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Submarine landslides and the importance of the initial sediment composition for run-out length and final deposit 总被引:1,自引:0,他引:1
Anders Elverhoi Hedda Breien Fabio V. De Blasio Carl B. Harbitz Matteo Pagliardi 《Ocean Dynamics》2010,60(4):1027-1046
Much remains to understand the dynamic processes during the flow of submarine landslides. A first relevant problem is to explain
the extraordinary mobility of submarine landslides, which has no comparison in subaerial mass movement. Another challenging
question is the apparent disparity between submarine landslides that remain compact for hundreds of kilometres and those that
disintegrate during the flow, finally evolving into turbidity currents. This problem is linked to a central ongoing debate
on the relative importance of turbidity currents versus submarine landslides in reshaping the continental margin. Based on
three epitomic case studies and on laboratory experiments with artificial debris flows of various composition, we suggest
a possible explanation for the disparity between compact and disintegrating landslides, identifying the clay-to-sand ratio
as the key control parameter. 相似文献
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Avalanche hazard mapping over large undocumented areas 总被引:3,自引:1,他引:2
An innovative methodology to perform avalanche hazard mapping over large undocumented areas is herewith presented and discussed.
The method combines GIS tools, computational routines, and statistical analysis in order to provide a “semi-automatic” definition
of areas potentially affected by avalanche release and motion. The method includes two main modules. The first module is used
to define zones of potential avalanche release, based on the consolidated relations on slope, morphology, and vegetation.
For each of the identified zones of potential release, a second module, named Avalanche Flow and Run-out Algorithm (AFRA),
provides an automatic definition of the areas potentially affected by avalanche motion and run-out. The definition is generated
by a specifically implemented “flow-routing algorithm” which allows for the determination of flow behaviour in the track and
in the run-out zone. In order to estimate the avalanche outline in the run-out zone, AFRA uses a “run-out cone”, which is
a 3D projection of the angle of reach α. The α-value is evaluated by statistical analysis of historical data regarding extreme
avalanches. Pre- and post-processing of the AFRA input/output data is done in an open source GIS environment (GRASS GIS).
The method requires only a digital terrain model and an indication of the areas covered by forest as input parameters. The
procedure, which allows rapid mapping of large areas, does not in principle require any site-specific historical information.
Furthermore, it has proven to be effective in all cases where a preliminary cost-efficient analysis of the territories potentially
affected by snow avalanche was needed. 相似文献
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