Wastewater disposal and problem soils in Lanzhou, China

Wastewater disposal and problem soils in Lanzhou, Chin

Quantification of road network vulnerability and traffic impacts to regional landslide hazards [abstract]

Slope instability represents a prevalent hazard to transport networks. In the UK regional road networks are frequently disrupted by multiple slope failures triggered during intense precipitation events; primarily due to a degree of regional homogeneity of slope materials, geomorphology and weather conditions. It is of interest to examine how different locations and combinations of slope failure impact road networks, particularly in the context of projected climate change and a 40% increase in UK road demand by 2040. In this study an extensive number (>50 000) of multiple failure event scenarios are simulated within a dynamic micro simulation to assess traffic impacts during peak flow (7 – 10 AM). Possible failure locations are selected within the county of Gloucestershire (3150 km2) using historic failure sites and British Geological Survey GeoSure data. Initial investigations employ a multiple linear regression analyses to consider the severity of traffic impacts, as measured by time, in respect of spatial and topographical network characteristics including connectivity, density and capacity in proximity to failure sites; the network distance between disruptions in multiple failure scenarios is used to consider the effects of spatial clustering. The UK Department of Transport road travel demand and UKCP09 weather projection data to 2080 provide a suitable basis for traffic simulations and probabilistic slope stability assessments. Future work will thus focus on the development of a catastrophe risk model to simulate traffic impacts under various narratives of future travel demand and slope instability under climatic change. The results of this investigation shall contribute to the understanding of road network vulnerabilities and traffic impacts from climate driven slope hazards

Cultural perceptions of hazard and risk in a dynamic environment

In the Bailong River corridor, Gansu, China, an estimated 1.7 million people are threatened by geohazards including earthquakes, landslides and debris flows, flooding and extreme rainfall. The area is also undergoing rapid economic growth and infrastructure development. This paper reports on recent work exploring the physical and social systems and their interactions, and highlights the need for further multidisciplinary research required to better understand human-landscape interactions in such dynamic environments. Knowledge of geohazard processes (including responses to rainfall, mapping of susceptibility, monitoring and triggering conditions for disaster events) and their interactions with society is advancing, but there is still much further work required to better understand how people living with risk perceive and adapt to their environment. Perceptions of risk are contextual, and influenced by culture and worldview; while society and culture may also be shaped by hazards, for example in the local knowledge and coping mechanisms which reduce risk. There is a need to answer questions such as how perceptions compare with scientifically-derived conclusions about hazard and risk? And can they inform policy that will reduce disaster risk

Indirect economic impact of landslide hazards by disruption to national road transportation networks; Scotland, United Kingdom

Indirect economic impact of landslide hazards by disruption to national road transportation networks; Scotland, United Kingdo

Characterising regional landslide initiation thresholds in Scotland, UK using NIMROD c-band precipitation radar and the BGS National Landslide Database

Characterising regional landslide initiation thresholds in Scotland, UK using NIMROD c-band precipitation radar and the BGS National Landslide Databas

Incidental terrestrial imagery for post disaster spatial data capture of debris flows

Consumer-grade digital imagery captured by non-experts has a great potential for DEM extraction. The portability of the equipment creates opportunities for data collection in difficult and inaccessible mountainous terrain. In this context it provides an important tool enabling rapid response post-disaster planning in regions affected by large scale natural hazard events. The potential of this methodology is illustrated by a case study of the large scale debris flow that killed several thousand people in the town of Zhouqu, China in August 2010. The case study briefly introduces the pertinent details of the debris flow event. Data collection, processing and representations are highlighted. It is concluded that the methodology can be beneficial for post-disaster planning, and that the relatively cheap instrument requirements and simple methodologies also provide an opportunity to involve local residents and municipal authorities for landscape monitoring in active terrains

Rainfall thresholds and susceptibility mapping for shallow landslides and debris flows in Scotland [poster]

Shallow translational slides and debris flows (hereafter ‘landslides’) pose a significant threat to life and cause sig- nificant annual economic impacts (e.g. by damage and disruption of infrastructure). The focus of this research is on the definition of objective rainfall thresholds using a weather radar system and landslide susceptibility mapping. In the study area Scotland, an inventory of 75 known landslides was used for the period 2003 to 2016. First, the effect of using different rain records (i.e. time series length) on two threshold selection techniques in receiver operating characteristic (ROC) analysis was evaluated. The results show that thresholds selected by ‘Threat Score’ (min- imising false alarms) are sensitive to rain record length and which is not routinely considered, whereas thresholds selected using ‘Optimal Point’ (minimising failed alarms) are not; therefore these may be suited to establishing lower limit thresholds and be of interest to those developing early warning systems. Robust thresholds are found for combinations of normalised rain duration and accumulation at 1 and 12 day’s antecedence respectively; these are normalised using the rainy-day normal and an equivalent measure for rain intensity. This research indicates that, in Scotland, rain accumulation provides a better indicator than rain intensity and that landslides may be gen- erated by threshold conditions lower than previously thought. Second, a landslide susceptibility map is constructed using a cross-validated logistic regression model. A novel element of the approach is that landslide susceptibility is calculated for individual hillslope sections. The developed thresholds and susceptibility map are combined to assess potential hazards and impacts posed to the national highway network in Scotland