The starting magnitude is one of the core parameters that determine the scanning results of the solid tide modulation ratio. Currently, the modulation ratio scanning analysis of solid tides is mostly based on a single, specific magnitude as the benchmark, and comparative studies of scanning results across bins of different magnitudes remain scarce. On January 10 and July 25, 2025, two earthquakes with magnitudes of 4.1 and 4.2 occurred consecutively in the southern section of the Fenwei fault zone in Linfen, Shanxi Province, within a six-month period, attracting the attention of seismologists. We scanned the solid tide modulation ratio images for the ML1.7 and ML2.5 magnitude ranges before the Linfen, Shanxi M4.1 and M4.2 earthquakes. The results show significant differences in the abnormal evolutionary characteristics of the solid tide modulation ratio across different magnitude ranges. As the initial scanning magnitude increased, the range of the high-value anomaly in the solid tide modulation ratio expanded, and its amplitude increased. Meanwhile, the correlation between the epicenter location and occurrence time becomes stronger. The high modulation ratio anomalies of solid tide obtained from pre-earthquake scanning are primarily attributed to the modulation effect of earthquakes ML≥2.5. Therefore, when using the solid tide modulation ratio method for earthquake tracking, an appropriate starting magnitude for the study area should be selected through a comparative analysis across multiple magnitude bins.
Site classification is of great significance for the site selection of major engineering projects and prevention of seismic geological hazards. This study considered Weining County as the research area. By collecting geological maps, digital elevation model data, and Landsat8-9ETM image data, we analyzed the main factors influencing the classification of site categories and determined three evaluation factors: rock category, slope, and normalized vegetation index. We used deterministic and fuzzy logic methods based on weighted superposition to build a model. We adjusted the model using measured borehole data, classified site categories, used research area survey data for verification, and compiled a spatial distribution map of the site categories in the study area. Results show that site categories are mainly related to lithology, slope, and NDVI. The softness and hardness of rocks play major roles in the classification of site categories. The classification method can be adjusted using the measured survey point data, and the deterministic method combining the slope and NDVI can more accurately classify the site categories. This research result is significant for the classification of large-scale site categories.
Seismic standards constitute an important technical foundation for the governance system and capacity of earthquake prevention and disaster reduction. Addressing the lack of systematic quantitative analysis in existing research on the latest landscape of seismic standardization against the backdrop of high-quality development, this study takes 286 effective seismic standards as of the end of July 2026 as its research object. Employing statistical analysis and comparative research methods, it systematically examines the current status and distribution characteristics of China’s seismic standard across three dimensions: hierarchical structure, temporal evolution, and technical domains. The paper elaborates the positioning and roles of four hierarchical levels：national standards, industry standards, local standards, and group standards, and reviews the achievements in standard development across four major domains: basic and general standards, monitoring and forecasting, seismic hazard prevention, and emergency (rescue). Building on this analysis, it identifies the persistent challenges in current seismic standardization, including imbalanced distribution across standard levels and domains, lagging updates to the top-level master system framework, insufficient supply of standards in emerging fields, low effectiveness of standard implementation, weak support from standardization professionals, and the need for further improvement in internationalization. In response, the paper proposes countermeasures and recommendations concerning improving the top-level design of the standard system, optimizing the standard structure, strengthening standard implementation, enhancing talent cultivation, and elevating the level of internationalization, with a view to providing a reference for the development of seismic standardization in the new era.
