Effective urban landslide hazard assessment
Landslide hazard assessment is a vitally important component of any strategy for the management of risk of instability in hilly areas. Within many urban areas, reactivation of landslides is an important component of risk. Yet, most qualitative approaches do not differentiate between the hazard of individual landslides. Two quantitative approaches are introduced in this paper both of which utilise GISbased accurate maps of geology and landslip as well as a landslide database. The first method is based on historical recurrence of individual landslides. The second method is based on monitoring of subsurface shear movements, and their relationships to rainfall. Both methods can provide reliable information on hazard. Hazard ranking based on the first method has been validated in the Greater Wollongong area of the State of New South Wales in Australia. This paper does not address the potential hazard associated with sites which are recognised to be stable with no known history of instability.
Consideration of probability assessments relevant to hazard and risk for landslides
Probability of occurrence is the most important component of landslide hazard and risk and this paper outlines different approaches for its assessment. The reasons for the popularity of qualitative approaches are first outlined. Quantitative approaches can be best applied if the important influencing factors and issues are fully understood. Formal probabilistic approaches are often based on geotechnical models or on a combination of hydrological and geotechnical models. The paper also highlights the situations for which the performance function must be formulated in terms of lateral displacements rather than the conventional safety factor. Reference is then made to a procedure, based on observational data on lateral displacements, which may be used for quantitative assessment of probability and hazard of slow-moving landslides. Finally, the results of a quantitative probabilistic assessment for a landslide site (natural slope) are presented considering different scenarios and assumptions. The example highlights the changing magnitude of hazard before and after landsliding and the factors which influence this magnitude.
La inseguridad jurídica en normas de contratación estatal
It is established by different studies that the issue of government procurement has been marred by several factors, the test objective to publicize these factors, we take as starting point the constant conflict between the branches of government to try and organize this subject; will collect and analyze diverse regulatory and case material in order to achieve evidence and demonstrate the different concepts of constant change that produces excessive regulation of the subject procurement and is in turn causing rapid changes that result in legal uncertainty for our law on the Contract Status.