Landslide Hazard Information System for Landslide Disaster Risk Financing: Earth Observation and Modelling Products for Near-Real-Time Assessment

Author(s):  
Clément Michoud ◽  
Jean-Philippe Malet ◽  
Dalia Kirschbaum ◽  
Thierry Oppikofer ◽  
Robert Emberson ◽  
...  

<p>The frequency and impact of disasters rise at the global scale, calling for effective disaster risk management and innovative risk financing solutions. Disaster Risk Financing (DRF) can increase the ability of national and local governments, homeowners, businesses, agricultural producers, and low-income populations to respond more quickly and resiliently to disasters by strengthening public financial management and promoting market-based disaster risk financing. For landslide events, the usage of DRF products is not yet extensive, mainly due to challenges in capturing the appropriate destabilization factors and triggers, as well as forecasting the physical properties of a landslide event (such as its type, location, size, number of people affected, and/or exposed infrastructure). The availability and quality of satellite EO derived data on rainfall that triggers landslides (Global Precipitation Measurement mission / GPM) and observations of the landslides themselves (Copernicus Sentinel radar and multispectral sensors, very high resolution -VHR- optical sensors) greatly improved in recent years. In the same time, effective models are refined and support near-real time landslide hazard assessment (e.g. Landslide Hazard Assessment for Situational Awareness / LHASA; Flow path assessment of gravitational hazards at a Regional scale / FLOW-R).</p><p>The objective of this work is to present the prototype platform LANDSLIDE HAZARD INFORMATION SYSTEM (LHIS) which aims to support landslide DRF priorities using Earth Observation data and models. The functions of the platform are to be able to anticipate, forecast and respond to incipient landslide events (in Near-Real Time, NRT) by providing estimates of parameters suitable for parametric insurance calculations, including landslide inventories, susceptibility and hazard maps, potential damages and costs analyses. The LHIS prototype is accessible on the GEP / Geohazards Exploitation Platform allowing easy access, processing and visualization of EO-derived products. The prototype consists of three modular components with respectively: 1) a Landslide Detection component to create Landslide Inventories, 2) a Landslide Hazard Assessment component using global and national geospatial datasets leading to Landslide Susceptibility Maps, Scenario-based Hazard Maps and NRT Rainfall-based Hazard Maps, and 3) Landslide Impact Assessment component combining landslide hazard maps with population and infrastructure datasets to derive Landslide Exposure Maps and Landslide Impact Index. The landslide detection module is based on the analysis of time series of optical and SAR data; the landslide hazard and impact assessment modules are based on the LHASA, FLOW-R and PDI models.</p><p>The information system is being developed and tested in Morocco in collaboration with the solidarity fund against catastrophic events (FSEC) and the World Bank for two contrasting use cases in the Rif area (North Morocco) and the Safi area (Central Morocco) exposed to various landslide situations occurring in different environmental and climatic contexts.</p>

Author(s):  
Clement Michaud ◽  
Jean-Philippe Malet ◽  
Thierry Oppikofer ◽  
Robert Emberson ◽  
Dalia Kirschbaum ◽  
...  

2020 ◽  
Author(s):  
Dalia Kirschbaum ◽  
Thomas Stanley ◽  
Robert Emberson ◽  
Pukar Amatya ◽  
Sana Khan ◽  
...  

