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3 - Earthquake ground motion and patterns of seismically induced landsliding
- Edited by John J. Clague, Simon Fraser University, British Columbia, Douglas Stead, Simon Fraser University, British Columbia
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- Book:
- Landslides
- Published online:
- 05 May 2013
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- 23 August 2012, pp 24-36
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Summary
Abstract Earthquake strong ground motion changes stresses in hillslopes and reduces the strength of surface materials. This can cause landsliding during earthquakes and enhance rates of slope failure in epicentral areas for longer periods. Rates of earthquake-triggered landsliding are strongly correlated with measured peak ground acceleration. Patterns of landslide density reflect the attenuation of seismic waves and geologic and topographic site effects. Using historic thrust fault ruptures with well-documented ground motion and landslide distributions as examples, we illustrate the links between earthquake mechanisms, seismic wave propagation, and triggered landsliding. The examples have shared geomorphic attributes: a maximum density of triggered landslides where earthquake slip is greatest; a progressive decrease of landslide density away from this maximum; clustering of triggered landslides on topographic ridges and other convex landscape elements; and preferential failure of slopes facing away from the earthquake source. We also show that rates of landsliding can remain high after an earthquake in a geomorphic crisis that fades over a period of years. Continued landsliding adds to the total erosion caused by an earthquake, reducing or possibly canceling seismic surface uplift. The examples underline the potential for the quantitative prediction of patterns of seismically triggered and induced landsliding, use of observed landslide patterns for study of earthquake mechanisms, and inclusion of seismically driven erosion in landscape evolution models.
Contributors
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- By Federico Agliardi, Andrea Alpiger, Gianluca Bianchi Fasani, Lars Harald Blikra, Brian D. Bornhold, Edward N. Bromhead, Marko H.K. Bulmer, D. Calvin Campbell, Marie Charrière, Masahiro Chigira, John J. Clague, John Coggan, Giovanni B. Crosta, Tim Davies, Marc-Henri Derron, Mark Diederichs, Erik Eberhardt, Carlo Esposito, Robin Fell, Paolo Frattini, Corey R. Froese, Monica Ghirotti, Valentin Gischig, James S. Griffiths, Stephen R. Hencher, Reginald L. Hermanns, Kris Holm, Seyyedmahdi Hosseyni, Niels Hovius, Christian Huggel, Florian Humair, Oldrich Hungr, D. Jean Hutchinson, Michel Jaboyedoff, Matthias Jakob, Julien Jakubowski, Randall W. Jibson, Katherine S. Kalenchuk, Nikolay Khabarov, Oliver Korup, Luca Lenti, Serge Leroueil, Simon Loew, Oddvar Longva, Patrick MacGregor, Andrew W. Malone, Salvatore Martino, Scott McDougall, Mika McKinnon, Mauri McSaveney, Patrick Meunier, Dennis Moore, Jeffrey R. Moore, David C. Mosher, Michael Obersteiner, Lucio Olivares, Thierry Oppikofer, Luca Pagano, Massimo Pecci, Andrea Pedrazzini, David Petley, Luciano Picarelli, David J.W. Piper, John Psutka, Nicholas J. Roberts, Gabriele Scarascia Mugnozza, David Stapledon, Douglas Stead, Richard E. Thomson, Paolo Tommasi, J. Kenneth Torrance, Nobuyuki Torii, Gianfranco Urciuoli, Gonghui Wang, Christopher F. Waythomas, Malcolm Whitworth, Heike Willenberg, Xiyong Wu
- Edited by John J. Clague, Simon Fraser University, British Columbia, Douglas Stead, Simon Fraser University, British Columbia
-
- Book:
- Landslides
- Published online:
- 05 May 2013
- Print publication:
- 23 August 2012, pp vii-x
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The exhumation of the western Greater Caucasus: a thermochronometric study
- STEPHEN J. VINCENT, ANDREW CARTER, VLADIMIR A. LAVRISHCHEV, SAMUEL P. RICE, TEIMURAZ G. BARABADZE, NIELS HOVIUS
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- Journal:
- Geological Magazine / Volume 148 / Issue 1 / January 2011
- Published online by Cambridge University Press:
- 05 May 2010, pp. 1-21
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This study provides 39 new thermochronometric analyses from the western part of the Greater Caucasus, a region in which existing data are extremely limited and of questionable quality. The new results are consistent with field studies that identify Triassic to Middle Jurassic (Cimmerian) and Oligo-Miocene (Alpine) orogenic erosional events. An inverse relationship between the fission track and depositional ages of Oligo-Miocene sedimentary samples also implies some degree of Eocene erosion of the Greater Caucasus and intermediate sediment storage. Cooling ages and field relationships within the core of the range, west of Mt Elbrus, require ~5 km of Permo-Triassic exhumation and restrict the overall amount of Cenozoic exhumation to ~2.5 km. Current exhumation rates are typically low, and do not support a Plio-Pleistocene increase in climate-driven denudation. High (~1 km Ma−1) rates of exhumation are restricted to the southern flank of the range in northwest Georgia. Despite a general lack of significant seismicity within the study region, this exhumation peak is close to the largest instrumentally recorded earthquake in the Caucasus (Ms = 7.0). This may suggest that exhumation is associated with the decoupling of the sedimentary succession from its crystalline basement in the southern part of the range and the inversion of the largely Jurassic fill of the Greater Caucasus basin. Rates of exhumation are compatible with this being driven by active shortening. Further sampling and analysis are required to provide a higher-resolution, low-temperature thermochronology of Alpine exhumation, to isolate the drivers for Palaeogene Dziruli Massif cooling and uplift, and to constrain better the extent of the current, localized phase of rapid exhumation.