Through the method developed by Snoke, which uses the ratio of initial motion and amplitude of P, SV and SH waves, we calculated the focal mechanism solution to 83 M_L≥2.5 earthquakes since 2008 in eastern Qinling—Dabie region. Based on these focal mechanisms, we inverted direction characteristic of the mean stress field using the FMSI method. The result shows that Qinling—Dabie eastern region is horizontally compressed in nearly E-W direction and horizontally dilated in nearly N-S direction, which is in accord with statistical results of focal mechanism parameters. We analyzed the variation information of the mean stress field direction through the consistency parameter of focal mechanisms, and the result shows that the focal mechanisms show a process from change in disorder and deviation from the mean stress field, to change in order and tendency to the mean stress field, then to change in disorder and deviation from the mean stress field. Consistency parameter of focal mechanisms in the studied region was in a continuous low value state before the significant earthquakes. Moreover, we calculated the apparent stress of 93 M_L≥2.5 earthquakes since 2008 in Qinling—Dabie eastern region, and fitted the relationship between apparent stress and magnitude, analyzed the time variation characteristic of the difference apparent stress that eliminated the effect of magnitude and reflected the variation of stress magnitude in the study area. The result shows that apparent stress in studied region showed a distinct process of first rising and then decreasing before significant earthquakes, and the significant earthquakes occurred during the process of decreasing. Finally, we analyzed the stress state in the study region by using consistency parameter of focal mechanism and difference apparent stress, and the result showed that regional stress field enhanced apparently before significant earthquakes. At present, the consistency parameter of focal mechanism in the study area is high, and difference apparent stress is low, so the regional stress level is low.

The East Kunlun fault zones are located in the northern margin of the Bayanhar block. Investigation of earthquake rupture behaviors of these fault zones is helpful for future seismic risk estimation for northwest Sichuan. We carried out a number of field geological investigation, typical micro-topography DGPS measurement and sample dating. Our results show that earthquake activities of the East Kunlun fault zones extend to the north bound of the Zoige basin. This part has been named Luocha segment, which belonged to the Tazang fault. Satellite images for Luocha segment are clear on the gray strips. The earthquake rupture zones are represented mainly by fault scarp, slope in the valley, gully and terraces dislocation, plant distribution in linear, plunge, fault springs, broken plug pond, landslide, collapsed and talus. These phenomena are distributed along the fault and formed an ~50 km long inverse “L-shaped” deformation strip. Fault activities produced gullies and left movement of terraces. Horizontal dislocations are in the range of 5.5~6 m, 18~23 m, 68~75 m, 200~220 m respectively. An earthquake happened recently between 340±30～500±30 BP, its macro-epicenter was located 5~7 kms northwest from the Benduo village, magnitude M_W7.3~7.4, with a maximum of 6 m coseismic displacement, horizontal dislocation 5.5~6 m, vertical dislocation 0.2~0.5 m. These phenomena show that the Tazang fault was the causative fault of the earthquake and raptured in Holocene. The fault has been controlled by compressive shear recently and shows horizontal movement with slight thrust components, similar to other segments of the East Kunlun fault zones. The results supports the “mainland escape” model.

In recent years, destructive eart hquakes have occurred frequently. With the re-constructed areas destroyed again, some projects that exposed quality problem have caused widespread concern. It is of important scientific significance to study post-earthquake re-construction evaluation. On the basis of the experiences on reconstruction study, we pres ented a post evaluation frame consisted of six firstrank evaluation indexes, which includ-ed? the engineering project, the economic benefit, the social effect, the sustainable devel-opment of ecological environment,the humanities construction and emergency capability. Then, we used the interpretative structural model to analyze their relations. In the paper, taking Lushan county as an example, we proved that the indexes are feasibe and rational. In addition, the second rank evaluation indexes had been built in Lushan. The results show that the post-earthquake reconstruction evaluation frame has both scientific and prac tical values.

In this paper, the important significance of the 2001 Kunlunshan large earthquake with M= 8. 1, theorderly characteristics of the time and space of strong earthquake activity from 1996 to 2001 in western China and the correlation of strong events between western part of China's mainl and and Taiwan have been discussed. The trend of M≥ 7 events in future in Northern part of Qinghai-Xizang block has beenestimated by using the method of orderliness analysis.

