ArticlePublisher preview available

Influence of source uncertainty on stochastic ground motion simulation: A case study of the 2022 Mw 6.6 Luding, China, earthquake

Authors:
Pengfei Dang at Ningbo University
Pengfei Dang
Jie Cui
Jie Cui
Jie Cui
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Qifang Liu
Qifang Liu
Qifang Liu
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Yadong Li at Guangzhou University
Yadong Li
Read publisher preview
Download citation
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

On September 5, 2022 (local time), a magnitude 6.6 earthquake was reported to have occurred in Luding County, Sichuan Province, Southwest China. In this simulation, a widely used stochastic finite-fault model was used to analyze how the source models affect the near-fault earthquake ground motion simulations of the 2022 Mw 6.6 Luding earthquake in China. Seven different slip models, one of them obtained from common fault parameters and random distributed slip amount, were used to yield the best match with the recordings. The simulated earthquake ground motions calculated in the frequency band of 0.05–20 Hz were compared with the observed values in both the time and frequency domains. Twelve acceleration observation stations located near the fault plane were selected in our simulation for comparison. The average H/V curves were estimated using the available acceleration records to consider the local site effect at each selected station. The research results indicate that none of the source models adopted in this study fully estimate the observed values at all the selected ground-motion stations. The simulated values of some slip models underestimate the level of the Fourier amplitude spectrum at frequencies above 6 Hz. The underestimation may be attributed to the directivity effect, which may produce a higher amplitude of observed ground motion in the high-frequency band. All the slip models show similar average model deviations except for the random slip model. Finally, the peak ground accelerations and peak ground velocities were predicted at these selected near-fault observation stations. The results indicate that the peak accelerations and velocities obtained from seven slip models correlate well with each other, but are slightly lower than the recorded values at most stations. In addition, the synthetized results calculated from the random and inverted slip models can be the same level only if a greater stress drop is adopted in the random model.
Figures - available from: Stochastic Environmental Research and Risk Assessment
This content is subject to copyright. Terms and conditions apply.
A preview of this full-text is provided by Springer Nature.
Learn more
Content available from Stochastic Environmental Research and Risk Assessment
This content is subject to copyright. Terms and conditions apply.
ORIGINAL PAPER
Influence of source uncertainty on stochastic ground motion
simulation: a case study of the 2022 Mw 6.6 Luding, China, earthquake
Pengfei Dang
1,2,3
•Jie Cui
1,2
•Qifang Liu
4
•Yadong Li
1,2
Accepted: 16 March 2023 / Published online: 30 March 2023
ÓThe Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023
Abstract
On September 5, 2022 (local time), a magnitude 6.6 earthquake was reported to have occurred in Luding County, Sichuan
Province, Southwest China. In this simulation, a widely used stochastic finite-fault model was used to analyze how the
source models affect the near-fault earthquake ground motion simulations of the 2022 Mw 6.6 Luding earthquake in China.
Seven different slip models, one of them obtained from common fault parameters and random distributed slip amount, were
used to yield the best match with the recordings. The simulated earthquake ground motions calculated in the frequency
band of 0.05–20 Hz were compared with the observed values in both the time and frequency domains. Twelve acceleration
observation stations located near the fault plane were selected in our simulation for comparison. The average H/V curves
were estimated using the available acceleration records to consider the local site effect at each selected station. The
research results indicate that none of the source models adopted in this study fully estimate the observed values at all the
selected ground-motion stations. The simulated values of some slip models underestimate the level of the Fourier
amplitude spectrum at frequencies above 6 Hz. The underestimation may be attributed to the directivity effect, which may
produce a higher amplitude of observed ground motion in the high-frequency band. All the slip models show similar
average model deviations except for the random slip model. Finally, the peak ground accelerations and peak ground
velocities were predicted at these selected near-fault observation stations. The results indicate that the peak accelerations
and velocities obtained from seven slip models correlate well with each other, but are slightly lower than the recorded
values at most stations. In addition, the synthetized results calculated from the random and inverted slip models can be the
same level only if a greater stress drop is adopted in the random model.
Keywords Source model Site effect Response spectra Ground motion simulation Finite-fault modeling
1 Introduction
The China Earthquake Networks Center (CENC) reported
that at 12:52 on September 5, 2022, local time, a Mw 6.6
earthquake struck Luding County, Ganzi Prefecture,
Sichuan Province, China, with a focal depth of approxi-
mately 16 km and the highest intensity of IX (China
Seismic Intensity Scale). As of September 14, 2022, 118
people were killed or lost contact, and the earthquake
damaged many roads and bridges (Fan et al. 2022). The
seismogenic background of this earthquake is the Xian-
shuihe fault zone. Since 1725, 23 earthquake events with
Mw [6.0 have occurred in this fault zone (Xu et al. 2014).
