Articles | Volume 20, issue 1
https://doi.org/10.5194/nhess-20-271-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/nhess-20-271-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Dynamic path-dependent landslide susceptibility modelling
Jalal Samia
CORRESPONDING AUTHOR
Laboratory of Geo-Information Science and Remote Sensing,
Wageningen University & Research, Droevendaalsesteeg 3, 6708 PB, Wageningen, the Netherlands
Soil Geography and Landscape Group, Wageningen University & Research, Droevendaalsesteeg 3, 6708 PB, Wageningen, the Netherlands
Department of Geography and Urban Planning, University of
Mazandaran, Pardis Campus, 47416-13534 PB, Babolsar, Iran
Arnaud Temme
Department of Geography, Kansas State University, 920 N17th Street,
Manhattan, KS 66506, USA
Institute of Arctic and Alpine Research, University of Colorado Boulder,
Campus Box 450, Boulder, CO 803309-0450, USA
Arnold Bregt
Laboratory of Geo-Information Science and Remote Sensing,
Wageningen University & Research, Droevendaalsesteeg 3, 6708 PB, Wageningen, the Netherlands
Jakob Wallinga
Soil Geography and Landscape Group, Wageningen University & Research, Droevendaalsesteeg 3, 6708 PB, Wageningen, the Netherlands
Fausto Guzzetti
Istituto di Ricerca per la Protezione Idrogeologica, Consiglio
Nazionale delle Ricerche, Via Madonna Alta 126, 06128 Perugia, Italy
Francesca Ardizzone
Istituto di Ricerca per la Protezione Idrogeologica, Consiglio
Nazionale delle Ricerche, Via Madonna Alta 126, 06128 Perugia, Italy
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W. Marijn van der Meij, Arnaud J. A. M. Temme, Steven A. Binnie, and Tony Reimann
Geochronology, 5, 241–261, https://doi.org/10.5194/gchron-5-241-2023, https://doi.org/10.5194/gchron-5-241-2023, 2023
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We present our model ChronoLorica. We coupled the original Lorica model, which simulates soil and landscape evolution, with a geochronological module that traces cosmogenic nuclide inventories and particle ages through simulations. These properties are often measured in the field to determine rates of landscape change. The coupling enables calibration of the model and the study of how soil, landscapes and geochronometers change under complex boundary conditions such as intensive land management.
Silvia Peruccacci, Stefano Luigi Gariano, Massimo Melillo, Monica Solimano, Fausto Guzzetti, and Maria Teresa Brunetti
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2023-61, https://doi.org/10.5194/essd-2023-61, 2023
Preprint under review for ESSD
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ITALICA (ITAlian rainfall-induced LandslIdes CAtalogue) is the largest catalogue of rainfall-induced landslides accurately located in space and time available in Italy. ITALICA currently lists 6312 landslides that occurred between January 1996 and December 2021. The information was collected using strict objective and homogeneous criteria. The high spatial and temporal accuracy makes the catalogue suitable for reliably defining the rainfall conditions capable of triggering future landslides.
Cindy Quik, Ype van der Velde, Jasper H. J. Candel, Luc Steinbuch, Roy van Beek, and Jakob Wallinga
Biogeosciences, 20, 695–718, https://doi.org/10.5194/bg-20-695-2023, https://doi.org/10.5194/bg-20-695-2023, 2023
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In NW Europe only parts of former peatlands remain. When these peatlands formed is not well known but relevant for questions on landscape, climate and archaeology. We investigated the age of Fochteloërveen, using radiocarbon dating and modelling. Results show that peat initiated at several sites 11 000–7000 years ago and expanded rapidly 5000 years ago. Our approach may ultimately be applied to model peat ages outside current remnants and provide a view of these lost landscapes.
Francesca Ardizzone, Francesco Bucci, Mauro Cardinali, Federica Fiorucci, Luca Pisano, Michele Santangelo, and Veronica Zumpano
Earth Syst. Sci. Data, 15, 753–767, https://doi.org/10.5194/essd-15-753-2023, https://doi.org/10.5194/essd-15-753-2023, 2023
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This paper presents a new geomorphological landslide inventory map for the Daunia Apennines, southern Italy. It was produced through the interpretation of two sets of stereoscopic aerial photographs, taken in 1954/55 and 2003, and targeted field checks. The inventory contains 17 437 landslides classified according to relative age, type of movement, and estimated depth. The dataset consists of a digital archive publicly available at https://doi.org/10.1594/PANGAEA.942427.
Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 21, 1467–1471, https://doi.org/10.5194/nhess-21-1467-2021, https://doi.org/10.5194/nhess-21-1467-2021, 2021
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This is a perspective based on personal experience on whether a large number of landslides caused by a single trigger (e.g. an earthquake, an intense rainfall, a rapid snowmelt event) or by multiple triggers in a period can be predicted, in space and time, considering the consequences of slope failures.
W. Marijn van der Meij, Arnaud J. A. M. Temme, Jakob Wallinga, and Michael Sommer
SOIL, 6, 337–358, https://doi.org/10.5194/soil-6-337-2020, https://doi.org/10.5194/soil-6-337-2020, 2020
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We developed a model to simulate long-term development of soils and landscapes under varying rainfall and land-use conditions to quantify the temporal variation of soil patterns. In natural landscapes, rainfall amount was the dominant factor influencing soil variation, while for agricultural landscapes, landscape position became the dominant factor due to tillage erosion. Our model shows potential for simulating past and future developments of soils in various landscapes and climates.
Elizabeth L. Chamberlain and Jakob Wallinga
Earth Surf. Dynam., 7, 723–736, https://doi.org/10.5194/esurf-7-723-2019, https://doi.org/10.5194/esurf-7-723-2019, 2019
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Sand and mud may take many different pathways within a river as they travel from inland to the coast. During the trip, grains may be exposed to daylight, resetting a signal trapped within certain minerals. The signal can be measured in a laboratory to estimate the time since last light exposure. Here, we measure the trapped signal of sand and mud grains from the Mississippi River and its banks. We use this information to infer sediment pathways. Such knowledge is useful for delta management.
Michele Santangelo, Massimiliano Alvioli, Marco Baldo, Mauro Cardinali, Daniele Giordan, Fausto Guzzetti, Ivan Marchesini, and Paola Reichenbach
Nat. Hazards Earth Syst. Sci., 19, 325–335, https://doi.org/10.5194/nhess-19-325-2019, https://doi.org/10.5194/nhess-19-325-2019, 2019
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The paper discusses the use of rockfall modelling software and photogrammetry applied to images acquired by RPAS to provide support to civil protection agencies during emergency response. The paper focuses on a procedure that was applied to define the residual rockfall risk for a road that was hit by an earthquake-triggered rockfall that occurred during the seismic sequence that hit central Italy on 24 August 2016. Road reopening conditions were decided based on the results of this study.
Anna Roccati, Francesco Faccini, Fabio Luino, Laura Turconi, and Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 18, 2367–2386, https://doi.org/10.5194/nhess-18-2367-2018, https://doi.org/10.5194/nhess-18-2367-2018, 2018
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Natural instability processes are very common. Almost every year, landslides, mud flows and debris flows in the Alpine and Apennine areas and flooding in the Po flood plain cause severe damage to structures and infrastructure and often claim human lives.
Geology researchers collect thousands of rain data and process them to try the most precise prediction about the triggering of superficial landslides in order to mitigate the risk and safeguard human goods and lives.
Jasper H. J. Candel, Maarten G. Kleinhans, Bart Makaske, Wim Z. Hoek, Cindy Quik, and Jakob Wallinga
Earth Surf. Dynam., 6, 723–741, https://doi.org/10.5194/esurf-6-723-2018, https://doi.org/10.5194/esurf-6-723-2018, 2018
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In this study we show how the Overijsselse Vecht river changed from a laterally stable to a meandering river ca. 500 years ago. We developed a methodology to reconstruct the historical discharge and found that the change in river style was caused by an increase in peak discharges. This increase was likely caused by the Little Ice Age and land use changes in the catchment (peat reclamation and exploitation). This study shows how river style changes as a result of discharge regime changes.
Cindy Quik and Jakob Wallinga
Earth Surf. Dynam., 6, 705–721, https://doi.org/10.5194/esurf-6-705-2018, https://doi.org/10.5194/esurf-6-705-2018, 2018
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Identifying contemporary river migration rates is often based on aerial photos or recent topographical maps. Here, we propose to use river sediments as an archive to look further back in time using optically stimulated luminescence (OSL) dating and develop a modelling procedure for the joint analysis of dating results and historical maps. The procedure is applied to the Overijsselse Vecht river in The Netherlands, and we show that the river migrated with 0.9–2.6 m yr−1 between 1400 and 1900 CE.
