scholarly journals Rainstorm Magnitude and Debris Flows in Pyroclastic Deposits Covering Steep Slopes of Karst Reliefs in San Martino Valle Caudina (Campania, Southern Italy)

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2274
Author(s):  
Guido Leone ◽  
Pasquale Clemente ◽  
Libera Esposito ◽  
Francesco Fiorillo
Keyword(s):  
Time Series ◽  
Debris Flow ◽  
Debris Flows ◽  
Southern Italy ◽  
Distribution Functions ◽  
Annual Rainfall ◽  
Standard Normal Distribution ◽  
Relative Significance ◽  
Campania Region ◽  
Steep Slopes

Debris flows that have occurred in the area of San Martino Valle Caudina (Campania, Southern Italy) are described by geomorphological and hydrological analyses, focusing on the recent event of December 2019. This area can be considered a key example for studying debris-flow phenomena involving the pyroclastic mantle that covers the karstified bedrock along steep slopes. A hydrological analysis of the time series of the maximum annual rainfall, of durations of 1, 3, 6, 12 and 24 h, was carried out based on a new approach to assess rainstorm magnitude. It was quantified by measuring the deviation of the rainfall intensity from the normal conditions, within a specified time period. As the time series of annual maxima are typically skewed, a preliminary transformation is needed to normalize the distribution; to obtain the Z-value of the standard normal distribution, with mean µ = 0 and standard deviation σ = 1, different probability distribution functions were fitted to the actual data. A specific boxplot was used, with box width Z = ±1 and whiskers length Z = ±2. The deviations from these values provide the performance of the distribution fits. For the normalized time series, the rates shown by the trends and relative significance were investigated for the available time series of 11 rain gauges covering the Western–Central Campania region. The most critical condition for the debris-flow initiation appears to occur when a severe or extreme rainfall has a duration ≥ 12 h. The trend analysis did not detect statistically significant increases in the intensity of the rainfall of duration ≥ 6 h.

scholarly journals Debris-flow susceptibility assessment through cellular automata modeling: an example from 15–16 December 1999 disaster at Cervinara and San Martino Valle Caudina (Campania, southern Italy)

2003 ◽  
Vol 3 (5) ◽  
pp. 457-468 ◽  
Author(s):  
G. Iovine ◽  
S. Di Gregorio ◽  
V. Lupiano
Keyword(s):  
Cellular Automata ◽  
Debris Flow ◽  
Urban Areas ◽  
Debris Flows ◽  
Soil Cover ◽  
Southern Italy ◽  
Landslide Risk ◽  
Campania Region ◽  
Optimal Values ◽  
Debris Flow Susceptibility

Abstract. On 15–16 December 1999, heavy rainfall severely stroke Campania region (southern Italy), triggering numerous debris flows on the slopes of the San Martino Valle Caudina-Cervinara area. Soil slips originated within the weathered volcaniclastic mantle of soil cover overlying the carbonate skeleton of the massif. Debris slides turned into fast flowing mixtures of matrix and large blocks, downslope eroding the soil cover and increasing their original volume. At the base of the slopes, debris flows impacted on the urban areas, causing victims and severe destruction (Vittori et al., 2000). Starting from a recent study on landslide risk conditions in Campania, carried out by the Regional Authority (PAI –Hydrogeological setting plan, in press), an evaluation of the debris-flow susceptibility has been performed for selected areas of the above mentioned villages. According to that study, such zones would be in fact characterised by the highest risk levels within the administrative boundaries of the same villages ("HR-zones"). Our susceptibility analysis has been performed by applying SCIDDICA S3–hex – a hexagonal Cellular Automata model (von Neumann, 1966), specifically developed for simulating the spatial evolution of debris flows (Iovine et al., 2002). In order to apply the model to a given study area, detailed topographic data and a map of the erodable soil cover overlying the bedrock of the massif must be provided (as input matrices); moreover, extent and location of landslide source must also be given. Real landslides, selected among those triggered on winter 1999, have first been utilised for calibrating SCIDDICA S3–hex and for defining "optimal" values for parameters. Calibration has been carried out with a GIS tool, by quantitatively comparing simulations with actual cases: optimal values correspond to best simulations. Through geological evaluations, source locations of new phenomena have then been hypothesised within the HR-zones. Initial volume for these new cases has been estimated by considering the actual statistics of the 1999 landslides. Finally, by merging the results of simulations, a deterministic susceptibility zonation of the considered area has been obtained. In this paper, aiming at illustrating the potential for debris-flow hazard analyses of the model SCIDDICA S3–hex, a methodological example of susceptibility zonation of the Vallicelle HR-zone is presented.

