Abstract:In order to further encrypt and optimize the construction of seismic stations,Anhui Province plans to build new seismic stations on the basis of the existing seismic observation network and closely combined with the earthquake situation in Anhui Province.According to the principle of taking into account the improvement of early warning ability of the whole province and appropriate encryption in key areas,this study takes the slope data,traffic road data,historical earthquake data,existing station distribution data,Tanlu fault zone data and population density data of Anhui Province as the influencing factors of seismic station location.The weight of each influencing factor is determined by the analytic hierarchy process.With the advantage of spatial analysis in ArcGIS,the suitable area for site selection is analyzed,the site selection model of Anhui Seismic Network is established,to optimize the scheme and obtain the optimal site area,so as to ensure the distribution rationality of Anhui seismic network planning.

Abstract:Five terms of gravity differential maps from Nov.2020 to Sep.2022 are offered,some water level and gravity time-varying curves of observation station are plotted and the effects of short time water level changes on gravity observation results in Sep.2024 are analyzed.The results shows that there are good correlation between Three Gorges Reservoir water level changes and regional gravity changes.If the reservoir water level changes greater,the gravity changes contour lines are denser.The rising and falling trend of water level are consistent with the direction of the gravity changes.If the distance between the observation station and the Yangtze River or its branch is less than 300 meter,the water level changes curve is nearly overlapped with the gravity time-varying curve of the observation station.The short time water level changes in two days will affect the self-difference of the survey segment near the Yangtze River or its branches which is observed in two days.If there is one station near the Yangtze river or its branch in a segment,the segment self-difference will exceed 7 μGal,which is far greater than the treble of the self-difference average 1.09 μGal.If the two stations are both near the Yangtze river or its branch or both away from that,the segment self-difference will remain below 5 μGal.

Abstract:To enhance the understanding of ambient noise characteristics in Fujian region and the quality of obser-vation data of Fujian Earthquake Early Warning Network,the continuous waveform data of 120 seismic stations in Fujian Earthquake Early Warning Network in 2023 were selected,and the seismic noise level and background noise characteristics in Fujian region were evaluated by using the analysis methods of seismic noise power spectral density(PSD),probability density function(PDF)and root mean square(RMS).The results show that the overall noise level of Earthquake Early Warning Network is mainly level Ⅱ,and the spatial distribution shows a certain re-gional pattern.The noise level of stations in coastal areas with dense population and frequent industrial activities is higher than that of stations in central and western mountainous areas.The analysis of noise spectrum characteristics shows that the noise in the low frequency band(<0.1 Hz)is mainly affected by temperature and humidity distur-bance and airflow,and the noise PSD value fluctuates between-170 dB and-130 dB.The noise of the horizontal channel of some stations is significantly higher than that of the vertical channel.It is suggested to strengthen the pro-tection measures of seismometers and the calibration of datum plane.The mid-frequency(0.1-1 Hz)noise is closely related to marine activities,with a PSD value about 20 dB higher than the global lowest noise model(NLNM).The dominant frequency(0.3 Hz)is 0.1 Hz offset from the global lowest noise model,and the dual-frequency microseis-mic energy in winter is slightly higher than that in summer.The high-frequency(>1 Hz)noise is dominated by hu-man noise,with significant diurnal variations.Installing away from densely populated towns or cave installation can effectively reduce interference sources around the station.

Abstract:This paper addresses the uncertainty of structural parameters and investigates the random response of base-isolated liquid storage tanks under seismic excitation.First,the base-isolated liquid storage tanks is modeled based on the Haroun-Housner model,from which an equivalent linearized equation of motion is derived.Second,using the pseudo excitation method combined with polynomial dimensional decomposition,a random vibration anal-ysis of the base-isolated liquid storage tank with uncertain parameters is conducted,The results are compared with those from Monte Carlo simulation,confirming the effectiveness of the proposed method.Finally,based on the sur-rogate model established through the proposed method,the probability density of the response standard deviation of the liquid storage tank is computed,and the influence of the coefficient of variation on the response standard de-viation is analyzed.