We first describe chemical and geochemical characteristics of hydrogen, as well as relations between hydrogen soil vapor concentrations and earthquake events. And then we discusse the possibility of using hydrogen soil vapor monitoring in the vicinity of fault zones to make short/immediate earthquake prediction. Hydrogen (H) is an element with the smallest particle size, the lightest weight, the fastest speed and the most powerful penetration ability. The concentration of hydrogen (H₂) in the atmosphere is very low, only 0.5 ppm. But it is higher in the crust, approximately n～nx10² ppm, which is mainly located at a depth ranging from 5 to 8 km, especially in the fault zones. There are good correlations between Hydrogen concentrations and seismic activities. Noticeable changes of hydrogen concentrations can normally be observed several to tens of days before an earthquake, and the ratio of signal to noise is very high. Recently, the successful development of a new digital hydrogen detecting instrument (ATG-6118H) makes continuous monitoring of hydrogen possible. We present some experimental observation results and propose to establish a large scale hydrogen monitoring network along some fault zones.

This paper proposed a new method for identification of ionospheric TEC anomalies using prophet forecasting model based on Facebook. First, we compared the precision of this new method with the traditional time series forecasting method (Autoregressive Integrated Moving Average, ARIMA models) and the identification method of the classical ionospheric TEC anomalies (Inter Quartile Range, IQR method), in predicting the background values of ionospheric TEC modeling. The results show that the precision of the former is obviously better than the latter two methods: about 2.55 times higher than that of the ARIMA models, and about 10.74 times higher than that of the IQR method. Meanwhile, when the best prediction modeling interval is established, the comparison of precision values is RMSE_IQR=10.5841>RMSE_ARIMA=3.2780>RMSE_Prophet=0.846, indicating that the traditional detection methods have insufficiency in predicting modeling background values. Second, taking the August 8, 2017 Jiuzhaigou earthquake as example, we analyzed its ionosphere TEC anomalies and proved the effectiveness and accuracy of the new method. The results show that obvious ionosphere TEC negative anomalies appeared on the 10th and 2nd days before the earthquake, and obvious ionosphere TEC positive anomalies occurred on the 7th day before the earthquake. In addition, the comparative experiments show that the validity and accuracy of the Prophet forecasting model is significantly better than the IQR method

the principle and algorithm of neural networks of Radial Basis Function (R BF) and its application to the expert system for earthquake prediction (ESEP 3.0) are introduced in this paper. The actual application in earthquake forecast shows that the neutral networks can overcome some demerit of BP neural networks in leaning process, the constringency excessively depend on initial value and optimization constringency and often can′t appear. The RBF neural networks possess the rapid operation speed in learning and strong nonlinear mapping ability and very good efficiency.

In this paper, general monitoring conditions of water temperature in our country and micro-behavior phenomena such as solid tide, co-seismic effect and precursory anomaly before earthquakes is introduced. And its mechanism is analyzed. The authors propose that the study of mechanism of water behavior should be carried out from some aspects, such as heat systems and heat process, for example, from two geotemperature gradients, two heat convections, one conductivity and one heat diffusion and so on.

Nearly 30 years of studies indicate that seismic quiescence may be the medium to long-term precursory phenomenon which contains seismicity rate changes. Z-Test is widely used for significance testing of seismicity rate changes, which is measured by Z-value. As a result of choosing spatial scanning window of fixed number of earthquakes, each window size of grid is usually different, which results in large amount of calculation. In this paper, we have realized the spatial scanning of Z-value based on the self-built cluster consisting of 4 nodes by parallel processing. The preliminary test shows that parallel program can run with high speedup ratio and prarallel efficiency, this is to say, the parallel process method of space scanning of seismicity parameters can be widely used.