The Xianshuihe fault zone is located in the southern
boundary of the Bayankala massif, which is an important
tectonic boundary of the eastern margin of the Qinghai-
&Yadong Li
liyadong@gzhu.edu.cn
1
School of Civil Engineering, Guangzhou University, No.230
Waihuan West Road,
Guangzhou 510006, Guangdong Province, China
2
Guangdong Engineering Research Center for Underground
Infrastructural Protection in Coastal Clay Area, No.230
Waihuan West Road,
Guangzhou 510006, Guangdong Province, China
3
Earth System Science Programme. Faculty of Science, The
Chinese University of Hong Kong,
Shatin 999077, Hong Kong, China
4
School of Civil Engineering, Suzhou University of Science
and Technology, No.1701 Binhe Road,
Suzhou 215011, Jiangsu Province, China
123
Stochastic Environmental Research and Risk Assessment (2023) 37:2943–2960
https://doi.org/10.1007/s00477-023-02427-y(0123456789().,-volV)(0123456789().,-volV)
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Concrete 02 and Steel 02 are adopted as the material of fiber elements, respectively. Moreover, for the pile-soil interaction, the equivalent linear spring is applied to pile foundation element nodes, and the pile bottom is consolidated (Dang et al., 2023;Liang et al., 2019;Shen, 2020;Wu et al., 2022). The soil is distributed around the pile foundation, so two nonlinear springs are installed at the node of the pile foundation unit. ...
Seismic vulnerability analysis of continuous beam bridge based on finite element Method
Article
Full-text available
  • Jun 2024
  • Environ Dev Sustain
Continuous beam bridges of monopile foundation are commonly used due to its good stress performance, stiffness and beautiful shape. However, scouring will weaken the lateral restraint of soil on pile foundation. It affects the dynamics of the bridge structure and make pile foundation vulnerable to earthquakes. Therefore, it is required to analyze its impacts on continuous beam bridges, especially the seismic vulnerability of the pile foundations. This paper establishes a 3D nonlinear analysis model with OpenSees software, which obtains the probabilistic seismic demand models at three scouring depths by linear regression analysis and incremental dynamic analysis (IDA). It has drawn and analyzed seismic vulnerability curves of pile foundation at three different scouring depths. The influence of scouring around pile foundations on bridge dynamics, seismic response, and vulnerability is obtained. The results indicate that the failure probability of pile foundation decreases with the increase in scouring depth. This demonstrates that scouring around the pile foundation weakens the lateral soil restraint, increasing the natural vibration period of bridge as well as softening the bridge structure. This reduces the maximum seismic response of pile foundation, which is conductive to the seismic resistance of bridge.
View
... The Potwar Basin is geographically divided into two segments by the Indus and Jhelum rivers, as well as the Salt (He et al., 2021;Huang et al., 2021;Li et al., 2021Li et al., , 2022a. table 1. Reservoirs' porosity as described qualitatively by Rider (1986) Average porosity with qualitative description Porosity ranging from 0 to 5% is considered Negligible Porosity ranging from 5 to 10% is considered Poor Porosity ranging from 10 to 20% is considered Good Porosity ranging from 20 to 30% is considered Very good Porosity greater >30% is considered Excellent Range and the Kalachitta-Margalla hill ranges (Shah and Abdullah, 2017;Chen et al., 2023;Cheng et al., 2023;Dang et al., 2023). This basin is characterized by intricate and compact east-west folds that incline southward and are influenced by steep-angle faults. ...
