Natural Hazards and Earth System Sciences最新文献

{"title":"Semi-automatic mapping of shallow landslides using free Sentinel-2 images and Google Earth Engine","authors":"D. Notti, M. Cignetti, D. Godone, D. Giordan","doi":"10.5194/nhess-23-2625-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2625-2023","url":null,"abstract":"Abstract. The global availability of Sentinel-2 data and the widespread coverage of cost-free and high-resolution images nowadays give opportunities to map, at a low cost, shallow landslides triggered by extreme events (e.g. rainfall, earthquakes). Rapid and low-cost shallow landslide mapping could improve damage estimations, susceptibility models and land management. This work presents a two-phase procedure to detect and map shallow\u0000landslides. The first is a semi-automatic methodology allowing for mapping\u0000potential shallow landslides (PLs) using Sentinel-2 images. The PL aims to\u0000detect the most affected areas and to focus on them an high-resolution mapping and further investigations. We create a GIS-based and user-friendly methodology to extract PL based on pre- and post-event normalised difference vegetation index (NDVI) variation and\u0000geomorphological filtering. In the second phase, the semi-automatic\u0000inventory was compared with a benchmark landslide inventory drawn on\u0000high-resolution images. We also used Google Earth Engine scripts to\u0000extract the NDVI time series and to make a multi-temporal analysis. We apply this procedure to two study areas in NW Italy, hit in 2016 and 2019 by extreme rainfall events. The results show that the semi-automatic mapping based on Sentinel-2 allows for detecting the majority of shallow landslides larger than satellite ground pixel (100 m2). PL density and distribution match well with the benchmark. However, the false positives (30 % to 50 % of cases) are challenging to filter, especially when they\u0000correspond to riverbank erosions or cultivated land.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49126009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in heat and cold wave risks for the Italian Trentino-Alto Adige region from 1980 to 2018","authors":"M. Morlot, S. Russo, L. Feyen, G. Formetta","doi":"10.5194/nhess-23-2593-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2593-2023","url":null,"abstract":"Abstract. Heat waves (HWs) and cold waves (CWs) can have considerable impact on\u0000people. Mapping risks of extreme temperature at local scale, accounting for\u0000the interactions between hazard, exposure, and vulnerability, remains a\u0000challenging task. In this study, we quantify risks from HWs and CWs for the\u0000Trentino-Alto Adige region of Italy from 1980 to 2018 at high spatial\u0000resolution. We use the Heat Wave Magnitude Index daily (HWMId) and the Cold\u0000Wave Magnitude Index daily (CWMId) as the hazard indicators. To obtain HWs\u0000and CW risk maps we combined the following: (i) occurrence probability maps of the hazard\u0000obtained using the zero-inflated Tweedie distribution (accounting directly\u0000for the absence of events for certain years), (ii) normalized population\u0000density maps, and (iii) normalized vulnerability maps based on eight\u0000socioeconomic indicators. The methodology allowed us to disentangle the\u0000contributions of each component of the risk relative to total change in\u0000risk. We find a statistically significant increase in HW hazard and\u0000exposure, while CW hazard remained stagnant in the analyzed area over the\u0000study period. A decrease in vulnerability to extreme temperature spells is\u0000observed through the region except in the larger cities where vulnerability\u0000increased. HW risk increased in 40 % of the region, with the increase\u0000being greatest in highly populated areas. Stagnant CW hazard and declining\u0000vulnerability result in reduced CW risk levels overall, except for the four\u0000main cities where increased vulnerability and exposure increased risk\u0000levels. These findings can help to steer investments in local risk\u0000mitigation, and this method can potentially be applied to other regions\u0000where there are sufficient detailed data.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42088730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of thermokarst evolution in debris flow initiation (Hüttekar Rock Glacier, Austrian Alps)","authors":"Simon Seelig, T. Wagner, K. Krainer, M. Avian, M. Olefs, K. Haslinger, G. Winkler","doi":"10.5194/nhess-23-2547-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2547-2023","url":null,"abstract":"Abstract. A rapid sequence of cascading events involving thermokarst lake outburst, local rock glacier front failure, debris flow development, and river blockage hit Radurschl Valley (Ötztal Alps, Tyrol) on 13 August 2019. Compounding effects from permafrost degradation and drainage network development within the rock glacier initiated the complex process chain. The debris flow dammed the main river of the valley, impounding a water volume of 120 000 m3 that was partly drained by excavation to prevent a potentially catastrophic outburst flood. We present a systematic analysis of destabilizing factors to deduce the failure mechanism. The identification and evaluation of individual factors reveals a critical combination of topographical and sedimentological disposition, climate, and weather patterns driving the evolution of a thermokarst drainage network. Progressively changing groundwater flow and storage patterns within the frozen sediment accumulation governed the slope stability of the rock glacier front. Our results demonstrate the hazard potential of active rock glaciers due to their large amount of mobilizable sediment, dynamically changing internal structure, thermokarst lake development, and substantial water flow along a rapidly evolving channel network.