Natural Hazards and Earth System Sciences

The potential of global coastal flood risk reduction using various DRR measures
Eric Mortensen, Timothy Tiggeloven, Toon Haer, Bas van Bemmel, Dewi Le Bars, Sanne Muis, Dirk Eilander, Frederiek Sperna Weiland, Arno Bouwman, Willem Ligtvoet, and Philip J. Ward
Nat. Hazards Earth Syst. Sci., 24, 1381–1400, https://doi.org/10.5194/nhess-24-1381-2024, 2024
Current levels of coastal flood risk are projected to increase in coming decades due to various reasons, e.g. sea-level rise, land subsidence, and coastal urbanization: action is needed to minimize this future risk. We evaluate dykes and coastal levees, foreshore vegetation, zoning restrictions, and dry-proofing on a global scale to estimate what levels of risk reductions are possible. We demonstrate that there are several potential adaptation pathways forward for certain areas of the world.

FOREWARNS: development and multifaceted verification of enhanced regional-scale surface water flood forecasts
Ben Maybee, Cathryn E. Birch, Steven J. Böing, Thomas Willis, Linda Speight, Aurore N. Porson, Charlie Pilling, Kay L. Shelton, and Mark A. Trigg
Nat. Hazards Earth Syst. Sci., 24, 1415–1436, https://doi.org/10.5194/nhess-24-1415-2024, 2024
This paper presents the development and verification of FOREWARNS, a novel method for regional-scale forecasting of surface water flooding. We detail outcomes from a workshop held with UK forecast users, who indicated they valued the forecasts and would use them to complement national guidance. We use results of objective forecast tests against flood observations over northern England to show that this confidence is justified and that FOREWARNS meets the needs of UK flood responders.

Characteristics of debris-flow-prone watersheds and debris-flow-triggering rainstorms following the Tadpole Fire, New Mexico, USA
Luke A. McGuire, Francis K. Rengers, Ann M. Youberg, Alexander N. Gorr, Olivia J. Hoch, Rebecca Beers, and Ryan Porter
Nat. Hazards Earth Syst. Sci., 24, 1357–1379, https://doi.org/10.5194/nhess-24-1357-2024, 2024
Runoff and erosion increase after fire, leading to a greater likelihood of floods and debris flows. We monitored debris flow activity following a fire in western New Mexico, USA, and observed 16 debris flows over a <2-year monitoring period. Rainstorms with recurrence intervals of approximately 1 year were sufficient to initiate debris flows. All debris flows initiated during the first several months following the fire, indicating a rapid decrease in debris flow susceptibility over time.

Scoring and ranking probabilistic seismic hazard models: an application based on macroseismic intensity data
Vera D'Amico, Francesco Visini, Andrea Rovida, Warner Marzocchi, and Carlo Meletti
Nat. Hazards Earth Syst. Sci., 24, 1401–1413, https://doi.org/10.5194/nhess-24-1401-2024, 2024
We propose a scoring strategy to rank multiple models/branches of a probabilistic seismic hazard analysis (PSHA) model that could be useful to consider specific requests from stakeholders responsible for seismic risk reduction actions. In fact, applications of PSHA often require sampling a few hazard curves from the model. The procedure is introduced through an application aimed to score and rank the branches of a recent Italian PSHA model according to their fit with macroseismic intensity data.

Modeling of indoor 222Rn in data-scarce regions: an interactive dashboard approach for Bogotá, Colombia
Martín Domínguez Durán, María Angélica Sandoval Garzón, and Carme Huguet
Nat. Hazards Earth Syst. Sci., 24, 1319–1339, https://doi.org/10.5194/nhess-24-1319-2024, 2024
In this study we created a cost-effective alternative to bridge the baseline information gap on indoor radon (a highly carcinogenic gas) in regions where measurements are scarce. We model indoor radon concentrations to understand its spatial distribution and the potential influential factors. We evaluated the performance of this alternative using a small number of measurements taken in Bogotá, Colombia. Our results show that this alternative could help in the making of future studies and policy.

Assessment of wind–damage relations for Norway using 36 years of daily insurance data
Ashbin Jaison, Asgeir Sorteberg, Clio Michel, and Øyvind Breivik
Nat. Hazards Earth Syst. Sci., 24, 1341–1355, https://doi.org/10.5194/nhess-24-1341-2024, 2024
The present study uses daily insurance losses and wind speeds to fit storm damage functions at the municipality level of Norway. The results show that the damage functions accurately estimate losses associated with extreme damaging events and can reconstruct their spatial patterns. However, there is no single damage function that performs better than another. A newly devised damage–no-damage classifier shows some skill in predicting extreme damaging events.

