| Based on researching the distribution law of geological hazards and their formingcondition in the upper region of the Yellow River, this paper researched the relationamong geological hazards, ground stress and neotectonic movement. In addition,combined the geological hazards with social economy, this paper did some researchingor evaluation in regionally, synthetically and quantificational. The result show thedifferent risk grade among different regions. Main results are as follows:1. The upper region of the Yellow River is one of regions that geological hazardoccurs especially frequently. Main geological hazards are presented by two kinds ofhazards: some are paroxysmal geological hazards including earthquake, collapse,landslide, debris flows, burst of gas and so on. The others are delay occurring hazardsincluding water-soil erosion, land desertiflcation, land solinaztion, land collapsing,disaster of special rock and soil, freezing and dissolving, coal spontaneous combustionand so on. Water-soil erosion, land desertification and land solinaztion are the mainlyhazards in northern of researching region. Earthquake, collapse, landslide, debris flowsand water-soil erosion are mainly hazards in middle researching region. Freezing anddissolving are the mainly hazards in west-southern and west-northern of researchingregion. Paroxysmal geological hazards are cyclic irregular periodicity, and delayoccurring geological hazards are gradually development.2.The harm of geological hazards is showed in three aspects, the direct harm,indirect harm and further harm in researching region. First, the direct harm can result indying and hurting of people, destroying of all kinds of engineering, and loss of wealthand economy. Second, the indirect harm results mainly in shutdown and stoppingproduction in industry, reducing production in agriculture and pasture, and interruptingtranspotation. Third, the further harm result in mainly damages of land resource andenvironment, which will sustain long time and prevents the continuance developmentof economy.3.Property of geological hazards include generally two aspects: natural propertyand social property. The activity of geological hazards caused mainly by naturalconditions, but human activity play an important role in part sometimes. The level ofsocial development, bearing ability of society, is the social forming condition ofgeological hazards: When activity of geological hazards affect to endured objects andcaused their loss or damage, the activity of geological hazards cause disaster.4. Different types geological hazards caused by different forming conditions anddomain controlling factors. Two types condition can be generalized from geologicalhazard activities. One is the basis of geological hazard activities; another is the powercondition and causing factors.5.The state of ground stress is consistent with character of present tectonic activityin researching region. The direction of the biggest principal stress is NE, and change inpart. The calculated result of two dimension finite element model indicated that thedirection, which are the biggest principal stress, the least principal stress and the biggestshear stress, is parallel with that of tectonic distribution. The distributions are very different among three-type stress. Activity of earthquake often occur in section thatstress value is higher. But other hazards, such as collapse, landslide and debris flows,often occur in the biggest shear stress section, but not in a section that stress value ishigher.6.From the origin, the ground stress activity, endogenic geologic process, is thebasis of geological hazards. Exogenic geologic process and human action promote thegeological hazard and accelerate occurrence of hazard. The relational pattern amongGeological hazards, ground stress and neotectonic action is a complex circle systemthat describe as stress-neotectonic-activity-landform-climate-environment-hazards.7.Through studying on theory and method about risk evaluation of geologicalhazards, this paper establishes a risk evaluation system of geological hazard that isbased on MapInfo and assisted with FoxPro database.8. So far, the power weight value of single factor was endowed according to relatingdegree in model of dangerous evaluation and vulnerable evaluation, which made thedangerous index and vulnerable index more subjective. In this paper, the power weightvalue of single factor was obtained according to relating degree divided by sum of allfactors, which avoids interference resulted from human activity. So the later way isgood to progress management and made calculating result more reasonable.9. Based on dangerous evaluation and vulnerable evaluation, the risk index ofevaluation can be expressed by multiplying dangerous index with vulnerable index.Risk index of 116 units indicates respectively risk degrees in researching region. Inorder to show risk degree of each unit of geological hazards, the risk index was dividedinto five grades. Moreover, the grade map of geological hazards was made. The Biggestshear stress, as a parameter, was added to the model in risk evaluation that has not beendone before.10.According to the result of risk evaluation, the conclusion is made that higherrisk is in middle region, and lower risk is in northern and southern region. From thecalculating result of risk evaluation, it is obviously that some result of units risk index isnearly boundary value. If the condition changed, some risk degree will be change. So inthis paper, some suggestion for reduce hazards are put forward according to the resultof risk evaluation.
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