Scientific challenges of research on natural hazards and disaster risk

As a discipline,the science of natural hazards and disaster risk aims to explain the spatial-temporal pattern,process and mechanism,emergency response and risk mitigation of natural hazards,which requires a multidisci-plinary and interdisciplinary approach.With the support of Natural Science Finance of China(NSFC)and Chinese Academy of Sciences(CAS),in-depth research and systematic analysis on natural hazards and disaster risk were conducted.In this paper,the state of the art in research on natural hazards is summarized from seven aspects:formation process,mechanism and dynamic of natural hazards,disaster risk assessment,forecast,monitoring and early warning,disaster mitigation,emergency treatment and rescue,risk management and post-disaster re-construction.The trends within the natural hazards and disaster risk as a discipline were identified,along with existing shortcomings and significant gaps that need to be addressed.This paper highlighted:1)the scientific challenges including the frontier scientific issues and technological gaps on natural hazards and disaster risk dis-cipline from 2025 to 2035 in China,and 2)the proposal to develop a systemic and holistic natural hazards and disaster risk discipline.

Natural hazards in Romania induced by heavy rainfalls in 1996-1997

Romania is one of the European countries most frequently affected by natural hazards due to its position within the alpine orogenic system and against the main atmospheric pressure centres.Hence the impact of exogenous factors that trigger strong earthquakes with several epicentres, and of exogenous or climate-driven factors with extreme climatic phenomena causing frequent floods, mass movements, soil erosion, droughts, hailstorms and strong winds. This paper deals mainly with natural disasters cased by the variability of climatic conditions (mostly by precipitations) in the years 1996 and 1997, their temporal and spatial distributions and the way they affected human life. In point of rainfall distribution and the ensuing natural hazards, the mentioned period shows two distinct intervals: December, 1996-March 1997 (mass movements) and June-August, 1997 (floods, hailstorm,Strong wind,landslides, soil erosion).

The Insurance Market of Natural Hazards for Residential Properties in Italy

Insurance is an effective complementary countermeasure for unexpected losses brought about by natural hazards. Coverage can be a useful tool considering in particular that public funds available to compensate for damages are limited and the consequences of catastrophes are becoming more severe over the time. Bearing this in mind, the authors performed a study aiming to clear up the main aspects and limits of the insurance market of natural hazards for residential properties in Italy. The opening sections of the paper give an overview of both the historical extreme events in Europe and Italy, and the reasons for the low insurance penetration rate in Italy. After that, the paper goes to the core of the research casting light upon the insurance market in Italy and examining the features and possible drawbacks of the available insurance covers. In this paper, the geophysical (seismic and volcanic) and hydrological (landslide and flood) hazards are analysed, and the residential stock is taken as a reference. After deepening in the local insurance market, the research focuses on the possible suggestions to stakeholders of how to increase the insurance penetration rate by taking advantage of the international experiences.

Social Vulnerability to Natural Hazards in Brazil

Although social vulnerability has recently gained attention in academic studies, Brazil lacks frameworks and indicators to assess it for the entire country.Social vulnerability highlights differences in the human capacity to prepare for, respond to, and recover from disasters. It varies over space and time, and among and between social groups, largely due to differences in socioeconomic and demographic characteristics. This article provides a social vulnerability index(SoVI~) replication study for Brazil and shows how SoVI~concepts and indicators were adapted to the country. SoVI~Brazil follows the place-based framework adopted in the Social Vulnerability Index initially developed for the United States. Using a principal component analysis(PCA), 45city-level indicators were reduced to 10 factors that explain about 67 % of the variance in the data. Clearly identified spatial patterns showed a concentration of the most socially vulnerable cities in the North and Northeast regions of Brazil, as well as the social vulnerability of metropolitan areas and state capitals in the South and Southeast regions.The least vulnerable cities are mainly concentrated in the inland regions of the Southeast. Although different factors contribute to the social vulnerability in each city, the overall results confirm the social and economic disparities among Brazilian’s regions and reflect a differential vulnerability to natural hazards at local to regional scales.