Size scaling of large landslides from incomplete inventories
Oliver Korup, Lisa Luna, and Joaquin Ferrer
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-55,2024
Preprint under review for NHESS (discussion: open, 0 comments)
Catalogues of mapped landslides are useful for learning and forecasting how frequently they occur in relation to their size. Yet, rare and large landslides remain most uncertain in statistical summaries of these catalogues. We propose a single, consistent method of comparing across different data sources, and find that landslide statistics disclose more about subjective mapping choices than trigger types or environmental setting.

Supershear crack propagation in snow slab avalanche release: new insights from numerical simulations and field measurements
Grégoire Bobillier, Bertil Trottet, Bastian Bergfeld, Ron Simenhois, Alec van Herwijnen, Jürg Schweizer, and Johan Gaume
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-70,2024
Preprint under review for NHESS (discussion: open, 0 comments)
Our study focuses on the initiation process of snow slab avalanches. By combining experimental data and numerical simulations, we show that on gentle slopes, a crack forms and propagates due to compression fracture within a weak layer, and on steep slopes, the crack velocity can increase dramatically after about 5 meters due to a fracture mode transition (compression to shear). Understanding these dynamics represents an essential additional piece in the dry-snow slab avalanche formation puzzle.

Lesser Antilles Seismotectonic Zoning Model for Seismic Hazard Assessment
Oceane Foix, Stéphane Mazzotti, Hervé Jomard, Didier Bertil, and the Lesser Antilles Working Group
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-53,2024
Preprint under review for NHESS (discussion: open, 0 comments)
By analyzing historical and instrumental seismic data, fault knowledge and geodetic measurements, we provide a new understanding of seismic hazard in the Lesser Antilles via seismotectonic zoning. We propose new models that can have a significant impact on seismic hazard assessment, such as the inclusion of mantle wedge seismicity, volcanic seismicity and a complete revision of the subduction interface zoning.

Factors of influence on flood risk perceptions related to Hurricane Dorian: an assessment of heuristics, time dynamics, and accuracy of risk perceptions
Laurine A. de Wolf, Peter J. Robinson, W. J. Wouter Botzen, Toon Haer, Jantsje M. Mol, and Jeffrey Czajkowski
Nat. Hazards Earth Syst. Sci., 24, 1303–1318, https://doi.org/10.5194/nhess-24-1303-2024, 2024
An understanding of flood risk perceptions may aid in improving flood risk communication. We conducted a survey among 871 coastal residents in Florida who were threatened to be flooded by Hurricane Dorian. Part of the original sample was resurveyed after Dorian failed to make landfall to investigate changes in risk perception. We find a strong influence of previous flood experience and social norms on flood risk perceptions. Furthermore, flood risk perceptions declined after the near-miss event.

Morphological characteristics and conditions of drainage basins contributing to the formation of debris flow fans: an examination of regions with different rock strength using decision tree analysis
Ken'ichi Koshimizu, Satoshi Ishimaru, Fumitoshi Imaizumi, and Gentaro Kawakami
Nat. Hazards Earth Syst. Sci., 24, 1287–1301, https://doi.org/10.5194/nhess-24-1287-2024, 2024
Morphological conditions of drainage basins that classify the presence or absence of debris flow fans were analyzed in areas with different rock strength using decision tree analysis. The relief ratio is the most important morphological factor regardless of the geology. However, the thresholds of morphological parameters needed for forming debris flow fans differ depending on the geology. Decision tree analysis is an effective tool for evaluating the debris flow risk for each geology.

Demonstrating the use of UNSEEN climate data for hydrological applications: case studies for extreme floods and droughts in England
Alison Kay, Nick Dunstone, Gillian Kay, Victoria Bell, and Jamie Hannaford
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-51,2024
Preprint under review for NHESS (discussion: open, 0 comments)
Hydrological hazards affect people and ecosystems but extremes are not fully understood due to limited observations. A large climate ensemble and simple hydrological model are used to assess unprecedented but plausible floods and droughts. The chain gives extreme flows outside the observed range; Summer 2022 ~28 % lower and Autumn 2023 ~42 % higher. Spatial dependence and temporal persistence are analysed. Planning for such events could improve water supply resilience and flood risk management.

Interannual variations in the seasonal cycle of extreme precipitation in Germany and the response to climate change
Madlen Peter, Henning W. Rust, and Uwe Ulbrich
Nat. Hazards Earth Syst. Sci., 24, 1261–1285, https://doi.org/10.5194/nhess-24-1261-2024, 2024
The paper introduces a statistical modeling approach describing daily extreme precipitation in Germany more accurately by including changes within the year and between the years simultaneously. The changing seasonality over years is regionally divergent and mainly weak. However, some regions stand out with a more pronounced linear rise of summer intensities, indicating a possible climate change signal. Improved modeling of extreme precipitation is beneficial for risk assessment and adaptation.