Abstract:With the rapid advancement of urban construction,the seismic observation environment is confronted with severe challenges.Taking Dongguan City as the research object,this paper elaborated on its innovative mea-sures in the protection of the seismic observation environment,including in-depth participation in planning formu-lation to delimit the yellow line,strengthening pre-approval by relying on the"One Map"System of Traffic and Municipal Yellow Line,and establishing a coordination and linkage mechanism to balance the relationship be-tween construction and protection.It also summarized the achievements,and finally put forward considerations on improving the level of earthquake prevention and disaster mitigation work in response to the existing problems.This study provides valuable practical experience and reference ideas for the protection of urban seismic observation en-vironments.

Abstract:To enhance the application capability of multi-source data in geological hazard monitoring and early warning,this study constructed a monitoring and early warning system that integrates multi-source data such as UAV photography,geological sensors,satellite remote sensing and other multi-source data.By calculating data similarity and setting a fusion threshold of 0.8,the system employs a three-layer convolutional neural network with 5×5 convolutional kernel to extract features and performs secondary fusion on data that does not meet the standard,addressing the consistency issue of multi-source heterogeneous data.Additionally,a deep kernel support vector ma-chine(DKSVM)model is proposed,which utilizes deep learning to automatically extract high-order feature associa-tions such as terrain slope and soil moisture,and combines the structured risk minimization principle of support vector machine to achieve classification prediction.The study selected nine types of geological hazards,including landslides,debris flows,and ground subsidence,and compared them with the early warning models in referenc-es[3]to[4].The results indicate that among the nine types of geological disasters such as landslide,debris flow and ground subsidence,the accuracy of disaster prediction of this system reached 98.7%,which is significantly im-proved compared with the comparison literature,with F1 values for landslide,debris flow and other disaster types exceeding 97.6%.After data fusion,the proportion of effective information increased from 65%to 92%,with an average similarity of 0.89,verifying the robustness and generalization ability of the model in complex geological en-vironments,and providing a technical reference for intelligent geological disaster early warning.

Abstract:Through regional and near-field seismic activity analysis and seismic tectonic environment evaluation,the activity level of far-field earthquakes and near-field earthquakes was studied,and the occurrence conditions of moderate-strong earthquakes in the region were evaluated.In this paper,the fault investigation and activity identifi-cation in the near field area were carried out to explore the distribution,scale and latest activity era of active faults.Based on the empirical relationship between fault rupture length and magnitude,the maximum potential magnitude of active faults was calculated,the setback distance for the active faults was proposed,and the dislocation effect of seismic faults at the site was evaluated.A set of plans for site selection and active fault avoidance of major proj-ects in Fuzhou City is proposed.

Abstract:Abstrct:The deep-water area of the Baiyun Sag in the northern South China Sea exhibits significant exploration po-tential.However,exploration in the shallow to middle strata has been limited by a relatively narrow target system and the depletion of available traps in these layers.Therefore,deep-water exploration in this region must extend in-to deeper strata.Early seismic data in this area were primarily acquired using narrow-azimuth towed-streamer(NATS)acquisition geometry,which restrict buried-hill prediction due to limited azimuthal coverage.To address this limitation,this study innovatively employs ES360 imaging processing technology to reprocess the existing NATS seismic data.This processing generates angle-domain wide-azimuth(WAZ)gather data,effectively compen-sating for the azimuthal information gap inherent in the original NATS data.Consequently,this enhanced dataset enables robust pre-stack fracture characterization of reservoirs.Furthermore,multi-attribute analysis was conduct-ed on the newly derived post-stack seismic volume.These post-stack attributes were then integrated with the pre-stack fracture characterization results through a multi-scale fusion approach.This integration facilitated the devel-opment of a hierarchical fracture system characterization technique.This integrated methodology was successfully applied to a targeted buried-hill prospect(Area L)within the deep-water Baiyun Sag,enabling effective prediction of buried-hill reservoir distribution and the identification of zones with high-quality fractured reservoir development based on the originally acquired offshore NATS seismic data.Moreover,the methodology is adaptable and can be extended to the exploration and development of similar buried-hill oil and gas reservoirs.

