Earthquake Prevention Research Articles

Numerical simulation of seismic stress evolution in the Lajishan Fault zone on the northeastern margin of the Qinghai-Xizang Plateau

To analyze the triggering relationship of historical earthquakes to the 2023 Jishishan earthquake and estimate the seismic risk in the adjacent region after the earthquake, we calculate the evolution process of seismic stress generated by 11 earthquakes with MS ≥ 6.0 and 1 earthquake with MS5.7 near the source in the past 100 years. The results show that before the 2023 Jishishan earthquake, the entire Lajishan Northern Edge Fault zone was under the stress shadow generated by the 12 earthquakes. The stress reduction at the 2023 Jishishan earthquake epicenter was approximately 15.1 kPa, and the contribution of this stress shadow mainly comes from the 1920 MS8.5 Haiyuan earthquake. The coseismic stress drop at the epicenter was around −292.1 kPa, and the maximum stress drop for the 2023 Jishishan earthquake was around −346.2 kPa. The Jishishan earthquake increased the stress of the two seismic gaps in the Lajishan Northern Edge Fault by 14.7 kPa and 59.7 kPa respectively, the stress on the Lajishan Southern Edge Fault zone increased by 10.9 kPa, and the stress on the east section of Xunhua Nanshan Fault increased by 11.1 kPa. These stress increments potentially elevate the seismic hazard along these fault zones. In the future earthquake prevention and disaster reduction, attention should be paid to the seismic risk of these fault zones.

An intervention study of adopting a health action model to improve the effectiveness of disaster prevention learning of preschool senior class students

This study investigates the effect of adopting the health action model (HAM) to improve disaster prevention learning among preschool senior class students. A quasi-experimental design with pre- and post-tests was used to track the extended effects. Convenient sampling selected 60 senior-class students from a private preschool in New Taipei City, divided into experimental and control groups. The HAM was incorporated into 5 earthquake prevention lessons. The effectiveness was assessed using a Checklist of Earthquake-Prevention Learning Effectiveness, analyzed by generalized estimating equations. Results showed significant positive effects of the intervention on earthquake-prevention knowledge (post-test: B = 0.41, p < .001; follow-up test: B = 0.23, p = .001), attitudes (post-test: B = 0.91, p < .001; follow-up test: B = 0.97, p < .001), skills (post-test: B = 1.10, p < .001; follow-up test: B = 1.09, p < .001), intentions (post-test: B = 0.88, p < .001; follow-up test: B = 0.85, p = .001), and behaviors (post-test: B = 0.71, p < .001; follow-up test: B = 0.61, p < .001), with effects lasting for at least 5 weeks. These findings suggest that the intervention significantly enhances earthquake-prevention knowledge, attitudes, skills, intentions, and behaviors, and can serve as a reference for designing preschool earthquake-prevention courses.

Fault geometry and kinematics at the intersection of the Zemuhe, Daliangshan and Xiaojiang Faults

The complexity of strike-slip fault segmentation affects the initiation, propagation, and termination of earthquake ruptures and the earthquake magnitude. Studying the fault geometry, kinematics, and segmentation provides fundamental knowledge for mitigating earthquake hazards along faults. The Zemuhe, Daliangshan, and Xiaojiang Faults intersect along the eastern boundary of the Tibetan Plateau in the area from Ningnan in Sichuan Province to Qiaojia in Yunnan Province. Although few large earthquakes have occurred on these faults, the relationships between the intersections of these three faults and earthquake rupture behavior in this region are poorly constrained. The interpretation of aerial photographs and detailed field surveys revealed the geometric pattern and fault kinematics in the area of intersection. The distribution patterns and focal depths near the faults were obtained via analysis of seismic data in the area of intersection. The northern segment of the Xiaojiang Fault deviates approximately 25° northwest of Qiaojia, forming a conspicuous bend. The Xiaojiang Fault continues to extend southeast of the Ningnan Basin, where it intersects with the southern segment of the Zemuhe Fault, forming a pull-apart basin approximately 4.5 km wide. The bend and Ningnan pull-apart basin mark the segmented boundary between the Zemuhe Fault and the Xiaojiang Fault, which may prevent the propagation of large earthquake ruptures along the eastern boundary fault. Moreover, the lack of obvious geometric complexity between the Daliangshan Fault and Xiaojiang Fault might hinder the prevention of earthquake rupture propagation. Additionally, our results suggest that different earthquake prevention and disaster reduction measures should be taken for different cities in the region.