Federica Fiorucci, Daniele Giordan, Michele Santangelo, Furio Dutto, Mauro Rossi, and Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 18, 405–417, https://doi.org/10.5194/nhess-18-405-2018, https://doi.org/10.5194/nhess-18-405-2018, 2018
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This paper describes the criteria for the optimal selection of remote sensing images to map event landslides, discussing the ability of monoscopic and stereoscopic VHR satellite images and ultra-high-resolution UAV images to resolve the landslide photographical and morphological signatures. The findings can be useful to decide on the optimal imagery and technique to be used when planning the production of a landslide inventory map.
Francesco Marra, Elisa Destro, Efthymios I. Nikolopoulos, Davide Zoccatelli, Jean Dominique Creutin, Fausto Guzzetti, and Marco Borga
Hydrol. Earth Syst. Sci., 21, 4525–4532, https://doi.org/10.5194/hess-21-4525-2017, https://doi.org/10.5194/hess-21-4525-2017, 2017
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Previous studies have reported a systematic underestimation of debris flow occurrence thresholds, due to the use of sparse networks in non-stationary rain fields. We analysed high-resolution radar data to show that spatially aggregated estimates (e.g. satellite data) largely reduce this issue, in light of a reduced estimation variance. Our findings are transferable to other situations in which lower envelope curves are used to predict point-like events in the presence of non-stationary fields.
Kees Nooren, Wim Z. Hoek, Tim Winkels, Annika Huizinga, Hans Van der Plicht, Remke L. Van Dam, Sytze Van Heteren, Manfred J. Van Bergen, Maarten A. Prins, Tony Reimann, Jakob Wallinga, Kim M. Cohen, Philip Minderhoud, and Hans Middelkoop
Earth Surf. Dynam., 5, 529–556, https://doi.org/10.5194/esurf-5-529-2017, https://doi.org/10.5194/esurf-5-529-2017, 2017
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We demonstrate that the world's largest beach-ridge plain in southern Mexico was formed under an ample long-term fluvial sediment supply. The beach-ridge elevation is strongly influenced by aeolian accretion during the time when the ridge is located next to the beach. The beach-ridge elevation is negatively correlated with the progradation rate, which we relate to the variability in sediment supply to the coastal zone, reflecting decadal-scale precipitation changes within the river catchment.
Maria Elena Martinotti, Luca Pisano, Ivan Marchesini, Mauro Rossi, Silvia Peruccacci, Maria Teresa Brunetti, Massimo Melillo, Giuseppe Amoruso, Pierluigi Loiacono, Carmela Vennari, Giovanna Vessia, Maria Trabace, Mario Parise, and Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 17, 467–480, https://doi.org/10.5194/nhess-17-467-2017, https://doi.org/10.5194/nhess-17-467-2017, 2017
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We studied a period of torrential rain between 1 and 6 September 2014 in the Gargano Promontory, Puglia, southern Italy, which caused a variety of geohydrological hazards, including landslides, flash floods, inundations and sinkholes. We used the rainfall and the landslide information available to us to design and test the new ensemble – non-exceedance probability (E-NEP) algorithm for the quantitative evaluation of the probability of the occurrence of rainfall-induced landslides.
Massimiliano Alvioli, Ivan Marchesini, Paola Reichenbach, Mauro Rossi, Francesca Ardizzone, Federica Fiorucci, and Fausto Guzzetti
Geosci. Model Dev., 9, 3975–3991, https://doi.org/10.5194/gmd-9-3975-2016, https://doi.org/10.5194/gmd-9-3975-2016, 2016
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Slope units are morphological mapping units bounded by drainage and divide lines that maximize within-unit homogeneity and between-unit heterogeneity. We use r.slopeunits, a software for the automatic delination of slope units. We outline an objective procedure to optimize the software input parameters for landslide susceptibility (LS) zonation. Optimization is achieved by maximizing an objective function that simultaneously evaluates terrain aspect segmentation quality and LS model performance.
Roberta Paranunzio, Francesco Laio, Marta Chiarle, Guido Nigrelli, and Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 16, 2085–2106, https://doi.org/10.5194/nhess-16-2085-2016, https://doi.org/10.5194/nhess-16-2085-2016, 2016
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We provide the results of the joint analysis of the main climate variables and spatiotemporal distribution of 41 rockfalls that occurred in the Italian Alps between 1997 and 2013 in the absence of an evident trigger. We compared the meteorological conditions preceding the failures with the historical datasets, to determine if rockfall initiation was associated with some climatic anomaly. We found out that temperature anomalies were associated with rockfall occurrence in 83 % of our case studies.
Paola Salvati, Umberto Pernice, Cinzia Bianchi, Ivan Marchesini, Federica Fiorucci, and Fausto Guzzetti
Nat. Hazards Earth Syst. Sci., 16, 1487–1497, https://doi.org/10.5194/nhess-16-1487-2016, https://doi.org/10.5194/nhess-16-1487-2016, 2016
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We designed the POLARIS website to communicate to a broader audience information on geohydrological (landslide and flood) hazards with potential consequences to the population. POLARIS publishes periodic reports, analyses of specific damaging events and blog posts. POLARIS can help multiple audiences understand how risks can be reduced through appropriate measures and behaviours, contributing to increasing the resilience of the population to geohydrological risk.
W. Marijn van der Meij, Arnaud J. A. M. Temme, Christian M. F. J. J. de Kleijn, Tony Reimann, Gerard B. M. Heuvelink, Zbigniew Zwoliński, Grzegorz Rachlewicz, Krzysztof Rymer, and Michael Sommer
SOIL, 2, 221–240, https://doi.org/10.5194/soil-2-221-2016, https://doi.org/10.5194/soil-2-221-2016, 2016
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This study combined fieldwork, geochronology and modelling to get a better understanding of Arctic soil development on a landscape scale. Main processes are aeolian deposition, physical and chemical weathering and silt translocation. Discrepancies between model results and field observations showed that soil and landscape development is not as straightforward as we hypothesized. Interactions between landscape processes and soil processes have resulted in a complex soil pattern in the landscape.
Saskia D. Keesstra, Johan Bouma, Jakob Wallinga, Pablo Tittonell, Pete Smith, Artemi Cerdà, Luca Montanarella, John N. Quinton, Yakov Pachepsky, Wim H. van der Putten, Richard D. Bardgett, Simon Moolenaar, Gerben Mol, Boris Jansen, and Louise O. Fresco
SOIL, 2, 111–128, https://doi.org/10.5194/soil-2-111-2016, https://doi.org/10.5194/soil-2-111-2016, 2016
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Soil science, as a land-related discipline, has links to several of the UN Sustainable Development Goals which are demonstrated through the functions of soils and related ecosystem services. We discuss how soil scientists can rise to the challenge both internally and externally in terms of our relations with colleagues in other disciplines, diverse groups of stakeholders and the policy arena. To meet these goals we recommend the set of steps to be taken by the soil science community as a whole.
S. L. Gariano, O. Petrucci, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 15, 2313–2330, https://doi.org/10.5194/nhess-15-2313-2015, https://doi.org/10.5194/nhess-15-2313-2015, 2015
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We study temporal and geographical variations in the occurrence of 1466 rainfall-induced landslides in Calabria, southern Italy, in the period 1921–2010. To evaluate the impact on the population, we compare the number of rainfall-induced landslides with the size of population in the 409 municipalities in Calabria. We find variations in yearly and geographical distribution of rainfall-induced landslides, variations in rainfall triggering conditions, and changes in the impact on the population.
M. Santangelo, I. Marchesini, F. Bucci, M. Cardinali, F. Fiorucci, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 15, 2111–2126, https://doi.org/10.5194/nhess-15-2111-2015, https://doi.org/10.5194/nhess-15-2111-2015, 2015
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In this work, we present a new semi-automatic procedure to prepare landslide inventory maps that uses GIS applications and tools for the digitization of photo-interpreted data. Results show that the new semi-automatic procedure proves more efficient for the production of landslide inventories and results in the production of more accurate maps, compared to the manual procedure. The presented work has potential consequences for multiple applications of landslide studies.