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41859731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review article: Snow and ice avalanches in high mountain Asia – scientific, local and indigenous knowledge","authors":"A. Acharya, J. Steiner, K. M. Walizada, Salarpouri Ali, Z. Zakir, A. Caiserman, Teiji Watanabe","doi":"10.5194/nhess-23-2569-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2569-2023","url":null,"abstract":"Abstract. The cryosphere in high mountain Asia (HMA) not only sustains the livelihoods of people residing downstream through its capacity to store water but also holds the potential for hazards. One of these hazards, avalanches, so far remains inadequately studied, as the complex relationship between climate and potential triggers is poorly understood due to lack of long-term observations, inaccessibility, severe weather conditions, and financial and logistical constraints. In this study, the available literature was reviewed covering the period from the late 20th century to June 2022 to identify research and societal gaps and propose future directions of research and mitigation strategies. Beyond scientific literature, technical reports, newspapers, social media and other local sources were consulted to compile a comprehensive, open-access and version-controlled database of avalanche events and their associated impacts. Over 681 avalanches with more than 3131 human fatalities were identified in eight countries of the region. Afghanistan has the highest recorded avalanche fatalities (1057), followed by India (952) and Nepal (508). Additionally, 564 people lost their lives while climbing peaks above 4500 m a.s.l., one-third of which were staff employed as guides or porters. This makes it a less deadly hazard than in the less populated European Alps, for example, but with a considerably larger number of people affected who did not voluntarily expose themselves to avalanche risk. Although fatalities are significant, and local long-term impacts of\u0000avalanches may be considerable, so far, limited holistic adaptation or\u0000mitigation measures exist in the region. These measures generally rely on\u0000local and indigenous knowledge adapted to modern technologies. Considering\u0000the high impact avalanches have in the region, we suggest to further develop adaptation measures including hazard zonation maps based on datasets of historic events and modelling efforts. This should, however, happen acknowledging the already existing knowledge in the region and in close coordination with communities, local government and civil society stakeholders. More research studies should also be attempted to understand the trends and drivers of avalanches in the region.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42505313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meteotsunami in the United Kingdom: the hidden hazard","authors":"Clare Lewis, Tim Smyth, David Williams, Jess Neumann, H. Cloke","doi":"10.5194/nhess-23-2531-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2531-2023","url":null,"abstract":"Abstract. This paper examines the occurrence and seasonality of meteotsunami in the\u0000United Kingdom (UK) to present a revised and updated catalogue of events\u0000that have occurred since 1750. Previous case studies have alluded to a summer\u0000prevalence and rarity of this hazard in the UK. We have verified and\u0000classified 98 events using a developed set of identification criteria. The\u0000results have revealed a prominent seasonal pattern of winter events which\u0000are related to mid-latitude depressions with precipitating convective\u0000weather systems. A geographical pattern has also emerged, highlighting three\u0000“hotspot” areas at the highest risk from meteotsunami. The evidence\u0000reviewed and new data presented here show that the hazard posed by\u0000meteotsunami has been underestimated in the UK.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48694563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Criteria-based visualization design for hazard maps","authors":"Max Schneider, F. Cotton, P. Schweizer","doi":"10.5194/nhess-23-2505-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2505-2023","url":null,"abstract":"Abstract. Probabilistic seismic hazard estimates are a key ingredient of earthquake risk mitigation strategies and are often communicated through seismic hazard maps. Though the literature suggests that visual design properties are key for effective communication using such maps, guidelines on how to optimally design hazard maps are missing from the literature. Current maps use color palettes and data classification schemes which have well-documented limitations that may inadvertently miscommunicate seismic hazard. We surveyed the literature on color and classification schemes to identify design criteria that have empirical support for communicating hazard information. These criteria were then applied to redesign the seismic hazard map for Germany. We established several communication goals for this map, including essential properties about moderate-hazard seismic regions and a critical hazard threshold related to the German seismic building codes. We elucidate our redesign process and the selection of new colors and classification schemes that satisfy the evidence-based criteria. In a mixed-methods survey, we evaluate the original and redesigned seismic hazard maps, finding that the redesign satisfies all the communication goals and improves users’ awareness about the spatial spread of seismic hazard relative to the original. We consider practical implications for the design of hazard maps across the natural hazards.