Seismic hazard prediction of the Hunhe Fault in the Shen-Fu New District

Earthquake prevention and disaster mitigation are crucial aspects of social welfare that significantly impact national public security. This paper presents a seismic risk assessment and hazard prediction of the Hunhe Fault in the Shengyang-Fushun (Shen-Fu) New District. The target area is at risk of seismic damage due to two major branch ruptures, namely, F9 and F1; these ruptures have the potential to generate maximum earthquakes with a magnitude of 6.0 in the next 50 to 100 years. A three-dimensional underground velocity structure and asperity source model were established for the target faults. Subsequently, a hybrid technique combining deterministic and empirical approaches was employed to simulate the broadband strong ground motion of the target region in anticipation of the occurrence of expected scenario earthquakes. The distributions of peak ground acceleration (PGA), peak ground velocity (PGV) and peak ground displacement (PGD) for the area are provided, and the results indicate that densely populated urban areas could experience PGA values close to 280 cm/s2 along the fault traces. This study provides a reliable basis for engineering construction and urban planning in the Shen-Fu New District.

Passivity-based control of underactuated mechanical systems with Coulomb friction: Application to earthquake prevention

Passivity property gives a sense of energy balance. The classical definitions and theorems of passivity in dynamical systems require time invariance and locally Lipschitz functions. However, these conditions are not met in many systems. Characteristic examples are nonautonomous and discontinuous systems due to the presence of Coulomb friction. This paper presents an extended result for the negative feedback connection of two passive nonautonomous systems with set-valued right-hand side based on an invariance-like principle. Such extension is the base of a structural passivity-based control synthesis for underactuated mechanical systems with Coulomb friction. The first step consists of designing the control able to restore the passivity in the considered friction law, achieving stabilization of the system trajectories to a domain with zero velocities. Then, an integral action is included to improve the latter result and perform a tracking over a constant reference (regulation). Finally, the control is designed considering dynamics in the actuation. These control objectives are obtained using fewer control inputs than degrees of freedom, as a result of the underactuated nature of the plant. The presented control strategy is implemented in an earthquake prevention scenario, where a mature seismogenic fault represents the considered frictional underactuated mechanical system. Simulations are performed to show how the seismic energy can be slowly dissipated by tracking a slow reference, thanks to fluid injection far from the fault, accounting also for the slow dynamics of the fluid’s diffusion.

Key technologies of earthquake early warning system for China’s high-speed railway

PurposeThe purpose of this study is to introduce the top-level design ideas and the overall architecture of earthquake early-warning system for high speed railways in China, which is based on P-wave earthquake early-warning and multiple ways of rapid treatment.Design/methodology/approachThe paper describes the key technologies that are involved in the development of the system, such as P-wave identification and earthquake early-warning, multi-source seismic information fusion and earthquake emergency treatment technologies. The paper also presents the test results of the system, which show that it has complete functions and its major performance indicators meet the design requirements.FindingsThe study demonstrates that the high speed railways earthquake early-warning system serves as an important technical tool for high speed railways to cope with the threat of earthquake to the operation safety. The key technical indicators of the system have excellent performance: The first report time of the P-wave is less than three seconds. From the first arrival of P-wave to the beginning of train braking, the total delay of onboard emergency treatment is 3.63 seconds under 95% probability. The average total delay for power failures triggered by substations is 3.3 seconds.Originality/valueThe paper provides a valuable reference for the research and development of earthquake early-warning system for high speed railways in other countries and regions. It also contributes to the earthquake prevention and disaster reduction efforts.

