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Loess is a meta-stable, cemented assemblage of mainly silt and clay-sized particles of low plasticity.When dry it behaves like a brittle material, but when wetted up the fabric rapidly collapses. Unique geomorphological features include extensive surface erosion, soil piping (loess 'karst'), catastrophic landslides, and widespread collapse (hydro-consolidation). The Chinese Loess Plateau is a more or less continuous drape of thick loess covering some 440,000 km 2 . It isone of China's regions that is most prone to geohazards. This paper reviews advances in the research related to loess geohazards, drawing particular attention tothe need to apply research findings to recent, very large (mega-)construction projects in loess terrain such as the Mountain Excavation and City 2 Construction in Yan'anlevelling 78 km 2 for urban expansion, the Lanzhou New District creating 246 km 2 , and large engineered interventions in the landscape for gully control and land reclamation such as those in Shaanxi and Gansu generating agricultural land covering an area of some 8,000 km 2 . These projects are in response to increasing pressures to facilitate expansion of urban centres, their interconnecting infrastructures and their agricultural support systems. It is argued that,where proper application of scientific knowledge for engineering control (e.g. density, drainage)of these new landscapes is absent, these project generate a substantial, and costly geohazard legacy for future generations.

[1] A four year-long accelerometric monitoring of a landslide-prone slope area in Italy provided evidence of amplifications with systematic directional differences in shaking energy by a factor of 2 -3, apparently correlated with the directions of local topographic features. The examination of regional-scale data revealed similar site response directivity phenomena also on some steep rock slopes not affected by amplification. The spectral properties of the site responses were investigated using HVSR analysis and a new approach based on the multiplication of spectra from several events. The results suggest that such phenomena are caused by a directional redistribution of spectral energy controlled by a combination of interrelated topographic and geologic factors acting in similar directions. Citation: Del Gaudio, V., and J. Wasowski (2007), Directivity of slope dynamic response to seismic shaking,