Fractal Structure of the Hypocenter Distributions and Focal Mechanism Solutions of Acoustic Emission in Two Granites of Different Grain Sizes.

Lei, Xinglin; Nishizawa, Osamu; Kusunose, Kazuhiro; Satoh, Takashi

doi:10.4294/jpe1952.40.617

Cited by 91 publications

(61 citation statements)

References 19 publications

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“…During propagation of compaction bands S-and C-type events represent about 24% and 72% of the source mechanisms, respectively, and tensile cracks represent less than 4%. The observations are in agreement with other studies [16,[25][26].…”

Section: Discussionsupporting

confidence: 94%

Advanced acoustic emission analysis of brittle and porous rock fracturing

Stanchits

Dresen

2010

EPJ Web of Conferences

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Abstract. Analysis of Acoustic Emission (AE) induced during brittle and porous rock fracturing at variety of loading conditions has been performed. On the base of advanced analysis of AE parameters, ultrasonic velocities and mechanical data we found that regardless of applied loading conditions the process of rock fracture can be separated into two main stages: (A) accumulation of non-correlated cracks localized almost randomly in the whole volume of uniformly stressed rock. (B) Final stage of sample fracturing could be characterized by appearance of AE nucleation site followed by initiation and propagation of the macroscopic fault. Contribution of tensile sources is reduced significantly, shear type and pore collapse type events dominate during propagation of a fracture process zone through the sample regardless of applied loading conditions. In the case of porous rock, nucleation of compaction bands could be clearly identified by the appearance of AE clusters inside the samples. Microstructural analysis of fractured samples shows excellent agreement between location of AE hypocenters and faults or the positions of compaction bands, confirming that advanced AE analysis is a powerful tool for the process of rock fracture investigation.

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Section: Discussionsupporting

confidence: 94%

Advanced acoustic emission analysis of brittle and porous rock fracturing

Stanchits

Dresen

2010

EPJ Web of Conferences

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“…Zhao 1998) or optical microscopy (Wong 1985;Cox and Scholz 1988) operated during or after a fracture test, and (2) monitoring of the spatiotemporal distribution of AE events caused by microcracking activity (e.g. Lockner et al 1991;Lei et al 1992), which is the so-called AE technique. Fracturing dynamics and the pre-failure damage can be inferred from AE statistics as the number of AE events is proportional to the number of growing cracks, and the AE amplitudes are proportional to the length of crack growth increments in the rock (e.g.…”

Section: Ae As An Analogue Model Of Earthquakesmentioning

confidence: 99%

“…Such heterogeneities are characterised by fractal self-similarity or hierarchical structures (e.g. Ouillon et al 1996;Lei et al 1992). As a result, the fractures in the crust are somehow governed by the heterogeneities they involve.…”

Section: Introductionmentioning

confidence: 99%

Laboratory acoustic emission study for earthquake generation process

Lei

2014

Earthq Sci

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Since the similarity in size distribution of earthquakes and acoustic emissions (AE) was found in the 1960s, many laboratory studies have been motivated by the need to provide tools for the prediction of mining failures and natural earthquakes. This paper aims, on the one hand, to draw an outline of laboratory AE studies in the last 50 years, which have addressed seismological problems. Topics include the power laws in which the similarity between AEs and earthquakes is involved and progress that has been made in AE technology and laboratory AE study. On the other hand, this study will highlight some key issues intensively discussed, especially in the last three decades, such as aspects related to the pre-failure damage evolution, fault nucleation and growth in brittle rocks and discuss factors governing these processes.

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“…Hasegawa and Tanemura (1986) reviewed statistical methods that can measure the distance between the observed distribution and various modeled statistical distributions. Nishizawa (1992) applied one of these methods (the two-body correlation function method) to the distribution of AE hypocenters in a granite sample during creep under 40MPa confining pressure and demonstrated that the L-statistic can express the detailed structure of the distribution (for further information about the method, see Besag, 1977).…”

Section: Stochastic Characters Of Ae Hypocenter Distributionmentioning

confidence: 99%

Fracture Mechanics of Rocks.

Kusunose

1995

J,Phys,Earth

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This paper reviews recent studies on (1) AE (acoustic emission) and cracking models, (2) failure processes and (3) frictional sliding processes, mainly based on work carried out in Japan. Techniques for AE data acquisition and hypocenter location have been greatly improved; one system can record twenty-one channels of waveforms and can locate the AE hypocenter automatically. Another system can also record the occurrence time and the maximum amplitude of the AE event without dead time. On the basis of these data, we are able to discuss the relation between the distribution of the hypocenters, the occurrence intervals, and the experimentally controlled physical parameters. For this purpose, many studies have tried to develop quantitative expression for the statistical characters of these distributions. Techniques for evaluating AE source parameters are still being developed; and there has been a great deal of improvement in our knowledge about cracking mode of AE. The focal mechanisms have been systematically studied based on the space distributions of the initial motion directions. The studies showed that shear type cracking becomes dominant with increasing axial stress. These mechanism solutions agree well with the local stress field suggested by the fracture plane. Increasing of the failure strength of rocks with increasing stress and strain rates under relatively low confining pressure has been studied experimentally. The failure process and the rate dependency of the fracture strength in the low pressure regime are discussed on the basis of a stress corrosion cracking model. The failure mechanism under higher confining pressures of up to 3GPa is also examined. Some behavior including the variation of AE activity with axial stress differs between low and high confining pressures although the stress-strain relations clearly show brittle deformation in both regimes. On the basis of these differences, the researchers proposed that 'high-pressure' brittle deformation was different from ordinarily observed brittle behavior at low pressure, and examined the failure micromechanisms through an optical and an electron microscopes. Frictional sliding has also been intensively examined in the past decade. Experiments using large samples have demonstrated that the slip propagation process is well described by a slip-weakening model. The relations between the dynamic parameters of slip propagation process and the physical parameters of slip surfaces is becoming clearer.

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Fractal Structure of the Hypocenter Distributions and Focal Mechanism Solutions of Acoustic Emission in Two Granites of Different Grain Sizes.

Cited by 91 publications

References 19 publications

Advanced acoustic emission analysis of brittle and porous rock fracturing

Advanced acoustic emission analysis of brittle and porous rock fracturing

Laboratory acoustic emission study for earthquake generation process

Fracture Mechanics of Rocks.

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