Study on seismic risk assessment model of water supply systems in mainland China

Abstract. Using the peak ground acceleration (PGA) under four exceedance probabilities calculated via a probabilistic seismic hazard analysis method for China, the probability density function of PGA was obtained by fitting with the Cornell seismic hazard exceedance probability PGA function model. Combined with the seismic fragility function of the water supply system calculated on the basis of the empirical matrix of actual earthquake damage and the exposure of fixed assets, the expected seismic loss and expected loss rate models of the water supply system were established, and the classification standard with the expected seismic loss rate of the water supply system as the index was proposed. The seismic fragility of the water supply system was classified, and the exposure of the water supply system was analyzed. The total fixed assets in the Statistical Yearbook of Urban Water Supply, henceforth called Water Supply Yearbook, were taken as the exposure to earthquake in the region. The accuracy of the fragility model in this paper was verified through the actual earthquake damage losses in Deyang. Taking the water supply system of 720 cities in mainland China as an example, the distribution maps of expected seismic loss and expected loss rate were calculated and drawn. The expected loss rate model was verified by the key earthquake prevention areas in mainland China. The assessment model based on the expected loss and expected loss rate was taken as the seismic risk assessment model of water supply systems in mainland China.

Definitions, Classification Schemes for Active Faults, and Their Application

Active faults are generally defined as faults that have moved in the past and will continue to be active in the future. They are expected to cause deformation and potential disasters if they are localized close to human activities. The definition and classification of active faults are important bases for evaluating the risk. This paper summarizes and compares the history, status, and progress of their definition and classification schemes used in representative countries and regions, as well as in some relevant standards, in active fault mapping, in the construction of spatial databases, and in some other aspects. It is concluded that the current geodynamic setting, existing technical means, geological operability, application purpose, and social acceptability of active faulting hazard in a specific area comprehensively determine the selection of the definition and classification. The key parameter in defining active faults is the time limit. It usually involves four time scales, i.e., Neotectonic (post-Neogene), Quaternary, Late Quaternary, and Holocene. The definition using a short time scale, such as Late Quaternary and Holocene, is usually suitable for the plate boundary zone, which has a high strain rate, but active faults in the intraplate deformation region and stable continental region should be defined with a long time scale, such as the Quaternary and Neotectonics. In addition, the magnitude standard can determine the activity intensity of active faults, which most generally includes three classes, namely, M ≥ 5.0 damaging earthquakes, M ≥ 6.0 strong earthquakes, and M ≥ 6.5 earthquakes that may produce surface displacement or deformation. The M ≥ 5.0 earthquake is generally applicable to regional earthquake prevention and risk mitigation in many countries or regions, but the M ≥ 6.5 earthquake magnitude benchmark is generally used as the standard in rules or regulations regarding active fault avoidance. The most common classification schemes in many countries or regions are based on fault activity, which is reflected mainly by the fault slip rate and fault recurrence interval (FRI), as well as by the last activation time. However, when determining the specific quantitative parameters of the different activity levels of faults, it is necessary to comprehensively consider the differences in activity and ages of the faults in the study region, as well as the amount and validity of existing data for the purpose of classifying different active levels of faults effectively.

Intrinsic and scattering attenuations of the Sichuan-Yunnan region in China from S coda waves

Seismic attenuation is a fundamental property of the Earth's media. Attenuation structure for the complicated geological structures with strong seismicity in the Sichuan-Yunnan region is poorly studied. In this study, we collected 108,399 waveforms of 11,517 local small earthquakes with magnitudes between 1.5 and 3.5 from January 2014 to September 2021 in the Sichuan-Yunnan region and its adjacent areas. We employed an envelope inversion technique for separating the intrinsic and scattering attenuations of the S coda wave, and obtained the intrinsic and scattering attenuation structures for frequencies between 0.25 and 8.00 Hz. The attenuation structures correlate well with the geological units, and some major faults mark the attenuation variations where historic large earthquakes have occurred. The regional average attenuation shows a negative frequency dependence. The average scattering attenuation has a faster descending rate than the average intrinsic attenuation, and is dominant at low frequencies, while at high frequencies the average intrinsic attenuation is stronger. The lateral variation in the intrinsic attenuation is consistent with the variation in heat flow, the scattering attenuation may be related to the scatter distribution and size. The total attenuation is consistent with the previous studies in this region, and the separate intrinsic and scattering attenuation may be useful in understanding regional tectonics and important in earthquake prevention and disaster reduction.

