Seismic constraints on dynamic links between geomorphic processes and routing of sediment in a steep mountain catchment
Landscape dynamics are determined by interactions amongst geomorphic processes. These interactions allow the effects of tectonic, climatic and seismic perturbations to propagate across topographic domains, and permit the impacts of geomorphic process events to radiate from their point of origin. Vis...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-01-01
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| Series: | Earth Surface Dynamics |
| Online Access: | http://www.earth-surf-dynam.net/2/21/2014/esurf-2-21-2014.pdf |
| Summary: | Landscape dynamics are determined by interactions amongst geomorphic
processes. These interactions allow the effects of tectonic, climatic and
seismic perturbations to propagate across topographic domains, and permit
the impacts of geomorphic process events to radiate from their point of
origin. Visual remote sensing and in situ observations do not fully resolve the
spatiotemporal patterns of surface processes in a landscape. As a result,
the mechanisms and scales of geomorphic connectivity are poorly understood.
Because many surface processes emit seismic signals, seismology can
determine their type, location and timing with a resolution that reveals the
operation of integral landscapes. Using seismic records, we show how
hillslopes and channels in an Alpine catchment are interconnected to produce
evolving, sediment-laden flows. This is done for a convective storm, which
triggered a sequence of hillslope processes and debris flows. We observe the
evolution of these process events and explore the operation of two-way links
between mass wasting and channel processes, which are fundamental to the
dynamics of most erosional landscapes. We also track the characteristics and
propagation of flows along the debris flow channel, relating changes of
observed energy to the deposition/mobilization of sediments, and using the
spectral content of debris flow seismic signals to qualitatively infer
sediment characteristics and channel abrasion potential. This seismological
approach can help to test theoretical concepts of landscape dynamics and
yield understanding of the nature and efficiency of links between individual
geomorphic processes, which is required to accurately model landscape dynamics
under changing tectonic or climatic conditions and to anticipate the
natural hazard risk associated with specific meteorological events. |
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| ISSN: | 2196-6311 2196-632X |