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)

International audienceOn 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

Predicting the impact of lava flows at Mount Etna (Italy)

Forecasting the time, nature and impact of future eruptions is difficult at volcanoes such as Mount Etna, in Italy, where eruptions occur from the summit and on the flanks, affecting areas distant from each other. Nonetheless, the identification and quantification of areas at risk from new eruptions is fundamental for mitigating potential human casualties and material damage. Here, we present new results from the application of a methodology to define flexible high-resolution lava invasion susceptibility maps based on a reliable computational model for simulating lava flows at Etna and on a validation procedure for assessing the correctness of susceptibility mapping in the study area. Furthermore, specific scenarios can be extracted at any time from the simulation database, for land-use and civil defence planning in the long-term, to quantify, in real-time, the impact of an imminent eruption, and to assess the efficiency of protective measures

VALANCA. A cellular automata model for simulating snow avalanches

Numerical modelling is a major challenge in the prevention of hazards related to the occurrence of catastrophic phenomena. Cellular Automata methods were developed for modelling large scale (extended for kilometres) dangerous surface flows of different nature such as lava flows, pyroclastic flows, debris flows, rock avalanches, etc. This paper presents VALANCA, a first version of a Cellular Automata model, developed for the simulations of dense snow avalanches. VALANCA is largely based on the most advanced models developed for flow-like landslides, and adopts some innovations such as outflows characterized by the position of mass centre and explicit velocity. First simulations of welldocumented snow avalanches occurred in the Davos region, Switzerland (i.e. the 2006 Rüchitobel and the 2006 Gotschnawang snow avalanches) show a satisfying agreement concerning the avalanche path, snow cover erosion depth, deposit thickness and areal distribution. Furthermore, preliminary simulations of the Gotschnawang snow-avalanche, by considering the presence of mitigation structures, were performed

3D Numerical Modelling of Submerged and Coastal Landslide Propagation

The analysis of the propagation phase plays a fundamental role in the assessment and forecasting of risks related to the occurrence of submerged and coastal landslides. At present there are few numerical models able to simulate the propagation of such a type of events. This paper presents fully 3D models and approaches developed by the authors and suitable for the simulation of both completely sub-aqueous landslides and combined subaerial submerged ones (i.e. coastal landslides with a subaerial source which propagate underwater). A Cellular Automata model is described which has been specifically designed for combined subaerial submerged landslides. Moreover, a new approach able to simulate submerged mass movements using commercial 3D software, originally developed for subaerial landslides, is presented. Calibration and validation of these models upon a real and well constrained coastal debris flow at Lake Albano (Rome, Italy) is also presented

Susceptibility assessment of subaerial (and/or) subaqueous debris-flows in archaeological sites, using a cellular model

This study analyzes landslide susceptibility for archaeological sites in the Albano lake and Nemi lake areas, both in subaerial and in submerged zones by simulations of SCIDDICA-SS2, a Cellular Automata (CA) model for subaerial, subaqueous, both subaerial-subaqueous debris/mud/granular flows. Successful applications of SCIDDICA-ss2 permitted to simulate past events for the Albano lake area. New numerical simulations allowed susceptibility evaluations for gravitational instability related to the abovementioned archaeological sites.Published405-4083V. Dinamiche e scenari eruttivirestricte

Maternal haplotypes in DHFR promoter and MTHFR gene in tuning childhood acute lymphoblastic leukemia onset-latency: Genetic/epigenetic mother/child Dyad study (GEMCDS)

Childhood acute lymphoblastic leukemia (ALL) peaks around age 2-4, and in utero genetic epigenetic mother-fetus crosstalk might tune ALL onset during childhood life. Folate genes variably interact with vitamin status on ALL risk and prognosis. We investigated DHFR and MTHFR gene variants in 235 ALL children and their mothers to disclose their role in determining ALL onset age and survival. Pyrosequence of DHFR 19bp ins/del (rs70991108; W/D), MTHFR C677T (rs1801133; C>T), and MTHFR A1298C (rs1801131; A>C) was assessed in children and in 72% of mothers for dyad-analysis comparison. DHFR DD-children had delayed ALL onset compared to WW-children (7.5 +/- 4.8 vs. 5.2 +/- 3.7 years; P = 0.002) as well as MTHFR 1298 CC-children compared to AA-children (8.03 +/- 4.8 vs. 5.78 +/- 4.1 years; P = 0.006), and according to the strong linkage disequilibrium between MTHFR 677 T-allele and 1298C-allele, MTHFR TT-children showed early mean age of onset though not significant. Offspring of MTHFR 677 TT-mothers had earlier ALL onset compared to offspring of 677 CC-mothers (5.4 +/- 3.3 vs. 7 +/- 5.3 years; P = 0.017). DHFR/MTHFR 677 polymorphism combination influenced onset age by comparing DD/CC vs. WW/TT children (8.1 +/- 5.7 vs. 4.7 +/- 2.1 years; P = 0.017). Moreover, mother-child genotype combination gave 5.5-years delayed onset age in favor of DD-offspring of 677 CC-mothers vs. WW-offspring of 677 TT-mothers, and it was further confirmed including any D-carrier children and any 677 T-carrier mothers (P = 0.00052). Correction for multiple comparisons maintained statistical significance for DHFR ins/del and MTHFR A1298C polymorphisms. Unexpectedly, among the very-early onset group (<2.89 years; 25th), DD-genotype inversely clustered in children and mothers (4.8% vs. 23.8% respectively), and accordingly ALL offspring of homozygous DD-mothers had increased risk to have early-onset (adjusted OR (odds ratio) = 3.08; 1.1-8.6; P = 0.03). The opposite effect DHFR promoter variant has in tuning ALL onset-time depending on who is the carrier (i.e., mother or child) might suggest a parent-origin-effect of the D-allele or a two-faced epigenetic role driven by unbalanced folate isoform availability during the in-utero leukemogenesis responsible for the wide postnatal childhood ALL latency