A Physics-Based Seismic Risk Assessment of the Qujiang Fault: From Dynamic Rupture to Disaster Estimation

This study achieved the construction of earthquake disaster scenarios based on physics-based methods—from fault dynamic rupture to seismic wave propagation—and then population and economic loss estimations. The physics-based dynamic rupture and strong ground motion simulations can fully consider the three-dimensional complexity of physical parameters such as fault geometry, stress field, rock properties, and terrain. Quantitative analysis of multiple seismic disaster scenarios along the Qujiang Fault in western Yunnan Province in southwestern China based on different nucleation locations was achieved. The results indicate that the northwestern segment of the Qujiang Fault is expected to experience significantly higher levels of damage compared to the southeastern segment. Additionally, there are significant variations in human losses, even though the economic losses are similar across different scenarios. Dali Bai Autonomous Prefecture, Chuxiong Yi Autonomous Prefecture, Yuxi City, Honghe Hani and Yi Autonomous Prefecture, and Wenshan Zhuang and Miao Autonomous Prefecture were identified as at medium to high seismic risks, with Yuxi and Honghe being particularly vulnerable. Implementing targeted earthquake prevention measures in Yuxi and Honghe will significantly mitigate the potential risks posed by the Qujiang Fault. Notably, although the fault is within Yuxi, Honghe is likely to suffer the most severe damage. These findings emphasize the importance of considering rupture directivity and its influence on ground motion distribution when assessing seismic risk.

Seismic Vulnerability Assessment in Tunnels: A Review

Vulnerability analysis is an important method for earthquake prevention and disaster reduction research in the field of tunnel engineering. Firstly, a detailed overview of the research history and current status of tunnel seismic vulnerability at home and abroad was provided; Secondly, the main methods for analyzing the seismic vulnerability of tunnels at home and abroad were summarized, and the practical applicability of various methods was summarized; Subsequently, the steps for evaluating the seismic vulnerability of tunnels were proposed, and three key contents in establishing theoretical vulnerability curves using numerical simulation as the main method were discussed: (1) Input parameter determination; (2) Classification of destructive states; (3) Calculation of relevant uncertainty parameters; Finally, point out some urgent problems and future research directions in this field. By summarizing the existing studies on the seismic vulnerability of tunnels at home and abroad, the results show that the seismic vulnerability analysis of tunnels can reflect the performance of tunnels under seismic loading by considering the relevant uncertainty factors, which is conducive to the future risk assessment and loss estimation, and is of great significance to the development of performance-based seismic design of tunnels.

Advances in Earthquake Prevention and Reduction Based on Machine Learning: A Scoping Review

Advances in Earthquake Prevention and Reduction Based on Machine Learning: A Scoping Review

A Rapid Earthquake Disaster Assessment Platform Based on Cloud Computing

In the past few decades, earthquakes have been a major cause of casualties and economic losses. The rapid assessment system for earthquake disasters plays an important role in earthquake prevention, disaster reduction, and emergency command by calculating the economic losses and casualties caused by earthquakes in a relatively short time after the occurrence of an earthquake. Although there are now many rapid assessment systems for earthquake disasters, most of them adopt C/S and B/S architectures, which have limited computational efficiency during large-scale earthquakes. Based on these factors, this study aims to build a cloud computing-based rapid assessment system for earthquake disasters. The main modules of the system include intensity impact field calculation, building damage assessment, economic loss assessment, casualties assessment, and model parameter calibration. The results show that the system significantly speeds up the calculation process and shortens the assessment time. It can provide timely disaster assessment information to relevant departments in a short period and provide technical support for emergency decision-making.