A. C. Cunningham, J. Wallinga, N. Hobo, A. J. Versendaal, B. Makaske, and H. Middelkoop
Earth Surf. Dynam., 3, 55–65, https://doi.org/10.5194/esurf-3-55-2015, https://doi.org/10.5194/esurf-3-55-2015, 2015
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Rivers transport sediment from mountains to coast, but on the way sediment is trapped and re-eroded multiple times. We looked at Rhine river sediments to see if they preserve evidence of how geomorphic variables have changed over time. We found that measured signals potentially relate to water level and river management practices. These relationships can be treated as hypotheses to guide further research, and our statistical approach will increase the utility of research in this field.
M. Mergili, I. Marchesini, M. Alvioli, M. Metz, B. Schneider-Muntau, M. Rossi, and F. Guzzetti
Geosci. Model Dev., 7, 2969–2982, https://doi.org/10.5194/gmd-7-2969-2014, https://doi.org/10.5194/gmd-7-2969-2014, 2014
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The article deals with strategies to (i) reduce computation time and to (ii) appropriately account for uncertain input parameters when applying an open source GIS sliding surface model to estimate landslide susceptibility for a 90km² study area in central Italy. For (i), the area is split into a large number of tiles, enabling the exploitation of multi-processor computing environments. For (ii), the model is run with various parameter combinations to compute the slope failure probability.
P. Salvati, C. Bianchi, F. Fiorucci, P. Giostrella, I. Marchesini, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 2589–2603, https://doi.org/10.5194/nhess-14-2589-2014, https://doi.org/10.5194/nhess-14-2589-2014, 2014
G. Vessia, M. Parise, M. T. Brunetti, S. Peruccacci, M. Rossi, C. Vennari, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 2399–2408, https://doi.org/10.5194/nhess-14-2399-2014, https://doi.org/10.5194/nhess-14-2399-2014, 2014
I. Marchesini, F. Ardizzone, M. Alvioli, M. Rossi, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 2215–2231, https://doi.org/10.5194/nhess-14-2215-2014, https://doi.org/10.5194/nhess-14-2215-2014, 2014
B. Merz, J. Aerts, K. Arnbjerg-Nielsen, M. Baldi, A. Becker, A. Bichet, G. Blöschl, L. M. Bouwer, A. Brauer, F. Cioffi, J. M. Delgado, M. Gocht, F. Guzzetti, S. Harrigan, K. Hirschboeck, C. Kilsby, W. Kron, H.-H. Kwon, U. Lall, R. Merz, K. Nissen, P. Salvatti, T. Swierczynski, U. Ulbrich, A. Viglione, P. J. Ward, M. Weiler, B. Wilhelm, and M. Nied
Nat. Hazards Earth Syst. Sci., 14, 1921–1942, https://doi.org/10.5194/nhess-14-1921-2014, https://doi.org/10.5194/nhess-14-1921-2014, 2014
A. Manconi, F. Casu, F. Ardizzone, M. Bonano, M. Cardinali, C. De Luca, E. Gueguen, I. Marchesini, M. Parise, C. Vennari, R. Lanari, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 1835–1841, https://doi.org/10.5194/nhess-14-1835-2014, https://doi.org/10.5194/nhess-14-1835-2014, 2014
A. C. Mondini, A. Viero, M. Cavalli, L. Marchi, G. Herrera, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 1749–1759, https://doi.org/10.5194/nhess-14-1749-2014, https://doi.org/10.5194/nhess-14-1749-2014, 2014
S. Raia, M. Alvioli, M. Rossi, R. L. Baum, J. W. Godt, and F. Guzzetti
Geosci. Model Dev., 7, 495–514, https://doi.org/10.5194/gmd-7-495-2014, https://doi.org/10.5194/gmd-7-495-2014, 2014
C. Vennari, S. L. Gariano, L. Antronico, M. T. Brunetti, G. Iovine, S. Peruccacci, O. Terranova, and F. Guzzetti
Nat. Hazards Earth Syst. Sci., 14, 317–330, https://doi.org/10.5194/nhess-14-317-2014, https://doi.org/10.5194/nhess-14-317-2014, 2014
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Maxime Morel, Guillaume Piton, Damien Kuss, Guillaume Evin, and Caroline Le Bouteiller
Nat. Hazards Earth Syst. Sci., 23, 1769–1787, https://doi.org/10.5194/nhess-23-1769-2023, https://doi.org/10.5194/nhess-23-1769-2023, 2023
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In mountain catchments, damage during floods is generally primarily driven by the supply of a massive amount of sediment. Predicting how much sediment can be delivered by frequent and infrequent events is thus important in hazard studies. This paper uses data gathered during the maintenance operation of about 100 debris retention basins to build simple equations aiming at predicting sediment supply from simple parameters describing the upstream catchment.
Elsa S. Culler, Ben Livneh, Balaji Rajagopalan, and Kristy F. Tiampo
Nat. Hazards Earth Syst. Sci., 23, 1631–1652, https://doi.org/10.5194/nhess-23-1631-2023, https://doi.org/10.5194/nhess-23-1631-2023, 2023
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Landslides have often been observed in the aftermath of wildfires. This study explores regional patterns in the rainfall that caused landslides both after fires and in unburned locations. In general, landslides that occur after fires are triggered by less rainfall, confirming that fire helps to set the stage for landslides. However, there are regional differences in the ways in which fire impacts landslides, such as the size and direction of shifts in the seasonality of landslides after fires.
Stefan Steger, Mateo Moreno, Alice Crespi, Peter James Zellner, Stefano Luigi Gariano, Maria Teresa Brunetti, Massimo Melillo, Silvia Peruccacci, Francesco Marra, Robin Kohrs, Jason Goetz, Volkmar Mair, and Massimiliano Pittore
Nat. Hazards Earth Syst. Sci., 23, 1483–1506, https://doi.org/10.5194/nhess-23-1483-2023, https://doi.org/10.5194/nhess-23-1483-2023, 2023
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We present a novel data-driven modelling approach to determine season-specific critical precipitation conditions for landslide occurrence. It is shown that the amount of precipitation required to trigger a landslide in South Tyrol varies from season to season. In summer, a higher amount of preparatory precipitation is required to trigger a landslide, probably due to denser vegetation and higher temperatures. We derive dynamic thresholds that directly relate to hit rates and false-alarm rates.
Yaspal Sundriyal, Vipin Kumar, Neha Chauhan, Sameeksha Kaushik, Rahul Ranjan, and Mohit Kumar Punia
Nat. Hazards Earth Syst. Sci., 23, 1425–1431, https://doi.org/10.5194/nhess-23-1425-2023, https://doi.org/10.5194/nhess-23-1425-2023, 2023
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The NW Himalaya has been one of the most affected terrains of the Himalaya, subject to disastrous landslides. This article focuses on two towns (Joshimath and Bhatwari) of the NW Himalaya, which have been witnessing subsidence for decades. We used a slope stability simulation to determine the response of the hillslopes accommodating these towns under various loading conditions. We found that the maximum displacement in these hillslopes might reach up to 20–25 m.
Yu Zhuang, Aiguo Xing, Perry Bartelt, Muhammad Bilal, and Zhaowei Ding
Nat. Hazards Earth Syst. Sci., 23, 1257–1266, https://doi.org/10.5194/nhess-23-1257-2023, https://doi.org/10.5194/nhess-23-1257-2023, 2023
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Tree destruction is often used to back calculate the air blast impact region and to estimate the air blast power. Here we established a novel model to assess air blast power using tree destruction information. We find that the dynamic magnification effect makes the trees easier to damage by a landslide-induced air blast, but the large tree deformation would weaken the effect. Bending and overturning are two likely failure modes, which depend heavily on the properties of trees.
Suzanne Lapillonne, Firmin Fontaine, Frédéric Liebault, Vincent Richefeu, and Guillaume Piton
Nat. Hazards Earth Syst. Sci., 23, 1241–1256, https://doi.org/10.5194/nhess-23-1241-2023, https://doi.org/10.5194/nhess-23-1241-2023, 2023
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Debris flows are fast flows most often found in torrential watersheds. They are composed of two phases: a liquid phase which can be mud-like and a granular phase, including large boulders, transported along with the flow. Due to their destructive nature, accessing features of the flow, such as velocity and flow height, is difficult. We present a protocol to analyse debris flow data and results of the Réal torrent in France. These results will help experts in designing models.
Carlos Millán-Arancibia and Waldo Lavado-Casimiro
Nat. Hazards Earth Syst. Sci., 23, 1191–1206, https://doi.org/10.5194/nhess-23-1191-2023, https://doi.org/10.5194/nhess-23-1191-2023, 2023
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This study is the first approximation of regional rainfall thresholds for shallow landslide occurrence in Peru. This research was generated from a gridded precipitation data and landslide inventory. The analysis showed that the threshold based on the combination of mean daily intensity–duration variables gives the best results for separating rainfall events that generate landslides. Through this work the potential of thresholds for landslide monitoring at the regional scale is demonstrated.
