T150 Landslide Hazards: Inventories, Hazard Maps, Risk Analysis, and Warning Systems (Posters)

Monday, 26 September 2016
9:00 AM - 6:30 PM
Exhibit Hall E/F

LOCAL AND DISTRIBUTED HYDROLOGICAL AND SLOPE STABILITY MODELING FOR ASSESSING DEBRIS FLOW HAZARDS ALONG THE SARNO MOUNTAINS (SOUTHERN ITALY)

Paper number: T150-7
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

  • Francesco Fusco Presenting Author
    Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse – University of Napoli Federico II, Napoli
  • Rex Baum
    Geologic Hazards Science Center, Denver, CO
  • Domenico Calcaterra
    Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse – University of Napoli Federico II, Napoli
  • Pantaleone De Vita
    Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse – University of Napoli Federico II, Napoli
  • Benjamin Mirus
    Geologic Hazards Sciences Center, Golden, CO

Abstract

The carbonate mountain ranges bordering the Campanian plain (southern Italy) are mantled by ash-fall pyroclastic deposits, associated with eruptions of Mount Somma-Vesuvius and the Phlegraean Fields volcanic centers. The urbanized foot slopes along these mountains are among the most landslide-prone areas of Italy, and have been subjected to repeated occurrences of rainfall-induced debris flows. After the most recent catastrophic landsliding event occurred in the Sarno Mountains in May 1998, many studies focused on understanding the predisposing factors and triggering mechanisms, which are controlled by morphological and hydrological conditions, respectively. Debris flows in ash-fall pyroclastic soils are triggered during heavy rainfall events, especially if also preceded by prolonged rainy periods. However, the assumption that slope instabilities are triggered by a rainfall event whose magnitude equals or exceeds a threshold value does not provide reliable prediction of landslide occurrence. Rainfall patterns indirectly influence the stability of a slope through changes in pore pressures, while stability is also related to the spatial variability of geotechnical properties and of ash-fall pyroclastic cover thickness along slopes and road-cuts. The objective of this work is to advance distributed assessments of landslide hazards for the Sarno Mountains by accounting for known variations in the distribution of this cover thickness along slopes. Physically-based hydrologic modeling was used to derive deterministic rainfall intensity/duration thresholds for several specific landslide source areas. We present preliminary results from work to extend these locally derived thresholds into a distributed hazards assessment using the TRIGRS model. Different scenarios were simulated with TRIGRS to evaluate the stability of the ash-fall mantles and develop maps of landslide potential under different rainfall conditions. We demonstrate that this integration of numerical modeling, from local to regional scales, is a useful approach for mapping the spatial and temporal probability of landslide hazards that can account for the different hydrological antecedent conditions of the spatially variable ash-fall cover and temporally variable rainfall triggering.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-282899

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.