Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristic of the surface. By exploiting the phase of the coherent radar signal, interferometry has transformed radar remote sensing from a largely interpretive science to a quantitative tool, with applications in cartography, geodesy, land cover characterization, and natural hazards. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

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Synthetic aperture radar interferometry

Landslide hazard evaluation: a review of current techniques and their application in a multi-scale study, Central Italy

Landsliding in response to rainfall involves physical processes that operate on disparate timescales. Relationships between these timescales guide development of a mathematical model that uses reduced forms of Richards equation to evaluate effects of rainfall infiltration on landslide occurrence, timing, depth, and acceleration in diverse situations. The longest pertinent timescale is A/D0, where D0 is the maximum hydraulic diffusivity of the soil and A is the catchment area that potentially affects groundwater pressures at a prospective landslide slip surface location with areal coordinates x, y and depth H. Times greater than A/D0 are necessary for establishment of steady background water pressures that develop at (x, y, H) in response to rainfall averaged over periods that commonly range from days to many decades. These steady groundwater pressures influence the propensity for landsliding at (x, y, H), but they do not trigger slope failure. Failure results from rainfall over a typically shorter timescale H2/D0 associated with transient pore pressure transmission during and following storms. Commonly, this timescale ranges from minutes to months. The shortest timescale affecting landslide responses to rainfall is H/g, where g is the magnitude of gravitational acceleration. Postfailure landslide motion occurs on this timescale, which indicates that the thinnest landslides accelerate most quickly if all other factors are constant. Effects of hydrologic processes on landslide processes across these diverse timescales are encapsulated by a response function, R(t*) = t*/π exp (−1/t*) − erfc (1/t*), which depends only on normalized time, t*. Use of R(t*) in conjunction with topographic data, rainfall intensity and duration information, an infinite-slope failure criterion, and Newton's second law predicts the timing, depth, and acceleration of rainfall-triggered landslides. Data from contrasting landslides that exhibit rapid, shallow motion and slow, deep-seated motion corroborate these predictions.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2000WR900090

Landslide triggering by rain infiltration

A copy of Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?" It said: "… Young friends, you are certainly very concerned about this problem'. So, we would like you to meet the young women workers Meng Xiaoyu and Meng Yamei and the older cadre Miss Feng. They are the three leading characters in the short story ‘The Place of Love.’ Through the description of the love lives of these three, the story induces us to think deeply about two questions that merit further examination.

This is How the Discussion Started

The application of GIS-based logistic regression for landslide susceptibility mapping in the Kakuda-Yahiko Mountains, Central Japan

Due to rapid industrialization, with high population density and constraints of land, it is expected that level of risks arising from the hazardous industries will increase in India in the coming decades. However, 30 years after the Bhopal accident (1984), except a few discrete regulations, there is as yet no integrated system for assessing and managing risks arising out of these hazardous industries in India. The gravity of aspects related to the management of industrial risk still remains crucially important. In particular, there is no standard guideline on risk analysis methodology, acceptability or tolerability criteria, nor is there an accident database or a risk reduction strategy for the areas where risk levels are already high. On top of this, there are technical and legislative gaps in the institutional framework to implement any of the above mentioned issues. With the backdrop of the Bhopal gas tragedy, the objective of this paper is therefore to evaluate the effectiveness of a comprehensive risk assessment framework for the emerging economy of India, in order to control and/or to reduce the risk level that exists. In this context, regulations and policies pertaining to industrial risk assessment were reviewed.