In this paper we have analy zed the data of mobile geodetic defo rmation across faults along northern section of North-South seismic belt and its both sides, and studied the activity lev el, dy namic ev olution and relation to st rong earthquakes of every fault zone. The results show that the average of fault movement rate is 0.19mm/a alongno rthern section of North-South seismic belt and its bo th sides. The fault activity has been in the lower level since Quaternary period. Regional fault activity st reng thening is an important symbol for occurrence of strong earthquakes. There is afeature that fault anomalous activity migrates from the outlying zone to the epicenters before strong earthquakes. Southwest Huashan-Liupanshan fault zone is the potential region of strong earthquake occurrence in the nea rfuture.

The construction of basic database for earthquake emergency response isone of the core contents of earthquake emerg ency response. The basic database for earthquake emerg ency response beingestablished exceeds any otherdatabase built before in the fields of data contents and the involveddepartments. In this paper, the significance and definition of the basic database for earthquake emerg ency response, data contents, function of the database, con-struction methods etc. are discussed and explained, which is a summary conclusion of the work we built the database in the previous stage.

DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite, the first electromagnetic satellite specially aiming to earthquake monitoring in the world, was launched in 2004 by France, and ended in the end of 2010, with operating time of 6.5 years. The data along more than 30000 orbits were obtained, which provided a solid data foundation for the research in earthquake monitoring and ionospheric physics. Scientists in many countries carried out a number of earthquake application studies by using the data from this satellite, with hundreds of paper published, and pushed the research in seismo-electromagnetic satellite to a new peak. CSES (China Seismo-Electromagnetic Satellite), the first space satellite for geophysical field detection in China, was successfully launched on February 2, 2018. At present, its in-situ commission has been finished, and the satellite has been put into service, with the scientific data released to the public officially. Under this condition, it is important to summarize and retrospect the improvement and achievements in technology and science from DEMETER, in order to maximize the effectiveness of CSES, and transform the space electromagnetic detection to the operational run in earthquake investigation. The remarkable progresses from DEMETER satellite will be introduced in this paper, and the future development domains are suggested in space electromagnetic detection technology and scientific research combined with the characteristics in CSES satellite.

Based on the statistics of cross-fault deformation anomalies before strong earthquakes during the last forty years, this article analyses the characteristics of the time duration, spatial distribution, amplitude of the anomalies and the relationship of all the three factors. it disgusses the anomaly characteristics of the measurement of cross-fault deformation as well as the maximum spacing of the cross-fault sites and observation cycle of the monitoring of different magnitude of earthquakes. The results suggest that: The anomalies are mainly of medium term as well as short and medium terms, occur more frequently one year before the earthquakes. The time duration of the anomalies is directly proportional to the earthquake magnitude. The spatial distribution of the anomalies also has a phenomenon that it extends as the augment of the epicenter distance. The amplitude of the anomalies enlarges with the increase of time duration and reaches to higher level when the epicenter distance is within 160 to 350 km. The anomaly shape is devided into two main types:trend and mutant. The spacing of monitoring cross-fault sites of different earthquake magnitude can be different: The spacings for monitoring magnitude 7 earthquakes should be less than 450 km, and 300 km, 200 km, 100 km for magnitude 6, 5, 4 earthquakes respectively. The measurement cycle is supposed to be within three months.

Machine learning (ML), especially deep learning (DL), has developed rapidly in recent years, which has made exciting progress in many applications such as data mining, computer vision, natural language processing, data feature extraction and prediction. Earthquake prediction is a complex, wide-ranging, immature, and controversial scientific issue. Its development is limited by unclear earthquake mechanisms and seismogenic structures, incomplete observation data, and unclear earthquake phenomena. However, machine learning may improve the mining and discovery of complex seismic data and promote the development of earthquake prediction science. This article reviews the application of machine learning in earthquake prediction, including the prediction of big earthquakes, big aftershocks and rock experimental fractures, finally looks forward to the research trends of machine learning in earthquake prediction.