Seismic Facies Analysis, 3D Horizon Mapping, Source and Reservoir Rock Characteristics of the Paleocene Sequence in Potwar Basin, Pakistan: with Emphasis on Petroleum Potential Prospect
Article
  • Feb 2024
  • RUSS GEOL GEOPHYS+
This study presents a comprehensive analysis of the Balkassar oilfield in the Potwar Basin, Pakistan. It integrates seismic reflection data, a 3D subsurface horizon model, and geochemical and petrophysical data. Evaluating the Lockhart Formation’s geochemical properties using well cuttings reveals consistent patterns of relatively low to fair total organic carbon (TOC). S2 values suggest a fair generation potential with a mixed Type II–III kerogen composition. Seismic facies analysis identifies five distinct categories with parallel attributes. Horizons from lower Permian to Eocene show varying amplitudes and prevalent parallel to wavy internal configurations. Geometries, mainly sheet-to-wedge, enhance stratigraphic understanding. The 3D seismic interpretation reveals the Lockhart Formation’s structural traits, with pronounced northwest dip and gentler southeast inclination. Faults flanking the formation truncate its limbs. A significant contour closure in the northwest, confined by fault boundaries, signifies attractive hydrocarbon potential. Petrophysical analysis indicates an average 9.17% porosity. Dominated by limestone, the formation shows average water saturation of around 25.29% and hydrocarbon saturation of roughly 74.71%, indicating favorable reservoir properties. The Lockhart Formation holds promise as a reservoir rock within the Potwar Basin, though its source rock suitability is limited. This study enhances understanding of Balkassar’s geological complexities and contributes to knowledge of hydrocarbon exploration in the Potwar Basin.
View
... Furthermore, the ANN model can predict outcomes based on input data, even when the interaction forms of the input factors are uncertain or difficult to explain physically. Consequently, the ANN model is frequently used for landslide susceptibility mapping and is a valuable tool in the field of landslides (Huang et al. 2021a, Bravo-López et al. 2022, Dang et al. 2023. ...
A novel evolutionary combination of artificial intelligence algorithm and machine learning for landslide susceptibility mapping in the west of Iran
Article
Full-text available
  • Nov 2023
  • ENVIRON SCI POLLUT R
Detecting and mapping landslides are crucial for effective risk management and planning. With the great progress achieved in applying optimized and hybrid methods, it is necessary to use them to increase the accuracy of landslide susceptibility maps. Therefore, this research aims to compare the accuracy of the novel evolutionary methods of landslide susceptibility mapping. To achieve this, a unique method that integrates two techniques from Machine Learning and Neural Networks with novel geomorphological indices is used to calculate the landslide susceptibility index (LSI). The study was conducted in western Azerbaijan, Iran, where landslides are frequent. Sixteen geology, environment, and geomorphology factors were evaluated, and 160 landslide events were analyzed, with a 30:70 ratio of testing to training data. Four Support Vector Machine (SVM) algorithms and Artificial Neural Network (ANN)-MLP were tested. The study outcomes reveal that utilizing the algorithms mentioned above results in over 80% of the study area being highly sensitive to large-scale movement events. Our analysis shows that the geological parameters, slope, elevation, and rainfall all play a significant role in the occurrence of landslides in this study area. These factors obtained 100%, 75.7%, 68%, and 66.3%, respectively. The predictive performance accuracy of the models, including SVM, ANN, and ROC algorithms, was evaluated using the test and train data. The AUC for ANN and each machine learning algorithm (Simple, Kernel, Kernel Gaussian, and Kernel Sigmoid) was 0.87% and 1, respectively. The Classification Matrix algorithm and Sensitivity, Accuracy, and Specificity variables were used to assess the models’ efficacy for prediction purposes. Results indicate that machine learning algorithms are more effective than other methods for evaluating areas’ sensitivity to landslide hazards. The Simple SVM and Kernel Sigmoid algorithms performed well, with a performance score of one, indicating high accuracy in predicting landslide-prone areas.
View
... For linear, parabolic, and sinusoidal foundations, the foundation force can be calculated by Eqs. (10)- (12), respectively [56][57][58]: where k 0 is the foundation modulus. Also, σ L , σ P , and σ S are linear, parabolic, and sinusoidal variation parameters of the foundation, respectively. ...
Impacts of Complex Fields and Surface Energy on Forced and Free Vibrations of Rayleigh Nanobeams Under a Traveling Load
Article
Full-text available
  • Oct 2023
The scale-dependent forced and free vibrational behaviors of a nanobeam located on variable elastic foundations subjected to a transverse moving load and an axial tensile force are analyzed based on the nonlocal Rayleigh beam theory. Meanwhile, a comprehensive parametric investigation is accomplished to elucidate the impacts of various system parameters, such as geometry, foundation coefficients, rotational inertia factor, surface energy, and hygro-thermo-magnetic fields on the dynamical response of the nanobeam. The dynamical equation of the system is derived by considering linear, parabolic, and sinusoidal distributions for the elastic foundation. Employing the Galerkin discretization technique and eigenvalue analysis, the vibrational frequencies of the system are determined numerically. The dynamical response of the system is also acquired analytically. The critical velocity of the moving load and the dynamical amplification factor for the forced vibration of the system are computed. In addition, the conditions of the cancellation phenomenon and the maximum amplitude of free vibration are determined. The outcomes indicated that, in contrast to the effects of axial tensile force and elastic foundations, the critical velocity of the moving load decreases with increasing the nonlocal parameter and the rotational inertia factor. Moreover, it is inferred that the cancellation velocities of the moving load can be increased by exerting a magnetic field and increasing the length-to-thickness ratio of nanobeams. The findings reveal that considering the impacts of the surface energy, rotational inertia factor, and environmental conditions is essential to the dynamical analysis of small-scale structures under traveling loads.
