A subaqueous hazard map for earthquake-triggered landslides in Lake Zurich, Switzerland
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Date
2018-01
Publication Type
Journal Article
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yes
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Abstract
The awareness of geohazards in the subaqueous environment has steadily increased in the past years and there is an increased need to assess these hazards in a quantitative sense. Prime examples are subaqueous landslides, which can be triggered by a number of processes including earthquakes or human activities, and which may impact offshore and onshore infrastructure and communities. In the literature, a plenitude of subaqueous landslide events are related to historical earthquakes, including cases from lakes in Switzerland. Here, we present an approach for a basin-wide earthquake-triggered subaquatic landslide hazard assessment for Lake Zurich, which is surrounded by a densely populated shoreline. Our analysis is based on high-resolution sediment-mechanical and geophysical input data. Slope stabilities are calculated with a grid-based limit equilibrium model on an infinite slope, which uses Monte Carlo sampled input data from a sediment-mechanical stratigraphy of the lateral slopes. Combined with probabilistic ground-shaking forecasts from a recent national seismic hazard analysis, subaquatic earthquake-triggered landslide hazard maps are constructed for different mean return periods, ranging from 475 to 9975 years. Our results provide a first quantitative landslide hazard estimation for the lateral slopes in Lake Zurich. Furthermore, a back-analysis of a case-study site indicates that pseudostatic accelerations in the range between 0.04 and 0.08 g were needed to trigger a well-investigated subaqueous landslide, dated to ~2210 cal. years B.P.
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published
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Journal / series
Volume
90 (1)
Pages / Article No.
51 - 78
Publisher
Springer
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Software
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Date collected
Date created
Subject
Subaquatic hazard; Spatial seismic slope-stability assessment; Lake Zurich; Subaqueous geomorphology; Paleoseismology
Organisational unit
02818 - Schweiz. Erdbebendienst (SED) / Swiss Seismological Service (SED)
Notes
It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.
Funding
133481 - DYNAMITE: Dynamic Nankai Trough (Japan) and Swiss Molasse Basin: Investigating NeoTectonics, Paleo-Earthquakes and associated Geohazards (SNF)