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Titel |
Are great Cascadia earthquakes recorded in the sedimentary records from small forearc lakes? |
VerfasserIn |
A. E. Morey, C. Goldfinger, C. E. Briles, D. G. Gavin, D. Colombaroli, J. E. Kusler |
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 ; 13, no. 10 ; Nr. 13, no. 10 (2013-10-09), S.2441-2463 |
Datensatznummer |
250085526
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Publikation (Nr.) |
copernicus.org/nhess-13-2441-2013.pdf |
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Zusammenfassung |
Here we investigate sedimentary records from four small inland lakes located
in the southern Cascadia forearc region for evidence of earthquakes. Three of
these lakes are in the Klamath Mountains near the Oregon–California border,
and one is in the central Oregon Coast range. The sedimentary sequences
recovered from these lakes are composed of normal lake sediment interbedded
with disturbance event layers. The thickest of these layers are graded, and
appear to be turbidites or linked debrites (turbidites with a basal
debris-flow deposit), suggesting rapid deposition. Variations in particle
size and organic content of these layers are reflected in the density and
magnetic susceptibility data. The frequency and timing of these events, based
on radiocarbon ages from detrital organics, is similar to the offshore
seismogenic turbidite record from trench and slope basin cores along the
Cascadia margin. Stratigraphic correlation of these anomalous deposits based
on radiocarbon ages, down-core density, and magnetic susceptibility data
between lake and offshore records suggest synchronous triggering. The areal
extent and multiple depositional environments over which these events appear
to correlate suggest that these deposits were most likely caused by shaking
during great Cascadia earthquakes. |
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