scholarly journals A semi-empirical approach to prediction of long-period ground motions from great earthquakes

1979 ◽  
Vol 69 (6) ◽  
pp. 1645-1670 ◽  
Author(s):  
Hiroo Kanamori
Keyword(s):  
Ground Motion ◽  
Upper Bound ◽  
Seismic Moment ◽  
Ground Motions ◽  
Empirical Approach ◽  
Individual Event ◽  
Period Range ◽  
Long Period ◽  
The Individual ◽  
Semi Empirical

abstract Predictability of long-period (1 sec or longer) ground motions generated by long strike-slip earthquakes such as the 1906 San Francisco and the 1857 Fort Tejon earthquakes, is investigated. Most large earthquakes are complex multiple events at this period range, and the resulting ground motion may be synthesized by convolving the ground motions of the individual event with the source function that describes the space-time history of the multiple shock sequence. Since it is not possible to predict deterministically the complexity of the rupture propagation, a semi-empirical approach was taken. For the ground motion from the individual events, the displacement records observed for the 1968 Borrego Mountain, California, earthquake were used after correcting for the distance and the radiation pattern. These records which were used as an empirical Green's function for the individual events were superposed, with some randomness, to produce ground motions resulting from a large earthquake. The models were constrained by gross seismological data at three periods. At 1 sec they are constrained by the observed upper bound of the local magnitude (ML = 714), and, at about 10 sec, by the upper bound of the seismic moment of the individual event of multiple shocks (5 × 1026 dyne-cm). At very long periods, the models have the correct total seismic moment. The results obtained for a model of the 1857 earthquake indicate that: (1) the velocity response spectra of ground motions in the near-field are nearly flat at about 50 cm/sec over the period range from 1 to 10 sec under normal conditions; (2) under certain circumstances they can be as large as 150 cm/sec; (3) the maximum duration of the ground motion is 6 min. These results are considered reasonable because they satisfy all the seismological constraints currently available over a wide period range.

Significance of Ground Motion Scaling Parameters on Amplitude of Scale Factors and Seismic Response of Short- and Long-Period Structures

2019 ◽  
Vol 35 (4) ◽  
pp. 1663-1688 ◽  
Author(s):  
Esengul Cavdar ◽  
Gokhan Ozdemir ◽  
Beyhan Bayhan
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Scaling Method ◽  
Period Range ◽  
Long Period ◽  
Scale Factors ◽  
Short Period ◽  
Response History Analysis

In this study, an ensemble of ground motions is selected and scaled in order to perform code-compliant bidirectional Nonlinear Response History Analysis for the design purpose of both short- and long-period structures. The followed scaling method provides both the requirements of the Turkish Earthquake Code regarding the scaling of ground motions and compatibility of response spectra of selected ground motion pairs with the target spectrum. The effects of four parameters, involved in the followed scaling method, on both the amplitude of scale factors and seismic response of structures are investigated. These parameters are the number of ground motion records, period range, number of periods used in the related period range, and distribution of weight factors at the selected periods. In the analyses, ground motion excitations were applied to both fixed-base and seismically isolated structure models representative of short- and long-period structures, respectively. Results revealed that both the amplitudes of scale factors and seismic response of short-period structures are more prone to variation of investigated parameters compared to those of long-period structures.

Ground-Motion Modeling of Hayward Fault Scenario Earthquakes, Part II: Simulation of Long-Period and Broadband Ground Motions

2010 ◽  
Vol 100 (6) ◽  
pp. 2945-2977 ◽  
Author(s):  
B. T. Aagaard ◽  
R. W. Graves ◽  
A. Rodgers ◽  
T. M. Brocher ◽  
R. W. Simpson ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Motion Modeling ◽  
Long Period ◽  
Scenario Earthquakes

scholarly journals Long-Period Ground Motion Simulation Based on Three-dimensional Centroid Moment Tensor Inversion Solutions in the Kanto Region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate (Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes. The seismic moments directly affect the amplitudes of ground motions. Thus, 3D CMT solutions are essential for the precise forward and inverse modeling of long-period ground motion. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT inversion well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin.