View
... As is known, simulation efforts have been the basis of finding solutions for many engineering problems (Xu et al. 2021, Dang et al. 2023. For instance, structural engineers (Abedini and Zhang 2022, Huang et al. 2022a, Huang et al. 2022b have used these approaches to model the behavior of relevant elements in a building. ...
An optimized ANFIS model for predicting pile pullout resistance
Article
  • Jul 2023
  • STEEL COMPOS STRUCT
Many recent attempts have sought accurate prediction of pile pullout resistance (Pul) using classical machine learning models. This study offers an improved methodology for this objective. Adaptive neuro-fuzzy inference system (ANFIS), as a popular predictor, is trained by a capable metaheuristic strategy, namely equilibrium optimizer (EO) to predict the Pul. The used data is collected from laboratory investigations in previous literature. First, two optimal configurations of EO-ANFIS are selected after sensitivity analysis. They are next evaluated and compared with classical ANFIS and two neural-based models using well-accepted accuracy indicators. The results of all five models were in good agreement with laboratory Puls (all correlations 〉 0.99). However, it was shown that both EO-ANFISs not only outperform neural benchmarks but also enjoy a higher accuracy compared to the classical version. Therefore, utilizing the EO is recommended for optimizing this predictive tool. Furthermore, a comparison between the selected EO-ANFISs, where one employs a larger population, revealed that the model with the population size of 75 is more efficient than 300. In this relation, root mean square error and the optimization time for the EO-ANFIS (75) were 19.6272 and 1715.8 seconds, respectively, while these values were 23.4038 and 9298.7 seconds for EO-ANFIS (300).
View
Investigation of Source and Reservoir Rock Petroleum Generative Potential of Early Eocene and Paleocene Sequences of the Punjab Platform Basin, Pakistan: A Geochemical and Petrophysical Approach
Article
  • Apr 2024
  • RUSS GEOL GEOPHYS+
Investigating Early Eocene and Paleocene deposits within the Punjab Platform, Pakistan, involved comprehensive analysis using advanced geochemical and petrophysical techniques. This study evaluates the source potential of three formations: Nammal and Sakesar of Early Eocene age and Dungan and Ranikot of Palaeocene age. The Sakesar Formation, a reservoir rock, was evaluated through interpretation of wireline logs to estimate key petrophysical properties—porosity, water saturation, and hydrocarbon saturation. Geochemical investigations focused on total organic carbon content and Rock-Eval pyrolysis of twenty-one cutting samples from a well. These samples displayed TOC values ranging from 0.21 to 2.04 wt.% and S2 values ranging from 0.09 to 2.14 mg HC/g rock. Analysis positioned all samples within the immature window zone with Type II/III and Type III kerogen, suggesting limited generative potential. Findings suggest limited hydrocarbon generation from these formations. Petrophysical analysis indicated average porosity of 11.2%, water saturation of 32.58%, and hydrocarbon saturation of 67.42% for the Sakesar Formation, categorizing it as average to good reservoir potential. This study highlights complex geochemical and petrophysical characteristics of these formations. While Sakesar shows promising reservoir qualities, significant hydrocarbon generation potential from Nammal, Dungan, and Ranikot formations is constrained. Informed decision-making is crucial when considering these formations as hydrocarbon sources.