Robust boundary tracking control of wave PDE: Insight on forcing slow-aseismic response

The output boundary tracking problem is addressed for a wave partial differential equation (PDE) with uncertain multiplicative parameters and additive boundary and in-domain terms. To solve this problem, a homogeneous boundary feedback controller is designed using collocated boundary measurements only. Global exponential Input-to-State Stability (eISS) of the closed-loop system and its insensitivity to matched disturbances are additionally achieved. The ultimate bound estimate is diminished by tuning of the controller gains and/or by an appropriate pre-selection of a reference signal to follow. The proposed homogeneity-based strategy is further evaluated in a simplified earthquake model for controlled dissipation of its stored energy and producing slow-aseismic response. Such a case study possesses important applications in earthquake prevention, renewable energy production and storage. Numerical simulations are additionally conducted to support the robustness and the smoothness of the resulting closed-loop system depending on the homogeneous control parameter selection.

A petal–cylindrical seismic metamaterial occupying low-frequency wide bandgaps in horizontally stratified soils

Earthquake prevention is of fundamental interest in seismic research area. Seismic metamaterials proved very useful for this purpose, but because they are mainly based on resonant structures, the working frequency bandwidth of these metamaterials is narrow. This work aims to increase the bandwidth by improving cylindrical resonant structure. Two types of cylindrical structures with four petals attached to the four sides of hollow and solid cylinders are proposed. Their bandgap properties have been investigated by using the finite element method. Particularly, considering more realistic site conditions for seismic surface wave propagation, we explored the properties of the proposed structures for horizontally stratified soils, besides homogeneous soil. The results show that a low-frequency wide bandgap is provided in case of homogeneous soil. Excitedly, in case of a stratified substrate, an additional bandgap is obtained in lower frequency region. Moreover, to confirm the feasibility of the proposed structures, the transmission coefficients for the finite unit cells are calculated for both homogeneous and horizontally stratified soils along with the different directions. The finding substantiates that the finite system for stratified soils can effectively attenuate seismic surface waves within the two low-frequency bandgaps occupying the relative bandwidths of 154% and 81%.

Multifractal analysis of temporal and spatial characteristics of earthquakes in Eurasian seismic belt

Abstract Seismic activity has complexity and randomness, and its temporal and spatial distribution has complexity, stage, level, and inheritance. The study of the temporal and spatial distribution characteristics of seismic activity is of great significance to the understanding of the law of seismic activity, such as the law that the time series of seismicity in the seismic belt is consistent with the complexity of geographical structure, the prediction of seismic risk, and other research related to earthquake. This article selects the seismic data catalog of the whole Eurasian seismic belt as the research object. Based on the characteristics of the seismic geological environment and tectonic environment characteristics, the multifractal analysis method is used for the seismic data of the seismic activity directory. The results show that the seismic activity of seismic zones has obvious multifractal structure of complex in time series and spatial scales, which can well reveal the seismic characteristics of seismic activity in time and space. In terms of time series, the study area D ∞ {D}_{{\rm{\infty }}} decreases significantly with time and energy before the occurrence of a large earthquake, and the time series of seismic activity in the study area is highly complex and highly correlated with the geological structure. Spatially, the spatial distribution of seismic intensity in the study area is infinite and sparse, showing the characteristics of infinite clustering. Therefore, it can reveal the basic rule of seismic activity effectively and lay a certain theoretical foundation for earthquake prevention and control in this seismic zone.

Assessment of Vulnerability Caused by Earthquake Disasters Based on DEA: A Case Study of County-Level Units in Chinese Mainland

