Seismic precursory patterns before a cliff collapse and critical point phenomena

Amitrano, David

doi:10.1029/2004gl022270

Cited by 180 publications

(196 citation statements)

References 24 publications

(51 reference statements)

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“…The b-value of 1.55 for the energy pdf (corresponding to 0.55 for the cdf), we observed for our data, is in the range expected for rocks experiencing uniaxial or triaxial compression stress state in laboratory experiences (Lockner, 1993) and is very close to that observed prior to the peak load (Amitrano, 2003;Lockner, 1993) and for creep of compression tests after the onset of tertiary creep (Grgic and Amitrano, 2009) and for seismic forerunners recorded in a cliff before its collapse (Amitrano et al, 2005) although the loading mode is very different. This provides an indication that the stress induced by thermal cycling and/or freezing/thawing of water in rock pores and cracks reaches values close to the rock strength.…”

Section: Discussionsupporting

confidence: 83%

Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall

Amitrano

Gruber

Girard

2012

Earth and Planetary Science Letters

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Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rock-wall induced by natural thermal cycling and freezing/thawing. The analysis of the large catalog of events obtained shows (i) robust power-law distributions in the time and energy domains, a footprint of rock micro-fracturing activity induced by stresses arising from thermal variations and associated freezing/ thawing of rock; (ii) an increase in AE activity under sub-zero rock-temperatures, suggesting the importance of freezing-induced stresses. AE activity further increases in locations of the rock-wall that are prone to receiving melt water. These results suggest that the framework of further modeling studies (theoretical and numerical) should include damage, elastic interaction and poro-mechanics in order to describe freezing-related stresses. Keywords: frost-cracking acoustic emission mechanical weathering scaling properties a b s t r a c t Ice formation within rock is known to be an important driver of near-surface frost weathering as well as of rock damage at the depth of several meters, which may play a crucial role for the slow preconditioning of rock fall in steep permafrost areas. This letter reports results from an experiment where acoustic emission monitoring was used to investigate rock damage in a high-alpine rock-wall induced by natural thermal cycling and freezing/thawing. The analysis of the large catalog of events obtained shows (i) robust power-law distributions in the time and energy domains, a footprint of rock micro-fracturing activity induced by stresses arising from thermal variations and associated freezing/ thawing of rock; (ii) an increase in AE activity under sub-zero rock-temperatures, suggesting the importance of freezing-induced stresses. AE activity further increases in locations of the rock-wall that are prone to receiving melt water. These results suggest that the framework of further modeling studies (theoretical and numerical) should include damage, elastic interaction and poro-mechanics in order to describe freezing-related stresses.

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Section: Discussionsupporting

confidence: 83%

Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall

Amitrano

Gruber

Girard

2012

Earth and Planetary Science Letters

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“…Understanding the origin and evolution of such instabilities implies the continuous monitoring of the various parameters characterizing the deformation process and its environment. Studies of rock slope stability often involve the monitoring of displacements (e.g., Kennedy and Niermeyer, 1970;Bhandari, 1988;Brunner et al, 2000;Mayer et al, 2000;Zvelebil and Moser, 2001) or morphological changes (Mikos et al, 2005;Dewez et al, 2007;Collins and Sitar, 2008) and less frequently the seismic monitoring, which was performed earlier for unstable slopes in open mines (Kennedy and Niermeyer, 1970;Hardy and Kimble, 1991) and more recently for natural slopes or cliffs (Willenberg et al, 2002;Senfaute et al, 2003;Kolesnikov et al, 2003;Eberhardt et al, 2004;Amitrano et al, 2005;Roth et al, 2005;Brückl and Mertl, 2006;Spillmann et al, 2007;Willenberg et al, 2008;Senfaute et al, 2009). Most of these studies were devoted to the monitoring and study of discrete seismic events.…”

Section: Introductionmentioning

confidence: 99%

“…Most of these studies were devoted to the monitoring and study of discrete seismic events. Amitrano et al (2005) evidenced the simultaneous power-law increase and b-value decrease of the highfrequency seismicity recorded by a seismic sensor located at ∼5 m of the rupture surface during the 2 h preceding a ∼10 3 m 3 collapse in the Mesnil-Val chalk cliff, Normandie, France.…”

Section: Introductionmentioning

confidence: 99%

Pre-failure behaviour of an unstable limestone cliff from displacement and seismic data

Got

Mourot

Grangeon

2010

Nat. Hazards Earth Syst. Sci.