An evaluation of risk assessment framework for industrial accidents in India

. Six years after the devastating Ms 8.0 Wenchuan earthquake, new landslides, debris flows, and flash floods still occur frequently in the earthquake-stricken regions. This shows that the geological hazards that occur after a major earthquake in a mountainous environment can be a long-term threat. However, post-earthquake reconstruction and relocation of local residents often neglect this evolving threat, and its interaction with existing and rebuilt houses has not been well studied. Here we show that the evolving mountain environment, including the changed geographic distribution of new landslides and the continuously uplifting riverbed, creates emerging risks for existing and rebuilt houses. We use spatial analysis of landslide debris and the location of houses from high-resolution images and field survey in the study area and find that new landslides and the houses rebuilt after the Wenchuan earthquake have a similar trend of moving to lower elevations, gentler slopes, and closer to rivers. This study confirms that the persistent downward movement of landslide debris has rapidly filled up riverbeds over the past 6 years. The elevated riverbeds make the study area extremely susceptible to flash floods, creating further risks to newly rebuilt houses that are closer to the river. We highlight the often neglected dynamic process that involves changes in the natural environment and man-made constructions and their interaction. This dynamic process requires long-term monitoring and adaptive management of mountainous regions after major earthquakes that can fully consider the sophisticated evolving risks caused by the changing environment, exposure, and vulnerability in the region.

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Analysis of changes in post-seismic landslide distribution and its effect on building reconstruction

The 2008 Wenchuan earthquake (China, Mw 79) highlighted the importance of assessing and mitigating the hazards from co-seismic landslides and landslide dams The seismic shaking triggered hundreds of thousands of landslides, about 800 of which dammed the course of rivers To understand whether distinctive factors concurred with the river-damming events, we analyzed the spatial patterns of the river-damming landslides and the non-damming landslides separately, with reference to a number of possible controlling factors Then, we quantified the significance of these factors using the weight of evidence method, and we used the results to perform a susceptibility assessment in a portion of the earthquake-affected region to verify the effectiveness of the method We find that the distance to the fault surface rupture, peak ground acceleration (PGA) and lithology play a controlling role for co-seismic landslides of any type The occurrence of river-damming landslides, rather than by a specific lithology or topography, is more related to hydrological factors, while topographic controls (slope, internal relief and terrain roughness) are more significant for the non-damming landslides

Distinctive controls on the distribution of river-damming and non-damming landslides induced by the 2008 Wenchuan earthquake

The analysis of multi-hazard risk requires the use of models that are very data demanding. Data is needed of the areas that might be affected and the characteristics of the hazard, but also of the elements at risk that might be impacted, and their vulnerability. In the framework of two European projects (FP6-PEOPLE-2006-ITN Marie curie Mountain risks and FP7 SafeLand) a training package has been developed on the use of spatial information for the assessment and management of mountain risks. This training package explains the procedures to collect, analyze and evaluate spatial information for risk assessment from natural hazards in a mountainous environment. It aims at researchers and practitioners that have to carry out risk assessments at a medium scale, and use the risk information in disaster risk reduction planning. The training package guides the participants through the entire process of risk assessment, on the basis of a case study of an area exposed to multiple hazards in Barcelonnette, France. In order to achieve maximum applicability the training package is made for use with Open Source software. Three-dimensional stereoscopic image interpretation using images downloaded from Google Earth is used to familiarize the participants with the hazard phenomena. These are then used in either a statistical or heuristic approach for modelling the initiation areas for landslides, debris flows, snow avalanches and rockfalls. The source areas are used for run-out modelling on a medium scale using a routing-spreading model and the results are converted into impact maps. Flood hazard assessment is done using a 1D-2D flood propagation model and flood impulse is calculated for different return periods. The source maps and run-out maps for mass movements and the flood maps are then used in a quantitative multi-hazard risk assessment, by calculating the exposed elements at risk, the temporal and spatial probability and the vulnerability of the elements at risk. Also emphasis is given to the evaluation of uncertainty in the risk assessment process. A qualitative method for multi-hazard risk assessment is also included, using Spatial Multi-Criteria Evaluation, in which a hazard index and a vulnerability index are generated. The final part of the training package deals with the use of risk information for disaster risk management, e.g. by incorporating the risk information in preparedness planning, cost-benefit analysis for the planning of remedial measures, and land use zoning.

C.J. van Westen

Papers

An evaluation of risk assessment framework for industrial accidents in India

Analysis of changes in post-seismic landslide distribution and its effect on building reconstruction

Distinctive controls on the distribution of river-damming and non-damming landslides induced by the 2008 Wenchuan earthquake

Development of training materials on the use of geo - information for multi - hazard risk assessment in a mountainous environment

GIS for the assessment of risk from geomorphological hazards