The southeastern part of the Sichuan-Yunnan fault block is located at the southeastern corner of the eastern Xizang-Sichuan-Yunnan fault block, which is a secondary tectonic unit on the eastern margin of the Qinghai-Xizang Plateau. It is intersected by the nearly northsouth trending Xiaojiang fault zone on the eastern side and adjoins the South China block. Currently, this region is experiencing intense tectonic activity and frequent strong earthquakes. An in-depth analysis of the current seismic activity characteristics of the southeastern Sichuan-Yunnan fault block is of great significance for assessing the seismic hazard of this region in the future. Combined with the regional tectonic setting, this study analyzes the characteristics of historical strong earthquakes in the southeastern part of the Sichuan-Yunnan fault block, discusses the correlation of seismic activity between adjacent structures on the eastern and western sides of the southern segment of the Honghe fault zone, and concludes that historical strong earthquakes among different structures in the southeastern Sichuan-Yunnan fault block show a certain temporal correlation. Historically, strong earthquakes in the southeastern Yunnan arcuate tectonic belt have occurred during three active periods, during which strong earthquakes in adjacent structures triggered each other, and their spatial distribution is closely related to the distribution of fault zones. Historically, strong earthquakes along the Qujiang and the Shiping-Jianshui fault zones have verified the rupture gap theory. Analyzing five earthquake cases in the southeastern Yunnan Arcuate Tectonic Belt since 1965 showed that seismicity clustering existed before some moderate to strong earthquakes. The adjacent structures on the eastern and western sides of the southern segment of the Honghe fault zone show a good correlation with seismic activity, which is conducive to the formation of seismic gaps. An analysis of geothermal anomalies on both sides of the Honghe fault zone before the 2022 Honghe MS5.0 earthquake shows that stress interactions may exist between the structures on the eastern and western sides of the southern segment of the Honghe fault zone.
As the center of China’s political, cultural, and international exchanges, the Beijing region’s seismic safety holds strategic national significance. With the advancement of the National Earthquake Intensity Rapid Reporting and Early Warning Project and the Beijing Mega-Catastrophe Prevention Project, Beijing’s seismic monitoring network has evolved from a “single-point, dispersed” configuration to a “networked, standardized, and intelligent” system. This study focuses on the standardized construction of integrated cabinet-based seismic stations and systematically summarizes their technical architectures, implementation approaches, and innovative features. In particular, it highlights the critical role of standardized cabinets in enhancing station operational efficiency, data quality, and maintenance capabilities. Drawing on Beijing’s experience building its seismic array, the study elaborates on key technologies such as the integrated design of standardized cabinets, environmental adaptation modifications, and the establishment of an intelligent operation and maintenance system. Operational data were used to validate the effectiveness of these standardized cabinets in applications such as early earthquake warnings and rapid intensity reporting. The results demonstrate that the standardized construction of integrated cabinets is the core foundation for supporting the efficient operation of high-density seismic networks, and its experiences can serve as an important reference for modernizing seismic monitoring networks nationwide.
Most of the geophysical observation instruments at the Jiaxiang Seismic Monitoring Station are installed in caves. These instruments are digital and networked precision monitoring devices. As the station is located in a lightning-prone area, it has suffered multiple failures caused by lightning strikes over a long period, resulting in interruptions to observation data. A comprehensive upgrade and renovation of the lightning protection system was conducted on the station’s office building and observation caves in 2022. The project included lightning protection measures for signal lines, the upgrade and renovation of the outdoor grounding grid, equipotential bonding systems and down conductors, and the installation of surge diverters. The aim was to improve the station’s overall lightning protection capability, ensure the stable operation of the station’s instruments, and guarantee the continuity and reliability of the station’s geophysical observation data. The post-renovation results have confirmed that the station’s comprehensive lightning protection capability has been well enhanced, providing protection against most induced lightning and direct lightning strikes at the station. However, they cannot provide effective protection against a small number of sudden and severe direct lightning strikes. Therefore, it is important to strengthen routine inspection and testing of the station’s power supply and lightning protection equipment.
Based on the parallel observational data from the DDL-2 and RAD7 radon monitors at well Anguo-1 in Pingliang, Gansu Province, this study systematically analyzes the influence of different sampling methods on DDL-2 instrument measurements by integrating traditional statistical methods (including Pearson correlation analysis and coefficient of variation calculation) with machine learning algorithms (including random forest regression and Isolation Forest anomaly detection). This study identified and evaluated the effects of key environmental parameters (temperature, humidity, and atmospheric pressure) on the measurement accuracy of the DDL-2 instrument and compared the long-term stability of the domestic DDL-2 radon monitor with that of the imported RAD7 radon monitor. The results indicate that temperature and atmospheric pressure had relatively significant effects on the precision of DDL-2 radon measurements. The adoption of standardized sampling methods and controlled observation conditions can substantially reduce primary duplicate-sample errors in DDL-2 measurements, bringing the stability of DDL-2 measurements to levels approaching those of the RAD7 instrument. Well Anguo-1 in Pingliang, Gansu Province, was used as a case study to evaluate the applicability of the DDL-2 radon detector in seismic monitoring, providing a scientific basis for data quality control and standardized operation of domestic radon detectors.