A probabilistic model for assessing debris flow propagation at regional scale: a case study in Campania region, Italy

2021 ◽  
Author(s):  
Luca Crescenzo ◽  
Gaetano Pecoraro ◽  
Michele Calvello ◽  
Richard Guthrie
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Regional Scale ◽  
Erosion And Deposition ◽  
Campania Region ◽  
Source Areas ◽  
Model Input ◽  
Travel Path ◽  
Debris Avalanches ◽  
Modelling Approach

<p>Debris flows and debris avalanches are rapid to extremely rapid landslides that tend to travel considerable distances from their source areas. Interaction between debris flows and elements at risk along their travel path may result in potentially significant destructive consequences. One of the critical challenges to overcome with respect to debris flow risk is, therefore, the credible prediction of their size, travel path, runout distance, and depths of erosion and deposition. To these purposes, at slope or catchment scale, sophisticated physically-based models, appropriately considering several factors and phenomena controlling the slope failure mechanisms, may be used. These models, however, are computationally costly and time consuming, and that significantly hinders their applicability at regional scale. Indeed, at regional scale, debris flows hazard assessment is usually carried out by means of qualitative approaches relying on field surveys, geomorphological knowledge, geometric features, and expert judgement.</p><p>In this study, a quantitative modelling approach based on cellular automata methods, wherein individual cells move across a digital elevation model (DEM) landscape following behavioral rules defined probabilistically, is proposed and tested. The adopted model, called LABS, is able to estimate erosion and deposition soil volumes along a debris flow path by deploying at the source areas autonomous subroutines, called agents, over a 5 m spatial resolution DEM, which provides the basic information to each agent in each time-step. Rules for scour and deposition are based on mass balance considerations and independent probability distributions defined as a function of slope DEM-derived values and a series of model input parameters. The probabilistic rules defined in the model are based on data gathered for debris flows and debris avalanches that mainly occurred in western Canada. This study mainly addresses the applicability and the reliability of this modelling approach to areas in southern Italy, in Campania region, historically affected by debris flows in pyroclastic soils. To this aim, information on inventoried debris flows is used in different study areas to evaluate the effect on the predictions of the model input parameter values, as well as of different native DEM resolutions.</p>

scholarly journals Atmospheric Forcing of Debris Flows in the Southern Swiss Alps

2013 ◽  
Vol 52 (7) ◽  
pp. 1554-1560 ◽  
Author(s):  
Andrea Toreti ◽  
Michelle Schneuwly-Bollschweiler ◽  
Markus Stoffel ◽  
Jürg Luterbacher
Keyword(s):  
Time Series ◽  
Debris Flow ◽  
Debris Flows ◽  
Large Scale ◽  
Reanalysis Data ◽  
Swiss Alps ◽  
Classification Algorithms ◽  
Precipitation Series ◽  
Large Scale Circulation

AbstractThis article addresses the role of large-scale circulation and thermodynamical features in the release of past debris flows in the Swiss Alps by using classification algorithms, potential instability, and convective time scale. The study is based on a uniquely dense dendrogeomorphic time series of debris flows covering the period 1872–2008, reanalysis data, instrumental time series, and gridded hourly precipitation series (1992–2006) over the area. Results highlight the crucial role of synoptic and mesoscale forcing as well as of convective equilibrium on triggering rainfalls. Two midtropospheric synoptic patterns favor anomalous southwesterly flow toward the area and high potential instability. These findings imply a certain degree of predictability of debris-flow events and can therefore be used to improve existing alert systems.

scholarly journals Multiple Effects of Intense Meteorological Events in the Benevento Province, Southern Italy

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1560 ◽  
Author(s):  
Paola Revellino ◽  
Luigi Guerriero ◽  
Neri Mascellaro ◽  
Francesco Fiorillo ◽  
Gerardo Grelle ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Debris Flows ◽  
Southern Italy ◽  
Statistical Characteristics ◽  
Total Rainfall ◽  
Campania Region ◽  
Rainfall Events ◽  
Pattern Distribution ◽  
The Town ◽  
Flooded Areas

