ALBERT

Description: Background: In aerodynamic levitation, solids and liquids are floated in a vertical gas stream. In combination with CO2-laser heating, containerless melting at high temperature of oxides and silicates is possible. We apply aerodynamic levitation to bulk rocks in preparation for microchemical analyses, and for evaporation and reduction experiments. Results: Liquid silicate droplets (~2 mm) were maintained stable in levitation using a nozzle with a 0.8 mm bore and an opening angle of 60°. The gas flow was ~250 ml min-1. Rock powders were melted and homogenized for microchemcial analyses. Laser melting produced chemically homogeneous glass spheres. Only highly (e.g. H2O) and moderately volatile components (Na, K) were partially lost. The composition of evaporated materials was determined by directly combining levitation and inductively coupled plasma mass spectrometry. It is shown that the evaporated material is composed of Na 〉 K 〉〉 Si. Levitation of metal oxide-rich material in a mixture of H2 and Ar resulted in the exsolution of liquid metal. Conclusions: Levitation melting is a rapid technique or for the preparation of bulk rock powders for major, minor and trace element analysis. With exception of moderately volatile elements Na and K, bulk rock analyses can be performed with an uncertainty of ± 5% relative. The technique has great potential for the quantitative determination of evaporated materials from silicate melts. Reduction of oxides to metal is a means for the extraction and analysis of siderophile elements from silicates and can be used to better understand the origin of chondritic metal.

Description: Four lake-bed sediment samples were collected in the Lucerne Bay of Lake Lucerne to study their lithological properties. The dataset provides the location of the samples, total carbon content (TC), total organic carbon content (TOC), total inorganic carbon content (TIC), total nitrogen content (TN), molar ratio of carbon to nitrogen and the mean grain-size (D50) analyzed with a Malvern Mastersizer 3000 particle size analyzer.

Description: Results of particle size analysis of the siliciclastic fraction of an event deposit. Samples were taken from sediment core LU18-2 at depths ranging from 37.5 to 101.5 cm at 1 cm intervals. Grain size measurements were made using a Malvern Mastersizer 3000 particle size analyzer.

Description: Processed core logging data of core LU18-1 analyzed with a Geotek multi-sensor core logger (MSCL) at the Institute of Geological Sciences, University of Bern. The dataset includes core ID, composite core depth, core thickness, P-wave velocity, density, and magnetic susceptibility.

Description: Results of the XRF core scanning of sediment core LU18-2. Measurements were performed using an ITRAX-XRF core scanner (Cox Ltd., Sweden) equipped with a Cr-tube set to 30 kV and 50 mA at the Institute of Geological Sciences, University of Bern.

Description: The project "Lake Tsunamis: Causes, Controls, and Hazard (Characterization of subaqueous unstable slopes with geophysical and geotechnical measurements.)" was initiated to understand their governing mechanisms of genesis, propagation, frequency, and the related hazard within an interdisciplinary context. Swiss lakes served as a laboratory for this holistic approach. The project was divided into five work packages (WP), where WP1 comprised a large number of geophysical (using amongst other techniques ocean bottom seismometers (OBS)) and geotechnical measurements to characterize the structure and stability of potentially unstable subaqueous lake slopes. To evaluate the potential and applicability of ambient vibration techniques in a shallow-water offshore environment, multiple single-station and array OBS measurements were performed on subaqueous slopes in Lake Lucerne. Eight DEPAS Lobster type broadband OBS from the German Instrument Pool for Amphibian Seismology (DEPAS) and one Nammu type OBS from ETH Zürich were successfully deployed and recovered at more than 170 distinct locations in 2018-2020. In 2020-2023 the single Nammu OBS was deployed several times for supplemental measurements. Surveys with an airgun of 1-inch³ volume were used on top of the deployment locations to determine the misorientation of the horizontal components. In addition, multibeam bathymetric surveys were performed to locate the positions of the OBS on the lake floor with high accuracy. A workflow for passive seismic investigations with OBS in such shallow-water settings was developed. The seismic response and its variability at the measured sites in terms of amplification functions during earthquakes and resonance frequencies was determined. Shear-wave velocity profiles at different morphological types of slopes down to a depth of 100-150 m below the lake floor were resolved and interpreted. Combining geophysical and geotechnical measurements and interpretation, static and dynamic slope-stability analyses were performed. Thresholds for the subaqueous slope-failure triggering in terms of earthquake magnitude and epicentral distance, macroseismic intensity, and ground-motion intensity measures were derived using earthquake ground-motion modelling.

Description: This dataset provides the interpolated bathymetry of Lake Lucerne used for the numerical wave propagation simulation performed in the study “Shallow-Water Tsunami Deposits: Evidence from Sediment Cores and Numerical Wave Propagation of the 1601 CE Lake Lucerne” by Nigg et al. (in review). The multibeam echo-sounder bathymetry dataset of Lake Lucerne acquired by Hibe et al. (2011) was resampled from a grid size of 1x1 m to 5x5 m to reduce computational time using ArcMap (version 10.8.1). In addition, large artificial shoreline modifications were cropped and interpolated based on historical maps. Shallow-water areas (water depth 0-4m), which are not entirely covered by the bathymetrical data were linearly interpolated to the shoreline. The original bathymetry was acquired using a Geo-Acoustics GeoSwath Plus 125 kHz interferometer by Hilbe et al. (2011). Positioning was acquired with a Leica SR 530 GPS receiver with real time kinematic positioning (RTK; swipos GIS/GEO from swisstopo). Acquisition control and data processing were conducted using the GeoAcoustics GS+ software package. Swiss basic hydrological monitoring network (BAFU, 2008) were used to normalize water depths to the mean lake level (433.6 m a.s.l.). See Hilbe et al. (2011) for further information. The original bathymetry dataset is available from swisstopo and should be referenced as Hilbe, M., Anselmetti, F. S., Eilertsen, R. S., Hansen, L., & Wildi, W. (2011). Subaqueous morphology of Lake Lucerne (Central Switzerland): implications for mass movements and glacial history. Swiss Journal of Geosciences, 104(3), 425-443.

Description: This datasets includes sediment core scan data (MSCL, XRF), sediment subsample measurements (particle size measurements with a Malvern Mastersizer Laser diffraction analyzer (LDA and Carbon, Nitrogen, and Sulfur (CNS) measurements), lake surface samples (CNS and mean particle size of LDA measurements) from the Lucerne Bay, Lake Lucerne, Switzerland and key wave parameters obtained from virtual gauges of numerical wave propagation with BASEMENT. This datasets has been carried out within the SNSF Singergia project" Lake Tsunami: Causes, Controls, and Hazard".

Description: For the sensitivity analysis of our numerical simulation, 6 different scenarios (LS-1 to LS6) with different bed-roughness values were calculated. This dataset contains the wave parameters observed at virtual gauge 2.