Luca Verrucci, Giovanni Forte, Melania De Falco, Paolo Tommasi, Giuseppe Lanzo, Kevin W. Franke, and Antonio Santo
Nat. Hazards Earth Syst. Sci., 23, 1177–1190, https://doi.org/10.5194/nhess-23-1177-2023, https://doi.org/10.5194/nhess-23-1177-2023, 2023
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Stability analyses in static and seismic conditions were performed on four rockslides that occurred during the main shocks of the 2016–2017 central Italy seismic sequence. These results also indicate that specific structural features of the slope must carefully be accounted for in evaluating potential hazards on transportation infrastructures in mountainous regions.
Enner Alcântara, José A. Marengo, José Mantovani, Luciana R. Londe, Rachel Lau Yu San, Edward Park, Yunung Nina Lin, Jingyu Wang, Tatiana Mendes, Ana Paula Cunha, Luana Pampuch, Marcelo Seluchi, Silvio Simões, Luz Adriana Cuartas, Demerval Goncalves, Klécia Massi, Regina Alvalá, Osvaldo Moraes, Carlos Souza Filho, Rodolfo Mendes, and Carlos Nobre
Nat. Hazards Earth Syst. Sci., 23, 1157–1175, https://doi.org/10.5194/nhess-23-1157-2023, https://doi.org/10.5194/nhess-23-1157-2023, 2023
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The municipality of Petrópolis (approximately 305 687 inhabitants) is nestled in the mountains 68 km outside the city of Rio de Janeiro. On 15 February 2022, the city of Petrópolis in Rio de Janeiro, Brazil, received an unusually high volume of rain within 3 h (258 mm). This resulted in flash floods and subsequent landslides that caused 231 fatalities, the deadliest landslide disaster recorded in Petrópolis. This work shows how the disaster was triggered.
Joshua N. Jones, Georgina L. Bennett, Claudia Abancó, Mark A. M. Matera, and Fibor J. Tan
Nat. Hazards Earth Syst. Sci., 23, 1095–1115, https://doi.org/10.5194/nhess-23-1095-2023, https://doi.org/10.5194/nhess-23-1095-2023, 2023
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We modelled where landslides occur in the Philippines using landslide data from three typhoon events in 2009, 2018, and 2019. These models show where landslides occurred within the landscape. By comparing the different models, we found that the 2019 landslides were occurring all across the landscape, whereas the 2009 and 2018 landslides were mostly occurring at specific slope angles and aspects. This shows that landslide susceptibility must be considered variable through space and time.
Shalev Siman-Tov and Francesco Marra
Nat. Hazards Earth Syst. Sci., 23, 1079–1093, https://doi.org/10.5194/nhess-23-1079-2023, https://doi.org/10.5194/nhess-23-1079-2023, 2023
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Debris flows represent a threat to infrastructure and the population. In arid areas, they are observed when heavy rainfall hits steep slopes with sediments. Here, we use digital surface models and radar rainfall data to detect and characterize the triggering and non-triggering rainfall conditions. We find that rainfall intensity alone is insufficient to explain the triggering. We suggest that antecedent rainfall could represent a critical factor for debris flow triggering in arid regions.
Xun Huang, Zhijian Zhang, and Guoping Xiang
Nat. Hazards Earth Syst. Sci., 23, 871–889, https://doi.org/10.5194/nhess-23-871-2023, https://doi.org/10.5194/nhess-23-871-2023, 2023
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A sensitivity analysis on the building impact force resulting from the representative built environment parameters is executed through the FLOW-3D model. The surrounding buildings' properties, especially the azimuthal angle, have been confirmed to play significant roles in determining the peak impact forces. The single and combined effects of built environments are analyzed in detail. This will improve understanding of vulnerability assessment and migration design against debris flow hazards.
Ascanio Rosi, William Frodella, Nicola Nocentini, Francesco Caleca, Hans Balder Havenith, Alexander Strom, and Veronica Tofani
Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2023-33, https://doi.org/10.5194/nhess-2023-33, 2023
Revised manuscript accepted for NHESS
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This work was carried out within the SFRARR Project (“Strengthening Financial Resilience and Accelerating Risk Reduction in Central Asia”), and is focused on the first landslide susceptibility analysis at a regional scale for Central Asia. The most detailed available landslide inventories were implemented in a Random Forest model. The final aim was to provide a useful tool for reduction strategies to landslide scientists, practitioners and administrators.
Jean-Claude Maki Mateso, Charles L. Bielders, Elise Monsieurs, Arthur Depicker, Benoît Smets, Théophile Tambala, Luc Bagalwa Mateso, and Olivier Dewitte
Nat. Hazards Earth Syst. Sci., 23, 643–666, https://doi.org/10.5194/nhess-23-643-2023, https://doi.org/10.5194/nhess-23-643-2023, 2023
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This research highlights the importance of human activities on the occurrence of landslides and the need to consider this context when studying hillslope instability patterns in regions under anthropogenic pressure. Also, this study highlights the importance of considering the timing of landslides and hence the added value of using historical information for compiling an inventory.
Jakob Rom, Florian Haas, Tobias Heckmann, Moritz Altmann, Fabian Fleischer, Camillo Ressl, Sarah Betz-Nutz, and Michael Becht
Nat. Hazards Earth Syst. Sci., 23, 601–622, https://doi.org/10.5194/nhess-23-601-2023, https://doi.org/10.5194/nhess-23-601-2023, 2023
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In this study, an area-wide slope-type debris flow record has been established for Horlachtal, Austria, since 1947 based on historical and recent remote sensing data. Spatial and temporal analyses show variations in debris flow activity in space and time in a high-alpine region. The results can contribute to a better understanding of past slope-type debris flow dynamics in the context of extreme precipitation events and their possible future development.
Camilla Lanfranconi, Paolo Frattini, Gianluca Sala, Davide Bertolo, Juanjuan Sun, and Giovanni Battista Crosta
EGUsphere, https://doi.org/10.5194/egusphere-2022-1521, https://doi.org/10.5194/egusphere-2022-1521, 2023
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This paper presents a study on rockfall dynamics and hazard, examining the impact of the presence of trees along slope and block fragmentation. We compared rockfall simulations that explicitly model the presence of trees and fragmentation with a classical approach that account for these phenomena in model parameters. Both the hazard and the kinetic energy change. We also used a non-parametric probabilistic rockfall hazard analysis method for hazard mapping.
Tom Birien and Francis Gauthier
Nat. Hazards Earth Syst. Sci., 23, 343–360, https://doi.org/10.5194/nhess-23-343-2023, https://doi.org/10.5194/nhess-23-343-2023, 2023
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On highly fractured rockwalls such as those found in northern Gaspésie, most rockfalls are triggered by weather conditions. This study highlights that in winter, rockfall frequency is 12 times higher during a superficial thaw than during a cold period in which temperature remains below 0 °C. In summer, rockfall frequency is 22 times higher during a heavy rainfall event than during a mainly dry period. This knowledge could be used to implement a risk management strategy.
Nunziarita Palazzolo, David J. Peres, Enrico Creaco, and Antonino Cancelliere
Nat. Hazards Earth Syst. Sci., 23, 279–291, https://doi.org/10.5194/nhess-23-279-2023, https://doi.org/10.5194/nhess-23-279-2023, 2023
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We propose an approach exploiting PCA to derive hydrometeorological landslide-triggering thresholds using multi-layered soil moisture data from ERA5-Land reanalysis. Comparison of thresholds based on single- and multi-layered soil moisture information provides a means to identify the significance of multi-layered data for landslide triggering in a region. In Sicily, the proposed approach yields thresholds with a higher performance than traditional precipitation-based ones (TSS = 0.71 vs. 0.50).
Raphael Knevels, Helene Petschko, Herwig Proske, Philip Leopold, Aditya N. Mishra, Douglas Maraun, and Alexander Brenning
Nat. Hazards Earth Syst. Sci., 23, 205–229, https://doi.org/10.5194/nhess-23-205-2023, https://doi.org/10.5194/nhess-23-205-2023, 2023
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In summer 2009 and 2014, rainfall events occurred in the Styrian Basin (Austria), triggering thousands of landslides. Landslide storylines help to show potential future changes under changing environmental conditions. The often neglected uncertainty quantification was the aim of this study. We found uncertainty arising from the landslide model to be of the same order as climate scenario uncertainty. Understanding the dimensions of uncertainty is crucial for allowing informed decision-making.
