A comparative study on seismic response of two unstable rock slopes within same tectonic setting but different activity level
Open access
Datum
2017-12Typ
- Journal Article
ETH Bibliographie
yes
Altmetrics
Abstract
In this study, the seismic response of two slope instabilities is investigated with seismic ambient vibration analysis. Two similar sites have been chosen: an active deep-seated slope instability at Cuolm da Vi and the geologically, structurally and morphologically similar, but presently not moving Alp Caschlè slope. Both slopes are located at the upper Vorderrheintal (Canton Graubünden, Switzerland). Ambient vibrations were recorded on both slopes and processed by time–frequency polarization and site-to-reference spectral ratio analysis. The data interpretation shows correlations between degree of disintegration of the rock mass and amplification. However, the ambient vibration analysis conducted, does not allow retrieving a resonance frequency that can be related to the total depth of the instability of Cuolm da Vi. Even though seismic waves can be hardly traced in rock instabilities containing open fractures, it was possible to retrieve a dispersion curve and a velocity profile from the array measurement at Cuolm da Vi due to the high level of disintegration of the rock material down to a depth of about 100 m. From the similar amplification pattern at the two sites, we expect a similar structure, indicating that also the slope at Alp Caschlè was active in the past in a similar manner as Cuolm da Vi. However, a smoother increase of amplification with frequency is observed at Alp Caschlè, which might indicate less disintegration of the rock mass in a particular depth range at this site, when comparing to Cuolm da Vi where a high level of disintegration is observed, resulting from the high activity at the slope.
From the frequency-dependent amplification, we can distinguish between two parts within both instabilities, one part showing decreasing disintegration of the rock mass with increasing depth, for the other parts less-fractured blocks are observed. Since the block structures are found in the lower part of the instabilities, they might contribute to the stability of the slopes. Using the velocity profiles, it was possible to estimate the depth of the two largest open fractures (i.e. tension cracks) at Cuolm da Vi. Mehr anzeigen
Persistenter Link
https://doi.org/10.3929/ethz-b-000225166Publikationsstatus
publishedExterne Links
Zeitschrift / Serie
Geophysical Journal InternationalBand
Seiten / Artikelnummer
Verlag
Oxford University PressThema
Seismic noise; Site effects; Wave propagationOrganisationseinheit
02818 - Schweiz. Erdbebendienst (SED) / Swiss Seismological Service (SED)
03465 - Löw, Simon (emeritus) / Löw, Simon (emeritus)
Zugehörige Publikationen und Daten
Is supplemented by: https://doi.org/10.3929/ethz-b-000538128
Anmerkungen
It was possible to publish this article open access thanks to a Swiss National Licence with the publisher.ETH Bibliographie
yes
Altmetrics