Beyond the Expected-Residual Risk and Cases of Overload in the Context of Managing Alpine Natural Hazards

Structural protection measures are designed to protect the population and infrastructure against natural hazards up to a specific predefined protection goal.Extreme events with intensities that exceed the capacity of these protection structures are called“cases of overload”and are associated with“residual risks”that remain after the implementation of protection measures.In order to address residual risks and to reduce the damages from overload events,a combination of structural protection measures with additional,nonstructural measures is required.Based on data collected through a literature review,a questionnaire survey,expert interviews,and an expert workshop we highlight the status quo as well as key challenges of dealing with residual risks and cases of overload in Alpine countries in the context of geohydrological hazards and gravitational mass movements.We present a holistic conceptual framework that describes the relationships of residual risks,cases of overload,and protection goals in the context of both risk governance and integrated risk management.This framework is valuable for decision makers aiming at an improved management of natural hazards that takes adequate account of residual risk and cases of overload in Alpine countries and mountain areas worldwide.

Distributed Simulation Platforms and Data Passing Tools for Natural Hazards Engineering: Reviews, Limitations,and Recommendations

here has been a strong need for simulation environments that are capable of modeling deep interdependencies between complex systems encountered during natural hazards,such as the interactions and coupled effects between civil infrastructure systems response,human behavior,and social policies,for improved community resilience.Coupling such complex components with an integrated simulation requires continuous data exchange between different simulators simulating separate models during the entire simulation process.This can be implemented by means of distributed simulation platforms or data passing tools.In order to provide a systematic reference for simulation tool choice and facilitating the development of compatible distributed simulators for deep interdependent study in the context of natural hazards,this article focuses on generic tools suitable for integration of simulators from different fields but not the platforms that are mainly used in some specific fields.With this aim,the article provides a comprehensive review of the most commonly used generic distributed simulation platforms(Distributed Interactive Simulation(DIS),High Level Architecture(HLA),Test and Training Enabling Architecture(TENA),and Distributed Data Services(DDS))and data passing tools(Robot Operation System(ROS)and Lightweight Communication and Marshalling(LCM))and compares their advantages and disadvantages.Three specific limitations in existing platforms are identified from the perspective of natural hazard simulation.For mitigating the identified limitations,two platform design recommendations are provided,namely message exchange wrappers and hybrid communication,to help improve data passing capabilities in existing solutions and provide some guidance for the design of a new domain-specific distributed simulation framework.

Capacities in Facing Natural Hazards: A Small Island Perspective

Isolated communities on small islands are often characterized as vulnerable and marginalized. We studied the recent history of Laingpatehi, a village on Ruang Island off the north coast of Sulawesi, Indonesia to show that the marginalization-vulnerability nexus can be offset by capacity and social cohesion to enable sustainable livelihoods. The island has been impacted by volcanic eruptions,earthquakes, and competition for marine resources from mainland-based fishermen. The community has shown a remarkable ability to cope and prosper in the face of a series of external hazards. We used a sustainable livelihoods approach to identify the assets that enabled the villagers to cope. Strong social cohesion was central to the ability to organize the community and confront hazards. A diversified livelihood strategy drawing on the small island environment and its coastal and marine resources, income generating activities in a distant satellite village, and significant remittances from employment in other parts of Indonesia underpinned people’s capacities to face hazards.Government assistance played a supporting role. The case of Laingpatehi demonstrates how remoteness, rather than being a source of vulnerability, can provide access to existing resources and facilitate innovation. Disaster risk reduction strategies should focus more on reinforcing these existing capacities to deal with hazards and less on physical protection and postdisaster responses.

The Challenging Place of Natural Hazards in Disaster Risk Reduction Conceptual Models:Insights from Central Africa and the European Alps

Based on a literature review and two case studies,this article presents the difficulties inherent in the main disaster risk reduction conceptual models.The method used to highlight such evidence is to compare two programs on disaster risk reduction with mainstream conceptual models.The authors participated in these programs,which were confronted with the need to integrate contributions and insights from both earth and social sciences.Our analysis found that the existing main conceptual models were unable to do justice to disaster risk reduction needs.This finding encouraged us to critique these models.Further effort led us to present possible solutions to compensate for the shortcomings of current models while taking into account the contextualization and dynamics of phenomena,as well as grappling with the more explicit integration of hazards and hazard risk into model design.

