Natural Hazards and Earth System Sciences最新文献

{"title":"Characteristics and mechanisms of near-surface negative atmospheric electric field anomalies preceding the 5 September 2022, Ms 6.8 Luding earthquake in China","authors":"Lixin Wu, Xiao Wang, Yuan Qi, J. Lu, Wenfei Mao","doi":"10.5194/nhess-24-773-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-773-2024","url":null,"abstract":"Abstract. A magnitude 6.8 strike-slip earthquake (EQ) struck Luding, Sichuan Province, China, on 5 September 2022, resulting in significant damage to nearby Ganzi Prefecture and the city of Ya'an. In this research, the near-surface atmospheric electric field (AEF) recorded at four sites 15 d before the Luding EQ was analyzed and differentiated, and multisource auxiliary data including precipitation, cloud base height, and low cloud cover were used at the same time. Nine possible seismic AEF anomalies at four sites were obtained preliminarily. Accordingly, microwave brightness temperature (MBT) data, which are very sensitive to the surface dielectrics and are closely related to the air ionization, together with surface soil moisture, lithology, and a 3D-simulated crustal stress field, were jointly analyzed to confirm the seismic relations of the obtained negative AEF anomalies. The geophysical environment for crustal high-stress concentration, positive charge carrier transfer, and surface accumulation was demonstrated to exist and to meet the conditions necessary to generate local negative AEF anomalies. Furthermore, to deal with the spatial disparities in sites and regions with potential atmospheric ionization, near-surface wind field data were employed to scrutinize the reliability of the AEF anomalies by comprehensively analyzing the spatial relationships among surface charges accumulation areas, wind direction and speed, and the AEF sites. Finally, four negative AEF anomalies were deemed to be closely related to the Luding EQ, and the remaining five possible anomalies were ruled out. A possible mechanism of negative AEF anomalies before the Luding EQ is proposed: positive charge carriers were generated from the underground high-stress concentration areas and then transferred to and accumulated on the ground surface to ionize the surface air, thus disturbing the AEF above the ground. This study presents a method for identifying and analyzing seismic AEF anomalies and is also beneficial for the examination of the pre-earthquake coupling process between the coversphere and the atmosphere.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261974","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":"Linkages between atmospheric rivers and humid heat across the United States","authors":"Colin Raymond, A. Shreevastava, E. Slinskey, D. Waliser","doi":"10.5194/nhess-24-791-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-791-2024","url":null,"abstract":"Abstract. The global increase in atmospheric water vapor due to climate change tends to heighten the dangers associated with both humid heat and heavy precipitation. Process-linked connections between these two extremes, particularly those which cause them to occur close together in space or time, are of special concern for impacts. Here we investigate how atmospheric rivers relate to the risk of summertime humid heat in the United States. We find that the hazards of atmospheric rivers and humid heat often occur in close proximity, most notably across the northern third of the United States. In this region, high levels of water vapor – resulting from the spatially organized horizontal moisture plumes that characterize atmospheric rivers – act to amplify humid heat, generally during the transition from dry high-pressure ridge conditions to wet low-pressure trough conditions. In contrast, the US Southeast, Southwest, and Northwest tend to experience atmospheric rivers and humid heat separately, representing an important negative correlation of joint risk.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140261417","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":"Nearshore tsunami amplitudes across the Maldives archipelago due to worst-case seismic scenarios in the Indian Ocean","authors":"S. Rasheed, S. Warder, Y. Plancherel, M. Piggott","doi":"10.5194/nhess-24-737-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-737-2024","url":null,"abstract":"Abstract. The Maldives face the threat of tsunamis from a multitude of sources. However, the limited availability of critical data, such as bathymetry (a recurrent problem for many island nations), has meant that the impact of these threats has not been studied at an island scale. Conducting studies of tsunami propagation at the island scale but across multiple atolls is also a challenging task due to the large domain and high resolution required for modelling. Here we use a high-resolution bathymetry dataset of the Maldives archipelago, as well as corresponding high numerical model resolution, to carry out a scenario-based tsunami hazard assessment for the entire Maldives archipelago to investigate the potential impact of plausible far-field tsunamis across the Indian Ocean at the nearshore island scales across the atolls. The results indicate that the bathymetry of the atolls, which are characterized by very steep boundaries offshore, is extremely efficient in absorbing and redirecting incoming tsunami waves. Results also highlight the importance