Long-period ground motions and dynamic strain field of Los Angeles basin during large earthquakes

1996 ◽  
Vol 86 (5) ◽  
pp. 1417-1433
Author(s):  
T. L. Teng ◽  
J. Qu
Keyword(s):  
Los Angeles ◽  
Displacement Field ◽  
Seismic Moment ◽  
Strain Field ◽  
San Andreas Fault ◽  
Ground Motions ◽  
Dynamic Strain ◽  
Los Angeles Basin ◽  
Long Period ◽  
San Andreas

Abstract During a big earthquake along the San Andreas fault in southern California, high excitation and low attenuation of long-period (3 to 10 sec) strong ground motions will cause wave motions to propagate efficiently far from the epicentral area. These ground motions could potentially be destructive to large-dimension structures in the Los Angeles basin. We performed calculations using the surface-wave Gaussian beam method for a 3D southern California crustal structure. Displacement field as well as the associated dynamic strain field produced by large propagating ruptures along the San Andreas fault are evaluated. Results indicate that in the presence of lateral heterogeneity, focusing and multipathing interference contribute significantly to a complex pattern of the displacement field and the associated dynamic strain field. For a big event on the San Andreas fault with a seismic moment of 1.8 × 1028 dyne-cm, long-period displacement in the Los Angeles basin could reach a maximum amplitude of meters in places. Since this calculation is fast, we have evaluated the displacement field for a dense grid of points; a differentiation gives the corresponding effective horizontal dynamic strain field. At times, the maximum effective dynamic strains may reach mid-10−3 to even 10−3—high enough to be of engineering concern. This computational result probably gives the upper bound values due to the large source assumed. For events of smaller seismic moment release along less extensive ruptures, these results can easily be scaled down proportionally. Different scenarios are considered in this study with different slip distributions. It is found that with a given seismic moment, a more evenly distributed fault slip over the rupture surface will result in lower peak values on both displacements and dynamic strains. Our displacement results give similar values to those obtained by Kanamori using empirical Green's functions but substantially higher than Bouchon and Aki's results.

Identification of Pulse Periods in Near‐Fault Ground Motions Using the HHT Method

2019 ◽  
Vol 109 (6) ◽  
pp. 2384-2398 ◽  
Author(s):  
Xiaoyu Chen ◽  
Dongsheng Wang ◽  
Rui Zhang
Keyword(s):  
Ground Motion ◽  
Time Course ◽  
Ground Motions ◽  
Flexible Structures ◽  
Peak Ground Velocity ◽  
Damage Effect ◽  
Near Fault ◽  
Long Period ◽  
Frequency Components ◽  
Ground Motion Records

Abstract Large‐amplitude and long‐period pulses are observed in velocity time histories of near‐fault ground‐motion records. The pulses in these records have significant damage effect on flexible structures due to their long‐period property; therefore, more attention should be paid to the frequency components in the ground motion. Based on the identification of frequency components in the original record, a new method based on the Hilbert–Huang transform (HHT) is proposed here. A ground‐motion record can be decomposed into several intrinsic mode functions (IMFs) that carry different frequency components by the HHT without contamination from any a prior function. Only two fixed parameters, the peak ground velocity (PGV)/peak ground acceleration (PGA) ratio and the energy change of every IMF, are used to classify pulse‐like ground‐motion records. The inherent pulses of these records can also be extracted, based on the selection of IMFs for which PGV/PGA ratios are larger than 0.12 and energy changes that are greater than 0.1. For multipulse cases, all the pulses can be captured after extracting once, and the time course of inherent pulses can also be obtained. Then, pulse periods are calculated based on the solutions of instantaneous frequency of the peak for the extracted pulses. All the periods obtained using the HHT method can be verified by the results obtained from Baker’s wavelet method. The 24 controversial records that are discussed in previous studies are examined here as well. The HHT method is a complete procedure that includes the classification of pulse‐like ground motions, the extraction of velocity pulses, and the solution of pulse periods. It works well for multipulse records, especially because it can provide the exact timing of all the inherent pulses.