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46764263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A neural network model for automated prediction of avalanche danger level","authors":"Vipasana Sharma, Sushil Kumar, R. Sushil","doi":"10.5194/nhess-23-2523-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2523-2023","url":null,"abstract":"Abstract. Snow avalanches cause danger to human lives and property\u0000worldwide in high-altitude mountainous regions. Mathematical models based on past data records can predict the danger level. In this paper, we are\u0000proposing a neural network model for predicting avalanches. The model is\u0000trained with a quality-controlled sub-dataset of the Swiss Alps. Training\u0000accuracy of 79.75 % and validation accuracy of 76.54 % have been\u0000achieved. Comparative analysis of neural network and random forest models\u0000concerning metrics like precision, recall, and F1 has also been carried out.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44605677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region","authors":"Melissa Wood, I. Haigh, Quan Le, H. Nguyen, Hoang Tran, S. Darby, R. Marsh, N. Skliris, J. Hirschi, R. Nicholls, N. Bloemendaal","doi":"10.5194/nhess-23-2475-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2475-2023","url":null,"abstract":"Abstract. Coastal floods, driven by extreme sea levels, are one of the most dangerous\u0000natural hazards. The people at highest risk are those living in low-lying\u0000coastal areas exposed to tropical-cyclone-forced storm surges. Here we\u0000apply a novel modelling framework to estimate past and/or present and future storm-surge-level and extreme-sea-level probabilities along the coastlines of southern\u0000China, Vietnam, Cambodia, Thailand, and Malaysia. A regional hydrodynamic\u0000model is configured to simulate 10 000 years of synthetic tropical cyclone\u0000activity, representative of a past/present (1980–2017) and high-emission-scenario future (2015–2050) period. Results show that extreme storm surges, and therefore total water levels, will increase substantially in the coming decades, driven by an increase in the frequency of intense tropical\u0000cyclones. Storm surges along the southern Chinese and northern and southern Vietnamese\u0000coastlines increase by up to 1 m, significantly larger than expected changes in mean sea-level rise over the same period. The length of coastline that is presently exposed to storm surge levels of 2.5 m or greater will more than double by 2050. Sections of Cambodian, Thai, and Malaysian coastlines are projected to experience storm surges (at higher return periods) in the\u0000future, not previously seen, due to a southward shift in tropical cyclone\u0000tracks. Given these findings, coastal flood management and adaptation in\u0000these areas should be reviewed for their resilience against future extreme\u0000sea levels.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41490100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing Typhoon Soulik-induced morphodynamics over the Mokpo coastal region in South Korea based on a geospatial approach","authors":"Sang-Guk Yum, Moon-Soo Song, M. Adhikari","doi":"10.5194/nhess-23-2449-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2449-2023","url":null,"abstract":"Abstract. The inner shelf and coastal region of the Yellow Sea along the Korean\u0000Peninsula are frequently impacted by typhoons. The Mokpo coastal region in\u0000South Korea was significantly affected by Typhoon Soulik in 2018, the\u0000deadliest typhoon strike to the southwestern coast since Typhoon Maemi in 2003.\u0000Typhoon Soulik overran the region, causing extensive damage to the coast,\u0000shoreline, vegetation, and coastal geomorphology. Therefore, it is important to investigate its impact on the coastal ecology, landform,\u0000erosion/accretion, suspended-sediment concentration (SSC), and associated\u0000coastal changes along the Mokpo region. In this study, the net shoreline movement (NSM), normalized difference\u0000vegetation index (NDVI), fractional vegetation coverage (FVC), coastal-landform change model, normalized difference suspended-sediment index\u0000(NDSSI), and SSC–reflectance relation have been used to analyze the coastal\u0000morphodynamics over the typhoon periods. We used pre- and post-typhoon\u0000Sentinel-2 MultiSpectral Instrument (MSI) images for mapping and monitoring the typhoon effect and\u0000recovery status of the Mokpo coast through short- and medium-term coastal-change analysis. The findings highlighted the significant impacts of\u0000typhoons on coastal dynamics, wetland vegetation, and sediment resuspension\u0000along the Mokpo coast. It has been observed that typhoon-induced SSC\u0000influences shoreline and coastal morphology. The outcome of this research\u0000may provide databases to manage coastal environments and a long-term plan to restore valuable coastal habitats. In addition, the findings may be useful for post-typhoon emergency response, coastal planners, and administrators involved in the long-term development of human life.","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46358022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brief communication: Towards a universal formula for the probability of tornadoes","authors":"R. Ingrosso, P. Lionello, M. Miglietta, G. Salvadori","doi":"10.5194/nhess-23-2443-2023","DOIUrl":"https://doi.org/10.5194/nhess-23-2443-2023","url":null,"abstract":"Abstract. A methodological approach is proposed to provide an analytical (exponential-like) expression for the probability of occurrence of tornadoes as a function of the convective available potential energy and the wind shear (or, alternatively, the storm relative helicity). The resulting expression allows the probability of tornado occurrence to be calculated using variables that are computed by weather prediction and climate models, thus compensating for the lack of resolution needed to resolve these phenomena in numerical simulations.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48048047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}