On Scaling of Earthquake Rise‐Time Estimates

2019 ◽  
Vol 109 (6) ◽  
pp. 2741-2745
Author(s):  
Alexander A. Gusev ◽  
Danila Chebrov
Keyword(s):  
Ground Motion ◽  
Strong Motion ◽  
Scaling Behavior ◽  
Corner Frequency ◽  
Source Spectrum ◽  
Self Similarity ◽  
Data Set ◽  
Motion Data ◽  
Time Estimates ◽  
Earthquake Ruptures

Abstract The scaling behavior of rise times Tr determined within earthquake source inversions that used strong‐motion data is determined using estimates as accumulated in the SRCMOD database. The Tr versus M0 trend derived from this data set is close to logTr=1/3logM0+ const; this agrees with the assumption of self‐similarity of earthquake ruptures. No biasing effect of station distance on Tr was found. The result was compared to recent scaling estimates based on mass teleseismic inversions. Absolute levels of teleseismic and local inversions match well; the slope of the trend of teleseismic estimates is somewhat more gradual. The absolute levels of Tr versus M0 trends recovered from finite source inversions may need reduction when used to predict parameters of near‐source ground motion. The observed scaling behavior of Tr is incompatible with the assumption that Tr defines the second corner frequency of the source spectrum.

scholarly journals Seismological and Engineering Characteristics of Strong Motion Data from 24 and 26 September 2019 Marmara Sea Earthquakes

2021 ◽  
Author(s):  
Fatma Sevil Malcıoğlu ◽  
Hakan Süleyman ◽  
Eser Çaktı
Keyword(s):  
Ground Motion ◽  
Prediction Models ◽  
Strong Motion ◽  
P Wave ◽  
Corner Frequency ◽  
Marmara Region ◽  
Marmara Sea ◽  
S Wave ◽  
Data Set ◽  
Motion Data

Abstract An MW 4.5 earthquake took place on September 24, 2019 in the Marmara Sea. Two days after, on September 26, 2019, Marmara region was rattled by an MW5.7 earthquake. With the intention of compiling an ample strong ground motion data set of recordings, we have utilized the stations of Istanbul Earthquake Rapid Response and Early Warning System operated by the Department of Earthquake Engineering of Boğaziçi University and of the National Strong Motion Network operated by AFAD. All together 438 individual records are used to calculate the source parameters of events; namely, corner frequency, radius, rupture area, average source dislocation, source duration and stress drop. Some of these parameters are compared with empirical relationships and discussed extensively. Duration characteristics are analyzed in two steps; first, by making use of the time difference between P-wave and S-wave onsets and then, by considering S-wave durations and significant durations. It is observed that they yield similar trends with global models. PGA, PGV and SA values are compared with three commonly used ground motion prediction models. At distances closer than about 60 km observed intensity measures mostly conform with the GMPE predictions. Beyond 60 km their attenuation is clearly faster than those of GMPEs. Frequency-dependent Q models are developed for both events. Their consistency with existing regional models are confirmed.

NGA Project Strong-Motion Database

2008 ◽  
Vol 24 (1) ◽  
pp. 23-44 ◽  
Author(s):  
Brian Chiou ◽  
Robert Darragh ◽  
Nick Gregor ◽  
Walter Silva
Keyword(s):  
Time Series ◽  
Ground Motion ◽  
Model Development ◽  
Strong Motion ◽  
Corner Frequency ◽  
Engineering Practice ◽  
Data Set ◽  
Acceleration Time ◽  
Crustal Earthquakes ◽  
Strong Motion Database

A key component of the NGA research project was the development of a strong-motion database with improved quality and content that could be used for ground-motion research as well as for engineering practice. Development of the NGA database was executed through the Lifelines program of the PEER Center with contributions from several research organizations and many individuals in the engineering and seismological communities. Currently, the data set consists of 3551 publicly available multi-component records from 173 shallow crustal earthquakes, ranging in magnitude from 4.2 to 7.9. Each acceleration time series has been corrected and filtered, and pseudo absolute spectral acceleration at multiple damping levels has been computed for each of the 3 components of the acceleration time series. The lowest limit of usable spectral frequency was determined based on the type of filter and the filter corner frequency. For NGA model development, the two horizontal acceleration components were further rotated to form the orientation-independent measure of horizontal ground motion (GMRotI50). In addition to the ground-motion parameters, a large and comprehensive list of metadata characterizing the recording conditions of each record was also developed. NGA data have been systematically checked and reviewed by experts and NGA developers.