<p>A remote sensing-based system has been developed to characterize the potential for rainfall-triggered landslides across the globe in near real-time. The Landslide Hazard Assessment for Situational Awareness (LHASA) model uses a decision tree framework to combine a static susceptibility map derived from information on slope, rock characteristics, forest loss, distance to fault zones and distance to road networks with satellite precipitation estimates from the Global Precipitation Measurement (GPM) mission. Since 2016, the LHASA model has been providing near real-time and retrospective estimates of potential landslide activity. Results of this work are available at https://landslides.nasa.gov.</p><p>In order to advance LHASA’s capabilities to characterize landslide hazards and impacts dynamically, we have implemented a new approach that leverages machine learning, new parameters, and new inventories. LHASA 2.0 uses the XGBoost machine learning model to bring in dynamic variables as well as additional static variables to better represent landslide hazard globally. Global rainfall forecasts are also being evaluated to provide a 1-3 day forecast of potential landslide activity. Additional factors such as recent seismicity and burned areas are also being considered to represent the preconditioning or changing interactions with subsequent rainfall over affected areas. A series of parameters are being tested within this structure using NASA’s Global Landslide Catalog as well as many other event-based and multi-temporal inventories mapped by the project team or provided by project partners.</p><p>In addition to estimates of landslide hazard, LHASA Version 2 will incorporate dynamic estimates of exposure including population, roads and infrastructure to highlight the potential impacts that rainfall-triggered landslides. The ultimate goal of LHASA Version 2.0 is to approximate the relative probabilities of landslide hazard and exposure across different space and time scales to inform hazard assessment retrospectively over the past 20 years, in near real-time, and in the future. In addition to the hazard. This presentation will outline the new activities for LHASA Version 2.0 and present some next steps for this system.</p>


2015 ◽  
Vol 15 (10) ◽  
pp. 2257-2272 ◽  
Author(s):  
D. B. Kirschbaum ◽  
T. Stanley ◽  
J. Simmons

Abstract. Landslides pose a serious threat to life and property in Central America and the Caribbean Islands. In order to allow regionally coordinated situational awareness and disaster response, an online decision support system was created. At its core is a new flexible framework for evaluating potential landslide activity in near real time: Landslide Hazard Assessment for Situational Awareness. This framework was implemented in Central America and the Caribbean by integrating a regional susceptibility map and satellite-based rainfall estimates into a binary decision tree, considering both daily and antecedent rainfall. Using a regionally distributed, percentile-based threshold approach, the model outputs a pixel-by-pixel nowcast in near real time at a resolution of 30 arcsec to identify areas of moderate and high landslide hazard. The daily and antecedent rainfall thresholds in the model are calibrated using a subset of the Global Landslide Catalog in Central America available for 2007–2013. The model was then evaluated with data for 2014. Results suggest reasonable model skill over Central America and poorer performance over Hispaniola due primarily to the limited availability of calibration and validation data. The landslide model framework presented here demonstrates the capability to utilize globally available satellite products for regional landslide hazard assessment. It also provides a flexible framework to interchange the individual model components and adjust or calibrate thresholds based on access to new data and calibration sources. The availability of free satellite-based near real-time rainfall data allows the creation of similar models for any study area with a spatiotemporal record of landslide events. This method may also incorporate other hydrological or atmospheric variables such as numerical weather forecasts or satellite-based soil moisture estimates within this decision tree approach for improved hazard analysis.


2021 ◽  
Author(s):  
Bastien Colas ◽  
Yannick Thiery ◽  
Yaël Guyomard ◽  
Mathieu Mengin ◽  
Olivier Monge ◽  
...  