In October 2015, two intense rainfall events hit the central and southern regions of Italy and triggered a combination of different and widespread effects, including floods, landslides, and soil erosion. These outcomes devastated about 68 municipalities of the Benevento province (Campania region), killed two people, and caused millions of euros worth of damage to structures, infrastructures, and agriculture. The town of Benevento was one of the sectors most affected by overflow. Extensive areas characterized by flyschoid outcrops experienced widespread occurrences of soil erosion and landslides, and destructive, high-velocity debris flows (about 50) afflicted areas that had experienced heavy rainfall of higher intensity (total rainfall of 415.6 mm). In this study, the characteristics of these rainfall events and related geomorphological processes were determined by (i) analyzing the available rainfall data to identify the spatial pattern, distribution, and statistical characteristics of the two storms and (ii) mapping the storm effects, such as flooded areas, landslide types, and soil erosion. These effects were then related to the spatial distribution of the storms and the local geological and geomorphologic settings that drove their initiation and development.

scholarly journals The debris flow hazard in the Lagarelle Creek in the eastern Umbria region, central Italy

2005 ◽  
Vol 5 (2) ◽  
pp. 275-283 ◽  
Author(s):  
P. Conversini ◽  
D. Salciarini ◽  
G. Felicioni ◽  
A. Boscherini
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Central Italy ◽  
Field Surveys ◽  
Creek Watershed ◽  
Empirical Relations ◽  
Umbria Region ◽  
High Hazard ◽  
Definition Of ◽  
Steep Slopes

Abstract. This paper analyzes the Lagarelle Creek watershed, situated in the Municipality of Vallo di Nera, in the eastern Umbria region, central Italy. In this part of the Region, narrow valleys and very steep slopes characterize the morphology of the Appennine ridge. The presence of strongly-tectonized rocky masses, subdivided by several joint systems, is the main cause for the formation of sorted debris deposits, which accumulate mainly along the topographic convergences. This determines the conditions for possible events of debris flows. According to previous studies, the basin of the Lagarelle Creek, has been classified as an area prone to a high hazard of debris flows (Regione dell'Umbria – C.N.R. I.R.P.I., 1996). For this reason, systematic studies have been carried out on the whole watershed which, in this first phase, have examined the definition of the geological and morphological features of the zone, by means of the acquisition of cartographies and of field surveys, and the elaboration of the topographical data of the basin, by means of a digital model of the terrain. Once the potential triggering areas of debris flows were identified, an assessment of the mobilizable volumes possibly involved in a debris flow event was carried out. To perform such an assessment both the geomorphologic method proposed by Hungr (Hungr et al., 1984) and the empirical relations calibrated on debris flow events of the alpine arc were applied. The results obtained were compared with those derived from information supplied by the inhabitants of the small mountain village, who have described in detail the most important events of the last century.

Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA

2011 ◽  
Vol 20 (1) ◽  
pp. 125 ◽  
Author(s):  
Sara E. Jenkins ◽  
Carolyn Hull Sieg ◽  
Diana E. Anderson ◽  
Darrell S. Kaufman ◽  
Philip A. Pearthree
Keyword(s):  
Debris Flow ◽  
Ponderosa Pine ◽  
Debris Flows ◽  
Late Holocene ◽  
Conifer Forests ◽  
Fire Behaviour ◽  
Mixed Conifer ◽  
Northern Arizona ◽  
Mixed Conifer Forests ◽  
Steep Slopes

Long-term fire history reconstructions enhance our understanding of fire behaviour and associated geomorphic hazards in forested ecosystems. We used 14C ages on charcoal from fire-induced debris-flow deposits to date prehistoric fires on Kendrick Mountain, northern Arizona, USA. Fire-related debris-flow sedimentation dominates Holocene fan deposition in the study area. Radiocarbon ages indicate that stand-replacing fire has been an important phenomenon in late Holocene ponderosa pine (Pinus ponderosa) and ponderosa pine–mixed conifer forests on steep slopes. Fires have occurred on centennial scales during this period, although temporal hiatuses between recorded fires vary widely and appear to have decreased during the past 2000 years. Steep slopes and complex terrain may be responsible for localised crown fire behaviour through preheating by vertical fuel arrangement and accumulation of excessive fuels. Holocene wildfire-induced debris flow events occurred without a clear relationship to regional climatic shifts (decadal to millennial), suggesting that interannual moisture variability may determine fire year. Fire-debris flow sequences are recorded when (1) sufficient time has passed (centuries) to accumulate fuels; and (2) stored sediment is available to support debris flows. The frequency of reconstructed debris flows should be considered a minimum for severe events in the study area, as fuel production may outpace sediment storage.