Francis K. Rengers, Luke A. McGuire, Katherine R. Barnhart, Ann M. Youberg, Daniel Cadol, Alexander N. Gorr, Olivia Hoch, Rebecca Beers, and Jason W. Kean
EGUsphere, https://doi.org/10.5194/egusphere-2022-1398, https://doi.org/10.5194/egusphere-2022-1398, 2022
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Debris flows often occur after wildfires. These debris flows move water, sediment, and wood. The wood can get stuck in channels and create piles of sediment within channels. We investigated how the channel and wood size/shape influence how much sediment is stored. We also used a series of equations to estimate how the wood size/shape would reflect the velocity needed to break the wood. These data will help improve models and insight from future field investigations.
Fabian Walter, Elias Hodel, Erik S. Mannerfelt, Kristen Cook, Michael Dietze, Livia Estermann, Michaela Wenner, Daniel Farinotti, Martin Fengler, Lukas Hammerschmidt, Flavia Hänsli, Jacob Hirschberg, Brian McArdell, and Peter Molnar
Nat. Hazards Earth Syst. Sci., 22, 4011–4018, https://doi.org/10.5194/nhess-22-4011-2022, https://doi.org/10.5194/nhess-22-4011-2022, 2022
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Debris flows are dangerous sediment–water mixtures in steep terrain. Their formation takes place in poorly accessible terrain where instrumentation cannot be installed. Here we propose to monitor such source terrain with an autonomous drone for mapping sediments which were left behind by debris flows or may contribute to future events. Short flight intervals elucidate changes of such sediments, providing important information for landscape evolution and the likelihood of future debris flows.
Marc Peruzzetto, Yoann Legendre, Aude Nachbaur, Thomas J. B. Dewez, Yannick Thiery, Clara Levy, and Benoit Vittecoq
Nat. Hazards Earth Syst. Sci., 22, 3973–3992, https://doi.org/10.5194/nhess-22-3973-2022, https://doi.org/10.5194/nhess-22-3973-2022, 2022
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Volcanic edifices result from successive construction and dismantling phases. Thus, the geological units forming volcanoes display complex geometries. We show that such geometries can be reconstructed thanks to aerial views, topographic surveys and photogrammetric models. In our case study of the Samperre cliff (Martinique, Lesser Antilles), it allows us to link destabilizations from a rocky cliff to the existence of a filled paleo-valley and estimate a potentially unstable volume.
Abdellah Khouz, Jorge Trindade, Sérgio C. Oliveira, Fatima El Bchari, Blaid Bougadir, Ricardo A. C. Garcia, and Mourad Jadoud
Nat. Hazards Earth Syst. Sci., 22, 3793–3814, https://doi.org/10.5194/nhess-22-3793-2022, https://doi.org/10.5194/nhess-22-3793-2022, 2022
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The aim of this study was to assess the landslide susceptibility of the rocky coast of Essaouira using the information value model. The resulting susceptibility maps could be used for both environmental protection and general planning of future development activities.
Kamal Rana, Nishant Malik, and Ugur Ozturk
Nat. Hazards Earth Syst. Sci., 22, 3751–3764, https://doi.org/10.5194/nhess-22-3751-2022, https://doi.org/10.5194/nhess-22-3751-2022, 2022
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The landslide hazard models assist in mitigating losses due to landslides. However, these models depend on landslide databases, which often have missing triggering information, rendering these databases unusable for landslide hazard models. In this work, we developed a Python library, Landsifier, consisting of three different methods to identify the triggers of landslides. These methods can classify landslide triggers with high accuracy using only a landslide polygon shapefile as an input.
Axel A. J. Deijns, Olivier Dewitte, Wim Thiery, Nicolas d'Oreye, Jean-Philippe Malet, and François Kervyn
Nat. Hazards Earth Syst. Sci., 22, 3679–3700, https://doi.org/10.5194/nhess-22-3679-2022, https://doi.org/10.5194/nhess-22-3679-2022, 2022
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Landslides and flash floods are rainfall-induced processes that often co-occur and interact, generally very quickly. In mountainous cloud-covered environments, determining when these processes occur remains challenging. We propose a regional methodology using open-access satellite radar images that allow for the timing of landslide and flash floods events, in the contrasting landscapes of tropical Africa, with an accuracy of up to a few days. The methodology shows potential for transferability.
Judith Uwihirwe, Alessia Riveros, Hellen Wanjala, Jaap Schellekens, Frederiek Sperna Weiland, Markus Hrachowitz, and Thom A. Bogaard
Nat. Hazards Earth Syst. Sci., 22, 3641–3661, https://doi.org/10.5194/nhess-22-3641-2022, https://doi.org/10.5194/nhess-22-3641-2022, 2022
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This study compared gauge-based and satellite-based precipitation products. Similarly, satellite- and hydrological model-derived soil moisture was compared to in situ soil moisture and used in landslide hazard assessment and warning. The results reveal the cumulative 3 d rainfall from the NASA-GPM to be the most effective landslide trigger. The modelled antecedent soil moisture in the root zone was the most informative hydrological variable for landslide hazard assessment and warning in Rwanda.
Hans-Balder Havenith, Kelly Guerrier, Romy Schlögel, Anika Braun, Sophia Ulysse, Anne-Sophie Mreyen, Karl-Henry Victor, Newdeskarl Saint-Fleur, Léna Cauchie, Dominique Boisson, and Claude Prépetit
Nat. Hazards Earth Syst. Sci., 22, 3361–3384, https://doi.org/10.5194/nhess-22-3361-2022, https://doi.org/10.5194/nhess-22-3361-2022, 2022
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We present a new landslide inventory for the 2021, M 7.2, Haiti, earthquake. We compare characteristics of this inventory with those of the 2010 seismically induced landslides, highlighting the much larger total area of 2021 landslides. This fact could be related to the larger earthquake magnitude in 2021, to the more central location of the fault segment ruptured in 2021 with respect to coastal zones, and/or to possible climatic preconditioning of slope failures in the 2021 affected area.
Maximillian Van Wyk de Vries, Shashank Bhushan, Mylène Jacquemart, César Deschamps-Berger, Etienne Berthier, Simon Gascoin, David E. Shean, Dan H. Shugar, and Andreas Kääb
Nat. Hazards Earth Syst. Sci., 22, 3309–3327, https://doi.org/10.5194/nhess-22-3309-2022, https://doi.org/10.5194/nhess-22-3309-2022, 2022
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On 7 February 2021, a large rock–ice avalanche occurred in Chamoli, Indian Himalaya. The resulting debris flow swept down the nearby valley, leaving over 200 people dead or missing. We use a range of satellite datasets to investigate how the collapse area changed prior to collapse. We show that signs of instability were visible as early 5 years prior to collapse. However, it would likely not have been possible to predict the timing of the event from current satellite datasets.
Bastian van den Bout, Chenxiao Tang, Cees van Westen, and Victor Jetten
Nat. Hazards Earth Syst. Sci., 22, 3183–3209, https://doi.org/10.5194/nhess-22-3183-2022, https://doi.org/10.5194/nhess-22-3183-2022, 2022
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Natural hazards such as earthquakes, landslides, and flooding do not always occur as stand-alone events. After the 2008 Wenchuan earthquake, a co-seismic landslide blocked a stream in Hongchun. Two years later, a debris flow breached the material, blocked the Min River, and resulted in flooding of a small town. We developed a multi-process model that captures the full cascade. Despite input and process uncertainties, probability of flooding was high due to topography and trigger intensities.
Lucas Pelascini, Philippe Steer, Maxime Mouyen, and Laurent Longuevergne
Nat. Hazards Earth Syst. Sci., 22, 3125–3141, https://doi.org/10.5194/nhess-22-3125-2022, https://doi.org/10.5194/nhess-22-3125-2022, 2022
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Landslides represent a major natural hazard and are often triggered by typhoons. We present a new 2D model computing the respective role of rainfall infiltration, atmospheric depression and groundwater in slope stability during typhoons. The results show rainfall is the strongest factor of destabilisation. However, if the slope is fully saturated, near the toe of the slope or during the wet season, rainfall infiltration is limited and atmospheric pressure change can become the dominant factor.
