Characteristics and Prevention of Secondary Geological Disasters of Wenchuan Earthquake

In the research, secondary geological disasters of Wenchuan earthquake were defined and the consequences were illustrated based on geological disasters, such as collapse, landslide and debris flow, and threats of barrier lakes. In addition, the characteristics of secondary disasters were analyzed, as follows： Rupture of geological faults lays foundation in terms of geological structure; loose solids provide resources of an earthquake; abundant rainfall and large runoffs are driving forces of an earthquake; rainstorm, flood, and long-term high temperature are major inducing factors. Furthermore, suggestions on prevention of secondary disasters were proposed in terms of prevention before, at and after an earthquake. Finally, the scientific and practical significances of secondary disasters were illustrated.

Application of oblique photogrammetry technique in geological hazard identification and decision management

With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dangerous mountainous areas under the premise of ensuring the safety of personnel while restoring the real geographic information as much as possible. However, geological disaster areas are often accompanied by many adverse factors such as cliffs and dense vegetation. Based on this, the paper introduced the flight line design of oblique photogrammetry, analyzed the multi-platform data fusion processing, studied the multi-period data dynamic evaluation technology and proposed the application methods of data acquisition, early warning, disaster assessment and decision management suitable for geological disaster identification through the analysis of actual cases, which will help geologists to plan and control geological work more scientifically and rationally, improve work efficiency and reduce the potential personnel safety hazards in the process of geological survey, to offer technical support to the application of oblique photogrammetry in geological disaster identification and decision making and provide the scientific basis for personal and property safety protection and later-stage geological disaster management in disaster areas.

RS and GIS-based Statistical Analysis of Secondary Geological Disasters after the 2008 Wenchuan Earthquake

Using RS and GIS means, this article analyzes the general geological characteristics and the structural belt distribution features in Wenchuan County, Sichuan province, P.R. China as well as the characteristics of the large-scale landslides, mud-rock flows, earthquake lakes, etc., after the earthquake on May 12, 2008. Based on the above work, comprehensive indoor and outdoor research is launched on disaster distribution characteristics and their relationship with earthquakes, terrains, strata, lithology, and structures. Weights of evidence method is utilized to quantitatively analyze and evaluate the spatial distribution of secondary geological disasters after the earthquake occurred. 3 remedying grades for secondary geological disasters are derived from the results of the weights of Evidence, followed by suggestions given to remedy earthquake secondary disasters.

New Thought of Meteorological Forecasting and Warning Models of Geological Disasters in Loess Plateau of North Shaanxi

The study established daily comprehensive precipitation equations and calculated respective critical daily comprehensive precipitation value of loess-collapse disasters and landslide disasters by dint of the geological disasters and corresponding precipitation data in 47 years.Considering geological disaster risk divisions,precipitation influence coefficient and daily comprehensive precipitation,hourly rolling daily-forecasting and hourly warning fine and no-gap models on the base of high temporal and spatial resolution rainfall data of automatic meteorological station were developed.Through the verifying of combination of dynamical forecasting model and warning model,the results showed that it can improve efficiency of forecast and have good response at the same time.

Factor analysis of earthquake-induced geological disasters of the M7.0 Lushan earthquake in China

The seismic intensities, lithologic characteristics and terrain features from a 3000 km2-region near the epicenter of the Lushan earthquake are used to analyze earthquake-induced geological disaster. The preliminary results indicate that secondary effects of the earthquake will affect specific areas, including those with glutenite and carbonate bedrock, a seismic intensity of IX, slopes between 40° and 50°, elevations of less than 2500 m, slope change rates between 20° and 30°, slope curvatures from - 1 to -0.5 and 0. 5 to 1, and relief between 50 and 100 m. Regions with susceptibility indices greater than 0.71 are prone to landslides and collapses. The secondary features are mainly distributed on both sides of the ridges that extend from Baosheng to Shuangshi and from Baosheng to Longxing. Other features are scattered on both sides of the ridges that extend from Qishuping to Baosheng and from Masangping to Lingguan. The distribution of the earthquake-related features trends in the NE direction, and the area that was most affected by the Lushan earthquake covers approximately 52.4 km^2.