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Abstract. We monitored the displacement and seismic activity of an unstable vertical rock slice in a natural limestone cliff of the southeast Vercors massif, southeast France, during the months preceding its collapse. Displacement measurements showed an average acceleration of the movement of its top, with clear increases in the displacement velocity and in the discrete seismic event production rate during periods where temperature falls, with more activity when rainfall or frost occurs. Crises of discrete seismic events produce high amplitudes in periodograms, but do not change the high frequency base noise level rate. We infer that these crises express the critical crack growth induced by water weakening (from water vapor condensation or rain) of the rock strength rather than to a rapid change in applied stresses. Seismic noise analysis showed a steady increase in the high frequency base noise level and the emergence of spectral modes in the signal recorded by the sensor installed on the unstable rock slice during the weeks preceding the collapse. High frequency seismic noise base level seems to represent subcritical crack growth. It is a smooth and robust parameter whose variations are related to generalized changes in the rupture process. Drop of the seismic noise amplitude was concomitant with the emergence of spectral modes -that are compatible with high-order eigenmodes of the unstable rock sliceduring the later stages of its instability. Seismic noise analysis, especially high frequency base noise level analysis may complement that of inverse displacement velocity in earlywarning approaches when strong displacement fluctuations occur.

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“…The accelerations recorded (with maximum value of about 0.02 g) on the cliff during storms show a regular distribution of observed values; this distribution can be correlated with the wave height offshore. In particular, it would be interesting to carry out a study aimed to analyze the data deriving from accelerometer recordings produced by instrument collocated in different sites and during different periods of the year [3]. The extension of the set of experimental data to a wider range of wave conditions would allow to: 1) check the validity of the presented methodology; 2) deepen both the characteristics of the wave breaking and the cliff-wave interaction; 3) to determine a number of cycles over which instability phenomena of the cliff could occur.…”

Section: Discussionmentioning

confidence: 99%

Analysis of Interaction Between Waves and Cliff Along the Adriatic Coast of Polignano (Apulia, Italy)

Spilotro

Pellicani

Miccoli

et al. 2014

Engineering Geology for Society and Territory - Volume 5

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The aim of this study is the analysis of the dynamic behavior of rocky cliff located below the old urban center of Polignano (Apulia, Southern Italy). In order to characterize the behavior of the cliff under the impulse generated by sea waves, two types of measures were carried out on the rocky mass: (1) environmental vibrations and (2) accelerometer records. The first type of measures, which may be executed in a short time with a high spatial density, has provided a recognition of the different types of dynamic behavior of the cliff.The accelerometer records, carried out during heavy storms in December 2009 and January 2010, have been allowed to confirm the results of previous measures and to evaluate the energy transfer from waves to cliff, in terms of maximum values and temporal distribution.In order to facilitate a correct interpretation of measures, geological surveys for studying fracturation of rocky mass were carried out.The main results were the following: 1. The cliff shows a subdivision into two zones: (a) with stable behavior and without amplification of wave impulse, characteristic of limestones, (b) with amplification of wave impulse along several preferential directions, some of which are substantially coincident with the directions of main systems of fractures, while others coincide with local orientation of the rocky cliff. 2. The accelerometer measures confirm the different behavior. The most stable and less fractured zone is crossed by the energy transmitted from waves to cliff without giving its own contributions, the other zone filters this energy with its own frequencies. 3. The accelerations recorded (with maximum value of about 0.02 g) on the cliff during storms show a regular distribution of observed values; this distribution can be correlated with the wave height offshore.

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Seismic precursory patterns before a cliff collapse and critical point phenomena

Cited by 180 publications

References 24 publications

Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall

Evidence of frost-cracking inferred from acoustic emissions in a high-alpine rock-wall

Pre-failure behaviour of an unstable limestone cliff from displacement and seismic data

Analysis of Interaction Between Waves and Cliff Along the Adriatic Coast of Polignano (Apulia, Italy)

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