scholarly journals Cellular automaton for realistic modelling of landslides

1995 ◽  
Vol 2 (1) ◽  
pp. 1-15 ◽  
Author(s):  
E. Segre ◽  
C. Deangeli
Keyword(s):  
Numerical Model ◽  
Debris Flow ◽  
Cellular Automaton ◽  
Field Data ◽  
Three Dimensional ◽  
Scaling Properties ◽  
Self Organized ◽  
Self Organized Criticality

Abstract. A numerical model is developed for the simulation of debris flow in landslides over a complex three dimensional topography. The model is then validated by comparing a simulation with reported field data. Our model is in fact a realistic elaboration of simpler "sandpile automata", which have in recent years been studied as supposedly paradigmatic of "self-organized criticality". Statistics and scaling properties of the simulation are examined, and show that the model has an intermittent behaviour.

FRACTALS, SCALING AND THE QUESTION OF SELF-ORGANIZED CRITICALITY IN MAGNETIZATION PROCESSES

Fractals ◽  
1995 ◽  
Vol 03 (02) ◽  
pp. 351-370 ◽  
Author(s):  
GIANFRANCO DURIN ◽  
GIORGIO BERTOTTI ◽  
ALESSANDRO MAGNI
Keyword(s):  
Fractal Dimension ◽  
Domain Wall ◽  
Power Spectra ◽  
Domain Wall Motion ◽  
Soft Magnetic Materials ◽  
Barkhausen Effect ◽  
Scaling Properties ◽  
Domain Wall Dynamics ◽  
Self Organized ◽  
Self Organized Criticality

The main physical aspects and the theoretical description of stochastic domain wall dynamics in soft magnetic materials are reviewed. The intrinsically random nature of domain wall motion results in the Barkhausen effect, which exibits scaling properties at low magnetization rates and 1/f power spectra. It is shown that the Barkhausen signal ν, as well as the size Δx and the duration Δu of jumps follow distributions of the form ν−α, Δx−β, Δu−γ, with α=1−c, β=3/2−c/2, γ=2–c, where c is a dimensionless parameter proportional to the applied field rate. These results are analytically calculated by means of a stochastic differential equation for the domain wall dynamics in a random perturbed medium with brownian properties and then compared to experiments. The Barkhausen signal is found to be related to a random Cantor dust with fractal dimension D=1−c, from which the scaling exponents are calculated using simple properties of fractal geometry. Fractal dimension Δ of the signal v is also studied using four different methods of calculation, giving Δ≈1.5, independent of the method used and of the parameter c. The stochastic model is analyzed in detail in order to clarify if the shown properties can be interpreted as manifestations of self-organized criticality in magnetic systems.

scholarly journals Entropy production and self-organized (sub)criticality in earthquake dynamics

2010 ◽  
Vol 368 (1910) ◽  
pp. 131-144 ◽  
Author(s):  
Ian G. Main ◽  
Mark Naylor
Keyword(s):  
Numerical Model ◽  
Entropy Production ◽  
Power Law ◽  
Subcritical State ◽  
Earthquake Dynamics ◽  
Broad Bandwidth ◽  
Rupture Area ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Definition Of

We derive an analytical expression for entropy production in earthquake populations based on Dewar’s formulation, including flux (tectonic forcing) and source (earthquake population) terms, and apply it to the Olami–Feder–Christensen numerical model for earthquake dynamics. Assuming the commonly observed power-law rheology between driving stress and remote strain rate, we test the hypothesis that maximum entropy production (MEP) is a thermodynamic driver for self-organized ‘criticality’ (SOC) in the model. MEP occurs when the global elastic strain is near-critical, with small relative fluctuations in macroscopic strain energy expressed by a low seismic efficiency, and broad-bandwidth power-law scaling of frequency and rupture area. These phenomena, all as observed in natural earthquake populations, are hallmarks of the broad conceptual definition of SOC (which has, to date, often included self-organizing systems in a near but strictly subcritical state). In the MEP state, the strain field retains some memory of past events, expressed as coherent ‘domains’, implying a degree of predictability, albeit strongly limited in practice by the proximity to criticality and our inability to map the natural stress field at an equivalent resolution to the numerical model.

Discussion of landslide self-organized criticality and the initiation of debris flow

2007 ◽  
Vol 32 (2) ◽  
pp. 197-209 ◽  
Author(s):  
Chen Chien-Yuan ◽  
Yu Fan-Chieh ◽  
Lin Sheng-Chi ◽  
Cheung Kei-Wai
Keyword(s):  
Debris Flow ◽  
Self Organized ◽  
Self Organized Criticality

Self-Organized Critical Dynamics and Phase Transition Behavior During Avalanche Breakdown in p-Germanium

1991 ◽  
Vol 46 (12) ◽  
pp. 1009-1011
Author(s):  
M. Knoop ◽  
J. Parisi ◽  
W. Clauß ◽  
U. Rau ◽  
J. Peinke
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Experimental Evidence ◽  
Avalanche Breakdown ◽  
Critical Dynamics ◽  
Phase Transition Behavior ◽  
Scaling Properties ◽  
Self Organized ◽  
Self Organized Criticality ◽  
Parameter Ranges

Abstract We give experimental evidence that self-organized criticality takes place during the formation of low-temperature semiconductor breakdown. Quantitative evaluation of the characteristic scaling properties together with the appropriate parameter ranges of validity further support the applicability of the model conjectured

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