Abstract:In the exploration of concealed oil and gas reservoirs in continental rift lake basins,the spatial distribu-tion patterns and reservoir control mechanisms of dominant sedimentary systems are frontier scientific issues in cur-rent oil and gas geological research.In this study,the Phase Ⅲ of Wenchang Formation in Lufeng Sag of Pearl Riv-er Mouth Basin is taken as the research object.Using high-precision three-dimensional seismic,logging,drilling,paleontology and geochemical data,through the quantitative analysis of source-sink system under the constraint of a high-resolution sequence stratigraphic framework,the prediction model of dominant sand body in lowstand sys-tem tract of faulted lake basin is constructed,and the development model of lithologic trap is revealed.The main achievements are as follows:For the first time,the T82_FFS sequence boundary was identified in the third mem-ber of the Phase Ⅲ of Wenchang Formation in the southern gentle slope zone of Lufeng Sag,and the complete low-stand system tract sedimentary system was divided.Four types of source-sink system evolution models are estab-lished:narrow-shallow fault-slot transport type,narrow-deep fault-slot vertical aggradation type,wide-shallow fault-slot lateral migration type,wide-deep fault-slot composite transport type.The wide-deep fault-slot system has the optimal reservoir conditions.Three kinds of lithologic trap development models are constructed.Among them,the upper-super pinch-out trap developed by the wide-deep fault-trough composite transport delta sedimentary body has the greatest exploration potential.Drilling confirmed that the maximum thickness of the single sand body is 38.6 m,and the daily oil production is more than 27 m3/d,and the exploration breakthrough is successfully achieved.The results of this study provide a research paradigm for the exploration of deep subtle reservoirs in fault-ed lacustrine basins based on the source-sink theory system from qualitative to semi-quantitative characterization of dominant sand bodies.

Abstract:Earthquake disasters exhibit characteristics of instantaneous occurrence,chain reactions,and wide spatial coverage,frequently resulting in"information silos"in the disaster area,which severely hinders emer-gency response decision-making.Rapid and accurate acquisition of post-disaster geographic information is crucial for supporting efficient response efforts.Traditional earth observation methods are difficult to meet the demands for fine evaluation within the critical"golden 72 hours"after the earthquake in terms of timeliness and resolution.Un-manned aerial vehicle(UAV)low-altitude remote sensing mapping technology has become an indispensable techni-cal system for emergency response due to its advantages of high mobility,high timeliness,low cost and high reso-lution.However,the data limitations from single sensor,the problem of route planning in complex disaster scenar-ios,and the post-processing pressure caused by"data explosion"are still the core challenges faced by current UAV emergency mapping.This paper focused on this,and proposed a fast acquisition and processing method of emergency geographic information that integrates multi-source information,aiming to provide more reliable geospa-tial data support for earthquake emergency command.

Abstract:The Liuhua deep-water oilfield is characterized by a tilted semi-anticline structure,with the main con-trolling faultexhibiting significant throw(approximately 300 m)and the substantial velocity variations across its two walls.Conventional velocity modeling techniques often fail to accurately capture the sharp velocity contrasts across the fault,leading to structural distortion within the fault shadow zone of the reservoir.Full waveform inversion(FWI),which comprehensively utilizes kinematic and dynamic information of the seismic wavefield,can recover higher frequency velocity components compared to conventional methods,offering distinct advantages for accurate imaging of complex structures.Therefore,high-precision FWI velocity modeling has been applied for the first time in the Liuhua deep water area.To address the geological and acquisitionchallenges in the study area,this study adopts a structural constraints,time-domain multi-scale FWI approach.First,a low-wavenumber velocity back-ground was established through velocity analysis and traveltime tomography.Subsequently,Gaussian beam tomog-raphy was employed to derive a high-precision,medium-wavenumber velocity field as the initial model for FWI pro-cess from low to high frequencies,structural trends were incorporated as constrains to mitigate cycle-skipping is-sues.Finally,a high wavenumber FWI velocity model was successfully constructed.The application of this method accurately delineates the velocity contrast across the fault walls and effictively corrects the"pull-up"distortion within the fault shadow zone.Post-test applysis demonstrates that structural errors have been reduced from 25 m to less than 5 m,improving structural interpretation accuracy by approximately 10%.This technique has effectively guided development adjustment and potential exploitation in the Liuhua deep-water oilfield and holdspromising val-ue for application in similar fields.

