Self-organized criticality and earthquake predictability: A long-standing question in the light of natural time analysis

Abstract

After the Bak-Tang-Wisenfeld seminal work on self-organized criticality (SOC), the following claim appeared by other workers in the 1990s: Earthquakes (EQs) cannot be predicted, since the Earth is in a state of SOC and hence any small earthquake has some probability of cascading into a large event. Here, we discuss that such claims do not stand in the light of natural time analysis, which was shown at the beginning of the 2000s to extract the maximum information possible from complex systems time series. A useful quantity to identify the approach of a dynamical system to criticality is the variance of natural time χ, which becomes equal to 0.070 at the critical state for a variety of dynamical systems. This also holds for experimental results of critical phenomena such as growth of ricepiles, seismic electric signals activities, and the subsequent seismicity before the associated main shock. Another useful quantity is the change of the dynamic entropy under time reversal, which is minimized before a large avalanche upon analyzing the Olami-Feder-Christensen model for EQs in natural time. Such a minimum actually occurred on 22 December 2010, well before the M9 Tohoku EQ in Japan on 11 March 2011, being accompanied by increases of both the complexity measure of the fluctuations and the variability of the order parameter of seismicity (which was minimized two weeks later). These increases conform to the seminal work on phase transitions by Lifshitz and Slyozov and independently by Wagner as well as to more recent work by Penrose et al. In addition, the evolution of the complexity measure of the fluctuations reveals a reliable estimation of the occurrence time of this M9 EQ.

Nowcasting Earthquakes: Imaging the Earthquake Cycle in California With Machine Learning

“…2019). Fundamentally, nowcasting is based on the concept of natural time (Sarlis et al., 2018; Varotsos, Sarlis, & Skordas et al., 2020; Varotsos, Skordas, & Sarlis et al., 2020; Varotsos et al., 2001, 2002, 2011, 2013, 2014), which is unique in its characteristics (Pasari, 2019).…”

Estimating the Epicenter of a Future Strong Earthquake in Southern California, Mexico, and Central America by Means of Natural Time Analysis and Earthquake Nowcasting

“…When focusing in the region N W (shown in Figure 1 ), more than twenty-eight EQs with a magnitude M have occurred there since 1989. In the present paper, we employ the natural time analysis (NTA) [ 5 , 6 , 7 , 8 , 9 , 10 ] and earthquake nowcasting (EN) [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ] aiming at forecasting the epicenter of such a strong future EQ.…”

Trapped Proton Fluxes Estimation Inside the South Atlantic Anomaly Using the NASA AE9/AP9/SPM Radiation Models along the China Seismo-Electromagnetic Satellite Orbit

“…[26,27]. A recent perspective [28] explained that claims based on self-organized criticality stating that at any moment any small earthquake can eventually cascade to a large event do not stand in view of the results obtained by natural time analysis [29,30]. The CSES-01 satellite, based on the Chinese 3-axis-stabilized CAST2000 platform (total mass ∼ 700 kg), is flying on a sun-synchronous polar orbit at a ∼507 km altitude, with a 97 • inclination, a period of 94.6 min, and a 5-day revisiting periodicity.…”