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| Titel |
Short-term retreat statistics of a slowly eroding coastal cliff |
| VerfasserIn |
A. P. Young, R. T. Guza, W. C. O'Reilly, R. E. Flick, R. Gutierrez |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 11, no. 1 ; Nr. 11, no. 1 (2011-01-21), S.205-217 |
| Datensatznummer |
250009048
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| Publikation (Nr.) |
 copernicus.org/nhess-11-205-2011.pdf |
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| Zusammenfassung |
| The frequency, spatial distribution, and dimensions of coastal cliff
retreats, a basic statistic underlying cliff top hazard assessment, are
presented for 7.1 km of unprotected and slowly retreating coastal cliffs
near Point Loma in San Diego, California, US. Using 8 airborne light
detection and ranging (lidar) surveys collected over 5.5 years,
130 individual cliff edge failures (primarily rockfalls, block falls, and
topples) were detected. Footprint areas varied from 3 to 268 m2, maximum
landward retreats from 0.8 to 10 m, and alongshore lengths from 2 to 68 m.
The failures with the largest landward retreats were also relatively long,
and 13% of the slides accounted for 50% of the lost cliff area over the
study period. On this short (5.5 years) time scale, "no change" was the
most common observation (84% of the cliff edge). Probability distributions
of non-zero cliff retreat during each time interval usually had a single peak
between 1 and 2.5 m. Intervals with high mean retreat had elevated numbers
of failure in all class sizes, and also contained the largest individual
retreats. Small and medium slides tended to reoccur preferentially (relative
to randomly) near previous small and medium slides, forming short-term hot
spots, while large slides were less likely to reoccur near previous large
slides. Cumulative distributions of landslide failure parameters (area, mean
retreat, maximum retreat, and length) follow an inverse power-law for medium
to large size events, similar to previously reported distributions of coastal
and inland landsliding. |
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