Unmanned fluid stations are a critical component of China’s earthquake monitoring system for observing regional geophysical fields. The stable operation and data quality of these stations are significant for regional short-term and imminent earthquake prediction and forecasting. This study systematically analyzed the key aspects of station operation and maintenance, addressing common issues such as power supply, communication, and equipment failures in unmanned fluid stations. Five modular operational strategies are proposed to ensure stable station operation and improve data quality: establishing a multimodal station power supply and lightning-protection system, optimizing the communication-link configuration, standardizing the design of fluid wellhead equipment, achieving rapid and accurate fault diagnosis, and implementing a regular inspection-and-maintenance workflow. Using the operational practices of three fluid stations under the Hebei Xingtai Earthquake Monitoring Center Station as examples, the effective implementation of these measures has improved the operational rate and quality of observation data for unmanned fluid stations. This can provide valuable experience and a reference for the operation and maintenance of similar stations at other provincial earthquake monitoring centers.
This study addresses the data security requirements of Oracle databases by designing and implementing an automated offline backup solution for Linux environments, built on shell scripts and scheduled tasks. An integrated shell script was developed to sequentially execute steps, including configuring environment variables, shutting down the database, packaging and compressing data files with the tar command, cleaning up historical backups, and restarting the database, ensuring the consistency of backup data. The solution incorporates both the system timer and the crontab scheduler to achieve periodic, reliable task execution, with an extended feature for remote synchronization via the SCP tool. Practical applications demonstrated that this scheme effectively safeguards data security and integrity, significantly reduces manual maintenance overhead, and provides a stable and efficient reference implementation for database backup in similar environments.
The stratigraphic classification of the Quaternary strata in the Yangtze River alluvial plain provides a fundamental basis for reconstructing the evolution of the Quaternary environment and serves as an effective standard for calibrating reflection layers and interpreting shallow seismic profiles. It also provides a basis for studies of active urban faults and seismic hazard assessments. In this study, we examined the lithology, color, material composition, sedimentary structures, and other characteristics of the 78 m thick Quaternary succession from Liqiao Village, Xilian Town, Yi’an District, Tongling City, China using the BZK1 drill core. Based on the detailed stratigraphic subdivision, a Quaternary age framework for the BZK1 core was established using a combination of optically stimulated luminescence and electron spin resonance dating techniques. Grain size analysis was conducted to investigate the regional sedimentary environment. The BZK1 core recorwds, from bottom to top, early Middle Pleistocene alluvial deposits (56.7～ 76.2 m), Late Pleistocene fluvial deposits (35.0～ 56.7 m), and Holocene floodplain deposits (0～ 35.0 m), but lacks deposits from the Early Pleistocene and the Middle to Late Middle Pleistocene. The establishment of the Quaternary stratigraphic framework for the BZK1 drill core provides a reliable geological reference for active fault detection, artificial seismic exploration, and integrated borehole profile interpretation in Tongling City. It also offers a valuable basis for regional Quaternary stratigraphic correlation, chronostratigraphic subdivision, and the reconstruction of the sedimentary environmental evolution in the Yangtze River alluvial plain.
To explore the correlation between small earthquakes and gravity field changes in Shandong Province under the weak seismic activity, this study takes the area around the Yishu fault zone as the core region. It selects earthquakes with magnitudes of ML3.0 and above, including the 2013 Laizhou ML4.9 earthquake, the 2015 Pingyi ML3.9 (collapse-induced) earthquake, and the 2020 Changqing ML4.6 earthquake. The data from the provincial mobile gravity observation network of the Shandong Earthquake Agency during 2010 to 2022, were processed using the classical adjustment method in the LGADJ software. Subsequently, the characteristics of gravity field changes before and after the earthquakes were analyzed across different time scales.The results show that: In the gravity field changes between adjacent phases before and after the occurrence of small earthquakes, areas with changes exceeding the threshold appear around the epicenters, and the epicenters are mostly located at the bends of the 0 μGal or 10 μGal contour line. In terms of time scales, the changes near the epicenters are significant in the maps of adjacent phases and 1-year interval changes, whereas the changes are not obvious in the maps of multi-year accumulations (2 years and above). The measuring points with significant changes show drastic variations only before and after the earthquakes and remain stable at other times. This study provides a scientific basis for the monitoring and medium-term prediction of small earthquakes in weak earthquake regions.