View
Evaluation of seismic hazard in the central seismic gap region of Himalaya based on site effects and simulated accelerograms
Article
  • Jan 2024
  • ACTA GEOPHYS
In the present study, a hypothetical earthquake of magnitude 8.5 has been simulated using the modified hybrid technique. Existing hybrid technique, as the name suggests, is the blend of two already existing simulation techniques, i.e. composite source technique and the envelope technique. In the present modified technique, site response functions and high-frequency decay parameter (kappa factor) have also been introduced in the existing hybrid technique. The waveforms have been simulated at more than 430 points using the calculated site response or transfer function estimated at 50 recording stations situated in the central seismic gap (CSG) region of Himalaya. Peak ground acceleration (PGA) and duration parameters have been estimated. Calculated PGA values helped estimating in the corresponding intensity for those PGA values at various stations. With the help of these PGA and intensity values, the scenario hazard map has been prepared for central seismic gap (CSG) region of Himalaya. It has been found that the stations situated close to rupture initiation point is ≥ 1 g. The estimated PGA values have been compared with the PGA values of other studies. The earthquake has been simulated using three different rupture points The station having highest PGA values changed with rupture initiation point. The intensity values are correlated with the damage pattern of region and therefore relatively more useful for agencies involved in the mitigation of seismic hazard of the region. Accordingly, the synthetic intensity maps have been generated in the present study by converting PGA values into MMI values using an empirical relation. The comparison with the other studies shows an agreement with the other studies. This modified technique is independent aftershocks database and velocity-Q structure. This research work will help bringing light on the effect of site response functions and kappa factor. This kind of study can help in mitigate the earthquake hazard and design an earthquake-resistant structures and building for that particular area.
View
View
Journal Pre-proofs Atmospheric precursors from multiple satellites associated with the 2020 Mw 6.5 Idaho (USA) earthquake Atmospheric precursors from multiple satellites associated with the 2020 Mw 6.5 Idaho (USA) earthquake
Article
  • Oct 2023
  • ADV SPACE RES
Please cite this article as: Qasim, M., Shah, M., Shahzad, R., Jamjareegulgarn, P., Atmospheric precursors from multiple satellites associated with the Abstract: Remote sensing has become a powerful tool for identifying lithosphere and atmosphere anomalies associated with the impending Earthquakes (EQs) in the vicinity of seismic breeding zone. In this paper, Land Surface Temperature (LST) of both the daytime and nighttime from the Moderate Resolution Imaging Spectroradiometer (MODIS) along with Air Temperature (AT), Relative Humidity (RH), Air Pressure (AP) and Outgoing Longwave Radiations (OLR) are studied for the 2020 Idaho (USA) EQ of Mw 6.5. We found the EQ induced surface and atmospheric parameters anomalies just one day prior to EQ main shock using statistical analysis. Moreover, we observed a sharp increment in LST and AT followed by the drop in both AP and RH, which are responsible for cooling the hot gases emitted from epicenter during EQ preparation period. Also, we observed a large increase in OLR on the same day confirming these anomalous variations to be related with the main shock. Furthermore, these abrupt variations are also confirmed using neural networks (nonlinear autoregressive network with exogenous inputs (NARX), multilayer perceptron (MLP) and continuous wavelet transformation (CWT). These multi-parameter and multi-technique analysis can contribute to assist in the main shock forecasting in future with an enhanced cluster of satellite observations.
View
View
Coseismic Deformation and Slip Distribution of the 2022 Luding Mw 6.6 Earthquake Revealed by InSAR Observations
Article
Full-text available
  • Oct 2022
The 5 September 2022 Mw 6.6 Luding earthquake is the largest earthquake occurring on the Xianshuihe fault, Eastern Tibet in the past 40 years, and is of great significance for investigating the tectonic activity and assessing future seismic hazards in the region. Methods: In this study, we used Sentinel-1 and ALOS-2 synthetic aperture radar (SAR) images to retrieve coseismic surface displacements and then to determine the fault geometry parameters and slip distribution with a dislocation model in an elastic half-space. Results: Our results show that the earthquake is a left-lateral sliding event with a maximum LOS surface displacement of ~15 cm and ~21 cm for the Sentinel-1 and ALOS-2 radar images, respectively. Conclusions: The fault ruptured along an NNW-SSE strike, and westward at a dip of 72°. The slip was concentrated at depths of 4-12 km with a maximum fault slip of 2.23 m occurring at a depth of ~5.8 km. By analyzing the distribution of the coseismic landslides interpreted by optical images, it is found that the coseismic landslides were mainly located on the west side of the fault, which is consistent with the aftershock distribution and can be considered due to hanging wall effects.