Abstract:Based on the Integrated Marketing Communication Theory(IMC),Technology Acceptance Model(TAM)and Cognition-Emotion-Behavior(CAB)theory,this study systematically explored the promotion mechanism of multi-channel integrated communication on the effectiveness of earthquake prevention and disaster reduction sci-ence popularization.By constructing a theoretical model with channel synergy degree,content matching degree and interactive participation degree as the core independent variables,information trust degree as the key intermediary variable,knowledge cognition improvement,risk perception enhancement and disaster prevention behavior inten-tion as the effect dimension,structured questionnaire survey and structural equation model were employed for em-pirical validation.Results indicate that channel synergy significantly improves the audiences'information trust by strengthening the communication network system.Content matching promotes cognitive-emotional transformation with the help of media feature adaptation,while deep interactive participation accelerates the generation of behav-ioral intention.Through the complete intermediary role of information trust,the integrated communication mode forms the core path of"systematic synergy→trust-building→cognitive internalization→behavioral drive",which verifies the chain gain effect of multi-dimensional communication elements on the effect of science popularization.

Abstract:The paper explores the present situation,hotspots and trends of earthquake early warning research in China,and provides reference for future researchers.Based on 818 journal papers collected by CNKI,CiteSpace software was used for a visualized analysis of information,including authors,institutions and keywords.The re-sults show that in terms of research status,the annual number of published papers shows obvious stage characteris-tics,the authors of the published papers show a state of"generally dispersed and locally concentrated",and there is less cooperation between research institutions,while the high-yield institutions have close cooperation,clear and intersecting research topics.The current research hotspots can be summarized as earthquake magnitude estimation,artificial intelligence earthquake early warning,earthquake early warning service and high-speed rail-way earthquake early warning.The research on earthquake early warning shows a trend of continuous increase in the number of annual publications and rapid update of topics.In the future,in-depth research can be carried out around the new methods of earthquake early warning and the refinement of early warning services.

Abstract:The construction method and accuracy of low-frequency models for seismic inversion are crucial for the accuracy of inversion,especially for buried hill reservoirs with deep burial and strong heterogeneity.The conventional well interpolation low-frequency model may reduce the prediction accuracy of inversion results due to ignoring the heterogeneity between wells.In order to solve the above problems,this paper takes the H buried hill in Huizhou Sag of the Pearl River Mouth Basin as an example to carry out optimal logging evaluation and petrophysical modeling of buried hill.The seismic interval velocity optimized by well control was used as the initial low frequency for prestack simultaneous inversion,and the lithology probability prediction was carried out based on the inversion results.Using elastic parameter bodies,lithology prediction bodies,and logging curves,a low-frequency model driven by lithology was created based on convolutional neural networks as the low-frequency model for subsequent pre-stack inversion.The research results show that the low-frequency model based on lithology-driven and convolutional neural network can effectively solve the problem of difficult construction of low-frequency models in the prediction of igneous rock reservoirs in the Pearl River Mouth Basin,improve the seismic inversion accuracy of igneous rock buried hill reservoirs,and provide strong support for the development of H buried hill.

