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Mahesh Prakash, James Hilton, Claire Miller, Vincent Lemiale, Raymond Cohen, and Yunze Wang

Remotely sensed data for the observation and analysis of natural hazards is becoming increasingly commonplace and accessible. Furthermore, the accuracy and coverage of such data is rapidly improving. In parallel with this growth are ongoing developments in computational methods to store, process, and analyze these data for a variety of geospatial needs. One such use of this geospatial data is for input and calibration for the modeling of natural hazards, such as the spread of wildfires, flooding, tidal inundation, and landslides. Computational models for natural hazards show increasing real-world applicability, and it is only recently that the full potential of using remotely sensed data in these models is being understood and investigated. Some examples of geospatial data required for natural hazard modeling include: • elevation models derived from RADAR and Light Detection and Ranging (LIDAR) techniques for flooding, landslide, and wildfire spread models • accurate vertical datum calculations from geodetic measurements for flooding and tidal inundation models • multispectral imaging techniques to provide land cover information for fuel types in wildfire models or roughness maps for flood inundation studies Accurate modeling of such natural hazards allows a qualitative and quantitative estimate of risks associated with such events. With increasing spatial and temporal resolution, there is also an opportunity to investigate further value-added usage of remotely sensed data in the disaster modeling context. Improving spatial data resolution allows greater fidelity in models allowing, for example, the impact of fires or flooding on individual households to be determined. Improving temporal data allows short and long-term trends to be incorporated into models, such as the changing conditions through a fire season or the changing depth and meander of a water channel.

Article

Mountain environments, home to about 12% of the global population and covering nearly a quarter of the global land surface, create hazardous conditions for various infrastructures. The economic and ecologic importance of these environments for tourism, transportation, hydropower generation, or natural resource extraction requires that direct and indirect interactions between infrastructures and geohazards be evaluated. Construction of infrastructure in mountain permafrost environments can change the ground thermal regime, affect gravity-driven processes, impact the strength of ice-rich foundations, or result in permafrost aggradation via natural convection. The severity of impact, and whether permafrost will degrade or aggrade in response to the construction, is a function of numerous parameters including climate change, which needs to be considered when evaluating the changes in existing or formation of new geohazards. The main challenge relates to the uncertainties associated with the projections of medium- (decadal) and long-term (century-scale) climate change. A fundamental understanding of the various processes at play and a good knowledge of the foundation conditions is required to ascertain that infrastructure in permafrost environment functions as intended. Many of the tools required for identifying geohazards in the periglacial and appropriate risk management strategies are already available.

Article

Society expects to have a safe environment in which to live, prosper, and sustain future generations. Generally, when we think of threats to our well-being, we think of human-induced causes such as overexploitation of water resources, contamination, and soil loss, to name just a few. However, natural hazards, which are not easily avoided or controllable (or, in many cases, predictable in the short term), have profound influences on our safety, economic security, social development, and political stability, as well as every individual’s overall well-being. Natural hazards are all related to the processes that drive our planet. Indeed, the Earth would not be a functioning ecosystem without the dynamic processes that shape our planet’s landscapes over geologic time. Natural hazards (or geohazards, as they are sometimes called) include such events as earthquakes, volcanic eruptions, landslides and ground collapse, tsunamis, floods and droughts, geomagnetic storms, and coastal storms. A key aspect of these natural hazards involves understanding and mitigating their impacts, which require that the geoscientist take a four-pronged approach. It must include a fundamental understanding of the processes that cause the hazard, an assessment of the hazard, monitoring to observe any changes in conditions that can be used to determine the status of a potential hazardous event, and perhaps most important, delivery of information to a broader community to evaluate the need for action. A fundamental understanding of processes often requires a research effort that typically is the focus of academic and government researchers. Fundamental questions may include: (a) What triggers an earthquake, and why do some events escalate to a great magnitude while most are small-magnitude events?; (b) What processes are responsible for triggering a landslide?; (c) Can we predict the severity of an impending volcanic eruption? (d) Can we predict an impending drought or flood?; (e) Can we determine the height of a storm surge or storm track associated with coastal storm well in advance of landfall so that the impact can be mitigated? Any effective hazard management system must strive to increase resilience. The only way to gain resiliency is to learn from past events and to decrease risk. To successfully increase resiliency requires having strong hazard identification programs with adequate monitoring and research components and very robust delivery mechanisms that deliver timely, accurate, and appropriate hazard information to a broad audience that will use the information is a wide variety of ways to meet their specific goals.