Risk Assessment of Secondary Geological Disasters Induced by the Yushu Earthquake

The Yushu Ms 7.1 earthquake occurred on April 14,2010 in Qinghai Province,China.It induced a mass of secondary geological disasters,such as collapses,landslides,and debris flows.Risk assessment maps are important for geological disaster prevention and mitigation,and also can serve as a guide for post-earthquake reconstruction.Firstly,a hazard assessment index system of secondary geological disasters in the earthquake region was built in this paper,which was based on detailed analysis of environmental and triggering factors closely related to geological disasters in the study area.GIS technology was utilized to extract and analyze the assessment index.Hazard assessment maps of secondary geological disasters were obtained by spatial modeling and overlaying analysis.Secondly,an analysis of the vulnerability of hazard bearing bodies in the area was conducted,important information,such as, population density,percentage of arable land, industrial and agricultural outputs per unit area were regarded as assessment indices to evaluate socioeconomic vulnerability.Thirdly,the risk level of secondary geological disasters of the area was obtained by the formula:Risk=Hazard×Vulnerability. Risk assessment maps were categorized into four levels,including"low","moderate","high"and"very high".These results show that some urban areas are at very high risk,including Jiegu,Chengwen,Xiaxiula and Sahuteng towns.This research can provide some references and suggestions to improve decisionmaking support for emergency relief and post- earthquake reconstruction in the study area.

Construction of Forecast and Early Warning System of Meteorological and Geological Disasters in Qinghai Province

Based on the meteorological and geological disaster data, ground observation data set, CLDAS grid point data set, and EC, BJ and other model product data during 2008-2020, the temporal and spatial distribution characteristics of meteorological and geological disasters and precipitation were analyzed, and the causes of the occurrence of meteorological geological disasters and the deviation of model precipitation forecast were revealed. Besides, an objective precipitation forecast system and a forecast and early warning system of meteorological and geological disasters were established. The results show that meteorological and geological disasters and precipitation were mainly concentrated from May to October, of which continuous precipitation appeared frequently in June and September, and convective precipitation was mainly distributed in July-August;the occurrence frequency of meteorological and geological disasters was basically consistent with the distribution of accumulated precipitation and short-term heavy precipitation, and they were mainly concentrated in the southern and eastern parts of Qinghai. Meteorological and geological disasters were basically caused by heavy rain and above, and meteorological and geological disasters were divided into three types: continuous precipitation(type I), short-term heavy precipitation(type II) and mixed precipitation(type III). For type I, the early warning conditions of meteorological and geological disasters in Qinghai are as follows: if the soil volumetric water content difference between 0-10 and 10-40 cm is ≤0.03 mm^(3)/mm^(3), or the soil volumetric water content at one of the depths is ≥0.25 mm^(3)/mm^(3), the future effective precipitation reaches 8.4 mm in 1 h, 10.2 mm in 2 h, 11.5 mm in 3 h, 14.2 mm in 6 h, 17.7 mm in 12 h, and 18.2 mm in 24 h, and such warning conditions are mainly used in Yushu, Guoluo, southern Hainan, southern Huangnan and other places. For type II, when the future effective precipitation is up to 11.5 mm in 1 h, 14.9 mm in 2 h, 16.2 mm in 3 h, 19.9 mm in 6 h, 25.3 mm in 12 h, and 26.3 mm in 24 h, such precipitation thresholds are mainly used in Hainan, Huangnan, and eastern Guoluo;as it is up to 13.3 mm in 1 h, 15.5 mm in 2 h, 16.6 mm in 3 h, 19.9 mm in 6 h, 31.1 mm in 12 h, and 34.0 mm in 24 h, such precipitation thresholds are mainly used in Hehuang valley. The precipitation thresholds of type III are between type I and type II, and closer to that of type II;such precipitation thresholds are mainly used in Hainan, Huangnan, and northern Guoluo. The forecasting ability of global models for heavy rain and above was not as good as that of mesoscale numerical prediction model, and global models had a wet bias for small-scale precipitation and a dry bias for large-scale precipitation;meso-scale models had a significantly larger precipitation bias. The forecast ability of precipitation objective forecast system constructed by frequency matching and multi-model integration has improved. At the same time, the constructed grid forecast and early warning system of meteorological and geological disasters is more precise and accurate, and is of instructive significance for the forecast and early warning of meteorological and geological disasters.

Analysis on the Relationship between Geological Disasters and Precipitation in Zhuanghe Region

To improve relevance and timeliness of forecasting and early warning for precipitation-type geological disasters in Zhuanghe City, by using case information of geological disasters and corresponding precipitation data in Zhuanghe City during 2009 -2011, the relationship between geological disasters and precipitation was analyzed. Results showed that precipitation-type geological disasters in Zhuanghe City had close relationships with precipitation intensity in prior period and rainfall on the day. The research had important actual significance for prevention of geological disasters.