scholarly journals Seismic hazard evaluation

2000 ◽  
Vol 33 (3) ◽  
pp. 371-386 ◽  
Author(s):  
Paul Somerville
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Earthquake Source ◽  
Hazard Evaluation ◽  
Data Set ◽  
Motion Models ◽  
The Past ◽  
Ground Motion Models

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.

scholarly journals A New Approach to Estimate a Mixed Model–Based Ground Motion Prediction Equation

2007 ◽  
Vol 23 (3) ◽  
pp. 665-684 ◽  
Author(s):  
Behrooz Tavakoli ◽  
Shahram Pezeshk
Keyword(s):  
Ground Motion ◽  
Mixed Model ◽  
Prediction Equation ◽  
Regression Coefficients ◽  
Motion Prediction ◽  
Ground Motion Prediction Equation ◽  
Predictive Equation ◽  
Ground Motion Prediction ◽  
Data Set ◽  
Motion Data

A derivative-free approach based on a hybrid genetic algorithm (HGA) is proposed to estimate a mixed model–based ground motion prediction equation (attenuation relationship) with several variance components. First, a simplex search algorithm (SSA) is used to reduce the search domain to improve the convergence speed. Then, a genetic algorithm (GA) is employed to obtain the regression coefficients and the uncertainties of a predictive equation in a unified framework using one-stage maximum-likelihood estimation. The proposed HGA results in a predictive equation that best fits a given ground motion data set. The proposed HGA is able to handle changes in the functional form of the equation. To demonstrate the solution quality of the proposed HGA, the regression coefficients and the uncertainties of a test function based on a simulated ground motion data set are obtained. Then, the proposed HGA is applied to fit two functional attenuation forms to an actual data set of ground motion. For illustration, the results of the HGA are compared with those used by previous conventional methods. The results indicate that the HGA is an appropriate algorithm to overcome the shortcomings of the previous methods and to provide reliable and stable solutions.

Exploring the dimensionality of ground motion data

2020 ◽  
Author(s):  
Reza Dokht Dolatabadi Esfahani ◽  
Kristin Vogel ◽  
Fabrice Cotton ◽  
Matthias Ohrnberger ◽  
Frank Scherbaum ◽  
...  
Keyword(s):  
Ground Motion ◽  
Predictive Power ◽  
Epistemic Uncertainty ◽  
Dimensional Space ◽  
Amplitude Spectrum ◽  
Strong Motion ◽  
Motion Prediction ◽  
Dimensional Manifold ◽  
Ground Motion Prediction ◽  
Motion Data

<p>For years, engineering seismologists aim to reduce the epistemic uncertainty related to ground motion prediction. Assuming that simple models with few variables are not sufficient to describe the complex phenomena, there is a trend in present-day science to increase complexity of ground motion models. Therefore, some of the most recent ground motion prediction equations use more than 20 variables to improve the predictive power of the model. However, the legitimate question to ask is whether the inclusion of additional variables leads to an improved predictive power of the model. In other words, what is the smallest number of predictive variables needed to reconstruct the distribution of ground motion induced shaking observed in data? In this study, by taking advantage of the exponential growth of ground motion data and new machine learning methods, we present a data-driven approach to derive the dimensionality of ground motion data in the Fourier amplitude spectrum (FAS) metric. We apply an autoencoder architecture, which is commonly used for mapping high dimensional data to a lower dimensional space (bottleneck) and search for the lowest dimensionality (minimum number of nodes in the bottleneck) required to reconstruct the FAS input data. The approach is tested on synthetic ground motion data with known dimensionality (2D and 4D) and finally applied to the FAS of recorded ground motion data. A simple autoencoder with variable nodes in the bottleneck is used to explore the dimensionality of the ground motion data. We use the relation between the total residual of the network with the number of codes in the bottleneck as an indicator of dimensionality. Its numerical value is estimated based on the reduction of residuals by increasing the number of codes in the bottleneck layer. In addition, we use the low dimensional manifold of the ground motion data to predict the ground motion shaking for a given scenario. The residual analyses between observed and reconstructed data and observed and predicted data are used to validate the training and prediction steps. We applied the method on different scenarios in two synthetic data sets which are simulated by a stochastic simulation method and secondly the Pan-European engineering strong motion data (EMS) to show the performance of the proposed method. The results show that the statistical properties of ground motion data can be captured by using a limited number of three to five parameters. Especially for low frequency data the most dominant features are already captured by two parameters (codes), which roughly correspond to magnitude and distance. For higher frequencies additional parameters, e.g. corresponding to stress drop and kappa, become more relevant. The standard deviation of the residuals can be reduced to its lower bound in comparison with the standard deviations of conventional methods. Finally, we use a two-dimensional manifold to predict the FAS for given magnitude and distance values.</p>