that local effects have in modulating tsunami amplitude nearshore, including the location of the atoll in question, the location of a given island within the atoll, and the distance of that island to the reef, as well as a variety of other factors. We also find that the refraction and diffraction of tsunami waves within individual atolls contribute to the maximum tsunami amplitude patterns observed across the islands in the atolls. The findings from this study contribute to a better understanding of tsunamis across complex atoll systems and will help decision and policy makers in the Maldives assess the potential impact of tsunamis across individual islands. An online tool is provided which presents users with a simple interface, allowing the wider community to browse the simulation results presented here and assess the potential impact of tsunamis at the local scale.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264909","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":"Evidence of Middle Holocene landslide-generated tsunamis recorded in lake sediments from Saqqaq, West Greenland","authors":"N. Korsgaard, K. Svennevig, A. Søndergaard, G. Luetzenburg, M. Oksman, N. K. Larsen","doi":"10.5194/nhess-24-757-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-757-2024","url":null,"abstract":"Abstract. The Vaigat strait (Sullorsuaq) in West Greenland is well known for its susceptibility to landslides and historical landslide-generated tsunamis. Recent mapping of the seabed in the Vaigat strait has revealed several prehistoric giga-scale (volumes of 109 m3) tsunamigenic landslides. However, the timing of these giga-scale tsunamis is largely unconstrained, but they are assumed to have occurred after the last deglaciation. Here, we report on lake sediment core records from four coastal lakes located between 19 and 91 m above sea level (a.s.l.) on the Saqqaq foreland at the eastern end of the Vaigat strait. We use a multiproxy approach including X-ray fluorescence (XRF) and magnetic susceptibility core scanning along with a screening for marine diatoms to identify at least two tsunami deposits in two of the four sediment cores. Radiocarbon dating of aquatic macrofossils and bulk samples suggest that the tsunami events occurred at ca. 7.6 and 7.3 ka cal BP. Using a previously published relative sea level curve from Vaskebugt, Arveprinsen Ejland (Alluttoq), located 40 km southeast of Saqqaq, we infer wave runup heights of ca. 41–66 and 45–70 m, respectively, for the two tsunami events. These runup heights from prehistoric tsunamis are 1 to 2 orders of magnitude higher than the historic landslide-tsunami runup heights at Saqqaq which only reached an elevation of ca. 3 m in November 2000. While we found deposits from two tsunami events in the lake sediments, landforms from at least nine giga-scale landslides are present on the seafloor of Vaigat. We infer that these deposits probably represent the two most recent tsunamis identified in the Vaigat strait and that the older tsunamis must have happened between the last deglaciation and the oldest sediment in the lakes, i.e., between ca. 10.0 and 8.5 ka cal BP.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140264204","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":"Mapping current and future flood exposure using a 5 m flood model and climate change projections","authors":"Connor Darlington, J. Raikes, D. Henstra, J. Thistlethwaite, Emma K. Raven","doi":"10.5194/nhess-24-699-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-699-2024","url":null,"abstract":"Abstract. Local stakeholders need information about areas exposed to potential flooding to manage increasing disaster risk. Moderate- and large-scale flood hazard mapping is often produced at a low spatial resolution, typically using only one source of flooding (e.g., riverine), and it often fails to include climate change. This article assesses flood hazard exposure in the city of Vancouver, Canada, using flood mapping produced by flood risk science experts JBA Risk Management, which represented baseline exposure at 5 m spatial resolution and incorporated climate-change-adjusted values based on different greenhouse gas emission scenarios. The article identifies areas of both current and future flood exposure in the built environment, differentiating between sources of flooding (fluvial, pluvial, storm surge) and climate change scenarios. The case study demonstrates the utility of a flood model with a moderate resolution for informing planning, policy development, and public education. Without recent engineered or regulatory mapping available in all areas across Canada, this model provides a mechanism for identifying possible present and future flood risk at a higher resolution than is available at a Canada-wide coverage.