing information. The users are encouraged to properly cite the data providers, using the digital object identifiers of the seismic networks.


Author(s):  
Soumya Kanti Maiti ◽  
Gony Yagoda-Biran ◽  
Ronnie Kamai

ABSTRACT Models for estimating earthquake ground motions are a key component in seismic hazard analysis. In data-rich regions, these models are mostly empirical, relying on the ever-increasing ground-motion databases. However, in areas in which strong-motion data are scarce, other approaches for ground-motion estimates are sought, including, but not limited to, the use of simulations to replace empirical data. In Israel, despite a clear seismic hazard posed by the active plate boundary on its eastern border, the instrumental record is sparse and poor, leading to the use of global models for hazard estimation in the building code and all other engineering applications. In this study, we develop a suite of alternative ground-motion models for Israel, based on an empirical database from Israel as well as on four data-calibrated synthetic databases. Two host models are used to constrain model behavior, such that the epistemic uncertainty is captured and characterized. Despite the lack of empirical data at large magnitudes and short distances, constraints based on the host models or on the physical grounds provided by simulations ensure these models are appropriate for engineering applications. The models presented herein are cast in terms of the Fourier amplitude spectra, which is a linear, physical representation of ground motions. The models are suitable for shallow crustal earthquakes; they include an estimate of the median and the aleatory variability, and are applicable in the magnitude range of 3–8 and distance range of 1–300 km.


2015 ◽  
Vol 31 (3) ◽  
pp. 1629-1645 ◽  
Author(s):  
Ronnie Kamai ◽  
Norman Abrahamson

We evaluate how much of the fling effect is removed from the NGA database and accompanying GMPEs due to standard strong motion processing. The analysis uses a large set of finite-fault simulations, processed with four different high-pass filter corners, representing the distribution within the PEER ground motion database. The effects of processing on the average horizontal component, the vertical component, and peak ground motion values are evaluated by taking the ratio between unprocessed and processed values. The results show that PGA, PGV, and other spectral values are not significantly affected by processing, partly thanks to the maximum period constraint used when developing the NGA GMPEs, but that the bias in peak ground displacement should not be ignored.


Author(s):  
Paul Somerville

This paper reviews concepts and trends in seismic hazard characterization that have emerged in the past decade, and identifies trends and concepts that are anticipated during the coming decade. New methods have been developed for characterizing potential earthquake sources that use geological and geodetic data in conjunction with historical seismicity data. Scaling relationships among earthquake source parameters have been developed to provide a more detailed representation of the earthquake source for ground motion prediction. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude - distance - soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near- fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes. The probabilistic approach to characterizing the ground motion that a given site will experience in the future is very compatible with current trends in earthquake engineering and the development of building codes. Performance based design requires a more comprehensive representation of ground motions than has conventionally been used. Ground motions estimates are needed at multiple annual probability levels, and may need to be specified not only by response spectra but also by suites of strong motion time histories for input into time-domain non-linear analyses of structures.


Author(s):  
Tomohisa Okazaki ◽  
Nobuyuki Morikawa ◽  
Asako Iwaki ◽  
Hiroyuki Fujiwara ◽  
Tomoharu Iwata ◽  
...  

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.


2004 ◽  
Vol 56 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Ryou Honda ◽  
Shin Aoi ◽  
Nobuyuki Morikawa ◽  
Haruko Sekiguchi ◽  
Takashi Kunugi ◽  
...  

2012 ◽  
Vol 10 (2) ◽  
pp. 131-154
Author(s):  
Borko Bulajic ◽  
Miodrag Manic ◽  
Djordje Ladjinovic

Eurocode 8 allows that any country can use its own shape of the elastic response spectrum after it defines it in the National Annex. Having in mind that such country-specific spectra are to be derived through analysis of the strong motion data recorded in the considered seismo-tectonic region, in this Paper we discuss the existing and a set of new empirical equations for scaling pseudo-acceleration spectra in Serbia and the whole region of north-western Balkans. We then compare the presented spectra to those proposed by Eurocode 8. Results show that the indiscriminate use of the strong motion data from different seismo-tectonic regions, improper classification of the local soil conditions, and neglect of the effects of deep geology, may all lead to unreliable scaling equations and to extremely biased ground motion estimates. Moreover, only two spectral shapes that are defined for wide magnitude ranges and scaled by a single PGA value, are not able to adequately represent all important features of real strong ground motion, and instead of using such normalized spectra one should rather employ the direct scaling of spectral amplitudes that is based on the analysis of regionally gathered and processed strong motion data.


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