Abstract This paper deals with the heuristic approach used for landslide hazard zonation along the coastal slopes and cliffs of the Cilento region between Agropoli and Sapri (Italy). This sector of coastline (about 118 km in length) is formed mainly of Mesozoic carbonates and Miocene flysch; Quaternary marine sandstones together with beach sands also crop out. Due to the destructive force of the waves, the coastline is affected by several landslides (mainly rock-falls and slides). The major geomorphological, geological and structural features of about 154 slopes and cliffs have been analysed and several parameters affecting the rock-masses were detected and measured. These parameters deal with topographical, geological, geomechanical, environmental and wave hydraulic characteristics of the studied area. In order to perform the heuristic approach, the Rock Engineering Systems (RES) proposed by Hudson was adopted with several modifications. The main steps of this work were: (1) the choice of parameters relevant to landslide hazard zonation, (2) the analysis of binary interaction between parameters, (3) the weighting of interaction importance, (4) the rating assignment to different classes of parameter values and (5) the final computation of an “Instability Index” (I.I.). A database containing the measured parameters was prepared, and using an interaction matrix, the outputs were linked into a Geographic Information System. It contains the following elements: geological and geomorphological features, historical data regarding landslides, images and values of I.I. for the studied slopes and cliffs. If new landslides occur or near-shore engineered structures are built, then the I.I. values will be automatically upgraded. Values of the I.I. were grouped into 3 classes marking low, medium and high landslide hazard. Both carbonatic rock-masses and flysch were distinguished with respect to I.I. values to show the differences in landslide susceptibility. In fact, rapid but small rock-falls can cause more casualties than moderate speed but large slides. High landslide hazard affects about 41% of carbonate cliffs and about 53% of slopes in arenaceous-marly flysch.
[1]
S. Evans,et al.
The assessment of rockfall hazard at the base of talus slopes
,
1993
.
[2]
John A. Hudson,et al.
Engineering Rock Mechanics: An Introduction to the Principles
,
2000
.
[3]
Marin Marin,et al.
Some Italian Experiences On The Mechanical Characterization Of Structurally Complex Formations
,
1979
.
[4]
A. Cinque,et al.
L'evoluzione delle pianure costiere della Campania: geomorfologia e neotettonica
,
1995
.
[5]
T. Sunamura,et al.
Geomorphology of rocky coasts
,
1992
.
[6]
P. Finlay,et al.
Landslide risk assessment: prediction of travel distance
,
1999
.
[7]
John A. Hudson,et al.
A comprehensive method of rock mass characterization for indicating natural slope instability
,
1996,
Quarterly Journal of Engineering Geology.
[8]
J. N. Hutchinson.
General report: morphological and geotechnical parameters of landslides in relation to geology and hydrogeology : Proc 5th International Symposium on Landslides, Lausanne, 10–15 July 1988V1, P3–35. Publ Rotterdam: A A Balkema, 1988
,
1988
.
[9]
John A. Hudson,et al.
ROCK ENGINEERING SYSTEMS. THEORY AND PRACTICE
,
1992
.
[10]
A. Santo,et al.
A methodology for the study of the relation between coastal cliff erosion and the mechanical strength of soils and rock masses
,
2000
.
[11]
DETECTION OF ROCK INSTABILITIES : MATTEROCK METHODOLOGY
,
1999
.