Earthquake activity can generate huge energy in a short period of time, bringing enormous risks to people’s lives and property safety. This poses a great challenge to regional sustainable development. Meanwhile, due to the complex mechanism, seismic activity is difficult to accurately predict. Therefore, it is of great significance to explore how to reduce earthquake disaster losses from the perspective of human society. In this study, we use vulnerability to reflect the relative impact of earthquake disasters on different counties. The vulnerability caused by earthquakes is calculated with the data envelopment analysis (DEA) method. We use CCR and BCC models to further decompose vulnerability into pure technology vulnerability and scale vulnerability. This study analyzes 69 earthquake disasters that occurred in the Chinese mainland from 2013 to 2020 and explores the influencing factors of pure technology vulnerability from both quantitative and qualitative perspectives. Three main conclusions are drawn. First, four factors, including the added value of the secondary industry, gross domestic product (GDP) per capita, investment density of fixed assets and energy released by earthquakes, have a significant impact on the pure technical vulnerability of counties caused by earthquake disasters. Second, in the samples under consideration, the average vulnerability of the regions with an earthquake magnitude below 5.0 is higher than that of the regions with an earthquake magnitude between 5.0 and 6.0. There are deficiencies in organization, management and facilities in regions with a small earthquake risk. Third, through qualitative analysis, it is shown that the seismic function of buildings affects the vulnerability of counties facing earthquake disasters. The results of the research can provide decision makers with new insights into earthquake prevention and disaster reduction management.

Seismic response analysis of shallowly buried subway station in inhomogeneous clay site

It is of great significance to study the seismic response of the shallowly buried subway station in the inhomogeneous site caused by the soil consolidation. The dynamic characteristics of Shanghai soft clay under different confining pressures were studied by a series of dynamic triaxial tests. The nonlinear analysis was used to investigate the influence of the inhomogeneous clay site on the seismic response of the shallowly buried subway station. The variations of dynamic shear modulus ratio and damping ratio under different buried depths were obtained. The research results indicate that the damage to subway stations is more serious in the inhomogeneous clay site under the same seismic wave. The inhomogeneity of the clay site has an amplification effect on the horizontal relative displacement between the ceiling and bottom slabs, as well as the vertical displacement of the ground surface. However, the effect of the inhomogeneous site on the acceleration of the slabs and the maximum horizontal relative displacement of the middle column is small. After the earthquake, the horizontal relative displacement of the middle column is strongly affected by the inhomogeneous site. The results can provide a reference to the earthquake prevention and disaster reduction in the soft clay area.

Research and Application of Negative Stiffness Device in The Field of Earthquake Prevention and Disaster Reduction

The negative stiffness device can reduce the equivalent stiffness of the structure, and has a good control effect on the peak shear force and acceleration response. The combination with the structural vibration theory makes the negative stiffness device fully play its role, and at the same time improves the seismic capacity of the structure, forming a negative stiffness vibration control device. Through reading and sorting out the research achievements of domestic and foreign scholars, the research progress of negative stiffness devices in the field of earthquake prevention and disaster reduction is discussed from the aspects of theoretical development, effect, device application and development trend, and the future development is prospected.

Seismic Hazard Analysis of China’s Mainland Based on a New Seismicity Model

Based on the seismic source model in the Fifth Generation Seismic Ground Motion Parameters Zonation Map of China (FGSGMPZMC), a new seismic fault model, the new zonation of seismic risk areas (SRAs), and the estimation of seismicity rates for 2021–2030, this study constructed a new time-dependent seismic source model of China’s mainland, and used the probabilistic seismic hazard analysis method to calculate seismic hazard by selecting the ground motion models (GMMs) suitable for seismic sources in China. It also provided the probabilities of China’s mainland being affected by earthquakes of modified Mercalli intensity (MMI) VI, VII, VIII, IX, and ≥ X in 2021–2030. The spatial pattern of seismic hazards presented in this article is similar to the pattern of the FGSGMPZMC, but shows more details. The seismic hazards in this study are higher than those in the FGSGMPZMC in the SRAs and fault zones that can produce large earthquakes. This indicates that the seismic source model construction in this study is scientific and reasonable. There are certain similarities between the results in this study and those of Rong et al. (2020) and Feng et al. (2020), but also disparities for specific sites due to differences in seismic source models, seismicity parameters, and GMMs. The results of seismic hazard may serve as parameter input for future seismic risk assessments. The hazard results can also be used as a basis for the formulation of earthquake prevention and mitigation policies for China’s mainland.