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| Titel |
Negative Power Law Scaling of Rockfalls along the Yorkshire Coast: Implications for Long Term Landscape Evolution |
| VerfasserIn |
John Barlow, Nick Rosser, Michael Lime, David Petley, Matthew Brain, Melanie Sapsford, Emma Norman |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250045265
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| Zusammenfassung |
| An increasing body of evidence suggests that rockfalls follow a negative power law
scaling in their magnitude-frequency distribution of the form F = aM-b. Where
F is the normalized frequency density, M is the event magnitude, and a / b are
dimensionless scaling coefficients. Investigation using Terrestrial Laser Scanning (TLS) has
produced an extremely high resolution inventory of rockfall magnitudes along the
sea cliffs near Staithes, UK. Such data is ideal for erosion modelling. Once the
scaling parameters have been estimated, the volume of eroded rock for events of
magnitude x (Vx) is derived as Vx = ax-b+1. Therefore, the total volume (V t) of eroded
rock between a minimum and maximum magnitude can be calculated by taking by
integrating the above. An examination of monthly fluctuations in the scaling coefficients
indicates greater variation within the winter months in response to higher deliveries of
wave energy during these months. Initial results using geophone data indicate a
relationship between the magnitude of the scaling coefficients and the amount of wave
energy delivered to the cliff. Such linkages suggest the possibility of a predictive
model for erosion based on wave climate, providing a predictive capability for the
implications of environmental change. Model testing is to be accomplished using an
innovative cliff recession model derived using cosmogenic isotope concentrations and
paleoenvironmental data. Our cosmogenic dating model considers marine variables
(tidal range, wave climate and inundation duration); Holocene relative sea level
change; lateral cliff retreat, and the consequent changes in geometrical and marine
shielding to establish the rate of retreat based on a continuum of Be10 concentrations. |
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