To advance software localization and ensure autonomous and controllable information systems in key industries, this study uses the domestically developed next-generation network monitoring system, Nightingale, as a research subject. It systematically analyzes its core features and overall technical architecture, and clarifies its advantages in terms of localization adaptation and autonomous controllability. This study elaborates on the implementation plan for an earthquake information network monitoring system based on Nightingale, focusing on key technical aspects such as system installation and deployment, monitoring data collection, and the design of an alarm mechanism. It further analyzes the practical performance of the system, providing technical support and practical guidance for the localization and application of software in earthquake information network monitoring.
As an important barrier to nuclear safety, nuclear island pit bosses need to maintain their integrity after a severe accident. Research by scholars at home and abroad on the safety of the nuclear island pit boss under the combined action of earthquakes and loss of coolant accidents (LOCA) in severe accident conditions remains relatively limited. Therefore, refined finite element models of different types of nuclear island pit boss components were established using ABAQUS. By simulating the most unfavorable working conditions for the combined action of earthquakes and LOCA, the stress distribution characteristics, deformation laws, and failure modes of various boss components under combined loads were systematically explored. The results show that different types of bosses can maintain structural integrity under the most unfavorable working conditions, and the arrangement of the steel bars can effectively improve their bearing and deformation capacities. The relevant conclusions can provide a reliable theoretical basis and technical support for the optimal design, safety verification, and emergency disposal of nuclear island pit bosses and further enhance the safety resilience of nuclear power plants under extreme combined working conditions.
The seismic data quality is crucial to the accuracy of seismic monitoring. Various interference events pose challenges to the daily data analysis and processing at seismic monitoring stations. Based on the extraction and analysis of interference events in the continuous three-year observation data of the Jingbo Lake volcano network from May 2022 to April 2025, in this study, the impact of human interference and natural environmental interference on the seismic analysis data of the Jingbo Lake volcano network was statistically analyzed. In addition, the occurrence patterns and important characteristics of typical interference events in volcanic areas were preliminarily explored. The study results can be directly used to rapidly identify interference events in volcanic areas and provide key references for optimizing the analysis of seismic observation data in volcanic networks.
To enhance the reliability of data transmission in seismic networks and mitigate service interruptions caused by single-point link failures, a high-availability dual-link transmission system was designed and deployed at 14 reference stations in the Shanghai earthquake early warning network. The system adopts an “MSTP optical fiber primary link + 5G wireless backup link” architecture. The primary link relies on a 2 Mbps MSTP (Multi-Service Transport Platform) dedicated fiber line, offering inherently low latency and high stability for core data transmission. The wireless backup link utilizes China Broadcasting Network’s 700 MHz 5G network, which provides extensive coverage and strong signal penetration. By incorporating a dedicated DNN (Data Network Name) and wireless network slicing technology, an end-to-end logical channel isolated from public networks was established to ensure transmission security and quality for the backup path. To enable intelligent redundancy and seamless failover, the architecture integrates IPSec tunnel encryption with an OSPF (Open Shortest Path First) dynamic routing protocol. Through differentiated OSPF cost settings and persistent link-state monitoring, the system achieves automatic subsecond switching to the 5G backup link upon failure of the primary fiber link. Operational experience, including performance during extreme weather conditions, confirmed that the system significantly improved station availability and data transmission resilience. This solution offers a practical and replicable approach for enhancing communication assurance in earthquake warning systems and other critical infrastructure applications.
