Statistical physics of fracture and earthquakes

Biswas, Soumyajyoti; Goehring, Lucas; Chakrabarti, Bikas K.

doi:10.1098/rsta.2018.0202

Cited by 4 publications

(2 citation statements)

References 33 publications

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“…This is because it has the potential to facilitate the creation of novel materials with enhanced fracture toughness and damage tolerance, as well as more precise models for predicting fracture behavior [1][2][3]. The understanding of this knowledge can have significant implications in various aspects, including the design and maintenance of engineering structures, as well as our comprehension of natural phenomena, such as earthquakes [4,5], and even aiding in the repair of cracks in living bones [6][7][8]. A method of comprehending natural fracture is by studying how rock samples respond under varying conditions, including stress distributions.…”

Section: Introductionmentioning

confidence: 99%

Analytical Relation between b-Value and Electromagnetic Signals in Pre-Macroscopic Failure of Rocks: Insights into the Microdynamics’ Physics Prior to Earthquakes

Venegas-Aravena

Cordaro

2023

Geosciences

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Field measurements in subduction regions have revealed the presence of non-seismic pre-earthquake signals such as electromagnetic or acoustic emission, gas liberation, changes in Earth’s surface temperature, changes at the ionospheric level, or fluid migration. These signals are commonly associated with impending earthquakes, even though they often rely solely on temporal and spatial correlations in impending earthquake zones without a comprehensive understanding of the underlying lithospheric processes. For example, one criticism is the measurement of increasing electromagnetic signals even in the absence of observable macroscopic stress changes, which challenges the conventional understanding that macroscopic stress changes are the primary energy source for non-seismic pre-earthquake signals. To address this gap, rock experiments provide valuable insights. Recent experiments have shown that rocks can become electrified under constant macroscopic stress changes, accompanied by a decrease in the b-value, indicating multiscale cracking. This suggests the existence of small-scale dynamics that generate electromagnetic signals independently of large-scale stress variations. In that sense, multiscale thermodynamics offers a valuable perspective in describing this multiscale phenomenon. That is why the main goal of this work is to demonstrate that the electromagnetic signals before macroscopic failures are not independent of the cracking generation because the origin of both phenomena is the same. In particular, we present analytical equations that explain the physical connection between multiscale cracking, the generation of electromagnetic signals, and its negative correlation with acoustic emission before the macroscopic failure of rocks even when the macroscopic load is constant. In addition, we also show that the thermodynamic fractal dimension, which corresponds to the global parameter that controls the cracking process, is proportional to the b-value when the large-scale crack generation is considerably larger than the small-scale cracks. Thus, the decreases in the b-value and the increases in the electromagnetic signals indicate that rocks irreversibly prepare to release energy macroscopically. These findings could be related to the dynamics at lithospheric scales before earthquakes.

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Section: Introductionmentioning

confidence: 99%

Analytical Relation between b-Value and Electromagnetic Signals in Pre-Macroscopic Failure of Rocks: Insights into the Microdynamics’ Physics Prior to Earthquakes

Venegas-Aravena

Cordaro

2023

Geosciences

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“…Particularly, for SOC the size distributions of avalanche events are known to scale as P(S) ∼ S −B , where S is the size of any rapid avalanche of activity and P(S) is the cumulative size distribution of those avalanches. For earthquakes, this is known as the Gutenberg-Richter (GR) Law [3], 1 and similar laws are also valid for laboratory-scale fracture [5], outages in power grids [6], etc. Much of the damage caused by intermittent failure events is naturally associated with the extreme tail of their size distributions, i.e.…”

Section: Introductionmentioning

confidence: 99%

Mapping heterogeneities through avalanche statistics

Biswas

Goehring

2018

Phil. Trans. R. Soc. A.

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Avalanche statistics of various threshold activated dynamical systems are known to depend on the magnitude of the drive, or stress, on the system. Such dependencies exist for earthquake size distributions, in sheared granular avalanches, laboratory scale fracture and also in the outage statistics of power grids. In this work we model threshold-activated avalanche dynamics and investigate the time required to detect local variations in the ability of model elements to bear stress. We show that the detection time follows a scaling law where the scaling exponents depend on whether the feature that is sought is either weaker, or stronger, than its surroundings. We then look at earthquake data from Sumatra and California, demonstrate the trade-off between the spatial resolution of a map of earthquake exponents (i.e. the b-values of the Gutenberg-Richter law) and the accuracy of those exponents, and suggest a means to maximise both.

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