Abstract:The Huzhou-Lin'an Fault is a large-scale NE-trending fault in Zhejiang region,witnessing the 2017 Lin'an M4.2 earthquake.The remote sensing image of the Longxi-Huanghu section of the Huzhou-Lin'an fault has obvious linear characteristics and has a significant control effect on the landform,with high mountains on the west side and a hilly plain transition zone on the east side.Through the analysis of the cross-fault geological profile and fault outcrop profile,it is concluded that the activity nature of the Longxi-Huanghu section of the Huzhou-Lin'an Fault is mainly a normal fault.Through field investigation,combined with satellite images and ESR age samples de-termination,it is determined that the fault is an active one in the early and middle Pleistocene of the Quaternary.

Abstract:This article explores the impact of the M7.9 earthquake that occurred in Myanmar on March 28,2025,on building construction,especially the damage to structural safety and material damage of different types of build-ings.Researches have shown that Myanmar's current seismic design standards have deficiencies.By combining nu-merical simulations and typical cases to verify seismic performance and disaster assessment,comprehensive im-provement measures covering seismic reinforcement technology,policy and regulatory optimization,and public education and training have been proposed to provide scientific basis and technical support for building protection.

Abstract:The foundation load of high-rise buildings in Beijing is large and the raft foundation is mostly irregular in shape.Conventional calculation methods cannot accurately reflect the settlement after design.Taking an L-shaped high-rise building as a case study,this paper developed a three-dimensional numerical analysis model to analyze the upper structure-raft-foundation soil-pile synergistic effects.The stress of the foundation soil,the force on the CFG pile body,and the variation law of settlement between the raft and foundation soil were analyzed.The settlement calculation results were compared with the measured values to verify the feasibility of this method.The results indicate that there is a phenomenon of stress concentration at the column foundation of the foundation soil.There is negative frictional resistance in the top area of CFG piles,and the distribution of lateral frictional resis-tance along the length of the pile is uneven.The maximum settlement in the core tube area of the L-shaped building is closely related to the length and stiffness of the lower pile group.The research results and methods provide refer-ence for the settlement analysis of similar high-rise buildings,and have practical engineering significance.

Abstract:Prestack elastic impedance inversion is one of the inversion methods for estimating elastic parameters and anisotropic parameters of reservoirs.However,as the complexity of the medium increases,the stability of the inversion results decreases.In this paper,a carbonate reservoir with a set of vertical orthogonal directional fractures was equivalent to an orthotropic(OA)medium.The wide-azimuth seismic data of carbonate fractured reservoirs were used to study a stable inversion method suitable for fracture prediction in carbonate reservoirs,so as to improve the inversion stability of fractured reservoirs.First,the PP wave elastic impedance expression for OA medium was derived.The equation was reduced from nine independent parameters to three parameters to be inverted,which lowered the contribution of different independent parameters to the reflection coefficient.Then,the elastic impedance inversion method based on Bayesian theory was adopted to improve the stability of the inversion algorithm.Under different noise conditions,the proposed elastic impedance inversion method for OA medium was tested in models and applied in actual work areas.The application results show that the fractured reservoir prediction method in this paper has a consistency rate of more than 90%with the actual drilling and logging,which verifies the reliability of the method in this paper in predicting fractures in carbonate reservoirs.

Abstract:With the construction of the National Seismic Intensity Rapid Reporting and Early Warning Project,na-tional and provincial early warning systems integrate decisions and produce massive amounts of early warning data.In order to analyze and study the early warning data in depth and meet the requirements of early warning business system evaluation,a set of earthquake early warning data output service platform was designed and developed.Through the detailed introduction of the platform overview,design architecture,platform functions,and applica-tion implementation,this paper explained how the platform can be used to collect and store earthquake early warn-ing data,and process and generate multiple service products for early warning system operation,maintenance,and evaluation.The earthquake early warning data output service platform is an important supplement to the nation-al intensity rapid reporting and early warning system,and its service products have important reference value for the operation and maintenance of the early warning system.