Anne Felsberg, Jean Poesen, Michel Bechtold, Matthias Vanmaercke, and Gabriëlle J. M. De Lannoy
Nat. Hazards Earth Syst. Sci., 22, 3063–3082, https://doi.org/10.5194/nhess-22-3063-2022, https://doi.org/10.5194/nhess-22-3063-2022, 2022
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In this study we assessed global landslide susceptibility at the coarse 36 km spatial resolution of global satellite soil moisture observations to prepare for a subsequent combination of the two. Specifically, we focus therefore on the susceptibility of hydrologically triggered landslides. We introduce ensemble techniques, common in, for example, meteorology but not yet in the landslide community, to retrieve reliable estimates of the total prediction uncertainty.
Txomin Bornaetxea, Ivan Marchesini, Sumit Kumar, Rabisankar Karmakar, and Alessandro Mondini
Nat. Hazards Earth Syst. Sci., 22, 2929–2941, https://doi.org/10.5194/nhess-22-2929-2022, https://doi.org/10.5194/nhess-22-2929-2022, 2022
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One cannot know if there is a landslide or not in an area that one has not observed. This is an obvious statement, but when landslide inventories are obtained by field observation, this fact is seldom taken into account. Since fieldwork campaigns are often done following the roads, we present a methodology to estimate the visibility of the terrain from the roads, and we demonstrate that fieldwork-based inventories are underestimating landslide density in less visible areas.
Katy Burrows, Odin Marc, and Dominique Remy
Nat. Hazards Earth Syst. Sci., 22, 2637–2653, https://doi.org/10.5194/nhess-22-2637-2022, https://doi.org/10.5194/nhess-22-2637-2022, 2022
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The locations of triggered landslides following a rainfall event can be identified in optical satellite images. However cloud cover associated with the rainfall means that these images cannot be used to identify landslide timing. Timings of landslides triggered during long rainfall events are often unknown. Here we present methods of using Sentinel-1 satellite radar data, acquired every 12 d globally in all weather conditions, to better constrain the timings of rainfall-triggered landslides.
Feiko Bernard van Zadelhoff, Adel Albaba, Denis Cohen, Chris Phillips, Bettina Schaefli, Luuk Dorren, and Massimiliano Schwarz
Nat. Hazards Earth Syst. Sci., 22, 2611–2635, https://doi.org/10.5194/nhess-22-2611-2022, https://doi.org/10.5194/nhess-22-2611-2022, 2022
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Shallow landslides pose a risk to people, property and infrastructure. Assessment of this hazard and the impact of protective measures can reduce losses. We developed a model (SlideforMAP) that can assess the shallow-landslide risk on a regional scale for specific rainfall events. Trees are an effective and cheap protective measure on a regional scale. Our model can assess their hazard reduction down to the individual tree level.
Chuxuan Li, Alexander L. Handwerger, Jiali Wang, Wei Yu, Xiang Li, Noah J. Finnegan, Yingying Xie, Giuseppe Buscarnera, and Daniel E. Horton
Nat. Hazards Earth Syst. Sci., 22, 2317–2345, https://doi.org/10.5194/nhess-22-2317-2022, https://doi.org/10.5194/nhess-22-2317-2022, 2022
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In January 2021 a storm triggered numerous debris flows in a wildfire burn scar in California. We use a hydrologic model to assess debris flow susceptibility in pre-fire and postfire scenarios. Compared to pre-fire conditions, postfire conditions yield dramatic increases in peak water discharge, substantially increasing debris flow susceptibility. Our work highlights the hydrologic model's utility in investigating and potentially forecasting postfire debris flows at regional scales.
Saskia de Vilder, Chris Massey, Biljana Lukovic, Tony Taig, and Regine Morgenstern
Nat. Hazards Earth Syst. Sci., 22, 2289–2316, https://doi.org/10.5194/nhess-22-2289-2022, https://doi.org/10.5194/nhess-22-2289-2022, 2022
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This study calculates the fatality risk posed by landslides while visiting Franz Josef Glacier and Fox Glacier valleys, New Zealand, for nine different scenarios, where the variables of the risk equation were adjusted to determine the range in risk values and associated uncertainty. The results show that it is important to consider variable inputs that change through time, such as the increasing probability of an earthquake and the impact of climate change on landslide characteristics.
Yiwei Zhang, Jianping Chen, Qing Wang, Chun Tan, Yongchao Li, Xiaohui Sun, and Yang Li
Nat. Hazards Earth Syst. Sci., 22, 2239–2255, https://doi.org/10.5194/nhess-22-2239-2022, https://doi.org/10.5194/nhess-22-2239-2022, 2022
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The disaster prevention and mitigation of debris flow is a very important scientific problem. Our model is based on geographic information system (GIS), combined with grey relational, data-driven and fuzzy logic methods. Through our results, we believe that the streamlining of factors and scientific classification should attract attention from other researchers to optimize a model. We also propose a good perspective to make better use of the watershed feature parameters.
Jan Pfeiffer, Thomas Zieher, Jan Schmieder, Thom Bogaard, Martin Rutzinger, and Christoph Spötl
Nat. Hazards Earth Syst. Sci., 22, 2219–2237, https://doi.org/10.5194/nhess-22-2219-2022, https://doi.org/10.5194/nhess-22-2219-2022, 2022
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The activity of slow-moving deep-seated landslides is commonly governed by pore pressure variations within the shear zone. Groundwater recharge as a consequence of precipitation therefore is a process regulating the activity of landslides. In this context, we present a highly automated geo-statistical approach to spatially assess groundwater recharge controlling the velocity of a deep-seated landslide in Tyrol, Austria.
Ivo Fustos-Toribio, Nataly Manque-Roa, Daniel Vásquez Antipan, Mauricio Hermosilla Sotomayor, and Viviana Letelier Gonzalez
Nat. Hazards Earth Syst. Sci., 22, 2169–2183, https://doi.org/10.5194/nhess-22-2169-2022, https://doi.org/10.5194/nhess-22-2169-2022, 2022
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We develop for the first time a rainfall-induced landslide early warning system for the south of Chile. We used forecast precipitation values at different scales using mesoscale models to evaluate the probability of landslides using statistical models. We showed the feasibility of implementing these models in future, supporting stakeholders and decision-makers.
Katrin M. Nissen, Stefan Rupp, Thomas M. Kreuzer, Björn Guse, Bodo Damm, and Uwe Ulbrich
Nat. Hazards Earth Syst. Sci., 22, 2117–2130, https://doi.org/10.5194/nhess-22-2117-2022, https://doi.org/10.5194/nhess-22-2117-2022, 2022
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A statistical model is introduced which quantifies the influence of individual potential triggering factors and their interactions on rockfall probability in central Europe. The most important factor is daily precipitation, which is most effective if sub-surface moisture levels are high. Freeze–thaw cycles in the preceding days can further increase the rockfall hazard. The model can be applied to climate simulations in order to investigate the effect of climate change on rockfall probability.
Andreas Schimmel, Velio Coviello, and Francesco Comiti
Nat. Hazards Earth Syst. Sci., 22, 1955–1968, https://doi.org/10.5194/nhess-22-1955-2022, https://doi.org/10.5194/nhess-22-1955-2022, 2022
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The estimation of debris flow velocity and volume is a fundamental task for the development of early warning systems and other mitigation measures. This work provides a first approach for estimating the velocity and the total volume of debris flows based on the seismic signal detected with simple, low-cost geophones installed along the debris flow channel. The developed method was applied to seismic data collected at three test sites in the Alps: Gadria and Cancia (IT) and Lattenbach (AT).
Judith Uwihirwe, Markus Hrachowitz, and Thom Bogaard
Nat. Hazards Earth Syst. Sci., 22, 1723–1742, https://doi.org/10.5194/nhess-22-1723-2022, https://doi.org/10.5194/nhess-22-1723-2022, 2022
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This research tested the value of regional groundwater level information to improve landslide predictions with empirical models based on the concept of threshold levels. In contrast to precipitation-based thresholds, the results indicated that relying on threshold models exclusively defined using hydrological variables such as groundwater levels can lead to improved landslide predictions due to their implicit consideration of long-term antecedent conditions until the day of landslide occurrence.
Andrea Manconi, Alessandro C. Mondini, and the AlpArray working group
Nat. Hazards Earth Syst. Sci., 22, 1655–1664, https://doi.org/10.5194/nhess-22-1655-2022, https://doi.org/10.5194/nhess-22-1655-2022, 2022
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Information on when, where, and how landslide events occur is the key to building complete catalogues and performing accurate hazard assessments. Here we show a procedure that allows us to benefit from the increased density of seismic sensors installed on ground for earthquake monitoring and from the unprecedented availability of satellite radar data. We show how the procedure works on a recent sequence of landslides that occurred at Piz Cengalo (Swiss Alps) in 2017.