Application of Electronic Sand Table System in Geological Disasters Meteorological Service Based on GIS

With complex terrain and developed economy, Zhejiang Province has suffered a lot from the frequent geological disasters, which have done great damages to the construction and development of the whole province. Therefore, it is particularly important to improve the geological disasters meteorological service. Electronic sand table system, a high-tech product of three-dimensional visualization, can provide the geological disaster meteorological service with the intuitive and visual application environment. In this study, we developed electronic sand table system based on GIS and established the geological disasters meteorological service database. In addition, we also analyzed and discussed the applications of meteorological service in online weather forecast, meteorological warning message, and multimedia meteorological electronic display. The application of electronic sand table system in geological disaster meteorological services for disaster prevention and mitigation is of great importance that it provides intuitive terrain analysis data for the forecast of geological disasters warning, which greatly enhances the ability of geological disasters meteorological service.

Geological Context and Statistical Assessment of the Impacts of Sugarloaf Twin Disasters, in Western Sierra Leone

In the event of natural disasters, Sierra Leone like any other country loses lives as well as properties and natural resources. Despite notable occurrences of small disasters in the country, only on August 14th sugarloaf landslide and the resulting flash flood (twin disasters) which affected Regent and other communities in 2017 have captured both national and international attention due to their alarming impacts. To obtain a better knowledge on the nature of the disasters, this research considered the geological context of the landslide and focused on statistical analysis of the impacts of the twin disasters using Statistical Package for Social Sciences (SPSS). Geological field-based approach and self-administered questionnaires of both closed and open-ended questions, personal interviews and observations were adopted as research techniques. Descriptive statistics and qualitative analysis were used to analyze the data of the research. Relevant literature from books, journals, and newspapers was also consulted, including Radio, Television discussions and the internet. Slope destabilization that caused the Landslide was linked to the geology of sub-surface formation (highly weathered olivine gabbro), lineaments and the rate of weathering. Study showed remarkable economic, social and political impacts as a consequence of the twin disasters. Study also revealed that families assisted the most in both financial and non-financial ways to the victims, and renowned misappropriation of donated disaster funds. All variables tested using student t-distribution and chi-square test of independence accepted the hypothesis. Information obtained from this work could be fundamental for policy makers and development practitioners (Osuteye & Leck, 2017).

Study on Emergency Management of Geological and Meteorological Disasters

The damage caused by geological and meteorological disasters was pointed out in this paper through analyzing the features and causes of geological and meteorological disasters.To strengthen emergency management of geological and meteorological disasters,it is suggested to rigorously investigate potential geological hazard points,to strengthen observation and warning system,to take group prevention and group test as a supplementary to professional observation,to build up the last line of defense to geological and meteorological disasters,to set up functional cooperation mechanism,and to publicize disaster prevention and mitigation.

The Forecasting and Warning System of Geological Disasters in China

Geological disasters such as landslide and mudslide can be caused by many factors. Collaborations among different governmental agencies and multi-disciplines are necessary to establish a forecasting and warning system of geological disasters (FWSGD). A FWSGD in China has been in operation since June 1, 2003 as a joint project between the China Meteorological Administration (CMA) and the Ministry of Land and Resources (MLR). This system has successfully shown very good social and economic benefits. The temporal-spatial distribu- tions of China geological disasters and their causes have been analyzed in this paper. The FWSGD is described and its possible existing issues are also discussed. Authors suggest a new approach to study these disasters from interactions of the earth systems. Finally, a monitoring, forecasting, warning and preventing system for geological disasters in China is proposed.

Study on Quantitative Assessment for the Social Risk of Major Geological Disasters

Based on the analysis of social risk of geological disasters,the index system of social risk evaluation was established. To assess the social risk quantitatively,a quantitative evaluation model of the social risk was established based on AHP,and the social risk of geological disasters was graded. Finally,the evaluation model was applied in a case.

