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.

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.

Near-Source Ground Motions and Their Variability Derived from Dynamic Rupture Simulations Constrained by NGA-West2 GMPEs

2021 ◽  
Author(s):  
Ľubica Valentová ◽  
František Gallovič ◽  
Sébastien Hok
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Synthetic Data ◽  
Ground Motion Prediction Equations ◽  
Dynamic Rupture ◽  
Motion Modeling ◽  
Mixed Effect ◽  
Effect Model ◽  
Stress Drops ◽  
Strong Ground

ABSTRACT Empirical ground-motion prediction equations (GMPEs) lack a sufficient number of measurements at near-source distances. Seismologists strive to supplement the missing data by physics-based strong ground-motion modeling. Here, we build a database of ∼3000 dynamic rupture scenarios, assuming a vertical strike-slip fault of 36×20  km embedded in a 1D layered elastic medium and linear slip-weakening friction with heterogeneous parameters along the fault. The database is built by a Monte Carlo procedure to follow median and variability of Next Generation Attenuation-West2 Project GMPEs by Boore et al. (2014) at Joyner–Boore distances 10–80 km. The synthetic events span a magnitude range of 5.8–6.8 and have static stress drops between 5 and 40 MPa. These events are used to simulate ground motions at near-source stations within 5 km from the fault. The synthetic ground motions saturate at the near-source distances, and their variability increases at the near stations compared to the distant ones. In the synthetic database, the within-event and between-event variability are extracted for the near and distant stations employing a mixed-effect model. The within-event variability is lower than its empirical value, only weakly dependent on period, and generally larger for the near stations than for the distant ones. The between-event variability is by 1/4 lower than its empirical value at periods >1  s. We show that this can be reconciled by considering epistemic error in Mw when determining GMPEs, which is not present in the synthetic data.

Estimation of seismic ground motions and attendant potential human fatalities from a scenario earthquake on the Sanchiao fault in northern Taiwan

2020 ◽  
Author(s):  
Kun-Sung Liu ◽  
Mei-Rong Yan ◽  
Yu-Hua Huang
Keyword(s):  
Ground Motion ◽  
Active Fault ◽  
Site Response ◽  
Ground Motions ◽  
City Government ◽  
Border Area ◽  
Scenario Earthquake ◽  
Scenario Earthquakes ◽  
Taipei City ◽  
Northern Taiwan

<p>The purpose of this study is to estimate maximum ground motions in northern Taiwan in the form of ShakeMaps as well as to assess potential human fatalities from a scenario earthquake on the Sanchiao active fault in this area. Analysis of seismic hazard potential becomes necessary in northern Taiwan for the Central Geological Survey (CGS) announced the Sanchiao active fault as Category II. The resultant ShakeMap patterns of maximum ground motion by using ground motion prediction equation (GMPE) method in a case of Mw6.88 show the areas of PGA above 400 gals are located in the regions inside the yellow lines in the corresponding figure. Furthermore, the areas of PGA greater than 637 gal are located in the northern Bali and the border area of Sinjhuang and Shulin. Likewise, the high PGV area greater than 60 cm/s are located in the border area of Sinjhuang, Taishan and Shulin. In addition, seismic hazards in terms of PGA and PGV in the vicinity of the Sanchiao fault are not completely dominated by the Sanchiao fault. The main reason is that some areas located in the vicinity of the Sanchiao fault are marked with low site response amplification values of 0.61 and 0.74 for PGA and PGV, respectively in northwestern Beitou. Finally, from estimation of potential human fatalities from scenario earthquakes on the Sanchiao active fault, it is noted that potential fatalities increase rapidly in people above age 45. Total fatalities reach a high peak in age groups of 55–64. Another to pay special attention by Taipei City Government is the number and percentage of fatalities above age 85 are more in Taipei City with values 419 and 8.54% than New than Taipei City with values of 319 and 5.02%. In addition, it is surprising that the number and percentage of fatalities are 1234 and 9.75%, respectively in Taoyuan City. Finally, the results of this paper will enable both local and central governments in Taiwan to take notice of potential earthquake threat in these areas, as well as to improve decision making with respect to emergency preparedness, response, and recovery activities for earthquakes in northern Taiwan.</p>

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.

Ground-Motion Modeling of Hayward Fault Scenario Earthquakes, Part I: Construction of the Suite of Scenarios

2010 ◽  
Vol 100 (6) ◽  
pp. 2927-2944 ◽  
Author(s):  
B. T. Aagaard ◽  
R. W. Graves ◽  
D. P. Schwartz ◽  
D. A. Ponce ◽  
R. W. Graymer
Keyword(s):  
Ground Motion ◽  
Motion Modeling ◽  
Scenario Earthquakes

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.

SEISMIC SHAKING IN SINGAPORE DUE TO PAST SUMATRAN EARTHQUAKES

2007 ◽  
Vol 01 (01) ◽  
pp. 49-70 ◽  
Author(s):  
TSO-CHIEN PAN ◽  
KUSNOWIDJAJA MEGAWATI ◽  
CHEE LEONG LIM
Keyword(s):  
Ground Motion ◽  
Prediction Models ◽  
Ground Motions ◽  
Critical Role ◽  
Research Work ◽  
Far Field ◽  
Seismic Stations ◽  
Attenuation Relationships ◽  
Scenario Earthquakes

In 1996, the Meteorological Service of Singapore (MSS) installed a network of seven seismic stations. Nanyang Technological University (NTU) has also installed two additional seismic stations. Together, the nine stations form a network called the Singapore Array for Earthquake Response (SAFER). One of the stations installed by NTU consists of two sets of four accelerometers installed in a 66-storey commercial building for the study of building response to far-field earthquakes. This paper summarizes the research work that has been developed from the network of sensors. During the operation of the SAFER array, far-field earthquake ground motions have been recorded for many Sumatra earthquake events. From this, local site characteristics have been studied and hazard maps showing the amplified peak ground acceleration of the earthquake has been developed for the local sites. A case study for the hazard map due to the Bengkulu earthquake (Mw = 7.7) of June 4, 2000, is shown. Based on numerical studies of typical building structures in Singapore, an additional response map showing spatial variation of approximate base shear of buildings has been developed for Singapore. A case study of the response map due to the Bengkulu earthquake (Mw = 7.7) of June 4, 2000, is also shown. For future seismic hazard assessments of Singapore, a set of attenuation relationships that can reasonably predict the ground-motion intensity in Singapore generated by potential seismic sources have to be established. These attenuation relationships have to be developed using synthetic seismograms because the ground motion data that have been recorded within the last 10 years is not sufficient to develop them empirically. However, the available ground motions play a critical role in validating the synthetic attenuation relationships. The ultimate objective of this continuing research work is to incorporate a real-time monitoring system with the ground motion prediction models into hazard and response maps for scenario earthquakes. Such an integrated system when developed may assist in the planning of emergency responses to various earthquake scenarios.

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