i1-net: The Iran Strong Motion Network

2021 ◽  
Author(s):  
Mohammad Pourmohammad Shahvar ◽  
Esmaeil Farzanegan ◽  
Attiyeh Eshaghi ◽  
Hossein Mirzaei
Keyword(s):  
Earthquake Engineering ◽  
Strong Motion ◽  
Current Status ◽  
Primary Input ◽  
The Road ◽  
Leading Position ◽  
Hazard And Risk ◽  
Ground Motion Records ◽  
Strong Motion Network ◽  
Strong Ground

Abstract Strong ground-motion records are the primary input data in earthquake engineering studies to improve understanding of seismic hazard and risk. As the overseer of the Iran Strong Motion Network (i1-net), the Road, Housing, and Urban Development Research Center occupies the leading position in this field in the country. With more than 1260 active accelerometers and a collection of over 14,129 earthquake recordings since 1973, the Iran Strong Motion Network is the major Iranian source of information for engineering seismology and earthquake engineering. The present article describes the current status and developments of the i1-net in the last 46 yr.

The Whittier Narrows, California Earthquake of October 1, 1987—Preliminary Assessment of Strong Ground Motion Records

1988 ◽  
Vol 4 (1) ◽  
pp. 55-74 ◽  
Author(s):  
A. G. Brady ◽  
E. C. Etheredge ◽  
R. L. Porcella
Keyword(s):  
Strong Motion ◽  
Mode Shapes ◽  
University Of Southern California ◽  
Preliminary Assessment ◽  
Resonant Modes ◽  
Basic Performance ◽  
Ground Motion Records ◽  
The University ◽  
Strong Ground

More than 250 strong-motion accelerograph stations were triggered by the Whittier Narrows, California, earthquake of 1 October 1987. Considering the number of multichannel structural stations in the area of strong shaking, this set of records is one of the more significant in history. Three networks, operated by the U.S. Geological Survey, the California Division of Mines and Geology, and the University of Southern California produced the majority of the records. The excellent performance of the instruments in these and the smaller arrays is attributable to the quality of the maintenance programs and their funding and personnel requirements. Readiness for a magnitude 8 event is directly related to these maintenance programs. Prior to computer analysis of the analog film records, a number of important structural resonant modes can be identified, and frequencies and simple mode shapes have been scaled. The structural records form a basic performance measurement for comparison with larger earthquake response in the future.

The Mexico Earthquake of September 19, 1985—Effect of Magnitude on the Character of Strong Ground Motion: An Example from the Guerrero, Mexico Strong Motion Network

1988 ◽  
Vol 4 (3) ◽  
pp. 635-646 ◽  
Author(s):  
J. G. Anderson ◽  
R. Quaas
Keyword(s):  
Subduction Zone ◽  
Ground Motion ◽  
Strong Ground Motion ◽  
Strong Motion ◽  
Earthquake Source ◽  
Hypocentral Distance ◽  
Source Theory ◽  
Mexico Earthquake ◽  
Strong Motion Network ◽  
Strong Ground

The Guerrero digital accelerograph network has been operating, since spring of 1985, on rock sites along the coast of Mexico, above an active subduction zone. The accelerograms collected through June 1987 include examples from events with magnitudes from 3 to 8, all recorded at nearly the same hypocentral distance. Spectra from these accelerograms scale in a manner that is qualitatively consistent with earthquake source theory. Based on four selected events, peak accelerations attenuate more rapidly for small events than for large events.

Empirical Attenuation Equations for Vertical Ground Motion in Turkey

2004 ◽  
Vol 20 (3) ◽  
pp. 853-882 ◽  
Author(s):  
Erol Kalkan ◽  
Polat Gülkan
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Strong Dependence ◽  
Strong Motion ◽  
Vertical Acceleration ◽  
Data Set ◽  
Attenuation Relationships ◽  
Geological Conditions ◽  
Ground Motion Records ◽  
Strong Ground

