Fracture Network Imaging on Rock Slope Instabilities Using Resonance Mode Analysis


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Date

2019-06-28

Publication Type

Journal Article

ETH Bibliography

yes

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Data

Abstract

We performed modal analysis using frequency domain decomposition of ambient seismic vibration data collected on large rock slope instabilities. This technique enables a robust detection of resonance frequencies and provides the corresponding mode shape vectors. We applied the technique to synthetic and field data sets acquired by seismometer arrays on two rock instabilities in Switzerland. We found that, at the fundamental mode, the entire instability vibrates in‐phase with the dominant mode shape vector oriented perpendicular to dominant fracture systems. At higher frequencies, different compartments of the instability resonate antiphase. Therefore, delineating the zero crossings between the phases allows dominant fractures to be efficiently mapped. Approximately 1 hr of ambient vibration data suffices to apply the method successfully. The method also potentially detects hidden fractures that cannot be observed by geological field mapping. In addition, this approach combines classic amplification and polarization analysis into one technique, simplifying data processing efforts.

Publication status

published

Editor

Book title

Volume

46 (12)

Pages / Article No.

6497 - 6506

Publisher

American Geophysical Union

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

rock slope instability; ambient seismic vibrations; Frequency Domain Decomposition; Resonance frequency; operational mode analysis; fracture mappings

Organisational unit

02818 - Schweiz. Erdbebendienst (SED) / Swiss Seismological Service (SED) check_circle

Notes

Funding

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