Spending more than 20 days in the Wenchuan earthquake zone, I conducted a systematic field investigation into the macro-anomaly cases occurred at the earthquake region in particular in Wenchuan, Dujiangyan, Yingxiu, Beichuan, Shifang, Mianzhu, Hanwang, Mianyang, Chengdu and other counties. This article is a summary of copious examples and instances and a series of abnormal phenomena taken place in electromagnetic field, underground fluid, geographical appearances, meteorological conditions, …etc. which are considered to be earthquake warning signs and premonitions in the seismic area. Regarding the emergence of the forewarnings of the earthquake as surely appearing phenomena, this article expresses a personal point of view about the reasons of the fail to anticipating the earthquake and maintains that the close cooperation between the experts and the mass people is an indispensable means for earthquake forecasting. Then, I suggests, firstly, to mobilize the mass people into the earthquake forecasting work and, secondly, to develop the macro-watching system for the prediction of earthquake and, finally, to promote a large education for popularizing seismic knowledge.

Using depth-dependent layers and considering the subduction angle the Pacific plate to NE China, we build a vertical static 2D finite element model about the Pacific plate diving into NE China with subduction velocity of the Pacific plate. By altering subducting angle, we discuss numerically the possible subducting process and its effects on deep and shallow earthquake. The results of our models show the stress distribution of the whole research region including total characteristic feature and region characteristic, and the active faults and its adjacent areas response to the stress from deep region. Our research results imply that the subduction angle of the Pacific plate and the environment around faults in the crust having great effects on deep and shallow earthquake activities.

Since the concept of WebGIS appeared, its theory and application have been researched in our count ry.But it is still under the ex perimentation until now, so it cannot be called the real “WebGIS”.So it is necessary to summarize the research results for these years. This paper sums up the main characteristics of WebGIS on the basis of collecting and studying agreat deal of published scientific thesises, research report s, deg ree thesises and applications. The paper also sums up the key problems and realizing technology of WebGIS, and its application status in agriculture, forest ry, weather, water conservancy, earthquake, ocean, land and resource, environment protection, railroad and t raffic, electric pow er, city const ruction and prog ramming are emphasized.Finally the paper discusses the development t rend of WebGIS. The conclusion is that WebGIS can be used more w idely as an opening application plat form.

By using the method of differential GPS, on the basis of observing the features of the terraces in Huangshui basin, we have surveyed the parameters of the terraces in Huangshui basin, and primarily ascertained the characteristics of neo-tectonics in this region, and also found out the distribution and movement features of the active faults around Xining City. Through the research described above, we draw a conclusion as follows: by using the DGPS, the coordinate and elevation of the terraces can be quickly and accurately acquired; so the DGPS is a feasible way to find the positions and other features of weak active or concealed faults. T₃, T₄, T₅ terraces is dislocated by Nan chuan river fault between 0.10 Ma B.P. and 0.05 Ma B.P. with the least velocity of 0.15 mm/a.

With the fast development of global industrialization, high-voltage power lines have become one of the man-made interferences in electromagnetic environment monitoring. In this paper, recent achievements on power line radiations have been summarized, especially by using the satellite electromagnetic observations from DEMETER, such as power line harmonic radiation (PLHR), magnetospheric line radiation (MLR), ELF/VLF emissions, high energetic particle precipitation, etc. And then the coupling models including electromagnetic wave propagation and nonlinear wave-particle interaction have been introduced and discussed. It is aimed to provide more information for the data processing and analyzing techniques in the upcoming China Seismo-Electromagnetic Satellite (CSES-1) mission when the same PLHR signals are dealt with or the weak earthquake-related disturbances are distinguished.

In order to study the geochemical characteristics of soil gas and the tectono-geochemical background reflected by fault gas in the Tong-Dong fault zone, the field monitoring method was used to analyze the concentration distribution of soil H₂ and Rn in the two observation lines of Zhanghe village and Xinglizhuang village. The results show that the distributions of H₂ and Rn concentration in Zhanghe village ranged from 0.24 to 174.7×10^-6 and 13.3 to 69.8 kBq·m^-3, respectively. The background values of H₂ and Rn concentration are 14.26×10^-6 and 24.8 kBq·m^-3, respectively. The range of concentration distribution of H₂ and Rn in Xinglizhuang observation line ranged from 11.8 to 67.06×10^-6 and 43.6 to 72.6 kBq·m^-3 respectively, with background values of 37.13×10^-6 and 72.6 kBq·m^-3, respectively. In the measure line of Zhanghe village, strong anomaly of H₂ and Rn appeared at 90～105 m, but a higher anomaly occurred at 120～150 m, with anomalous values near the fault zone, which indicates the location of the fracture effectively. Integrated geological structure and physical geography, it is concluded that the high value anomaly of the gas composition in the survey line are mainly controlled by the tectonic conditions, and it is also affected by sediment properties and meteorological factors. Therefore, we should further track and monitor the gas composition in the soil layer of the target fault zone, and analyze the temporal and spatial variation of fault activity, and take gas isotope techniques to explore the source of the components, so as to enhance the important role of gas geochemical indicators for fault tectonics activity and to strengthen the efficiency of earthquake prevention.