<p>Requiring spatial and temporal quantified information on landslide hazard over a large area is a prerequisite to forecast them. However, in many cases, the quantification remains partial, because of a lack of information on the phenomena, on predisposing and triggering factors or because the scientific approaches used in research domain are complex to apply in a regulatory framework. Thus, in this context, for many sites and end-users, the documents produced by empirical methods are used, without quantification of hazards.</p><p>In 2019, a collaboration between the DIMENC Geological Survey Service of New-Caledonia (South-Pacific) and the BRGM planed the development of a global methodology of landslide hazard assessment at the 1:25,000 scale of work according to the recommendations of the JTC-1. Indeed, landslide hazard in New Caledonia is insufficiently assessed and few taken into account in land-use planning. However, this large mountainous island is regularly affected by different type of instabilities (i.e. rock-falls; rock-slides; slides; debris-flows) due to intense rainfalls. The consequences can be material and human, as in 2016 for the municipality of Houaïlou, where debris-flows occurred, inducing 5 deaths, 3 missing persons, 8 injuries along with large material damages. Few heuristic landslide hazard maps based on expert opinion are available, but the methodology is not homogeneous and harmonized. Therefore, even if these maps constitute a solid base of knowledge, their valorization for land use planning remains difficult.</p><p>To overcome these shortcomings, the methodology chosen is quantitative, taking into account the susceptibility of the territory (i.e. spatial probability of phenomena occurrence with discrimination of initiation and run-out), the temporal probability of occurrence (i.e. from diachronic analyses) and the phenomena intensity (i.e. through the considered velocity of runout and the potential of induced damages). The methodology is declined by type of phenomena and is based on a comprehensive inventory. Six main steps are defined with:</p><ul><li>An inventory of the events by visual remote sensing and field observations;</li> <li>Discriminated mapping of bedrock and surficial formations (i.e. regolith: weathered formations and gravitational deposits);</li> <li>Computation of each landslide initiation susceptibility by a bivariate method;</li> <li>Integration of the temporal occurrence probability;</li> <li>Computation of the phenomena runout by a numerical approach taking into account the reach angle;</li> <li>Integration of the intensity of the phenomena according to the estimated volumes and/or velocity to quantify landslide hazard.</li> </ul><p>The classes of spatial and temporal probabilities are based on the JTC-1 agreement and allow obtaining quantified hazard maps. The validation of the results is performed by a field validation, by phenomena not used for the computations, and by statistical tests. The method is tested in the municipality of Mont-Dore (643 km²), which was heavily impacted in 1988 by cyclone 'Anne'. Beyond the fact that the methodology will be applied throughout the territory in an operational framework and will allow the adaptation of local planning, the project allows the improvement of:</p><ul><li>Knowledge of the different kind of landslides in a volcano-sedimentary and metamorphic context strongly weathered;</li> <li>Knowledge of the regolith, which newly integrated for this type of analysis for the island’s municipalities.</li> </ul>


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Yuan-Chang Deng ◽  
Jin-Hung Hwang ◽  
Yu-Da Lyu

In this research, a real-time nowcasting system for regional landslide-hazard assessment under extreme-rainfall conditions was established by integrating a real-time rainfall data retrieving system, a landslide-susceptibility analysis program (TRISHAL), and a real-time display system to show the stability of regional slopes in real time and provide an alert index under rainstorm conditions for disaster prevention and mitigation. The regional hydrogeological parameters were calibrated using a reverse-optimization analysis based on an RGA (Real-coded Genetic Algorithm) of the optimization techniques and an improved version of the TRIGRS (Transient Rainfall Infiltration and Grid-based Regional Slope-Stability) model. The 2009 landslide event in the Xiaolin area of Taiwan, associated with Typhoon Morakot, was used to test the real-time regional landslide-susceptibility system. The system-testing results showed that the system configuration was feasible for practical applications concerning disaster prevention and mitigation.