HINA'S MOST DESTRUCTIVE NATURAL HAZARDS IN 1994

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Application of BeiDou navigation satellite system in emergency rescue of natural hazards: a case study for field geological survey of Qinghai−Tibet plateau

In recent years,geological and mineral resources exploration in China has expanded to deep hinterland of the Qinghai−Tibet Plateau and other regions with complex geological conditions.The special natural conditions of Qinghai−Tibet Plateau determine the characteristics of“life-forbidden zone”that is characterized by alpine hypoxia,changeable weather,complex road conditions,and beast attack.In particular,the work in wild depopulated zones with severe environment and poor communications imposes serious threats to the life safety of geological personnel.Therefore,how to guarantee the safety of geological personnel working on the Qinghai−Tibet Plateau and how to reduce or even avoid casualty of geological personnel have currently become the urgent challenge.In this study,an emergency rescue information system for field geological survey is constructed based on BeiDou Navigation Satellite System.A case study of emergency rescue has been conducted in the depopulated zone of the Qinghai−Tibet Plateau and good effects have been achieved,providing security assurance for personnel engaged in field geological survey on the Qinghai−Tibet Plateau and technical support for the emergency rescue in case of natural hazards on the Qinghai−Tibet Plateau.The BeiDou Navigation Satellite System(BDS)can be effectively used to locate and communicate in the emergency rescue for rigorous Geological survey task where there is no network signal for the mobile phone,and the emergency rescue guarantee system is independent,reliable,and relatively cheap.The application value of BDS is demonstrated in the geological field.

Cartographic-Environmental Analysis of the Landscape in Natural Protected Parks for His Management Using GIS.Application to the Natural Parks of the“Las Batuecas-Sierra de Francia”and“Quilamas”(Central System,Spain)

In this work we report a methodological procedure with an integrated physical-perceptual approach that allows units of landscape in protected natural areas to be differentiated. First, indirect methods were applied by means of a mapping procedure, which identified the physical components of major relevance. We then generated maps of natural units, anlyzing the “printed” landscape of a territory. Secondly, we developed direct methods to identify and describe the reresentative elements of the landscape, analyzing the “perceived” landscape. The identification and delimitation of these landscape units with geographical information systems provide detailed maps facilitate the tasks of planning and management. The procedure was validated by means of its application in two protected natural spaces. The treatment used here considers landscape not only as an aesthetic element but also as something “live” elaborating maps that should be of use in land planning and management of natural areas.

Opinion: the use of natural hazard modeling for decision making under uncertainty

Decision making to mitigate the effects of natural hazards is a complex undertaking fraught with uncertainty. Models to describe risks associated with natural hazards have proliferated in recent years. Concurrently, there is a growing body of work focused on developing best practices for natural hazard modeling and to create structured evaluation criteria for complex environmental models. However, to our knowledge there has been less focus on the conditions where decision makers can confidently rely on results from these models. In this review we propose a preliminary set of conditions necessary for the appropriate application of modeled results to natural hazard decision making and provide relevant examples within US wildfire management programs.

Tornado Impacts in the US from 1950-2015: A GIS-Based Analysis of Vulnerability and Evolving Risk Zones for Human Casualties

The United States is one of the major countries in the world that faces a numerous number of tornadoes every year, directly and indirectly experiencing extensive property damage and human casualties as well as a variety of demographic, socioeconomic, and environmental impacts. This research provides a GIS-based examination of the ways past tornadoes that occurred in the US in the period 1950-2015 have played out in the context of bodily injuries and loss of human life. To this end, the research collected major secondary data (i.e., georeferenced tornado point data) from the Storm Prediction Center (SPC) tornado database and conducted raster-based spatial analysis, utilizing techniques like point density analysis and map algebra to locate areas that have a high risk of tornadoes and to create maps that show relationships between the past tornado events and human casualties. One of the major research findings shown by the spatial analysis was that the geographic areas or regions impacted by tornadoes varied over time. In addition, the statistical results showed a trend that the tornado-prone regions extend from “Tornado Alley” to the states of Illinois, Mississippi, Tennessee, Alabama, and Florida, indicating that the communities in those states that are newly considered to be vulnerable to tornadoes should step up to develop their own tornado mitigation plan to help protect the public and its property from tornadoes. Such plans can play a crucial role in safeguarding the public and protecting property from tornadoes’ potential impact. Additionally, urban planners and policymakers can use this information to make informed decisions about building codes and infrastructure development in tornado-prone areas, potentially reducing the impact of future tornado events on human lives and property.