scholarly journals Application of wavelet for seismic wave analysis in Kathmandu Valley after the 2015 Gorkha earthquake, Nepal

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Binod Adhikari ◽  
Subodh Dahal ◽  
Monika Karki ◽  
Roshan Kumar Mishra ◽  
Ranjan Kumar Dahal ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Random Process ◽  
Ground Motion ◽  
Structural Damage ◽  
Ground Motions ◽  
Vertical Motion ◽  
Earthquake Ground Motion ◽  
Kathmandu Valley ◽  
Time Frequency ◽  
Long Period

AbstractIn this paper, we estimate the seismogenic energy during the Nepal Earthquake (25 April 2015) and studied the ground motion time-frequency characteristics in Kathmandu valley. The idea to analyze time-frequency characteristic of seismogenic energy signal is based on wavelet transform which we employed here. Wavelet transform has been used as a powerful signal analysis tools in various fields like compression, time-frequency analysis, earthquake parameter determination, climate studies, etc. This technique is particularly suitable for non-stationary signal. It is well recognized that the earthquake ground motion is a non-stationary random process. In order to characterize a non-stationary random process, it is required immeasurable samples in the mathematical sense. The wavelet transformation procedures that we follow here helps in random analyses of linear and non-linear structural systems, which are subjected to earthquake ground motion. The manners of seismic ground motion are characterized through wavelet coefficients associated to these signals. Both continuous wavelet transform (CWT) and discrete wavelet transform (DWT) techniques are applied to study ground motion in Kathmandu Valley in horizontal and vertical directions. These techniques help to point out the long-period ground motion with site response. We found that the long-period ground motions have enough power for structural damage. Comparing both the horizontal and the vertical motion, we observed that the most of the high amplitude signals are associated with the vertical motion: the high energy is released in that direction. It is found that the seismic energy is damped soon after the main event; however the period of damping is different. This can be seen on DWT curve where square wavelet coefficient is high at the time of aftershock and the value decrease with time. In other words, it is mostly associated with the arrival of Rayleigh waves. We concluded that long-period ground motions should be studied by earthquake engineers in order to avoid structural damage during the earthquake. Hence, by using wavelet technique we can specify the vulnerability of seismically active region and local topological features out there.

scholarly journals Long-period ground motion simulation using centroid moment tensor inversion solutions based on the regional three-dimensional model in the Kanto region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate ( Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes, which are related to fault size estimation. A detailed discussion for intraslabe seismicity can be conducted by using the 3D CMT catalog. The seismic moments also directly affect the amplitudes of ground motions. The 3D CMT catalog allows us to directly conduct the precise forward and inverse modeling of long-period ground motion without adjusting source models, which have been typically applied in the cases using the 1D CMT catalog. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate the reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT solutions well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin. The reproducibility of simulations was improved from those using solutions in the 1D catalog.

Evaluation of models for earthquake source spectra in eastern North America

1998 ◽  
Vol 88 (4) ◽  
pp. 917-934
Author(s):  
Gail M. Atkinson ◽  
David M. Boore
Keyword(s):  
North America ◽  
Ground Motion ◽  
High Frequency ◽  
Ground Motions ◽  
Source Model ◽  
Eastern North America ◽  
Long Period ◽  
Source Models ◽  
Felt Area ◽  
Large Earthquakes