View
Site amplification and rupture velocity in EXSIM and updated EXSIM during the 2017 Mw6.6 Jiuzhaigou, China earthquake
Article
Full-text available
  • Nov 2022
  • NAT HAZARDS
The stochastic finite-fault technique based on dynamic corner frequency (EXSIM) is the most commonly used approach for obtaining near-field high-frequency ground motion and is regarded as an effective tool by researchers worldwide for simulating near-fault high-frequency ground motion. Because many model parameters in the finite-fault stochastic method are related to the source, site, and path, and the uncertainty of the input parameters frequently creates uncertainty of the synthesis results, it is difficult to obtain reasonable model parameters. The key point to consider when using EXSIM is how to determine the model parameters for ground motion simulation. Thus, the study investigated and discussed the sensitivity of some model parameters, such as site amplification and rupture velocity, to EXSIM synthesis results and updated modeling. The results showed that when the improved EXSIM was used, only the crustal site amplification function (CA) was adequate for Class A sites, whereas when EXSIM was used, both the CA and local site amplification (LA) functions had to be considered concurrently. Both CA and LA functions must be considered in the EXSIM for Class C and D sites. To obtain satisfactory synthesis results, the improved EXSIM requires only one LA function to be considered. Furthermore, the amplitude spectrum increased with rupture velocity, and the influence of rupture velocity was noticeable in the short period. These findings can serve as a foundation for highly reasonable and rapid model parameter determination, as well as improve simulation accuracy.
View
Ground Motion Simulations for the 19 January 2020 Jiashi, China, Earthquake Using Stochastic Finite-fault Approach 【Accepted Manuscript】
Article
Full-text available
  • Dec 2022
A 6.0‐magnitude (Mw) earthquake was reported to have occurred in Jiashi County, Xinjiang at 21:27 on 19 January 2020, Beijing time (13:27 UTC). This study applied a stochastic finite‐fault approach based on the dynamic corner frequency (EXSIM) to simulate 23 near‐field stations within a distance of 120 km from the epicenter. The stochastic finite‐fault approach is the simplest and most effective method for simulating high‐frequency ground motions. According to studies and empirical relationships, we estimated a region‐specific parameter (κ0) for use in simulations. In this study, two different slip models, namely, random and inverted slip models, were used to explain their influence on the simulation results. For most stations, the simulated seismic characteristics, such as the peak ground acceleration (PGA), pseudo spectral acceleration ,and Fourier acceleration spectrum, are highly compatible with the observed values in the frequency range (f > 1 Hz), indicating that the stochastic finite‐fault approach is not highly sensitive to input slip distributions and fault dimensions. The simulation results indicated no significance between the two slip models under high‐frequency conditions. Finally, based on the predicted PGA values of 1891 field points selected near the fault, the acceleration field of the Jiashi earthquake is plotted. The results show that the use of the acceleration time history predicted by modified EXSIM is feasible and practical in the high‐frequency band above 1 Hz.
View
A Method for Predicting Hybrid Source Model of Near-Field Ground Motion: Application to Yangbi Earthquake in China【Corresponding author】
Article
Full-text available
  • Jan 2023
Based on the finite-fault model, combined with the empirical relationship or semiempirical relationship between the moment magnitude and the global source parameters (GSP) and the local source parameters (LSP), the Hybrid Source Model (HSM) of the Yangbi earthquake has been predicted. Considering the regional seismotectonic, crustal structure, seismicity, and semiempirical relationships, the GSP (fault size, average slip, etc.) used in the simulation are given. The LSP primarily includes two parts, one is the asperity parameters describing the deterministic slip, and the other is the k2 model describing the random slip. LSP is determined based on the empirical or semiempirical relationship, and the average value and standard deviation of the GSP are calculated according to the empirical relationship. To generate a series of source parameters that meet the mean and standard deviation, an improved truncated normal distribution function is used. The pseudospectral acceleration (PSA; damp = 5%) of four stations satisfying different geological conditions and orientations are simulated by the stochastic finite-fault approach. The group with the smallest residual error with the average PSA is selected as the final selected focal parameters using the principle of minimum residual error. Eventually, the reliability of this method is verified by comparing it with the inverted source model, and it can be concluded that this method can quickly predict the source model of a given magnitude.