Spike-interference is one of the most common disturbances in 1-second geomagnetic sampling data, and its proper correction directly affects the quality of 1-second geomagnetic observations. Conventional methods, such as the median-average approach, require extensive manual intervention and show limited adaptability when dealing with interference lasting longer than one second. To improve the accuracy of spike-interference correction, this study formulates the task as a machine-learning regression problem and proposes an XGBoost-based model for correcting spike disturbances in 1-second geomagnetic sampling data. Using raw Z-component observational data from the automated geomagnetic station at the Manzhouli Seismic Observatory between January 2024 and April 2025, 17720 samples of magnetic-field variations—capturing and surrounding spike-interference events—were extracted to construct the dataset for model training. The model achieved the following performance metrics on the test set: a mean squared error of 0.010971 nT², a root mean squared error of 0.104742 nT, a mean absolute error of 0.074217 nT, and a coefficient of determination of 0.999852. The results demonstrate the excellent performance of the XGBoost model in correcting spike-interference in 1-second geomagnetic sampling data, providing a robust and high-precision method for automated correction of such disturbances.
This study is based on the Evaluation Indicators and Standards for Observation Quality at Municipal and County Stations established by the China Earthquake Networks Center in 2022. Fifteen underground fluid observation datasets in the Chuxiong area were evaluated by considering the observation environment, observation system, data quality, and forecasting effectiveness. First, the analysis provides clear assessment results for each measured item. Second, for both qualified and conditionally qualified measurement items, specific solutions and rectification measures are proposed based on actual observation conditions. Third, for measurement items with good predictive significance, the study includes quantitative tracking. The comprehensive assessment results showed that seven measurement items were qualified, accounting for 46.7%, while the remaining eight items achieved basic qualification, and no items were rated as unqualified. Based on the evaluation results for underground fluid observation projects in the Chuxiong Prefecture, a grading classification was developed to guide improvements at stations with existing problems, which can effectively enhance the monitoring quality of city and county stations and support future anomaly identification and verification.
Facing challenges of multiple operation and maintenance entities, extensive materials, and multiple users, a question-answering system based on the knowledge graph of earthquake communication network operation and maintenance in Shaanxi Province has been established. The system utilizes Neo4j for knowledge storage, employs the Django framework for system development, and achieves the digitization and visualization of network operation knowledge and experience. A question-answering system based on retrieval-augmented generation was implemented based on this knowledge graph, providing accurate answers to users, effectively reduce time costs, and improve work efficiency.
The background noise characteristics of 477 strong-motion stations in the Beijing-Tianjin-Hebei region were analyzed using power spectral density, whereas the horizontal-to-vertical spectral ratio (HVSR) was applied to investigate site response characteristics across regional stations. Background noise levels across the Beijing-Tianjin-Hebei region displayed distinct spatial patterns, with mountainous stations exhibiting the lowest and most consistent noise levels, whereas stations in plains and coastal areas demonstrated higher noise levels with greater susceptibility to anthropogenic activities and natural environmental factors. HVSR analysis revealed that plains and coastal regions with thick sedimentary deposits exhibited lower predominant frequencies (0.5～2 Hz) with pronounced low-frequency amplification effects, whereas mountain stations featured higher predominant frequencies (exceeding 5 Hz) attributable to bedrock exposure and elevated shear wave velocities. The spatial distribution and frequency domain characteristics of background noise levels were highly correlated with site response features, reflecting the combined effects of geological structures and environmental conditions, thereby providing scientific evidence for optimizing station distribution and improving seismic monitoring and early warning capabilities.
After the completion of the Beijing subproject of the “National Seismic Intensity Rapid Reporting and Early Warning” project, a seismic intensity rapid reporting and early warning network consisting of seismometers and intensity meters with an average station spacing of 9 km was established in the Beijing area. This high-density integrated network provides data support for the accurate and rapid output of intensity reporting results. To meet the demand for rapid intensity reporting in Beijing’s earthquake emergency response work, and based on local reporting conditions, a rapid output system for earthquake intensity reporting was designed and implemented. The system was developed in Python and integrated with ArcGIS’s ArcPy geographic data-processing library to build a set of rapid intensity reporting thematic map templates. After an earthquake occurs, the rapid reporting information system automatically downloads seismic waveform data, calculates instrument intensity values, and applies prefabricated thematic map templates. Within 5～10 minutes of the official measurement results, strong-motion reports and instrument intensity distribution maps are automatically generated. Use of this system by duty officers can significantly shorten the time required for mapping and report generation, improve the efficiency of report and image production, provide preliminary information on post-earthquake impacts to relevant departments, and offer a basis for government and leadership decision-making.