Abstract:Through the mathematical statistics of high-precision continuous observation data of hydrogen emitted from two soil sites and two hot spring wells in northwestern Yunnan for more than two years,the correlation fitting with meteorological elements,and the analysis of the periodic components of the observation data by using S-trans-form,the following understandings are obtained:The background value of hydrogen emitted from hot spring wells in the northwestern Yunnan is higher than that from soil;the observation data of the four measurement sites gener-ally show the characteristic of zigzag fluctuations,and the high value and low value of concentration are often in a large difference.Among them,both high and low abnormal values of hydrogen emitted from hot spring wells are present,while only high abnormal values of hydrogen emitted from soil are observed.Hydrogen emitted from hot spring wells in northwestern Yunnan has clear annual periodic components and slightly weaker semi-annual period-ic components,but it does not have semi-diurnal components.However,hydrogen emitted from the soil does not have clear annual periodic components,but shows relatively clear semi-diurnal periodic components.From the fit-ting results with meteorological elements,the change in hydrogen concentration emitted from hot spring wells shows a certain correlation with atmospheric temperature and pressure,while hydrogen emitted from the soil is ba-sically not related to both.Moreover,there is no correlation between the concentration of gas emitted from soil and hot spring wells and rainfall,which is quite different from previous research results.Therefore,it is believed that the correlation between trace hydrogen concentration in fault zones and meteorological elements still needs further analysis and research.

Abstract:The special properties of near-fault pulse-type ground motion in response spectrum and frequency spectrum are the main influencing factors causing seismic damage to near-field medium and long-period structures.Accurately identifying and extracting the pulse characteristics of near-fault ground motion is of great significance for simulating and inverting pulse-type ground motion,analyzing structural responses characteristic under pulse action,evaluating the seismic performance of near-field structures,and conducting seismic fortification design of structures.By studying the recognition principles and recognition effects of three typical recognition methods for pulse-type ground motion based on continuous wavelet transform,energy,and EM&G,respectively,the paper analyzed the advantages and disadvantages of different methods,summarized the suggestions for confirming pulse characteristics that multiple methods should be adopted for repeated recognition,and conducted recognition and verification of pulse-type ground motion based on the PEER database.The distribution characteristics of pulse-type ground motion in terms of fault distance and site type were sorted out.

Abstract:In response to the current issue of low precision in landslide detection,a deep learning-based landslide detection framework was proposed.This framework includeed three parts:data collection and processing,feature selection,and detection model,which can effectively improve the detection capability of landslides by integrating multi-source data.A multimodal KlAlexNet model was proposed,which could achieve pixel-level segmentation pre-diction and effectively fuse spatial features.Experimental results indicate that the proposed KlAlexNet model has high precision in landslide detection.Compared with methods such as U-Net,U-Net++,FC_DenseNet,and YO-LOv9-seg,it demonstrates advantages.The experimental results validate the effectiveness and practicality of the proposed method,indicating its broad application prospects.

Abstract:Structural vulnerability analysis is one of the important aspects of earthquake disaster risk assessment.This paper took the masonry structure with a large proportion in Jiaxing City as an example,selected the appropri-ate strength index and damage index,and adopted the incremental dynamic analysis method.The amplitude modu-lation of multiple ground motions was carried out to obtain the corresponding structural response structures under the action of each ground motion intensity,and the structural vulnerability curves were analyzed.Finally,the vul-nerability curves of typical masonry structures in Jiaxing City were analyzed.The results of vulnerability analysis show that the typical masonry structure in Jiaxing City can basically meet the local VII seismic fortification require-ments,and the exceedance probability of collapse of the structure is less than 10%under a large earthquake,indi-cating that the structure has good anti-collapse ability.The research results can provide a theoretical basis for the re-fined seismic disaster risk assessment and risk prevention of buildings in Zhejiang Province.