View
Seismic Performance Assessment of Velocity Pulse-Like Ground Motions Under Near-Field Earthquakes
Article
Full-text available
  • May 2021
  • ROCK MECH ROCK ENG
As a part of the earthquake ground motion, large velocity pulses are probably one of the important factors leading to serious rock structural damage and geological disasters. It is vitally important to identify the response characteristics of large-scale structures under near-field pulse-like ground motions for earthquake prevention and disaster reduction. In this study, the pulse parameters from the 1999 Chi-Chi and 2018 Hualien earthquakes are extracted using the wavelet transform method, and the potential consequences of velocity pulses on the seismic response of the buildings are assessed. Our results show that the near-field ground motions affected by the directivity effect contain some rich large pulse contents in the velocity time histories. The Chi-Chi earthquake presents a more obvious directivity effect than the Hualien earthquake, and the near-field velocity pulses are closely related to the severely damaged structures. The potential damage of both earthquakes to high-rise buildings can be evaluated by the relationship between the characteristic period of the velocity pulse and the fundamental natural period of the engineering structure. By comparing the periods, it can be revealed that some long-period spectral values in the range of 0.8–3.0 s exceed the seismic design values in the vicinity of the causative faults, and the vulnerability of high-rise buildings against pulse-like ground motions in the Chi-Chi earthquake is stronger than that in the Hualien earthquake. Interestingly, the ratio of peak ground velocity to acceleration (PGV/PGA) and maximum pseudo response velocity (PSV) are suitable as seismic intensity indicators of pulse-like ground motions, which can reflect the rupture direction of source characteristic and site amplification of near-surface soft deposition area around the causative fault. This study provides some references for seismic hazard assessment and post-earthquake structural design.
View
Source modelling and strong ground motion simulations for the 24 January 2020, Mw 6.8 Elazig earthquake, Turkey
Article
Full-text available
  • Jul 2020
On 24 January 2020 an Mw 6.8 earthquake occurred at 20:55 local time (17:55 UTC) in eastern Turkey, close to the town of Sivrice in the Elazığ province, causing widespread considerable seismic damage in buildings. In this study, we analyse the main features of the rupture process and the seismic ground shaking during the Elazığ earthquake. We first use Interferometric Synthetic Aperture Radar (InSAR) interferograms (Sentinel-1 satellites) to constrain the fault geometry and the coseismic slip distribution of the causative fault segment. Then, we utilize this information to analyse the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations. The absence of seismic registrations in near-field for this earthquake imposes major constraints on the computation of seismic ground motion estimations in the study area. To do this, we have used a stochastic finite-fault simulation method to generate high-frequency ground motions synthetics for the Mw 6.8 Elazığ 2020 earthquake. Finally, we evaluate the potential state of stress of the unruptured portions of the causative fault segment as well as of adjacent segments, using the Coulomb stress failure function variations. Modelling of geodetic data shows that the 2020 Elazığ earthquake ruptured two major slip patches (for a total length of about 40 km) located along the Pütürge segment of the well-known left-lateral strike-slip East Anatolian Fault Zone (EAFZ), with up to 2.3 m of slip and an estimated geodetic moment of 1.70 × 1019 Nm (equivalent to a Mw 6.8). The position of the hypocenter supports the evidence of marked WSW rupture directivity during the mainshock. In terms of ground motion characteristics, we observe that the high-frequency stochastic ground motion simulations have a good capability to reproduce the source complexity and capture the ground motion attenuation decay as a function of distance, up to the 200 km. We also demonstrate that the design spectra corresponding to 475 years return period, provided by the new Turkish building code is not exceeded by the simulated seismograms in the epicentral area where there are no strong motion stations and no recordings available. Finally, based on the Coulomb stress distribution computation, we find that the Elazığ mainshock increased the stress level of the westernmost part of the Pütürge fault and of the adjacent Palu segment and as a result of an off-fault lobe.
View
Simulation of finite fault hybrid source models for the Mw 6.6 Jiuzhaigou, China, earthquake
Article
Full-text available
  • Dec 2020
  • J SEISMOL
A hybrid source model for the Mw 6.6 Jiuzhaigou earthquake, China, based on the finite fault is established. The global parameters are estimated mainly according to the regional seismic structure, crustal structure, seismicity, and semi-empirical calibration laws. The local parameters are divided into two parts: the asperity part describing the deterministic slip and the k-square model describing the random slip. The source models are generated by 30 groups of simulation and are compared with those retrieved by other scholars. The results show that this method can be used as an effective approach to predict seismic source models.
