中国地质灾害时空分布特征与形成条件

SPATIAL AND TEMPORAL DISTRIBUTION CHARACTERISTICS AND FORMING CONDITIONS OF CHINESE GEOLOGICAL DISASTERS

中国地质灾害种类多、分布广、频次高、强度大、灾情严重。在气候、地形、地质构造和社会条件等多种因素影响下，不同地区地质灾害的种类、强度和破坏程度差异巨大，全国可分为东部和西部两大灾害区，两大灾害区又可进一步划分为12个亚区。地质灾害活动具有不规则准周期性和累进性特点。多数地质灾害在强弱变化中显示不断增强的趋势。从可持续发展高度来说，防治地质灾害是一项长期而又艰巨的任务。

China is one of the few countries with the highest level of geological disasters in the world. Geological disasters which occurred in China are characterized by various kinds, widespread distribution and high frequency. The geological disasters not only threaten the lives and property of humankind, but also make heavy damages to our environment and resources which pose profound impacts on our society and economy. According to rough statistics there were more than 50000 times of geological disasters in our country from 1949 to 1998, of which there were 2000 heavy geological disasters that caused the death of dozens of people and over ten million RMB economic losses. Totally, the geological disasters have resulted in several hundred thousands of people dying and dozens of million houses demolished. Owing to the influence of various factors such as climate, topograghy, geological structure and social conditions, geological disasters of different regions diversified in the type, intensity and damaging degree. The whole country can be divided into two big regions, namely, eastern region and western region, both of them can also be divided into a few subregions. Western region is made up of high mountains, plateaus and big continental basins with arid climate and few people living in, and the dominant disasters are earthquake, desertification, freezing-thawing, debris-flows and water-soil erosion. Although geological disasters distribute very extensively and occur very frequently, direct damage to people and property is of low extent for its single type of disaster and rare density of people and economy. Eastern region is made up of coastal plains, low mountains and transitional mountains, where climate oscillates tempestuously between the period of cooling and warming while precipitation fluctuates between abundance and shortage with intensive practice of mankind and relatively severe geological disasters. Because of high density of people and economy, and because most cities, corporations and major projects of our country locate in this region, the geological disasters will cause huge losses to our economy and great damages to our environment and resources. There are severe geological disasters in Taiwan, Huanghuai plain, Loess Plateau, Sichuan-Yunnan mountain and Liaodong peninsula. The activities of geological disasters are cyclic irregular and progressive. Most geological disasters appear to be more severe gradually in their fluctuations of magnitude. In the future, earthquake in our country is still in its active period, hence earthquake will be more intensive and become more powerful in western region, and it is possible that severe earthquakes will occur in eastern region. The collapse, landslide and debris-flow will also tend to be more severe in their fluctuations. From the viewpoint of sustainable development, the prevention and mitigation of geological disasters are a piece of long-term and formidable task. It is necessary to exploit resources in a large scale and build all kinds of projects,while it is continuing progress of the western development in China, and the economic rapidly increasing, population enlarging, cities and industries more developed.Then, the capability of natural environment is tending to be weak. It is increasing on the scale, frequency, damages and losses of the geological disasters. Therefore, man must investigate and survey before exploiting resources and acting all kinds of economic actions. We must consider our actions from sustainable development, not only for ourselves but also for our children. We must leave a space for our children so that they can live well.