Lakes as paleoseismic records in a seismically-active, low-relief area (Rieti Basin, central Italy)

QUATERNARY SCIENCE REVIEWS

卷:211

Article

Archer, Claire¹  Noble, Paula¹  Rosen, Michael R.²  Sagnotti, Leonardo³  Florindo, Fabio³  Mensing, Scott¹  Piovesan, Gianluca⁴  Michetti, Alessandro Maria⁵ 

[1] Univ Nevada, Reno, NV 89557 USA

[2] US Geol Survey, Carson City, NV USA

[3] Ist Nazl Geofis & Vulcanol, Rome, Italy

[4] Tuscia Univ, Dept Agr & Forest Sci, Viterbo, Italy

[5] Univ Insubria, Dipartimento Sci & Alta Tecnol, Como, Italy

关键词: Central Italy;    Limnology;    Paleolimnology;    Paleoseismicity;    Paleomagnetism;    Stable isotopes;    Scanning XRF;   

DOI  :  10.1016/j.quascirev.2019.03.004

来源: Elsevier

【 摘 要 】

Small lakes in low relief areas are atypical candidates for studies on paleoseismicity, but their sediments can contain seismically induced event layers (seismites) generated through strong ground shaking, sediment transport, hydrological reorganization and/or changes in groundwater chemistry and flow. Lakes Lungo and Ripasottile are shallow lakes (<10 m deep) located in the tectonically active Rieti Basin in the central Apennines, Italy, where strong normal faulting earthquakes (Mw 6.5 to 7.0) regularly occur. Sediment cores from these lakes provide paleoseismic indicators for the past similar to 1000 years. Sedimento-logical and geochemical analysis reveals four event layers identified in both lakes that correspond with documented large-scale earthquakes in 1298, 1349, 1639, and 1703 AD. Chronological correlation between earthquakes and paleoseismic features is reliable because of the resolution of sediment dating available for the studied cores. The common physical structure is a physically homogenous bed (homogenite) of re-suspended sediment consisting of a denser, high magnetic susceptibility (kappa) clastic base, with organic matter concentrated above. Co-seismic to post-seismic chemical signatures are associated with some event layers and may represent abrupt or transient shifts to a groundwater-dominated system, or permanent changes in groundwater flow and/or spring discharge. Excursions in delta C-13(org) may represent disruptions or changes in carbon source. Not all event layers show the same features, a result attributed to differences in seismic processes as well as the lake attributes, and anthropogenic modification. The observations made here may provide a new means of detecting paleoseismicity and may be applied to other low relief lakes in seismically active areas. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

Free