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.
A New Distribution for Extreme Value Analysis
The shape of the commonly used distributions in extreme value analysis is determined by either a specific functional form or a shape parameter. In this paper, we develop a family of distributions which uses two parameters to determine the shape: a balance parameter to control symmetry and a tail order parameter to control the thickness of the tail and modes. Each member in this family has closed forms for its density, cumulative distribution, and quantile function. We discuss the maximum likelihood and minimum distance estimation of the unknown parameters and illustrate the usefulness of the new distribution in extreme value analysis with a real data set.
Geological and land instability mapping using a GIS package as a building block for the development of a risk assessment procedure
Abstract A modern land instability risk assessment procedure must include an accurate geological framework and landinstability database. Geological and land instability mapping of the northern suburbs of the City ofWollongong represents a considerable challenge and is to be achieved using computer generated 1:4000topographic base maps. Using an integrated series of techniques, including computer modelling of theescarpment geology and field mapping techniques, a new series of geological maps has been produced.Meanwhile an exhaustive land instability database of the region has been compiled. A flexible approach tomapping and data compilation is very useful and confirms the viability and resourcefulness of a computerbased Geographic Information System package. The second stage of this research project (outside the scope ofthis paper) is the development and validation of a risk assessment procedure. Validation will generally involvesteps to test the assessments on the basis of field observations.