Natural time analysis of acoustic emissions before fracture: Results compatible with the Bak-Tang-Wiesenfeld model

Abstract

Natural time analysis has been recently applied for the elaboration of data recorded by means of the Acoustic Emission (AE) sensing technique while specimens and structures are mechanically loaded at levels approaching those causing macroscopic fracture. In terms of the variance κ1, the entropy in natural time S, as well as the entropy in natural time under time reversal S-, a complex behavior was observed, which could be understood by the Burridge- Knopoff train model and the Olami-Feder-Christensen earthquake model. Here, the AE data recorded when notched fiber-reinforced concrete specimens were subjected to three-point bending until fracture, are analysed in natural time. The analysis leads to κ1, S, and S- values that are compatible with those obtained by a centrally fed Bak-Tang-Wiesenfeld sandpile model, which was theoretically studied in natural time almost a decade ago.

Complexity in Geophysical Time Series of Strain/Fracture at Laboratory and Large Dam Scales: Review

“…Tilts . The data on tilts illustrate the evolution of corresponding crust tilt dynamics from the natural state, stages 1–2 (1974–1977), to the period of initial impoundment of the reservoir, stages 3–6 (1978–1982), and lastly, to the beginning of the regular water load/unload regime, stage 7 (1983–1985) [ 41 ]. Below we present the results of Tsallis entropy ( Figure 7 ) and mutual information ( Figure 8 ) calculation.…”

“…The initial contact area is restored due to the immediate closure of the elementary cracks after the final rupture (strain release) of the solid or due to ageing after some characteristic time. Experimental acoustic emission (AE) systems developed in recent years allow us to obtain detailed data on the microphysics of stick–slip processes, including important details on the precursory events signaling that the system is close to the critical (macro-slip) phase [ 40 , 41 ].…”

Direct interconnection of seismicity with variations of the Earth's electric and magnetic field before major earthquakes

“…is defined, which becomes equal to 0.070 at the critical state for several dynamical systems studied [13][14][15][16][17][18]. This quantity, as shown by a careful study [19], may be considered as an order parameter of seismicity, see also ref.…”