Loess Deposit and Loess Landslides on the Chinese Loess Plateau
Chinese Loess is a wind origin deposit which records the continuous Quaternary history. In the past 30 years, the loess stratigraphy has achieved a great advantage that the absolute age and the litho-strata were well defined by dating and correlating with
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Abstract Chinese Loess is a wind origin deposit which records the continuous Quaternary history. In the past 30 years, the loess stratigraphy has achieved a great advantage that the absolute age and the litho-strata were well defined by dating and correlating with deep sea core isotopic curves. That set up a formed basis for further study in the loess properties and geological hazards in view of origin and mechanism. Loess has special characters of typical topographies, vertical joints, loose texture and water sensitivity, which makes it easy to slide. Landslides on the Chinese Loess Plateau are the most severe geological hazards, which deprive people of life, damage gas and oil routes, destroy roads and railways and decrease farmlands. Control of landslides is a long-term strategy. Besides the general used structural methods being applied in the slides related to some engineering, improvement of ecological environment, innovation of irrigation way and availability of drainage systems are more significant. Building of early warning system based on monitoring is a practical and economic way to check landslides as much as possible in considering of the present natural environment and national condition. Keywords Loess
Stratigraphy Loess Plateau Landslide Deposit
1 Introduction Loess is an aeolian sediment formed by the accumulation of wind-blown fine sand and clay components. Loess is distributed in arid and semi-arid regions where favourable weather conditions help in its generation and deposition. Globally, loess T. Li (&) C. Wang P. Li Department of Geological Engineering, Chang’an University, Xi’an 710054, China e-mail: [email protected]
F. Wang et al. (eds.), Progress of Geo-Disaster Mitigation Technology in Asia, Environmental Science and Engineering, DOI: 10.1007/978-3-642-29107-4_12, Ó Springer-Verlag Berlin Heidelberg 2013
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Fig. 1 Global deposits of Loess (After Sun 2005)
covers 10 percent of the earth surface and is distributed mostly in regions spanning 30–55° North and 30–40° South latitudes, which are monsoon dominated zone. As shown in Fig. 1, loess deposits are mainly distributed in the northern hemisphere, from Europe to Siberia in Russia, northern China and north America, with relative lesser deposits in the southern hemisphere, such as the center of New Zealand and the South America. In addition, loess deposits have been discovered in the ocean floor, such as the Atlantic ocean around west Africa, the north Arabian sea, the Japan sea and the sea around eastern Philippine. Loess deposits, unlike water-deposited sediments, are not only distributed in river basins; they are also distributed in the seas and oceans, which strongly prove its wind-blown origin. Loess in China covers a total area of approximately 631,000 km2, occupies 4.4% of the national land (Liu 1996), of which, the Loess Plateau has the best developed deposit in the world (Fig. 2). The thickness of loess deposits in this area vary from few meters to more than 300 m. The Loess Plateau of northern
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