Abstract:Taking the geological disasters in Saga County,Shigatse after the"4·25"M8.1 earthquake in Nepal as the research object,combined with remote sensing interpretation,field surveys,surveying and mapping,ex-ploration and experiments,this paper systematically analyzed the development characteristics of post-earthquake geological disasters and discussed their formation conditions and inducing factors.The results show that Saga Coun-ty's relatively uniform terrain and limited elevation variance restrict the diversity and scale of geological disasters.The region is primarily affected by debris flow disasters,which are closely related to the exposed bedrock and the Quaternary alluvial strata.The development and distribution of geological disasters are strongly influenced by the re-gional topography.Specifically,the area with a slope of 30° to 50° is dominated by landslides,the area with a slope of 40°to 60°is dominated by unstable slopes,and the area with a slope of 50°to 90°is dominated by col-lapse,and debris flows mainly occur in area with a slope of less than 40°.The"4·25"Nepal earthquake had a significant impact on the regional geological environment,resulting in a decrease in slope stability.The mecha-nism of earthquake-induced disasters mainly includes direct excitation and latent recurrence:direct excitation is more pronounced in areas with hard rock,while latent recurrence is more common in soft rock and loose surface rock and soil.Geological conditions are the main factors affecting the geological disasters in Saga County,followed by rainfall and human activities.The interaction among the three has jointly shaped the mechanism of geological di-sasters in the region.

Abstract:The tectonic activity since the Late Pleistocene plays a critical role in evaluating crustal stability in the coastal areas of South China.Previous studies have systematically examined the relationship between sedimentation and faulting in subsidence zones,whereas uplift areas have received limited attention due to dating constrains.Cos-mogenic nuclide dating effectively resolves the chronological challenges in uplift regions.This study investigates ma-rine erosional landforms along the eastern Guangdong coastal zone,focusing on granite-based marine terraces in Zhelang,Shanwei.By determining the exposure ages of four marine terraces using cosmogenic nuclides,we quan-tify the differential movement rates in uplift areas.The results reveal that the four marine terraces correspond to modern sea level,the Holocene highstand,and paleo-sea levels during MIS3 and MIS4.The elevation differences between paleo-sea levels and contemporary terraces indicate tectonic uplift in Shanwei since MIS4.The maximum uplift exceeding 100 m since MIS3 yields an average rate of～2 mm/a,consistent with current uplift rates observed in the southwestern Pearl River Delta.Similarly,a local average uplift of 106 m since MIS4 corresponds to a rate of～1.5 mm/a calculated over 70 ka,aligning with uplift rates derived from the Shipai Formation in the Pearl River Delta.These results reveal that the basement faults(blocks)in the Shanwei area have exhibited relatively pro-nounced activity characteristics since the Last Glacial Period.These findings provide an important geological refer-ence for assessing the safety of the Shanwei urban area and the neighboring city clusters of the Guangdong-Hong Kong-Macao Greater Bay Area,and should be given high priority in regional stability evaluations.

Abstract:In this study,the focal mechanism solution of Haicheng M4.4 earthquake on December 19,2017,was determined using a"Coarse-to-Fine"meshing scheme and the CAP method.The seismogenic fault plane was rapid-ly identified by applying the Hypocenter-Centroid(H-C)method.Geometric parameters of major faults in the Hai-cheng and Xiuyan regions were automatically extracted through an improved DBSCAN algorithm,and their slip characteristics were analyzed in combination with the regional tectonic stress field.The results show that the optimal centroid location of the Haicheng M4.4 earthquake is(40.4672°N,123.1494°E).Its focal mechanism solution yields a strike of 288°(standard deviation is 5.80°),a dip of 81°(standard deviation is 5.69°),a rake of-13°(stan-dard deviation is 5.71°),a moment magnitude MW4.34,and a centroid depth of 11 km(standard deviation is 0.38 km).Integrating the P-wave first-motion solution(strike 34.10°,dip angle 67.48°,rake-159.64°)with previous studies gives a central focal mechanism solution of strike 287.51°,dip angle 78.66°,rake-22.90°.All 25 identifi-cation tests—base on focal parameters provided by multiple institutions and diverse focal mechanisms—consistently indicate that nodal planeⅡ(NWW-striking)correspinds to the primary fault plane of the Haicheng M4.4 earthquake.Automated identification revealed three strike-slip faults and one normal fault.Faults A and C were determined as the seismogenic structures of the 1975 Haicheng MS7.3 earthquake and the 1999 Xiuyan MS5.4 earthquake,respec-tively,while the parametric characteristics of faults B and D align with existing knowledge from prior studies.