Coupling WRF with HEC-HMS and WRF-Hydro for flood forecasting in typical mountainous catchments of northern China
Sheik Umar Jam-Jalloh, Jia Liu, Yicheng Wang, and Yuchen Liu
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-20,2024
Preprint under review for NHESS (discussion: open, 1 comment)
Explore our paper on improving flood prediction using advanced weather models. We coupled the WRF model with WRF-Hydro and HEC-HMS to enhance accuracy. Discover how our findings contribute to adaptive atmospheric-hydrologic systems for effective flood forecasting.

A dense micro-electromechanical system (MEMS)-based seismic network in populated areas: rapid estimation of exposure maps in Trentino (NE Italy)
Davide Scafidi, Alfio Viganò, Jacopo Boaga, Valeria Cascone, Simone Barani, Daniele Spallarossa, Gabriele Ferretti, Mauro Carli, and Giancarlo De Marchi
Nat. Hazards Earth Syst. Sci., 24, 1249–1260, https://doi.org/10.5194/nhess-24-1249-2024, 2024
Our paper concerns the use of a dense network of low-cost seismic accelerometers in populated areas to achieve rapid and reliable estimation of exposure maps in Trentino (northeast Italy). These additional data, in conjunction with the automatic monitoring procedure, allow us to obtain dense measurements which only rely on actual recorded data, avoiding the use of ground motion prediction equations. This leads to a more reliable picture of the actual ground shaking.

Regional-scale analysis of weather-related rockfall triggering mechanisms in Norway, and its sensitivity to climate change
Rosa M. Palau, Kjersti Gleditsch Gisnås, Anders Solheim, and Graham Lewis Gilbert
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-46,2024
Preprint under review for NHESS (discussion: open, 0 comments)
This paper looks at the relationship between rockfalls and weather conditions in two regions of Norway. The study explores how often rockfalls occur and how this might change in the future due to climate change. The results indicate that changes in temperature, rather than just heavy rain or snow melt, can have a big impact on the time rockfalls happen. In particular, when temperatures oscillate up and down, rockfalls are observed more often.

Exploring inferred geomorphological sediment thickness as a new site proxy to predict ground-shaking amplification at regional scale: application to Europe and eastern Türkiye
Karina Loviknes, Fabrice Cotton, and Graeme Weatherill
Nat. Hazards Earth Syst. Sci., 24, 1223–1247, https://doi.org/10.5194/nhess-24-1223-2024, 2024
Earthquake ground shaking can be strongly affected by local geology and is often amplified by soft sediments. In this study, we introduce a global geomorphological model for sediment thickness as a protentional parameter for predicting this site amplification. The results show that including geology and geomorphology in site-amplification predictions adds important value and that global or regional models for sediment thickness from fields beyond engineering seismology are worth considering.

SEATANI: hazards from seamounts in Southeast Asia, Taiwan, and Andaman and Nicobar Islands (eastern India)
Andrea Verolino, Su Fen Wee, Susanna F. Jenkins, Fidel Costa, and Adam D. Switzer
Nat. Hazards Earth Syst. Sci., 24, 1203–1222, https://doi.org/10.5194/nhess-24-1203-2024, 2024
Submarine volcanic eruptions represent the majority of eruptions taking place on Earth. Still, they are vastly understudied worldwide. Here we compile a new dataset and assess the morphology, depth, and height of submarine volcanoes in Southeast Asia and its surroundings to understand their hazard-exposure potential in the region. This study will serve as a stepping stone for future quantitative hazard assessments from submarine eruptions in Southeast Asia and neighbouring countries.

An updated EAWS matrix to determine the avalanche danger level: derivation, usage, and consistency
Karsten Müller, Frank Techel, and Christoph Mitterer
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-48,2024
Preprint under review for NHESS (discussion: open, 0 comments)
Avalanche forecasting is crucial for mountain safety. Tools like the European Avalanche Danger Scale and Matrix set standards for forecasters, but consistency still varies. We analyzed the use of the EAWS Matrix, aiding danger level assignment. Our analysis shows inconsistencies, suggesting further need for refinement and training.

Current status of water-related planning for climate change adaptation in the Spree River basin, Germany
Saskia Arndt and Stefan Heiland
Nat. Hazards Earth Syst. Sci. Discuss., https//doi.org/10.5194/nhess-2024-59,2024
Preprint under review for NHESS (discussion: open, 0 comments)
This study provides an overview of the current status of climate change adaptation in water management, spatial and landscape planning in the Spree River basin. Only 39 % of 28 plans analysed specify objectives and measures for adaptation to climate change. To fill this planning gap, more frequent updates of plans, a stronger focus on multifunctional measures and the adaptation of best practice examples for systematic integration of climate change impacts and adaptation are needed.