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140092250","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":"Seasonal forecasting of local-scale soil moisture droughts with Global BROOK90: a case study of the European drought of 2018","authors":"Ivan Vorobevskii, Thi Thanh Huyen Luong, R. Kronenberg","doi":"10.5194/nhess-24-681-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-681-2024","url":null,"abstract":"Abstract. Prolonged deficit of soil moisture can result in significant ecosystem and economical losses. General slowdown of vegetation growth and development, withering of foliage cover, reduction of carbon, nutrients and water cycling, increase of fire and insect outbreaks are just a few examples of soil moisture drought impacts. Thus, an early and timely warning via monitoring and forecast could help to prepare for a drought and manage its consequences. In this study, a new version of Global BROOK90, an automated framework to simulate water balance at any location, is presented. The new framework integrates seasonal meteorological forecasts (SEAS5 forecasting system) from European Centre for Medium-Range Weather Forecasts (ECMWF). Here we studied how well the framework can predict the soil moisture drought on a local scale. Twelve small European catchments (from 7 to 115 km2) characterized by various geographical conditions were chosen to reconstruct the 2018–2019 period, when a large-scale prolonged drought was observed in Europe. Setting the ERA5-forced soil moisture simulations as a reference, we analysed how the lead time of the SEAS5 hindcasts influences the quality of the soil moisture predictions under drought and non-drought conditions. It was found that the hindcasted soil moisture fits well with the reference model runs only within the first (in some cases until the second and third) month of lead time. Afterwards, significant deviations up to 50 % of soil water volume were found. Furthermore, within the drought period the SEAS5 hindcast forcings resulted in overestimation of the soil moisture for most of the catchment, indicating an earlier end of a drought period. Finally, it was shown that application of the probabilistic forecast using the ensembles' quantiles to account for the uncertainty of the meteorological input is reasonable only for a lead time of up to 3 months.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140090462","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":"Tsunami hazard perception and knowledge of alert: early findings in five municipalities along the French Mediterranean coastlines","authors":"J. Douvinet, Noé Carles, Pierre Foulquier, Matthieu Péroche","doi":"10.5194/nhess-24-715-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-715-2024","url":null,"abstract":"Abstract. Along the French Mediterranean coastlines, most of the studies dealing with tsunamis have focused on hazards, evacuations, or effects of awareness actions, as opposed to hazard perception and knowledge of alert declared locally by the population. To bridge this gap, in this study, data collection yielded 750 responses coming from 150 people living and/or working in the tsunami evacuation zones of five municipalities (e.g., Bandol, Bastia, Cannes, Six-Fours-les-Plages, Sanary-sur-Mer). Early findings confirmed the tendency to underestimate tsunami hazard and a misunderstanding of the alert process. Interestingly, age or location of respondents explained differences between the five surveyed municipalities – more so than gender and residency status. Discrepancies are also observed when we compare the rate of correct answers for similar questions addressed in other areas in the NEAMTWS (North-eastern Atlantic, Mediterranean and connected seas Tsunami Warning System) region, thus confirming local effects. More surprisingly, the respondents who well perceive the tsunami hazard are not those who have a good knowledge of alerts, and the awareness actions do not really impact the tsunami knowledge we evaluated. Also, the results of this study could help local authorities to develop future tsunami awareness actions and to determine more suitable strategies to be applied in the short term at local scales.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140084543","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":"Seismogenic depth and seismic coupling estimation in the transition zone between Alps, Dinarides and Pannonian Basin for the new Slovenian seismic hazard model","authors":"P. Zupančič, Barbara Šket Motnikar, M. Carafa, Petra Jamšek Rupnik, M. Živčič, V. Kastelic, Gregor Rajh, Martina Čarman, J. Atanackov, A. Gosar","doi":"10.5194/nhess-24-651-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-651-2024","url":null,"abstract":"Abstract. Seismogenic depth and seismic coupling are important inputs into seismic hazard estimates. Although the importance of seismic coupling is often overlooked, it significantly impacts seismic hazard results. We present an estimation of upper and lower seismogenic depth and expected hypocentral depth and seismic coupling in the transition zone between the Alps, Dinarides and Pannonian Basin, characterized by a complex deformation pattern, highly variable crustal thickness, and moderate seismic hazard, supporting the development of the 2021 seismic hazard model of Slovenia. The hazard model was based on three seismic source models: area source model, fault source model and smoothed seismicity (point) source model. We estimated the lower seismogenic depth using seismological and geological data and compared them. The seismological estimate was based on two regional earthquake catalogues prepared for this study. In the area source model, estimates of lower seismogenic depth from seismological data are deeper or equal to the ones derived from geological data, except in one case. In the fault source model, we analysed each fault individually and chose seismological lower depth estimates in 12 among 89 faults as more representative. The seismogenic thickness for