Imbalance Between Scientific Technology and Human Rights and Measures to Rectify the Imbalance——Taking Geological Disasters as an Example

I. Increase in Human Activity and Occurrence of Geological Disasters ＂A geological disaster is a natural disaster that happens in a geo- logical environment. It is a geological effect （phenomenon） caused or in- fluenced by Nature and （or） human factors that leads to losses to human life, property and the environment.TM Based on their cause, geological disasters can be divided into natural geological and artificial geological disasters. Natural geological disas- ters include those caused by natural effects. These include typhoons, rain- fall, melting snow and earthquakes,

Study on the Analysis System of Meteorological and Geological Disaster Grades Early Warning of WebGIS

The method of realizing meteorological and geological disaster forecast and early warning information system in Qixian County of Shanxi Province was studied. According to meteorological factor parameter of the geological disasters for many years in Qixian County Land Bureau, and data of average meteorological element parameters that corresponded by evolution of geological disaster region each year, evaluation algorithm model of the forecast and eady warning of geological disasters in Qixian County was obtained, and the database of meteorological factor of geological disaster was established. On this basis, WebGIS geographic information system based on C/S and B/S which could real-time monitor geological disaster region was studied and designed. After data analysis system could evaluate the geological disaster forecast and early warning and make the real-time and accurate early warning, which greatly improved the timeliness of meteorological geological disasters forecast and early warning in Qixian County. System set of data processing and forecast and early warning issued in one, to realize the dynamic information release function of grade of geological disaster early warning, and had the characteristics of easy sharing, real-time dynamic update.

The evaluation of mine geology disasters based on fuzzy mathematics and grey theory

Mine geology disasters include mine water, mine solid waste, apron and slide, ground collapse sink and underground fracture, etc.. The subject was studied in many ways, and fuzzy mathematics was usually used. It may assure the result and distinguish the dangerous rank of different areas. But it has two defects： The first is the result is not very exact, especially the border; The second is it is short of quantity. Fuzzy mathematics and grey theory were used in order to solve the problem. Firstly, mathematical model was constructed by using grey theory, so as to evaluate and forecast the dangerous rank of mining geology disaster in different areas. Then different areas were analyzed and divided by fuzzy mathematics. By doing these, similitude rules are not only studied but also differences are discriminated. Through the practice it can be known that the result is more accurate than before.

Entropy-Based Set Pair Analysis Model on Geological Disaster Risk for Military Engineering

Measuring the geological disaster-risked situation, is a typical non-deterministic decision-making issue in disaster pre- vention and emergency response science for military engineering. Based on the given geological disaster risk analysis mechanism, geological disaster risk monitoring matrix was established, and risk characters’ value was obtained by mining the hidden information in the monitoring matrix with Entropy theory;with Identity, Discrepancy, and Contrary of Set Pair Analysis and distance measurement, geological disaster-risked model was erected for military engineering, and the steps were given for measuring geological disaster risk, which determined geological disaster-risked SPA force and order relationship of military engineering. Finally, case showed that model has the feasibility and effectiveness over measuring the geological disaster-risked situation for military engineering.

The stress state of geological structure and mining dynamic disaster in Fuxin basin

Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed stress is near EW.At this stress field,geological structures with deferent strike have deferent stress state and dis- place mode.NNE and near SN geological structures are compressed to thrust and come into being high stress zone.NWW and NEE geological structures are tensile to separate and not prone to being low stress zone.NW structure is intervenient of them.So NEE and near SN structures are easy to occurre mining dynamic disasters and NWW and NEE structures is 'safety' comparatively.The mining dynamic disaster is controlled by stress state of geologic structure,which is determined by its strike.

Risk assessment of coastal flooding disaster by storm surge based on Elevation-Area method and hydrodynamic models:Taking Bohai Bay as an example

The future inundation by storm surge on coastal areas are currently ill-defined.With increasing global sealevel due to climate change,the coastal flooding by storm surge is more and more frequently,especially in coastal lowland with land subsidence.Therefore,the risk assessment of such inundation for these areas is of great significance for the sustainable socio-economic development.In this paper,the authors use Elevation-Area method and Regional Ocean Model System(ROMS)model to assess the risk of the inundation of Bohai Bay by storm surge.The simulation results of Elevation-Area method show that either a 50-year or 100-year storm surge can inundate coastal areas exceeding 8000 km^(2);the numerical simulation results based on hydrodynamics,considering ground friction and duration of the storm surge high water,show that a 50-year or 100-year storm surge can only inundate an area of over 2000 km^(2),which is far less than 8000 km^(2);while,when taking into account the land subsidence and sea level rise,the very inundation range will rapidly increase by 2050 and 2100.The storm surge will greatly impact the coastal area within about 10-30 km of the Bohai Bay,in where almost all major coastal projects are located.The prompt response to flood disaster due to storm surge is urgently needed,for which five suggestions have been proposed based on the geological background of Bohai Bay.This study may offer insight into the development of the response and adaptive plans for flooding disasters caused by storm surge.

Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology

China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area.