Abstract There have been several relations proposed in the last few years to describe the amplitudes of ground motion in eastern North America (ENA). These relations differ significantly in their assumptions concerning the amplitude and shape of the spectrum of energy radiated from the earthquake source. In this article, we compare ground motions predicted for these source models against the sparse ENA ground-motion database. The source models evaluated include the two-corner models of Boatwright and Choy (1992), Atkinson (1993a), Haddon (1996), and Joyner (1997a,b), and the one-corner model of Brune [as independently implemented by Frankel et al. (1996) and by Toro et al. (1997)]. The database includes data from ENA mainshocks of M > 4 and historical ENA earthquakes of M > 5.5, for a total of 110 records from 11 events of 4 ≦ M ≦ 7.3, all recorded on rock. We also include 24 available rock records from 4 large earthquakes in other intraplate regions; conclusions are checked to determine whether they are sensitive to the addition of these non-ENA data. The Atkinson source model, as implemented in the ground-motion relations of Atkinson and Boore (1995), is the only model that provides unbiased ground-motion predictions over the entire period band of interest, from 0.1 to 10 sec. The source models of Frankel et al. (1996), Toro et al. (1997), and Joyner (1997a,b) all provide unbiased ground-motion estimates in the period range from 0.1 to 0.5 sec but overestimate motions at periods of 1 to 10 sec. The Haddon (1996) source model overpredicts motions at all periods, by factors of 2 to 10. These conclusions do not change significantly if data from non-ENA intraplate regions are excluded, although the tendency of all models toward overprediction of long-period amplitudes becomes more pronounced. The tendency of most proposed ENA source models to overestimate long-period motions is further confirmed by an evaluation of the relationship between Ms, a measure of the spectrum at 20-sec period, and moment magnitude. A worldwide catalog of shallow continental earthquakes (Triep and Sykes, 1996) is compared to the Ms-M relations implied by each of the source models. The Atkinson source model is consistent with these data, while other proposed ENA models overpredict the average Ms for a given M. The implications of MMI data from historical earthquakes are also addressed, by exploiting the correlation between felt area and high-frequency source spectral level. High-frequency spectral amplitudes, as specified by the Atkinson and Boore (1995), Frankel et al. (1996), Toro et al. (1997), and Joyner (1997a,b) source models, equal or exceed the levels inferred from the felt areas of most of the large ENA events, with the noteable exception of the Saguenay earthquake. By contrast, high-frequency spectral amplitudes specified by the Haddon (1996) source model agree with the felt area of the Saguenay earthquake but overpredict the felt areas of nearly all other large events. In general, models that fit the Saugenay data—be it intensity data, strong-ground-motion data, regional seismographic data, or telescismic data—will not fit the data from the remaining earthquakes. A source model derived from the California database, suitably modified for regional differences in crustal properties, is also evaluated. This model is not significantly different from the Atkinson model for ENA. There is an important practical application of this similarity, which we develop as an engineering tool: Empirical ground-motion relations for California may be modified to predict ENA ground motions from future large earthquakes.

Study on Long-Period Inelastic Spectra of near-Fault Pulse-Like Strong Ground Modeled Using Analytical Model

2011 ◽  
Vol 374-377 ◽  
pp. 2316-2319
Author(s):  
Chun Feng Li ◽  
Wei Xin Tian ◽  
Zhuo Lin
Keyword(s):  
Ground Motion ◽  
Analytical Model ◽  
Ground Motions ◽  
Near Field ◽  
Near Fault ◽  
Long Period ◽  
Acceleration Time Histories ◽  
Long Period Ground Motion ◽  
Ground Motion Records ◽  
Strong Ground

Because the parameters of Mavroeidis analytical model of pulse-like strong ground motion have an unambiguous physical meaning, the analytical model has been calibrated using a large number of actual near-field ground-motion records, and It can successfully simulate available near-fault pulse-like acceleration time histories, in this paper, we synthesize ground motions using the model to investigate elasto-plastic earthquake responses of long period single-degree-of-freedom system to the pulse-like ground motions, revealing the elasto-plastic long-period ground motion characteristics of pulse-like ground motion.

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