Andrew Mitchell, Sophia Zubrycky, Scott McDougall, Jordan Aaron, Mylène Jacquemart, Johannes Hübl, Roland Kaitna, and Christoph Graf
Nat. Hazards Earth Syst. Sci., 22, 1627–1654, https://doi.org/10.5194/nhess-22-1627-2022, https://doi.org/10.5194/nhess-22-1627-2022, 2022
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Debris flows are complex, surging movements of sediment and water. Discharge observations from well-studied debris-flow channels were used as inputs for a numerical modelling study of the downstream effects of chaotic inflows. The results show that downstream impacts are sensitive to inflow conditions. Inflow conditions for predictive modelling are highly uncertain, and our method provides a means to estimate the potential variability in future events.
Sansar Raj Meena, Silvia Puliero, Kushanav Bhuyan, Mario Floris, and Filippo Catani
Nat. Hazards Earth Syst. Sci., 22, 1395–1417, https://doi.org/10.5194/nhess-22-1395-2022, https://doi.org/10.5194/nhess-22-1395-2022, 2022
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The study investigated the importance of the conditioning factors in predicting landslide occurrences using the mentioned models. In this paper, we evaluated the importance of the conditioning factors (features) in the overall prediction capabilities of the statistical and machine learning algorithms.
Pierpaolo Distefano, David J. Peres, Pietro Scandura, and Antonino Cancelliere
Nat. Hazards Earth Syst. Sci., 22, 1151–1157, https://doi.org/10.5194/nhess-22-1151-2022, https://doi.org/10.5194/nhess-22-1151-2022, 2022
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In the communication, we introduce the use of artificial neural networks (ANNs) for improving the performance of rainfall thresholds for landslide early warning. Results show how ANNs using rainfall event duration and mean intensity perform significantly better than a classical power law based on the same variables. Adding peak rainfall intensity as input to the ANN improves performance even more. This further demonstrates the potentialities of the proposed machine learning approach.
Robert Emberson, Dalia B. Kirschbaum, Pukar Amatya, Hakan Tanyas, and Odin Marc
Nat. Hazards Earth Syst. Sci., 22, 1129–1149, https://doi.org/10.5194/nhess-22-1129-2022, https://doi.org/10.5194/nhess-22-1129-2022, 2022
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Understanding where landslides occur in mountainous areas is critical to support hazard analysis as well as understand landscape evolution. In this study, we present a large compilation of inventories of landslides triggered by rainfall, including several that are described here for the first time. We analyze the topographic characteristics of the landslides, finding consistent relationships for landslide source and deposition areas, despite differences in the inventories' locations.
Alexander L. Handwerger, Mong-Han Huang, Shannan Y. Jones, Pukar Amatya, Hannah R. Kerner, and Dalia B. Kirschbaum
Nat. Hazards Earth Syst. Sci., 22, 753–773, https://doi.org/10.5194/nhess-22-753-2022, https://doi.org/10.5194/nhess-22-753-2022, 2022
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Rapid detection of landslides is critical for emergency response and disaster mitigation. Here we develop a global landslide detection tool in Google Earth Engine that uses satellite radar data to measure changes in the ground surface properties. We find that we can detect areas with high landslide density within days of a triggering event. Our approach allows the broader hazard community to utilize these state-of-the-art data for improved situational awareness of landslide hazards.
Qiwen Lin, Yufeng Wang, Yu Xie, Qiangong Cheng, and Kaifeng Deng
Nat. Hazards Earth Syst. Sci., 22, 639–657, https://doi.org/10.5194/nhess-22-639-2022, https://doi.org/10.5194/nhess-22-639-2022, 2022
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Fracturing and fragmentation of rock blocks are important and universal phenomena during the movement of rock avalanches (large and long-run-out rockslide-debris avalanches). The movement of a fragmenting rock block is simulated by the discrete element method, aiming to quantify the fracturing and fragmentation effect of the block in propagation. The fracturing and fragmentation processes and their influences on energy transformation in the system are described in detail.
Napoleon Gudino-Elizondo, Matthew W. Brand, Trent W. Biggs, Alejandro Hinojosa-Corona, Álvaro Gómez-Gutiérrez, Eddy Langendoen, Ronald Bingner, Yongping Yuan, and Brett F. Sanders
Nat. Hazards Earth Syst. Sci., 22, 523–538, https://doi.org/10.5194/nhess-22-523-2022, https://doi.org/10.5194/nhess-22-523-2022, 2022
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Mass movement hazards in the form of gullies and landslides pose significant risks in urbanizing areas yet are poorly documented. This paper presents observations and modeling of mass movement events over a 5-year period in Tijuana, Mexico. Three major events were observed, and all were linked to water resources infrastructure failures (WRIFs), namely leaks and breaks in water supply pipes. Modeling shows that WRIF-based erosion was also a non-negligible contributor to the total sediment budget.
Cited articles
Akaike, H.: Information theory and an extension of the maximum likelihood
principle, in: Selected Papers of Hirotugu Akaike, Springer, New York, 199–213, 1998.
Alvioli, M., Marchesini, I., Reichenbach, P., Rossi, M., Ardizzone, F.,
Fiorucci, F., and Guzzetti, F.: Automatic delineation of geomorphological slope units with r.slopeunits v1.0 and their optimization for landslide
susceptibility modeling, Geosci. Model Dev., 9, 3975–3991,
https://doi.org/10.5194/gmd-9-3975-2016, 2016.
Ardizzone, F., Cardinali, M., Galli, M., Guzzetti, F., and Reichenbach, P.: Identification and mapping of recent rainfall-induced landslides using elevation data collected by airborne Lidar, Nat. Hazards Earth Syst. Sci., 7, 637–650, https://doi.org/10.5194/nhess-7-637-2007, 2007.
Ardizzone, F., Fiorucci, F., Santangelo, M., Cardinali, M., Mondini, A. C.,
Rossi, M., Reichenbach, P., and Guzzetti, F.: Very-high resolution stereoscopic satellite images for landslide mapping, in: Landslide science
and practice, Springer, Berlin, Heidelberg, 95–101, 2013.
Ardizzone, F., Fiorucci, F., Mondini, A. C., and Guzzetti, F.: TXT-tool 1.039-1.1: Very-High Resolution Stereo Satellite Images for Landslide Mapping, in: Landslide Dynamics: ISDR-ICL Landslide Interactive Teaching Tools: Volume 1: Fundamentals, Mapping and Monitoring, edited by: Sassa, K., Guzzetti, F., Yamagishi, H., Arbanas, Ž., Casagli, N., McSaveney, M., and Dang, K., Springer International Publishing, Cham, 83–94, 2018.
Brabb, E. E.: Innovative approaches to landslide hazard and risk mapping, in:
International Landslide Symposium Proceedings, Toronto, Canada, 17–22, 1985.
Cardinali, M., Ardizzone, F., Galli, M., Guzzetti, F., and Reichenbach, P.:
Landslides triggered by rapid snow melting: the December 1996–January 1997
event in Central Italy, in: Proceedings 1st Plinius Conference on Mediterranean Storms, 14–16 October 1999, Maratea, 439–448, 2000.
Carrara, A., Cardinali, M., Detti, R., Guzzetti, F., Pasqui, V., and Reichenbach, P.: GIS techniques and statistical models in evaluating landslide hazard, Earth Surf. Proc. Land., 16, 427–445, 1991.
Costanzo, D., Rotigliano, E., Irigaray, C., Jiménez-Perálvarez, J. D., and Chacón, J.: Factors selection in landslide susceptibility modelling on large scale following the gis matrix method: application to the river Beiro basin (Spain), Nat. Hazards Earth Syst. Sci., 12, 327–340, https://doi.org/10.5194/nhess-12-327-2012, 2012.
Diggle, P. J., Chetwynd, A. G., Häggkvist, R., and Morris, S. E.:
Second-order analysis of space-time clustering, Stat. Meth. Med. Res., 4, 124–136, 1995.
Galli, M., Ardizzone, F., Cardinali, M., Guzzetti, F., and Reichenbach, P.:
Comparing landslide inventory maps, Geomorphology, 94, 268–289, 2008.
Gavin, D. G., Hu, F. S., Lertzman, K., and Corbett, P.: Weak Climatic Control of Stand-Scale Fire History During The Late Holocene, Ecology, 87, 1722–1732, 2006.
Gorum, T., Fan, X., van Westen, C. J., Huang, R. Q., Xu, Q., Tang, C., and
Wang, G.: Distribution pattern of earthquake-induced landslides triggered by
the 12 May 2008 Wenchuan earthquake, Geomorphology, 133, 152–167, https://doi.org/10.1016/j.geomorph.2010.12.030, 2011.