each individual fault source was determined for seismic coupling determination. The seismic coupling was assessed by two approaches, i.e. we chose the most trusted value from the literature, and the value determined for each fault individually by using the approach based on the updated regional fault and earthquake data sets. The final estimate of seismic coupling ranges from 0.77 to 0.38. We compared the tectonic moment rate based on long-term slip rate using different values of seismic coupling with the seismic moment rate obtained from the earthquake catalogue. The analysis is done for the whole area, as well as for the individual area zones. The analysis of N–S components of estimated slip for the largest faults in the area of west Slovenia shows that the regional geological and geodetic shortening rates are comparable. The total activity rate of three global seismic source models is compared, which gives up to a 10 % difference. Our results contribute to a better understanding of the seismic activity in the region. The presented approach for seismic coupling estimation can be applied in cases where the total slip rate is given instead of its seismic part and can be used at regional or national level. The approach is also suitable for the cross-border harmonization of the European seismic hazard modelling data.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140424143","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":"Optimization strategy for flexible barrier structures: investigation and back analysis of a rockfall disaster case in southwestern China","authors":"Li-Ru Luo, Zhixiang Yu, Li-Jun Zhang, Qi Wang, Lin-Xu Liao, Li Peng","doi":"10.5194/nhess-24-631-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-631-2024","url":null,"abstract":"Abstract. Field investigations and back analyses were conducted on a rockfall hazard. The flexible barrier protection system constructed along the roadside was damaged by the rockfall impact and lost its mitigation ability. Vital physical characteristics such as rockfall trajectory and kinetic energy were presumed based on the data from the aerial survey and the slope digital model. A numerical model, including slope, rockfalls, and flexible barrier, was created and thus the impacting process was reproduced. It demonstrates that the impact kinetic energy of the rockfall is only around 40 % of its design protection energy. The improper connections of members are the leading causes of damage, which prevent the flexible barrier from producing significant deformation and reduce its capacity to absorb impact force. The damage can be avoided by changing the connections of the members to improve the ability of the nets and ropes to slide and deform. The calculation results indicate that the impact resistance of the optimized model is 3 times better than the actual project. The findings can be used as a guide when designing a flexible protection system that performs better.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140429681","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":"How to mitigate flood events similar to the 1979 catastrophic floods in the lower Tagus","authors":"D. Fernández-Nóvoa, A. M. Ramos, J. Gonzalez-Cao, O. García-Feal, Cristina Catita, M. Gómez-Gesteira, R. M. Trigo","doi":"10.5194/nhess-24-609-2024","DOIUrl":"https://doi.org/10.5194/nhess-24-609-2024","url":null,"abstract":"Abstract. The floods that struck the lower Tagus valley in February 1979 correspond to the most intense floods in this river and affected the largest number of people in a river flow event in Portugal during the last 150 years. In fact, the vast area affected significantly impacted circa 10 000 people in the lower Tagus sector (and an additional 7000 in other regions of Portugal), including thousands of people evacuated or made homeless. In this context, the present study focuses on an in-depth analysis of this event from a hydrodynamic perspective by means of the Iber+ numerical model and on developing strategies to mitigate the flood episodes that occur in the lower section of the Tagus River using the exceptional floods of February 1979 as a benchmark. In this sense, dam operating strategies were developed and analyzed for the most important dam along the Tagus River basin in order to propose effective procedures to take advantage of these infrastructures to minimize the effect of floods. Overall, the numerical results indicate a good agreement with watermarks and some descriptions of the 1979 flood event, which demonstrates the model capability to evaluate floods in the area under study. Regarding flood mitigation, results obtained indicate that the frequency of floods can be reduced with the proposed strategies, which were focused on providing optimal dam operating rules to mitigate flooding in the lower Tagus valley. In addition, hydraulic simulations corroborated an important decrease in water depth and velocity for the most extreme flood events, and also a certain reduction in the flood extension was detected. This confirms the effectiveness of the proposed strategies to help in reducing the flood impact in the lower Tagus valley through the efficient functioning of dams.\u0000","PeriodicalId":18922,"journal":{"name":"Natural Hazards and Earth System Sciences","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140444698","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}