S-Wave Imaging of Glacial Overdeepened Alpine Valleys – Multi-Components

Abstract

Summary S-wave seismic imaging complements the application of P-waves with benefits, e.g., in resolution and petrophysical parameters. However S-wave imaging strongly depends on subsurface conditions. We investigate two overdeepened Alpine basins with P-wave and S-wave seismic methods using single-component and multi-components: (1) The Tannwald basin, located in the Alpine foreland, and (2) the inner-alpine Lienz Basin. These basins have a 3-D shape and a spatially-varying internal structure that constitute promising study areas. Here, we present two profiles of S-wave seismic reflection imaging using 6-components, i.e. 3-C geophones and a horizontal vibrator sources exciting in two directions. The interpretation of coincident P-wave profiles benchmark the S-wave data. The seismic S-wave sections show most geological structures on the components that have same source-receiver orientation and, thus, corresponds to the SV- and SH-domains. We are able to detect S-wave reflections and diffractions of the basin base down to 600 m depth (2 s TWT). Reflectivity on the other (mixed) components indicate a large amount of wave conversion. The application of S-waves increases the resolution and is able to improve seismic imaging in these environments.