The Whittier Narrows, California Earthquake of October 1, 1987—CSMIP Strong Motion Data

1988 ◽  
Vol 4 (1) ◽  
pp. 75-100 ◽  
Author(s):  
A. Shakal ◽  
M. J. Huang ◽  
T. Q. Cao
Keyword(s):  
Los Angeles ◽  
Strong Motion ◽  
Suspension Bridge ◽  
State University ◽  
Peak Acceleration ◽  
Ground Response ◽  
Data Set ◽  
Strong Motion Records ◽  
Motion Data ◽  
Soft Story

The Whittier Narrows earthquake of October 1, 1987 generated the largest set of strong-motion records ever obtained from a single earthquake. The California Strong Motion Instrumentation Program (CSMIP) recovered 128 strong-motion records from 101 stations. Of these 101 stations, 63 are ground-response stations and 38 are extensively-instrumented structures. The structures include 27 buildings, eight dams, a suspension bridge, an airport tower, and a power plant. This paper summarizes that data set and highlights records of particular interest. The duration of strong shaking was approximately 3 to 4 seconds at most stations. The maximum peak acceleration values in the CSMIP data set are 0.62 g on the ground and 0.54 g in a structure. The largest acceleration (0.62 g) was recorded at a station near Tarzana, approximately 45 km from the epicenter. Other records of particular interest discussed here include the record from a soft-story building on the Los Angeles State University campus and the records from the Vincent Thomas suspension bridge near Long Beach. Digitization and processing of the accelerograms are underway, and accelerograms from 12 ground-response stations have been digitized as of this writing. The spectra show that the motion at the Tarzana station was dominated by 3 Hz energy. Spectra from other sites are relatively flat and do not show this spectral peak. The attenuation of peak acceleration with distance for this earthquake is compared with the relationship of Joyner and Boore (1981) derived from past earthquakes. On average, the peak acceleration data from this earthquake are higher than would be predicted by the Joyner-Boore model.

scholarly journals Ground motion and rupture process of the 2003 Tokachi-oki earthquake obtained from strong motion data of K-NET and KiK-net

2004 ◽  
Vol 56 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Ryou Honda ◽  
Shin Aoi ◽  
Nobuyuki Morikawa ◽  
Haruko Sekiguchi ◽  
Takashi Kunugi ◽  
...  
Keyword(s):  
Ground Motion ◽  
Strong Motion ◽  
Rupture Process ◽  
Strong Motion Data ◽  
Motion Data

scholarly journals Rupture model of the 1989 Loma Prieta earthquake from the inversion of strong-motion and broadband teleseismic data

1991 ◽  
Vol 81 (5) ◽  
pp. 1540-1572 ◽  
Author(s):  
David J. Wald ◽  
Donald V. Helmberger ◽  
Thomas H. Heaton
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
High Gain ◽  
Temporal And Spatial Distribution ◽  
Origin Time ◽  
Loma Prieta Earthquake ◽  
Motion Data ◽  
Teleseismic Data ◽  
Loma Prieta

Abstract We have used 24 broadband teleseismic and 48 components of local strong-motion velocity records of the 1989 Loma Prieta earthquake in a formal inversion to determine the temporal and spatial distribution of slip. Separate inversions of the teleseismic data (periods of 3 to 30 sec) or strong-motion data (periods of 1 to 5 sec) result in similar models. The data require bilateral rupture with relatively little slip in the region directly updip from the hypocenter. Slip is concentrated in two patches: one centered 6 km northwest of the hypocenter at a depth of 12 km and with a maximum slip of 350 cm, and the other centered about 5 km southeast of the hypocenter at a depth of 16 km and with a maximum slip of 460 cm. The bilateral nature of the rupture results in large amplitude ground motions at sites located along the fault strike, both to the northwest and the southeast. However, the northwestern patch has a larger moment and overall stress drop and is, consequently, the source of the largest ground motion velocities, consistent with the observed recordings. This bilateral rupture also produces relatively modest ground motion amplitudes directly updip from the hypocenter, which is in agreement with the velocity ground motions observed at Corralitos. There is clear evidence of a foreshock (magnitude between 3.5 and 5.0) or a slow rupture nucleation about 2 sec before the main part of the rupture; the origin time implied by strong-motion trigger times is systematically 2 sec later than the time predicted from the high-gain regional network data. The seismic moment obtained from either of the separate data sets or both sets combined is about 3.0 × 1026 dyne-cm and the potency is 0.95 km3.

Sign in / Sign up

Export Citation Format

Share Document