Detailed field investigation showed that three seismogenic faults ruptured in the Wenchuan M_S8.0 earthquake, which are Beichuan-Yinxiu fault, Penxian-Guanxian fault, and Xiaoyudong fault. The Beichuan-Yinxiu fault is characterized by reverse faulting in the south and right-lateral faulting in the north, which lasted for 220 km long and vertically displaced 3 meters on average, and can be divided into three segments. The Penxian-Guanxian fault rupture is characterized by reverse faulting which is 5.6 km long and vertically displaced 1.5 meters on average, and can be divided into two segments. Xiaoyudong secondary fault is characterized by tear faulting and was formed in this earthquake, left-laterally faulted 5.6 km long with 1.5 m vertical displacement on average, which accommodated the different deformations of tectonic units on both side. The surface rupture on Yaodu town may show the different characteristics between Nanba segment and Beichuan segment. The geometry and motion mode indicate that the maximum horizontal main stress in this region is in the direction of NWW.

We developed a quasi-automatic real-time waveform inversion system for focal mechanisms of small to moderate earthquakes in Capital area, by using the Cut-And-Paste (CAP) method and continuously monitor regional broadband waveform data provided by the Institute of Earthquake Science, CEA, which can automatically detect the occurrences of seismic events and determine the focal mechanism solutions in real-time. In this study, automatic solutions can be obtained rapidly when the earthquake has occurred (M>3.5). In addition, since some bad or low signal-to-noise ratio (SNR) data can be included and participated in the inversion, the focal mechanism solutions can also be manually obtained. The system operation process and construction consideration are detailedly elaborated in the paper, and the system has preferable practicability by comparing the results with others.

This paper describes the development of water temperature research from three aspects—influence factors, response mechanism of water temperature to dynamic loading and hydro-thermodynamic theoretical model. High-precision digital observation technology provides reliable and effective data support for the scientific research of well water temperature. Source of replenishment and hydrodynamic action are two major factors that affect the dynamic change of well water temperature. The source of replenishment determines the shape of the vertical distribution curve of the temperature of the well and aquifer system. Hydrodynamic action determines the amount of groundwater recharge and the speed of groundwater flow in the aquifer, thus affecting the temperature change of the well-aquifer system. And the dynamic loading affects the flow speed of water within the well-aquifer system and changes the water temperature. Through the summary of the study on the factors influencing the water temperature of the well and the formation mechanism of water-thermal dynamics, it is helpful to clarify the relationship between the water temperature of the well and the aquifer, and provides an important research method for the quantitative analysis and mechanism interpretation of the water temperature of the well.

On the base of data collection and on-the-spot investigation,this paper studies some characteristics of the Hujiaping M_S4.1 earthquake on 22 November, 2008 in Guizhou township, Zigui county, Hubei province, and the geology-hydrogeology condition and earthquake active background in the area. The earthquake disaster are investigated and analysed. Some scientific problems on earthquake precursors and causes of the earthquake are discussed. In our opinion, the Hujiaping M_S4.1 earthquake is a reservoir-induced earthquake belonging to tectonic type,induced by reservoir water-loading and water infiltration along the Xiannvshan fault,and there are some indications that the cause of earthquake possibly relates to the 2008 Wenchuan earthquake influence on the stress field of this region.

