Digital Commons Network^™

On Tsunami Risk Assessment For The West Coast Of Thailand, Farrokh Nadim, Thomas Glade

Geohazards

The catastrophic Indian Ocean tsunami of 26 December 2004 raised a number of questions for scientists and politicians on how to deal with the tsunami risk in coastal regions. This paper discusses the challenges in tsunami risk evaluation and presents the results of a tsunami risk mitigation study for the west coast of Thailand. It is argued that a scenario-based approach is particularly well suited for evaluation of the risk posed by tsunamis. The approach consists of considering scenarios of plausible extreme, tsunami-generating events, computing the tsunami inundation levels caused by these events, estimating the possible range of casualties for …

A Capacity Spectrum Method For Seismic Risk Assessment, Sergio Molina, Conrad D. Lindholm

Geohazards

Although earthquakes and the associated damage occur in a fundamentally deterministic way, the processes are so complex that our prediction scenarios are basically uncertain approximations. In the first attempts to model hazard and risk, point estimates based on empirical data were used, however, for quite some time the more advanced seismic hazard modelling has been based on models in which the variability/uncertainty of the input parameters are consistently carried through the computations so that the results are probabilistically combined to give a median value and confidence levels that reflect on the input parameter uncertainty. For seismic damage scenarios the first …

Cost Evaluation For Traffic And Transport Infrastructure Projects Taking Account Of Project Risks, Rudolf Poettler, H. F. Schweiger

Geohazards

The realisation of large transport infrastructure projects is influenced by a wide range of different factors. The general expectation that a project should be carried out under defined boundary conditions within the planned period and on budget requires a high level of design, planning and controlling. This paper discusses standardised comprehensible fundamental rules and guidelines for defining project costs and project budgets of infrastructure projects taking into account risk assessment and risk management. Adhering to these guidelines and rules contributes to ensure that the structure can be built in the required quality, on schedule and on budget, as well as …

Dealing With Uncertainty In Engineering Design For Large-Scale Gravel Soil Slopes In The Three Gorges Reservoir Zone, Wilson H. Tang, L. M. Zhang, Y. R. Zheng

Geohazards

The objective of this paper is to first present a general formulation for analysis of uncertainties and evaluation of risks associated with large-scale slopes. The risks may be expressed in terms of the reliability of the system and the consequence. Preliminary studies regarding the mitigation of landslides in the Three-Gorge reservoir zone (TGRZ) of the Yangtze River is presented next. At the normal water level of 175 m, the Three-Gorge reservoir stretches for 665 km along the Yangtze River and extends into many tributaries. Some 684 colluvial deposits, ancient slides and hanging rock blocks, which are larger than 100,000 m3 …

Urban Earthquake Risk, Mustafa Erdik

Geohazards

The impact of earthquakes in urban areas is a complex problem compounded by multi-hazard and consequential risk issues, enormous inventory of vulnerable physical elements and the attendant socio-economic problems. A review of our state-of-knowledge and applications on the assessment of urban earthquake risk is provided. Rational urban risk predictions and expected losses from major earthquakes in the future serve the basis and also provide strong reasons for the proactive risk mitigation activities.

Dam Risk Analysis Using Bayesian Networks, Marc Smith

Geohazards

The risks related to existing hydraulic structures have been analyzed using bayesian networks. The proposed multidisciplinary approach allowed the comparison, according to the probability of failure being used as a common denominator, of the geotechnical, hydrological and structural risks. The factors contributing the most to the overall risk have been identified as well as the interventions to be realized in priority. The presented concepts consider dam risk in a more global and holistic way.

Risk Assessment Due To Debris Flows In Paz De Río-Colombia, Carlos Eduardo Rodriguez, O. I. Chaparro, G. Flechas

Geohazards

Paz de Río is an important economic area of Colombia where iron mines produce most of the mineral for the steel production in the country. Along the La Chapa creek some debris flows have occurred since 1963 producing economic losses and human deaths at Santa Teresa village. Economical losses are related to disruption of the main access to La Chapa iron mine facilities, and flooding of Paz de Río due to damming of Chicamocha River, the main drainage system of the region, which is blocked by debris flows.

The local authority for Natural Disaster Management (CREPAD) jointly with the Universidad …

3d Visualization For Urban Earthquake Risk, S. Kemec, S. Duzgun

Geohazards

Visualization is the graphical presentation of information, with the goal of improving the viewer’s understanding of the information contents. As today’s world is getting richer in information, visualization of the information is important for effective communication and decision making. In this study, generation of a 3D city model in CAD environment and its use in a spatial decision support system for earthquake risk in an urban area is presented. As CAD products’ quality is more enhanced than the other tools the 3D city model is generated in CAD environment. In CAD environment, a 2D building foot print vector layer is …

Risk Analyses And Risk Management - Slope Instabilities In Alpine Environments, S. Eder, G. Poscher, C. Prager

Geohazards

Two prominent deep-seated gravitational slope deformations in the Eastern Alps (Tyrol, Austria) have been activated in the last seven years and pose serious threats to the densely populated valleys. Based on multidisciplinary field investigations, different hazard scenarios of slope failures have been evaluated for risk management processes. These event scenarios, which are characterised by strongly varying volumes of the failing slide masses as well as by different probabilities of occurrence, and varying disintegration factors control different accumulation and damage scenarios. Finally, these evaluations and risk analyses aimed to define “design events”, i.e. which scenarios are relevant for the dimensioning of …

Quantitative Risk Assessment As Applied To Natural Terrain Landslide Hazard Management In A Mid-Levels Catchment, Hong Kong, Ian Muir, K. K. S. Ho, H. W. Sun, T. H. H. Hui, Y. C. Koo

Geohazards

This paper presents a case study of the application of quantitative risk assessment techniques to a site-specific natural terrain hazard study in Hong Kong. The development of the landslide hazard and susceptibility models is described and salient details of the consequence model are given, including the assessment of debris flowpaths and runout using state-of-the-art Geographic Information System (GIS) tools and debris runout computer models. A synthesis of the risk quantification process and schematic design of risk mitigation works is presented.

The 1999 Colorado Springs, Colorado Landslides – Federal, State And Local Government Response; Public Involvement; And Future Long-Term Risks And Challenges, Mark W. Squire

Geohazards

In the spring of 1999, heavy rain precipitated landslides in over 12 developed areas in Colorado Springs. The landslide damage and destruction exceeded $80 million dollars. A combined federal, state and local response included active participation by property owners in an open and transparent public process. The resulting federally funded mitigation project was a success, but this can only be considered an interim objective for an inherent serious local problem. Colorado Springs is normally an arid environment but high moisture years, like 1999, can result in activation of new landslides and reactivation of existing landslides. Residential neighborhoods continue to expand …