Günther, A., Van Den Eeckhaut, M., Malet, J.-P., Reichenbach, P., and
Hervás, J.: Climate-physiographically differentiated Pan-European landslide susceptibility assessment using spatial multi-criteria evaluation
and transnational landslide information, Geomorphology, 224, 69–85,
https://doi.org/10.1016/j.geomorph.2014.07.011, 2014.
Guzzetti, F., Reichenbach, P., Cardinali, M., Galli, M., and Ardizzone, F.:
Probabilistic landslide hazard assessment at the basin scale, Geomorphology,
72, 272–299, 2005.
Guzzetti, F., Galli, M., Reichenbach, P., Ardizzone, F., and Cardinali, M.: Landslide hazard assessment in the Collazzone area, Umbria, Central Italy, Nat. Hazards Earth Syst. Sci., 6, 115–131, https://doi.org/10.5194/nhess-6-115-2006, 2006a.
Guzzetti, F., Reichenbach, P., Ardizzone, F., Cardinali, M., and Galli, M.:
Estimating the quality of landslide susceptibility models, Geomorphology, 81, 166–184, https://doi.org/10.1016/j.geomorph.2006.04.007, 2006b.
Guzzetti, F., Ardizzone, F., Cardinali, M., Rossi, M., and Valigi, D.: Landslide volumes and landslide mobilization rates in Umbria, central Italy,
Earth Planet. Sc. Lett., 279, 222–229, https://doi.org/10.1016/j.epsl.2009.01.005, 2009.
Guzzetti, F., Mondini, A. C., Cardinali, M., Fiorucci, F., Santangelo, M., and Chang, K.-T.: Landslide inventory maps: New tools for an old problem,
Earth-Sci. Rev., 112, 42–66, 2012.
Haines, E.: Point in polygon strategies, Graphics gems IV, 994, 24–26, 1994.
Hinman, S. E., Blackburn, J. K., and Curtis, A.: Spatial and temporal
structure of typhoid outbreaks in Washington, DC, 1906–1909: evaluating
local clustering with the G i* statistic, Int. J. Health Geogr., 5, 13, 2006.
Jebur, M. N., Pradhan, B., and Tehrany, M. S.: Optimization of landslide
conditioning factors using very high-resolution airborne laser scanning (LiDAR) data at catchment scale, Remote Sens. Environ., 152, 150–165, 2014.
Keefer, D. K.: Statistical analysis of an earthquake-induced landslide
distribution – the 1989 Loma Prieta, California event, Eng. Geol., 58, 231–249, https://doi.org/10.1016/S0013-7952(00)00037-5, 2000.
Levine, N.: Crime mapping and the Crimestat program, Geogr. Anal., 38, 41–56, 2006.
Lynch, H. J. and Moorcroft, P. R.: A spatiotemporal Ripley's K-function to
analyze interactions between spruce budworm and fire in British Columbia,
Canada, Can. J. Forest Res., 38, 3112–3119, 2008.
Mason, S. J. and Graham, N. E.: Areas beneath the relative operating
characteristics (ROC) and relative operating levels (ROL) curves: Statistical significance and interpretation, Q. J. Roy. Meteorol. Soc., 128, 2145–2166, 2002.
Mirus, B. B., Smith, J. B., and Baum, R. L.: Hydrologic Impacts of Landslide
Disturbances: Implications for Remobilization and Hazard Persistence, Water
Resour. Res., 53, 8250–8265, https://doi.org/10.1002/2017wr020842, 2017.
Moore, I. D. and Wilson, J. P.: Length-slope factors for the Revised Universal Soil Loss Equation: Simplified method of estimation, J. Soil Water Conserv., 47, 423–428, 1992.
Moore, I. D., Gessler, P., Nielsen, G., and Peterson, G.: Soil attribute
prediction using terrain analysis, Soil Sci. Soc. Am. J., 57, 443–452, 1993.
Neuhäuser, B., Damm, B., and Terhorst, B.: GIS-based assessment of landslide susceptibility on the base of the weights-of-evidence model,
Landslides, 9, 511–528, 2012.
Phillips, J. D.: Evolutionary geomorphology: thresholds and nonlinearity in landform response to environmental change, Hydrol. Earth Syst. Sci., 10, 731–742, https://doi.org/10.5194/hess-10-731-2006, 2006.
Reichenbach, P., Rossi, M., Malamud, B. D., Mihir, M., and Guzzetti, F.: A
review of statistically-based landslide susceptibility models, Earth-Sci. Rev., 180, 60–91, https://doi.org/10.1016/j.earscirev.2018.03.001, 2018.
Riley, S. J., DeGloria, S., and Elliot, R.: Index that quantifies topographic heterogeneity, Intermount. J. Sci., 5, 23–27, 1999.
Ripley, B. D.: The second-order analysis of stationary point processes, J. Applied Probabil., 13, 255–266, 1976.
Ripley, B. D.: Modelling spatial patterns, J. Roy. Stat. Soc. B, 172–212, 1977.
Rossi, M., Guzzetti, F., Reichenbach, P., Mondini, A. C., and Peruccacci, S.: Optimal landslide susceptibility zonation based on multiple forecasts,
Geomorphology, 114, 129–142, https://doi.org/10.1016/j.geomorph.2009.06.020, 2010.
Samia, J., Temme, A., Bregt, A., Wallinga, J., Guzzetti, F., Ardizzone, F.,
and Rossi, M.: Do landslides follow landslides? Insights in path dependency
from a multi-temporal landslide inventory, Landslides, 14, 547–558,
https://doi.org/10.1007/s10346-016-0739-x, 2017a.
Samia, J., Temme, A., Bregt, A., Wallinga, J., Guzzetti, F., Ardizzone, F.,
and Rossi, M.: Characterization and quantification of path dependency in
landslide susceptibility, Geomorphology, 292, 16–24, https://doi.org/10.1016/j.geomorph.2017.04.039, 2017b.
Samia, J., Temme, A., Bregt, A. K., Wallinga, J., Stuiver, J., Guzzetti, F.,
Ardizzone, F., and Rossi, M.: Implementing landslide path dependency in
landslide susceptibility modelling, Landslides, 15, 2129–2144, 2018.
Sato, H. P., Hasegawa, H., Fujiwara, S., Tobita, M., Koarai, M., Une, H., and Iwahashi, J.: Interpretation of landslide distribution triggered by the
2005 Northern Pakistan earthquake using SPOT 5 imagery, Landslides, 4, 113–122, https://doi.org/10.1007/s10346-006-0069-5, 2007.
Schlögel, R., Torgoev, I., De Marneffe, C., and Havenith, H. B.: Evidence of a changing size–frequency distribution of landslides in the Kyrgyz Tien Shan, Central Asia, Earth Surf. Proc. Land., 36, 1658–1669, 2011.
Smith, T.: Notebook on spatial data analysis, Lecture Note, University of Pennsylvania, available at: http://www.seas.upenn.edu/~ese502/#notebook (last access: January 2020) , 2016.
Tonini, M., Pedrazzini, A., Penna, I., and Jaboyedoff, M.: Spatial pattern
of landslides in Swiss Rhone Valley, Natural Hazards, 73, 97-110, 2014.
Van Westen, C. J., Rengers, N., and Soeters, R.: Use of geomorphological information in indirect landslide susceptibility assessment, Nat. Hazards, 30, 399–419, 2003.
Van Westen, C. J., Castellanos, E., and Kuriakose, S. L.: Spatial data for
landslide susceptibility, hazard, and vulnerability assessment: an overview,
Eng. Geol., 102, 112–131, 2008.
Varnes, D. J.: Landslide hazard zonation: a review of principles and practice, UNESCO, Paris, 1984.
Ye, X., Xu, X., Lee, J., Zhu, X., and Wu, L.: Space–time interaction of
residential burglaries in Wuhan, China, Appl. Geogr., 60, 210–216,
https://doi.org/10.1016/j.apgeog.2014.11.022, 2015.
Short summary
For the Collazzone study area in Italy, we quantified how much landslides follow others using Ripley's K function, finding that susceptibility is increased within 60 m and 17 years after a previous landslide. We then calculated the increased susceptibility for every pixel and for the 17-time-slice landslide inventory. We used these as additional explanatory variables in susceptibility modelling. Model performance increased substantially with this landslide history component included.
For the Collazzone study area in Italy, we quantified how much landslides follow others using...
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