Ambient noise tomography is a rapidly emerging field of seismological research. Applying ambient noise to earth structure research can avoid dependence of earthquake signals effectively, meanwhile, ambient noise method can obtain upper crust structure with higher resolution as well as the structure beneath urban area because ambient noise contains abundant short period information. This paper aims to analysis advantages and disadvantages using ambient noise tomography by showing its present state, process method and progress. Anisotropy inverted by a combination of ambient noise data, surface and body waves can accurately reveal crust-mantle structure and geodynamic characteristics of deep structure. Combining noise analysis and other active signal analysis techniques can further study variations of seismological parameter and physical properties before and after earthquake.

Features of seismic sequence can directly reflect the differences among tectonic stress field, seismotectonic and seismogenic environment. For example, mainshock-aftershock-type earthquakes mostly occur in a relatively uniform medium environment. However, foreshock-mainshock-aftershock-type earthquakes and swarms mainly occur in complex structure. On 17 June, 2019, the M6.0 an earthquake occurred in Changning County, Yibin City, Sichuan Province. Its aftershock totally distributed along a NW direction belt, bit in the northwest part of the belt, the aftershock distribution showed the cluster features. There is an obvious difference between the southeast part and northwestern part for aftershock activity. The southeast part can be considered as a mainshock-aftershock type with a fast decay. The northwestern part shows a feature of swarm, which decay is slowly and many aftershocks with M5 or more in the early stage. The M6.0 earthquake occurred in the Changning-Shuanghe anticline which is complicated and composed of several secondary fold structures and associated faults. The segmentation characteristics of the Changning M6.0 earthquake indicate that it is hardly to be produced by a single fault but a cascade fractures. Moreover, the aftershock focal depths in the northwestern part are more deeply, this means that the seismic activity in this area has been controlled by the Huaying Shan fault zone. Oppositely, the possible influence of the 2019 Changning M6.0 earthquake on Huaying Shan fault zone should be emphasized in the future.

The advanced results of subsurface fluid dynamics in the crust observed by vanous workers are introduced. Based on integrated and systematic analysis of these results, a conceptual model and its corresponding mathematical model are developed. In this model, the crustal seepage field was divided into three zones according to its permeability and dominant factors on which the fluid dynamic characteristics affect, that is shallow zone(0 ~ 6 km), transitional zone(6 ~ 17 km) and deeper zone(> 17 km). The various driving forces on subsurface fluids were normalized as''geological force" and represented as sources or sinks in flow equation. The rates and magnitudes of diverse geologic processes are analyzed in different geologic environments. The widely occurred phenomenon in the crust, anomalous pore pressure, is explained from the viewpoint of subsurface fluid dynamics, and it is suggested that the periodic earthquakes is the dominant factor in forming the anomalous pore pressure process.

The Haiyuan fault zone and the Zhongwei-Tongxin fault zone are main faults in the northeastern corner of the Tibet Plateau. Basedon analysis of geology and geomor-phology of the region and study on structure and revolution of the two faults, a strain par-tition model is built to adjust the strike slipping and com pressional deformation of the area. Through rupture segmentation study along main faults, rupture units of large earth-quakes are also identified in the region. The seismic tectonic model of the region consists of strain partitioning and fault segmentation.

The depth of Zhao Gezhuang well is 200 m. The observation aquifer is located in 182—200 m, which is a mixture of shallow cold water and deep hot water. Under the influence of mining and rainfall, the water level and water temperature have synchronous coordination changes in the long trend and annual variation. Due to groundwater exploitation, the ratio of cold water in the shaft reduces, the water level of the well decreases, and the water temperature raises. The rainfall infiltration recharge makes the cold water in wellbore increase, water level rise and water temperature drop. However, at the end of the rainy season, the inflow of cold water into the shaft decreases, and the water temperature rises gradually. The air pressure and the solid tide cause the diurnal variation of water movement between the wellbore and the aquifer, so that well water level has periodic fluctuation. This changes of the ratio of cold and hot water in the wellbore and causes the secondary effect of water temperature's periodic fluctuation. Both of them show synchronous and coordinated changes in diurnal variation. Different kind of interference factors causes different periodic change. It is necessary to choose different method and sampling period in order to eliminate the disturbance and extract the information of seismic anomaly.