scholarly journals Experimental study on the rheological behaviour of debris flow

2010 ◽  
Vol 10 (12) ◽  
pp. 2507-2514 ◽  
Author(s):  
A. Scotto di Santolo ◽  
A. M. Pellegrino ◽  
A. Evangelista
Keyword(s):  
Debris Flow ◽  
Yield Stress ◽  
Debris Flows ◽  
Soil Mechanics ◽  
Rheological Behaviour ◽  
Simple Relation ◽  
Campania Region ◽  
Failure Behaviour ◽  
Fluid Behaviour

Abstract. A model able to describe all the processes involved in a debris flow can be very complex owing to the sudden changing of the material that turns from solid into liquid state. The two phases of the phenomenon are analysed separately referring to soil mechanics procedures with regard to the trigger phase, and to an equivalent fluid for the post-failure phase. The present paper is devoted to show the experimental results carried out to evaluate the behaviour assumed by a pyroclastic-derived soil during the flow. A traditional fluid tool has been utilized: a standard rotational rheometer equipped with two different geometries. The soils tested belong to deposits that cover the slopes of the Campania region, Italy, often affected by debris flows. The influence of solid concentration Cv and grain size distribution was tested: the soils were destructurated, sieved and mixed with water starting from the in situ porosity. All material mixtures showed a non-Newtonian fluid behaviour with a yield stress τy that increases with a solid volumetric concentration and decreases for an increase of sand fraction. The experimental data were fitted with standard model for fluids. A simple relation between Cv and τy was obtained. The yield stress seems to be a key parameter for describing and predicting the post-failure behaviour of debris flows. These results suggest that in the field a small change in solid fraction, due to rainfall, will cause a slight decrease of the static yield stress, readily inducing a rapid flow which will stop only when the dynamic yield stress is reached, namely on a much smoother slope. This can explain the in situ observed post-failure behaviour of debris flows, which are able to flow over very long distances even on smooth slopes.

scholarly journals Factors, determining the origin of debris flows on the southern slopes of the Crimean Mountains

Geografie ◽  
2015 ◽  
Vol 120 (1) ◽  
pp. 50-63
Author(s):  
Karel Šilhán ◽  
Tomáš Pánek ◽  
Jan Hradecký
Keyword(s):  
Time Series ◽  
Debris Flow ◽  
Low Temperatures ◽  
Debris Flows ◽  
Pinus Nigra ◽  
Short Term ◽  
Crimean Mountains ◽  
Lack Of Information ◽  
Triggering Factor

There is a lack of information about enabling and triggering factors of debris flows in the densely populated coastal slopes of the Crimean Mountains. In such respect, it is useful to reconstruct a chronology of historical debris flow events and correlate them with time series of relevant meteorological characteristics. We utilized dendrogeomorphological methods using 566 individuals of Pinus nigra for inferring age of 215 debris flow events. The oldest event is dated to 1701 and the highest decadal frequency of debris flows (20 events) is determined to 1940s. Long periods with anomalously low temperatures generating sufficient amount of debris are a major factor enabling debris flow. The dominant triggering factor for regional (multiply) debris flow events are long-term periods with above-average precipitations, but local (isolated) events are more related to short-term periods (~one month) with above-average precipitations.

scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2011 ◽  
Vol 1(10)2011 (1(10)) ◽  
pp. 38-46
Author(s):  
T.B. Chepurna ◽  
◽  
E. D. Kuzmenko ◽  
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Debris Flow ◽  
Debris Flows ◽  
Flow Formation ◽  
Integral Rate

Analysis of the debris flow formation factors which cause the long-term activity of debris flows is made. The methodology of the debris flows prediction subject to meteorological, hydrological, seismic, heliophysical factors is proposed. The regularities of long-term seasonality of these factors by using autocorrelation and spectral analysis are revealed. The integral rate of probability of debris flow intensification is calculated. The time series of this integral rate is extrapolated and the following peak of debris flows activation is predicted.

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