A novel index to evaluate discretization methods: A case study of flood susceptibility assessment based on random forest

The selection of a suitable discretization method(DM) to discretize spatially continuous variables(SCVs)is critical in ML-based natural hazard susceptibility assessment. However, few studies start to consider the influence due to the selected DMs and how to efficiently select a suitable DM for each SCV. These issues were well addressed in this study. The information loss rate(ILR), an index based on the information entropy, seems can be used to select optimal DM for each SCV. However, the ILR fails to show the actual influence of discretization because such index only considers the total amount of information of the discretized variables departing from the original SCV. Facing this issue, we propose an index, information change rate(ICR), that focuses on the changed amount of information due to the discretization based on each cell, enabling the identification of the optimal DM. We develop a case study with Random Forest(training/testing ratio of 7 : 3) to assess flood susceptibility in Wanan County, China.The area under the curve-based and susceptibility maps-based approaches were presented to compare the ILR and ICR. The results show the ICR-based optimal DMs are more rational than the ILR-based ones in both cases. Moreover, we observed the ILR values are unnaturally small(<1%), whereas the ICR values are obviously more in line with general recognition(usually 10%–30%). The above results all demonstrate the superiority of the ICR. We consider this study fills up the existing research gaps, improving the MLbased natural hazard susceptibility assessments.

Estimation of Ground Deformation in Landslide Prone Areas Using GPS: A Case Study of Bududa, Uganda

Landslides are a frequent phenomenon on mountain Elgon, particularly in Bududa district on the SW side of this extinct shield volcano. Landslides have led to the destruction of property and loss of life we, therefore, need to monitor them. Monitoring how landslides build-up makes it possible to timely evacuate people and build barriers to protect property against damage by landslides. Residents in Bududa have reported cracks developing in the ground and houses. These cracks continue to grow, suggesting a future catastrophic event. Such an event may resemble the 2010 landslide in Bududa, which killed approximately 450 people and destroyed much property. In order to mitigate the consequences of a new landslide as much as possible, we monitored ground motion in Bududa in eleven stations from June 2018 to June 2019. Six-hour session GPS observations were made, and deformation was determined over the observation period, June to September 2018, September to November 2018, November 2018 to February 2019 and February to June 2019. A congruency test was performed to determine how significant the deformation was. It appeared that the ground deformation differed largely at various monitored stations, ranging from 0.004 to 0.076 m, 0.001 to 0.067 m and 0 to 0.078 m in the East, North and vertical directions respectively. The values indicate that most slopes in the district are unstable, particularly in the wet seasons, which implies that future landslides pose a high risk for society.

Detecting abrupt change in land cover in the eastern Hindu Kush region using Landsat time series(1988-2020)

Land cover change in the semi-arid environment of the eastern Hindu Kush region is driven by anthropogenic activities and environmental change impacts. Natural hazards, such as floods presumably influenced by climatic change, cause abrupt change of land cover. So far, little research has been conducted to investigate the spatiotemporal aspects of this abrupt change in the valleys. In order to explore the abrupt change in land cover and floods as its possible drivers in the eastern Hindu Kush, a semi-arid mountain region characterized by complex terrain, vegetation variation, and precipitation seasonality, we analyzed long-term Landsat image time series from 1988 to 2020 using Breaks For Additive Seasonal and Trend(BFAST). Overall, BFAST effectively detected abrupt change by using Landsat-derived Modified Soil Adjusted Vegetation Index(MSAVI). The results of our study indicate that approximately 95% of the study area experienced at least one abrupt change during 1988-2020. The years 1991, 1995, 1998, 2007, and 2016 were detected as the peak years, with the peaks occurring in different seasons. The annual trend of abrupt change is decreasing for the study area. The seasonality of abrupt change at the catchment level shows an increasing trend in the spring season for the southern catchments of Panjkora and Swat. The spatial distribution patterns show that abrupt change is primarily concentrated in the floodplains indicating that flooding is the primary driver of the land cover change in the region. We also demonstrated the accurate detection of past flood events(2015) based on the two case examples of Ayun, Rumbur, and Kalash valleys. The detection of the flood events was verified by fieldwork and historical high-resolution Google Earth imagery. Finally, our study provides an example of applying Landsat time series in a dry mountain region to detect abrupt changes in land cover and analyze impact of natural hazards such as floods.

Numerical modeling of bed deposition in rapid flow-like landslides:a case study of the Gaolou landslide in Shaanxi Province,China

Some flow-like landslides tend to lose materials while moving on a relatively dry sliding surface.This phenomenon is called bed deposition.In contrast to the bed entrainment phenomenon,bed deposition is relatively poorly understood.Therefore,an improved depth-averaged model is proposed to quantify this phenomenon.The deposition depth is calculated according to the momentum conservation of the deposited mass,and the rheological property of the sliding mass on the bottom is modified considering an abrupt increase in the depth of the sliding surface after deposition.Utilizing the proposed model,the Gaolou landslide,a typical flowlike landside occurring on October 6 th,2006 with an obvious bed deposition phenomenon in Shaanxi Province of China,is simulated to investigate the influence of bed deposition on its propagation process.The results indicate that the proposed model can effectively depict the bed deposition phenomenon in the Gaolou landslide.Bed deposition dissipates part of the kinetic energy of this landslide;thus,the simulated debris inundation area would likely be overestimated when this effect is neglected.On the other hand,the thin liquefied layer formed by the bed deposition process reduces the friction energy dissipation,contributing to the high mobility of this landslide.