2021 ◽  
Author(s):  
Thomas Stanley ◽  
Dalia Kirschbaum ◽  
Robert Emberson

<p>The Landslide Hazard Assessment for Situational Awareness system (LHASA) gives a global view of landslide hazard in nearly real time. Currently, it is being upgraded from version 1 to version 2, which entails improvements along several dimensions. These include the incorporation of new predictors, machine learning, and new event-based landslide inventories. As a result, LHASA version 2 substantially improves on the prior performance and introduces a probabilistic element to the global landslide nowcast.</p><p>Data from the soil moisture active-passive (SMAP) satellite has been assimilated into a globally consistent data product with a latency less than 3 days, known as SMAP Level 4. In LHASA, these data represent the antecedent conditions prior to landslide-triggering rainfall. In some cases, soil moisture may have accumulated over a period of many months. The model behind SMAP Level 4 also estimates the amount of snow on the ground, which is an important factor in some landslide events. LHASA also incorporates this information as an antecedent condition that modulates the response to rainfall. Slope, lithology, and active faults were also used as predictor variables. These factors can have a strong influence on where landslides initiate. LHASA relies on precipitation estimates from the Global Precipitation Measurement mission to identify the locations where landslides are most probable. The low latency and consistent global coverage of these data make them ideal for real-time applications at continental to global scales. LHASA relies primarily on rainfall from the last 24 hours to spot hazardous sites, which is rescaled by the local 99<sup>th</sup> percentile rainfall. However, the multi-day latency of SMAP requires the use of a 2-day antecedent rainfall variable to represent the accumulation of rain between the antecedent soil moisture and current rainfall.</p><p>LHASA merges these predictors with XGBoost, a commonly used machine-learning tool, relying on historical landslide inventories to develop the relationship between landslide occurrence and various risk factors. The resulting model relies heavily on current daily rainfall, but other factors also play an important role. LHASA outputs the probability of landslide occurrence on a grid of roughly one kilometer over all continents from 60 North to 60 South latitude. Evaluation over the period 2019-2020 shows that LHASA version 2 doubles the accuracy of the global landslide nowcast without increasing the global false alarm rate.</p><p>LHASA also identifies the areas where the human exposure to landslide hazard is most intense. Landslide hazard is divided into 4 levels: minimal, low, moderate, and high. Next, the number of persons and the length of major roads (primary and secondary roads) within each of these areas is calculated for every second-level administrative district (county). These results can be viewed through a web portal hosted at the Goddard Space Flight Center. In addition, users can download daily hazard and exposure data.</p><p>LHASA version 2 uses machine learning and satellite data to identify areas of probable landslide hazard within hours of heavy rainfall. Its global maps are significantly more accurate, and it now includes rapid estimates of exposed populations and infrastructure. In addition, a forecast mode will be implemented soon.</p>


2015 ◽  
Vol 3 (4) ◽  
pp. 2847-2882 ◽  
Author(s):  
D. B. Kirschbaum ◽  
T. Stanley ◽  
J. Simmons

Abstract. Landslides pose a serious threat to life and property in Central America and the Caribbean Islands. In order to allow regionally coordinated situational awareness and disaster response, an online decision support system was created. At its core is a new flexible framework for evaluating potential landslide activity in near real-time: Landslide Hazard Assessment for Situational Awareness. This framework was implemented in Central America and the Caribbean by integrating a regional susceptibility map and satellite-based rainfall estimates into a binary decision tree, considering both daily and antecedent rainfall. Using a regionally distributed, percentile-based threshold approach, the model outputs a pixel-by-pixel nowcast in near real-time at a resolution of 30 arcsec to identify areas of moderate and high landslide hazard. The daily and antecedent rainfall thresholds in the model are calibrated using a subset of the Global Landslide Catalog in Central America available for 2007–2013. The model was then evaluated with data for 2014. Results suggest reasonable model skill over Central America and poorer performance over Hispaniola, due primarily to the limited availability of calibration and validation data. The landslide model framework presented here demonstrates the capability to utilize globally available satellite products for regional landslide hazard assessment. It also provides a flexible framework to interchange the indiviual model components and adjust or calibrate thresholds based on access to new data and calibration sources. The availability of free, satellite-based near real-time rainfall data allows the creation of similar models for any study area with a spatiotemporal record of landslide events. This method may also incorporate other hydrological or atmospheric variables such as numerical weather forecasts or satellite-based soil moisture estimates within this decision tree approach for improved hazard analysis.


2018 ◽  
Vol 237 ◽  
pp. 217-228 ◽  
Author(s):  
Christian Ambrosi ◽  
Tazio Strozzi ◽  
Cristian Scapozza ◽  
Urs Wegmüller

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