In the aftermath of two destructive urban earthquakes in 1999 in Turkey, empirical models of strong motion attenuation relationships that have been previously developed for North American and European earthquakes have been utilized in a number of national seismic hazard studies. However, comparison of empirical evidence and estimates present significant differences. For that reason, a data set created from a suite of 100 vertical strong ground motion records from 47 national earthquakes that occurred between 1976 and 2002 has been used to develop attenuation relationships for strong ground motion in Turkey. A consistent set of empirical attenuation relationships was derived for predicting vertical peak and pseudo-absolute vertical acceleration spectral ordinates in terms of magnitude, source-to-site distance, and local geological conditions. The study manifests the strong dependence of vertical to horizontal (V/H) acceleration ratio on spectral periods and relatively weaker dependence on site geology, magnitude, and distance. The V/H ratio is found to be particularly significant at the higher frequency end of the spectrum, reaching values as high as 0.9 at short distances on soil sites. The largest long-period spectral ratios are observed to occur on rock sites where they can reach values in excess of 0.5. These results raise misgivings concerning the practice of assigning the V/H ratio a standard value of two-thirds. Hence, nonconservatism of this value at short periods and its conservatism at long periods underline the need for its revision, at least for practice in Turkey.

Strong Motion Attenuation Relations: A Ten-Year Perspective

1985 ◽  
Vol 1 (4) ◽  
pp. 759-804 ◽  
Author(s):  
Kenneth W. Campbell
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Strong Ground Motion ◽  
Strong Motion ◽  
The United States ◽  
Attenuation Relations ◽  
Empirical Prediction ◽  
Motion Data ◽  
Motion Characteristics ◽  
Strong Ground

Research on strong ground-motion characteristics conducted in the United States within the last 10 years (1974-1984) forms the basis for a detailed discussion of important factors to be considered when selecting or developing strong-motion attenuation relations for use in earthquake engineering and seismic hazard studies. While emphasis is placed on the empirical prediction of ground-motion amplitudes, a brief discussion of procedures is presented that can be used when insufficient strong-motion data are available to perform an adequate statistical analysis. The discussion is followed by a tabulated summary of selected strong-motion attenuation relations proposed and developed in the last 10 years (1974-1984) to acquaint the reader with the types of relationships currently available.

Analysis of Near-Source Ground Motion from the 2019 Ridgecrest Earthquake Sequence

2020 ◽  
Vol 110 (4) ◽  
pp. 1495-1505 ◽  
Author(s):  
Georgios Baltzopoulos ◽  
Lucia Luzi ◽  
Iunio Iervolino
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Strong Motion ◽  
Rupture Directivity ◽  
Surface Rupture ◽  
Ground Acceleration ◽  
Ground Motion Records ◽  
Manual Classification ◽  
Forward Rupture Directivity

ABSTRACT The Ridgecrest seismic sequence began on 4 July 2019 in California, on a hitherto relatively unmapped orthogonal cross-faulting system, causing mainly nonstructural or liquefaction-related damage to buildings in the vicinity of Ridgecrest and Trona, and also causing substantial surface rupture. The present study considers the near-source ground-acceleration recordings collected during the two principal events of the sequence—the 4 July moment-magnitude M 6.4 foreshock and the 6 July M 7.1 mainshock—to identify pulse-like ground motions, which may have arisen due to forward rupture directivity. Pulse-like seismic input is of particular interest to earthquake engineering due to its peculiar spectral shape and possibly increased damaging potential, and expanding the strong-motion databases with such records is a topical issue. In this context, a pulse identification methodology is implemented, partially based on computer-aided signal processing, but also involving manual classification. Nine ground-motion records were classified as pulse-like by this procedure. Further investigation led to the conclusion that, for some of these records, the impulsive characteristics could most likely be attributable to forward rupture directivity, whereas for others fling step may have also been an issue. Finally, clear signs of directionality were observed in these ground motions at periods near the pulse duration, manifesting as a polarization of the spectral ordinates toward the orientation of the impulsive component.

Study on Strong Motion Records Database and Selection Methods

2012 ◽  
Vol 256-259 ◽  
pp. 2117-2121
Author(s):  
Li Lin ◽  
Rui Zhi Wen ◽  
Bao Feng Zhou ◽  
Da Cheng Shi
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Strong Motion ◽  
Selection Methods ◽  
Strong Motion Records ◽  
Engineering Research ◽  
Conditional Mean Spectrum ◽  
Great Earthquakes ◽  
The Pacific ◽  
Ground Motion Records

In this paper, PEER Ground Motion Databases (PGMD) at the Pacific Earthquake Engineering Research Center (PEER) was updated by 314 sets of ground motion records of great earthquakes in recent years, which expanded the application of this database. This paper reviews alternative selection methods for strong ground motion records. The expanded database could make the different selection and scaling of strong motion records in great earthquakes, and the conditional mean spectrum (CMS) method could be applied for the strong motion records selection in structural spectrum analysis.

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.

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