With the rapid development of China's national economic construction and the increasing complex of the power environment, power frequency interference effects on the geo-electric field are becoming more and more serious. Power frequency interferences produced by power supply system are a kind of electro-magnetic interference in the geo-electric field observation in China. We first briefly introduce the method of geo-electric field observation. Second, we analyze in detailed the principle, methods, effects and the mechanism of power frequency interferences in the geo-electric field observation. And then, we systematically investigate suppression method for power frequency interferences and its particularity in geo-electric field observation. Finally, the effects of power frequency interferences suppression is discussed, combined with the actual geo-electric field observation.

Hebei province is one of the most active areas of seismic activity in north and even east mainland China, there is complex tectonic background and fault development. Along with the development of the province’s 11 urban active fault detection and seismic risk evaluation project, some scientific projects and the accumulation of the fault structural study data, late Pleistocene fault data is further updated. Then, there is an important question of how to assess the maximum potential earthquake magnitude and the risk of these active faults on long-term earthquake prediction. Using the maximum potential earthquake magnitude assessment model proposed by Wen Xue-ze, we first divided fault cell to the active faults in Hebei region, then formed the empirical relationship between the maximum magnitudes M_max and the a_t/b values of the sub-areas' frequency-magnitude relationship in the Hebei area, and got the upper limit of the potential magnitude in fault cells by the formula. Furthermore, we calculated the seismogenic probability of partial fault area in the future strong earthquakes through the exponential relation with earthquake waiting time.

In this paper, the fluid in earth crust is briefly presented. Some relation between seismic activity and the fluid in a source body, the fluid activity in a fault zone and period of seismic activity, the fluid promo ting earthquake o ccurrence are emphatically discussed. New ideas on predicting the dang erous area of strong ear thquakes, observing the earthquake precursors are adv anced.

The Tazang fault is located in the eastern part of the East Kunlun fault zone with a length of 170 km, which constitutes the northeast border of Bayan Har block with Minshan fault zone. Satellite image and geological survey have revealed evidence for Holocene movement along the fault. The fault can be divided into three sections by the segmental signs of strike-slip fault, such as geometric and tectonic discontinuities in combination of geomorphic features and fault zone materials. The Locha section generally strikes NWW, developed sinistral left-step with Maqu fault in the west, and rotates clockwise on the Xiahuangzhai village in the east. The Dongbei village section generally strikes NW, and rotates anticlockwise on the entrance of Jiuzhaijou in the east. We divided the Dongbei village section into two sub-sections, and the northern and southern sub-sections are separated by the Minjiang fault. The Majiamo section is divided into three sub-sections, namely Zharu, Tangzhai, Wujiao sections. The elapsed time in Loucha and Majiamo sections was relatively short. The linear horizontal slip of the east Kunlun fault zone transforms into the vertical movement of the Minjiang fault zone and Huya fault zone which trends nearly SN~NNE, and the uplift of Minshan. The fault sections splay out from NW to SE that has good correlation with the slip gradients along the east Kunlun fault.

Through the analysis of petrol seismic exploration profiles and the tectonic background of Jianghan Basin in Hubei province,a evolution model of the basin with 3 phases is proposed. The foreland basin phase was controlled mainly by the thrust of Qinlin-Dabie orogenic area during later Jurassic and middle Triassic; the rift basin phase is controlled by fault and deasil circumvolving with the change of stressing during Cretaceous and Paleocene, with strong magma activity; and in the depression basin phase the basin descends as a whole, and magma activity stopped. With the study of the sections and the basin evolution,a structure pattern is set up. 4 NNW descend belts and 3 NEE descend belts is the main structure separated by faults and low uplands. Combining the data of present stress,GPS and earthquakes,the low risk of earthquake and low activity is concluded for the Jianghan basin,and the hypocentral depth is about 14km or by the bottom of the basin in middle descend belt of Qianjiang-Mianyang.