Abstract:To study the effect of anchor cable prestress loss on the stability of dual structure slopes,the calculation method for anchor cable prestress loss under the influence of multiple factors was constructed.The finite element software Midas GTS NX was used to establish the numerical models of dual structure slope reinforced by prestressed anchor cable under self-weight and rainfall conditions.Based on the finite element limit equilibrium method,the variation laws of slope safety factors under different anchor cable prestress loss rates,anchor cable angles,softening coefficients,and rainfall-affected layer thicknesses were analyzed.The research results show that when the loss rate of anchor cable prestress varies from 0 to 80%,the safety factor of dual structure slope under self weight conditions decreases by about 12.0%,and the smaller the anchor cable inclination angle,the greater the decrease in safety factor.With the increase of the prestress loss rate of the anchor cable,the smaller the softening coefficient or the thicker the rainfall-affected layer,the greater the decrease in the safety factor.Under the dual effects of rainfall infiltration and prestress loss of anchor cable,the stable slopes reinforced with prestressed anchor cables may experience instability and failure.The research results provide theoretical support for the prevention and control of dual structure slopes during operation,and have practical engineering significance.

Abstract:Aiming at the problem that the large-span space structure with roof isolation design may lead to an in-creased response of the lower frame structure to increase,this paper utilizes the simplified three-mass model and its equations of motion to derive the transfer function of the structure via Laplace transform,and compares the re-sponses of the conventional seismic-resistant structure,the roof-isolated structure,and the Tuned Mass Damper(TMD)structure under different excitation frequencies.Furthermore,by adjusting the mass of the upper roof struc-ture,the seismic response of the ground vibration roof isolation structure under different mass ratios was compared and analyzed.When the mass of the roof structure is relatively small,with mass ratio μm3 of 3%,5%,and 6%,optimal damping cannot be achieved if the natural frequency of the roof structure is deviates from the first-order nat-ural frequency of the main structure.Moreover,the insufficient mass cannot effectively lengthen the structural pe-riod,resulting in increased seismic demands on the lower frame structure.However,for these small mass ratio(μm3 for 3%,5%,6%),adjusting the stiffness of the roof structure so that its frequency approaches the first-order natural frequency of the main structure can reduce the seismic demands on the lower frame stucture,achieving a tuned damping effect analogous to that of a TMD.Nevertheless,this approach simultaneously increases the seis-mic demands on the roof structure itself,which is unfavorable for the grid structure.In contrast,by significantly increasing the mass of the roof structure to a mass ratio μm3 of 30%,the response of the lower frame structure can be reduced,primarily realized through period elongation.

Abstract:This study focuses on a 100-meter-high asphalt concrete core sand-gravel dam located in a high seismic intensity zone in western China.By employing a three-dimensional nonlinear finite element method,the static and dynamic characteristics of the dam were analyzed.The computational results indicate that the absolute values of the dam's acceleration response under dynamic conditions without reinforcement are notably large,and the upstream dam slope faces instability risks under the checking seismic condition(645 gal).Based on these findings,geogrid reinforcement measures are proposed for the dam crest area.The effectiveness of these engineering measures and the ultimate seismic capacity of the reinforced dam are evaluated from perspectives including slope stability,seis-mic permanent deformation,and safety of the asphalt core.The results demonstrate that the geogrid reinforcement enhances the dam's seismic safety,with the ultimate seismic capacity reaching 0.70-0.75 g,showing a safety margin compared to the checking seismic intensity of 645 gal.