Multitemporal landslide inventory analysis of an intertropical mountain in west-central Mexico——Basis for hazard management

Landslides in intertropical mountainous areas of Mexico are a natural hazard that could potentially generate a disaster. Despite this, many areas lack landslide inventories, making it difficult to monitor and efficiently manage the associated risks for local populations. For this reason, the aim of this research was to undertake a multitemporal landslide inventory and analyze its conditioning factors in the Pico de Tancítaro stratovolcano, which, in recent decades, has presented several high-risk geomorphological events with disastrous consequences for nearby localities. The spatial distribution of landslides and its conditioning factors were mapped at a 1:50,000 scale for the 1995-2020 period, through visual interpretation of orthophotos and satellite images(Landsat, SPOT, and SENTINEL). The conditioning factors that link the most to landslides were Quaternary andesite and basaltic andesite rocks;volcanic cones, mountain river valleys, and very steep to steep slopes(30° to >45°), oriented to the South, North, and East;Andosols and Leptosols;and the oyamel fir and mixed forests. 505 landslide events classified into slides and flows that occurred in 1995, 2004, 2010, and 2015 were identified. New scars generated by the reactivation of landslide processes were also observed. The landslides in the study area were triggered by torrential rains caused by hurricanes and tropical storms;such as hurricanes Alex and Patricia. The inventory and analysis of conditioning factors highlighted the distribution and dynamics of slides and flows in the study area. In addition, the most important factors for studies of landslide susceptibility, hazards, and risks in the Pico de Tancítaro stratovolcano were identified, contributing to the management of geomorphological risks in intertropical mountain areas.

Palaeoseismic Events in Karst Terrains along the Northern Bulgarian Black Sea Coast

The study of the palaoseismic events in the karst terrains of the Bulgarian Black Sea coast is a very important up-to-date problem. The investigated region is one of the highest-energy regions in Bulgaria with established and recorded catastrophic historic and contemporary earthquakes. The terrain is subjected to the influence not only of its own earthquake foci but also of those in Romania and Russia. The palaeoearthquakes that caused considerable disturbances in the karst terrains along the Northern Bulgarian Black Sea coast have left significant traces. They caused disturbances in the environment and the relief (rearrangement of the surface and ground water karst basins, partially or entirely collapsed caves, deformed caves, oil, gas and salt intrusions and gravitationally formed caves). The ecological consequences in historic and contemporary aspects were catastrophic. The palaeoseismic dislocations were formed as a result of global, regional and local geodynamic events related with the destruction of the Moezian platform and the regional extension of the Black Sea basin. The time of their display and their spatial interrelations were established as a result of complex investigations accompanied by original documents.

Geophysical Investigation of the Triassic Salt Material Hazard: El Fahs Case Example (Northern Tunisia)

The Tunisian territory (area of diapirs) is exposed to the risks of ground movements linked to water, some of which are related to the phenomenon of dissolution of gypsum, allowing the appearance of underground cavities which present natural risks and set people in danger. The analysis of the hazard was determined by the field study coupled with the application of geophysical methods to locate and map the cavities and identify their dimensions and their positions in the subsoil. In the region of El Fahs (40 km NW of Tunis): we used a non-destructive method, georadar (GPR) with a 200 MHz antenna band-width, and an electric method, by using the electric tomography of which we have applicated the sequence of dipole-dipole measurement. The results ob-tained were examined and interpreted according to 2D profiles. The geophysi-cal methods of GPR and electrical tomography aim to detect many calvities in different depths. However, the geological radar was able to identify several cavities and the zones of dissolution whose investigation depth did not exceed the first 3 meters. On the contrary, the electric tomography method allowing the presence of several deeper underground cavities with larger dimensions ex-tended to 64 meters. To conclude, the geological and hydrogeological contexts of the terrain studied and on the state of the soil and subsoil allow us to better understanding the mechanisms of the establishment of the dissolution phe-nomenon and the appearance of cavities in the basement. The analysis of the predisposing factors present in the study area shows that the geodynamic con-text of the Triassic ascent takes place according to a precise thermodynamic process that favors the phenomenon of dissolution of the gypsum.