View
Estimation of the finite fault source model for the 2018 Mw7.1 Acari, Peru earthquake using a hybrid simulation prediction approach
Article
  • Jan 2023
  • SOIL DYN EARTHQ ENG
The near-field motion of large earthquakes is generally simulated using finite fault source models (FFSMs). Most of these models use post-earthquake observation data as the constraints for the inversion model, and therefore, it is difficult to generate FFSMs until after the earthquake has occurred. We use parameters from previous earthquakes to generate FFSMs in a hybrid simulation prediction approach that combines the asperity model and the k⁻² model. New scaling laws for global and local parameters are used to estimate the asperity model parameters and the coordinates of the fracture initiation point. Using the k⁻² model, 30 sets of FFSMs are established using truncated normal distributions and several regional geological structural parameters. After applying the residual evaluation criteria to the various response spectra, we select the average source model. We then apply our methodology to the 2018 Acari earthquake in Peru. Both our average model and the USGS inversion model have two asperities, but their positions are different. The response spectra of the four representative points of our model are similar to those of the USGS model, and the peak difference is between −13.4% and 18.4%. The USGS model is a post-earthquake model, which requires many parameters and post-earthquake observation data. Our FFSM requires few parameters and represents the most representative source model for future earthquakes in this area with similar magnitudes, and it is intended to be supplementary to the inversion model. Therefore, our hybrid approach may be used for the early prediction or rapid estimation of the resulting ground motions.
View
Parameter estimation for predicting near-fault strong ground motion and its application to Lushan earthquake in China【Corresponding author】
Article
  • Mar 2022
  • SOIL DYN EARTHQ ENG
Stochastic finite-fault modelling based on the dynamic corner frequency is a widespread method for synthesizing near-fault ground motions at high frequencies and has been proven to be an effective tool for simulating high-frequency ground motions by researchers globally. Many input parameters, which have more uncertain effects on the synthetic result, are related to sources, sites, and paths in stochastic modelling. Thus, it is difficult to select reasonable parameters. When using the stochastic finite-fault method, the key link to be considered is how to determine the input parameters required for simulations. Based on this fact, this study analyzed and discussed the sensitivity of several important input parameters in the simulation parameters to the simulation results. The results showed that for the Class C site stations, the crustal and local site amplification factors must be considered simultaneously. Overall, the influence of the high-frequency attenuation parameter κ0 calculated using different methods on the simulation results is not evident. For near-fault stations, various upper-edge buried depth synthetic response spectra can be set, and finally, the average value is taken as the final synthetic recorded response spectra. When using the random source model, the rupture starting point must be set on the subfault in the middle along the fault length and width direction. The conclusions provide a basis for a highly reasonable and rapid determination of input parameters when using the stochastic finite-fault simulations for practical engineering applications and can improve the simulation accuracy to apply the finite source modelling to rebuild scenarios and evaluate and alleviate the seismic hazard in the target region.
View
Simulating the near-field pulse-like ground motions of the Imperial Valley, California, earthquake
Article
  • Aug 2020
  • SOIL DYN EARTHQ ENG
Long-period pulse-like ground motions in the near-field are likely to induce severe damage to large structures due to resonance at the natural frequencies of engineered construction. To investigate the origin and characteristics of large velocity pulses from the seismic source, this study identifies 14 stations with velocity pulses from 32 strong-motion seismographs located in the near-field of the Imperial Valley MW 6.5 earthquake. The pulse-like ground motions are simulated by a kinematic approach using a fourth-order accurate finite-difference method. The results show that the slip asperity in the northern part of the fault plane contributes more to large velocity pulses than the asperity that originates in the hypocentral zone. The two-sided pulses on the fault-normal component and the one-sided pulses on the fault-parallel component are mainly regulated by the fault rupture and slip directions, respectively. Compared with the pseudo-velocity response spectrum, the displacement response spectrum better captures the resonance effect of long-period pulse-like ground motion on large structures. The location of the maximum ground motion coincides with the surface projection area of the large asperity, and the amplitude and the attenuation rate of each horizontal component vary with increasing distance from the fault. The difference in the ground motion peaks on both sides of the fault implies that the fault-normal component is more sensitive to the fault dip angle than the fault-parallel component. We reproduce the pulse-like ground motions up to 1 Hz by fitting the simulated velocity time histories, response spectrum and ground motions to observed data. Using the pulse records of the Imperial Valley earthquake, the 1994 Northridge MW 6.7 earthquake, and the 1999 Chi-Chi MW 7.6 earthquake, we compare the effects of earthquake magnitude on peak value and distribution of large velocity pulses, in which a reasonable consistency can be observed. Our simulated results of near-field pulse-like ground motions are beneficial to clarify the pulse mechanism.
View