In this paper, the detection criterion and quantification of deformation anomaly inten-sity on the basis of the F-detection theory have been discussed. We have applied these def-initio ns to study the heterogeneity of anomalous deformation intensity before the Datong and Lijiang earthquakes by using the observed deformation data, and have also compared the research results with earthquake activity characteristics. It is demonstrated that the quasi-synchronous deformation anomalies about 1. 5 year before the earthquake in a region can be detected, and then the anomaly intensity should be increased in the former anomalygap before earthquake occurrence. Therefore the authors consider that the key of earth-quake prediction is to identify the stages of earthquake preparation because the precursors may occur in different forms during various preparation stages.

Da ta processing at the center for the Crustal Movement Observation Network of China is introduced in this paper, with the emphasis on the GPS (Global Positioning System) data processing . Therefore the observation system of the project and the data center are introduced at first. Data stream, methods and software used at the data center in GPS data processing for crustal movement are described in detail.Selection of solutions, estimation of accuracy, analysis of displacements, strain and time series of displacement is discussed. The results of crustal movement obtained from fiducial network from Sep. 1998 to Nov . 1999 are analyzed as well as the displacement of various fiducial stations, strains in different parts of the network and the time series of displacements of weekly solutions of the fiducial stations. During this period, the crustal movement in the eastern part of China is relatively small and stable; in relation to the eastern part of China the southwestern part moves northeastward and is compressed in NNE direction; the northwestern part moves northwestward, and the Yunnan region moves southward. The North-south Seismic Belt in the middle part of China is a belt of strong shear deformation. The result shows that the northward push by the Indian Plate has played the dominant role in the crustal movement in China's mainland.

From the perspectives of energy of deep and shallow earthquakes and their energy release ratio as well as duration, the rhythm repetition of the end earthquakes of the fifth activity period and orderly activity image of moderate strong earthquake in the fifth activity period in northeastern China, we analyzed and compared characteristics with that of the former four periods. The results show that the energy release of the fifth activity period is far lower than other activity periods, energy release ratio of deep earthquakes and shallow earthquake is large, and the sustained time is long. The “closing door” earthquakes sustained the rhythm repetition of the former 4 activity periods. The properties of the “closing door” earthquakes include time and spatial clustering as well as earthquake swarm, seismic gap and banded orderly distribution image. The 7 earthauakes of M_S≥5.0 in 2013 may be the “end” earthquakes of the fifth activity period.

The characteristics of long period w aves, reco rded at several representative wells before large earthquakes, are analy zed.The reasonable explanation on these long period events occurred before earthquakes is given in theory.It is thought that the long period w ater level events, occurred at some sensitive wells before earthquakes, may be related to the process such as fault creeping, silent and slow earthquake, fault pre-ex tending and seismic source nucleation.The system consisting of well and w ater layers behaves like a long period seismograph. The system responds very well to the valuable precursor low frequency w aves.

Maduo-Gande fault is an active fault within the Bayan Har block. According to our field investigation, there was an earthquake rupture zone on the Gande segment of Maduo-Gande fault zone. We found that the length of the rupture zone is about 50 km, with the general trend of NW. The maximum sinistral-horizontal dislocation is about 7.6 m and the maximum vertical dislocation is about 4m. A large number of earthquake traces were found along the rupture zone and the surface rupture phenomena were also various. It is believed that the rupture zone with the formation of a relatively new era through the field investigation and analysis on the geological and geomorphological phenomena. A series of linear arranged pass, fault triangles, fault scarps, fault springs, gullies dislocation, ridges twisted, sag-ponds, pressure ridges, et al. exist along the fault. Based on the field investigation and the materials available, we believe that the rupture zone is due to a strong earthquake in the history of this area. And it is inferred that the Maduo-Gande fault in the Bayan Har block had intense activities since late quaternary and may still be active nowadays.

A quick assessment method of earthquake damage loss based on Remote Sensing (RS) is introduced in the paper, which includes two parts, damage information acquisition and loss assessing. Damage information acquisition contains earthquake damage index mode and image classification mode. The former obtains macro earthquake damage of resident sites on ground through the relationship between damage index and intensity, and the latter uses digital image processing technique to gain the classified earthquake damage. The loss assessment is different according to the different modes of damage information acquisition. This method based on RS and GIS satisfies the actual demand, establishing a multi-person working mode and increasing the speed of earthquake damage assessment based on RS.