Tsunamis and tectonic deformation at the northern Cascadia margin: a 3000-year record from Deserted Lake, Vancouver Island, British Columbia, Canada
| Autor: | John J. Clague, Ian Hutchinson, Jean-Pierre Guilbault, Peter Bobrowsky |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
010506 paleontology
Archeology Global and Planetary Change geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Ecology Subduction Paleontology Fjord 01 natural sciences law.invention Tectonics Oceanography law Radiocarbon dating Sedimentology Geology Sea level Holocene 0105 earth and related environmental sciences Earth-Surface Processes Gyttja |
| Zdroj: | The Holocene. 10:429-439 |
| ISSN: | 1477-0911 0959-6836 |
| DOI: | 10.1191/095968300666654539 |
| Popis: | Three layers of sand occur within a sequence of muddy gyttja in a 3 m core recovered from Deserted Lake, which lies at the head of a fjord on the central west coast of Vancouver Island, British Columbia, Canada. The sedimentology and microfossil assemblages of these layers are consistent with deposition by tsunamis. Radiocarbon ages suggest that the tsunamis were generated by plate-boundary earthquakes at the Cascadia subduction zone about 2600, 1600 and 300 years ago. Diatom and protozoan contents of the gyttja layers indicate that relative sea level fell in the periods between tsunamis. The sea-level changes are probably a product of interseismic uplift of the North America plate margin. Post-tsunami diatom and protozoan assemblages are generally more marine than their pre-tsunami counterparts, suggesting that the study site subsided during earth quakes. Estimates of interseismic and coseismic deformation during one earthquake cycle indicate that less than half of the interseismic uplift was recovered during the earthquake, leading to cumulative, or permanent, uplift of the area. |
| Databáze: | OpenAIRE |
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