Long-range Automaton Models of Earthquakes: Power-law Accelerations, Correlation Evolution, and Mode-switching

Weatherley, Dion; Móra, Péter; Xia, Meng

doi:10.1007/s00024-002-8743-6

Cited by 30 publications

(18 citation statements)

References 27 publications

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“…A strong correlation is evident between the AMR/AER and LURR critical region sizes, suggesting these two observations have a common physical mechanism. Recent simulations demon-strate Accelerating Moment/Energy Release (MORA et al, 2000) and an evolution in stress correlations prior to large events WEATHERLEY et al, 2002) consistent with that predicted by the Critical Point Hypothesis. This suggests a mechanism that is CPH or CPH-like.…”

Section: A Test For a Common Physical Mechanism For Lurr And Amr/aersupporting

confidence: 68%

Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction

Yin¹,

Móra²,

Peng³

et al. 2002

Pure and Applied Geophysics

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-The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have led different research groups to suggest intermediate-term earthquake prediction is possible and imply that the LURR and AMR/AER observations may have a similar physical origin. To study this possibility, we conducted a retrospective examination of several Australian and Chinese earthquakes with magnitudes ranging from 5.0 to 7.9, including Australia's deadly Newcastle earthquake and the devastating Tangshan earthquake. Both LURR values and best-fit power-law time-to-failure functions were computed using data within a range of distances from the epicenter. Like the best-fit powerlaw fits in AMR/AER, the LURR value was optimal using data within a certain epicentral distance implying a critical region for LURR. Furthermore, LURR critical region size scales with mainshock magnitude and is similar to the AMR/AER critical region size. These results suggest a common physical origin for both the AMR/AER and LURR observations. Further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate-term earthquake prediction.

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Section: A Test For a Common Physical Mechanism For Lurr And Amr/aersupporting

confidence: 68%

Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction

Yin¹,

Móra²,

Peng³

et al. 2002

Pure and Applied Geophysics

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“…In contrast, model F has no systematic dependence of l=r on the fractal dimension D. These observations support our assertion that the distribution type RW is more efficient for tuning the dynamics with a single heterogeneity parameter. ZO¨LLER et al (2004) have shown that high stress fluctuations occurring along cell boundaries on a heterogeneous fault can cause a spontaneous mode-switching between a Gutenberg-Richter and a characteristic earthquake distribution (DAHMEN et al, 1998;BEN-ZION et al, 1999;WEATHERLEY et al, 2002). Although the type of distribution does not change in the simulations leading to Figure 7, the results (especially those for model RW) have time periods with clearly different maximum magnitudes.…”

Section: Analysis Of Earthquake Catalogsmentioning

confidence: 95%

The Role of Heterogeneities as a Tuning Parameter of Earthquake Dynamics

Zöller

Holschneider

Ben‐Zion

2005

Pure appl. geophys.

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We investigate the influence of spatial heterogeneities on various aspects of brittle failure and seismicity in a model of a large strike-slip fault. The model dynamics is governed by realistic boundary conditions consisting of constant velocity motion of regions around the fault, static/kinetic friction laws, creep with depth-dependent coefficients, and 3-D elastic stress transfer. The dynamic rupture is approximated on a continuous time scale using a finite stress propagation velocity (''quasidynamic model''). The model produces a ''brittle-ductile'' transition at a depth of about 12.5 km, realistic hypocenter distributions, and other features of seismicity compatible with observations. Previous work suggested that the range of size scales in the distribution of strength-stress heterogeneities acts as a tuning parameter of the dynamics. Here we test this hypothesis by performing a systematic parameter-space study with different forms of heterogeneities. In particular, we analyze spatial heterogeneities that can be tuned by a single parameter in two distributions: (1) high stress drop barriers in near-vertical directions and (2) spatial heterogeneities with fractal properties and variable fractal dimension. The results indicate that the first form of heterogeneities provides an effective means of tuning the behavior while the second does not. In relatively homogeneous cases, the fault self-organizes to large-scale patches and big events are associated with inward failure of individual patches and sequential failures of different patches. The frequency-size event statistics in such cases are compatible with the characteristic earthquake distribution and large events are quasi-periodic in time. In strongly heterogeneous or near-critical cases, the rupture histories are highly discontinuous and consist of complex migration patterns of slip on the fault. In such cases, the frequency-size and temporal statistics follow approximately power-law relations.

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“…Carlson 1991;Rice 1993;Ben-Zion 1996;Langer et al 1996;Fisher et al 1997;Dahmen et al 1998;Lapusta et al 2000;Shaw & Rice 2000;Weatherley et al 2002;Heimpel 2003;Zöller et al 2005;Mehta et al 2006;Hillers et al 2007). Properties such as the energy dissipation and stress interaction distance, dimension, the degree of heterogeneity, and the range of size scales have been used as control parameters.…”

Section: Fault Zone Dynamicsmentioning

confidence: 99%

Seismicity in a model governed by competing frictional weakening and healing mechanisms

Hillers

Carlson

Archuleta

2009

Geophysical Journal International

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S U M M A R YObservations from laboratory, field and numerical work spanning a wide range of space and time scales suggest a strain dependent progressive evolution of material properties that control the stability of earthquake faults. The associated weakening mechanisms are counterbalanced by a variety of restrengthening mechanisms. The efficiency of the healing processes depends on local material properties and on rheologic, temperature, and hydraulic conditions. We investigate the relative effects of these competing non-linear feedbacks on seismogenesis in the context of evolving frictional properties, using a mechanical earthquake model that is governed by slip weakening friction. Weakening and strengthening mechanisms are parametrized by the evolution of the frictional control variable-the slip weakening rate R-using empirical relationships obtained from laboratory experiments. In our model, weakening depends on the slip of an earthquake and tends to increase R, following the behaviour of real and simulated frictional interfaces. Healing causes R to decrease and depends on the time passed since the last slip. Results from models with these competing feedbacks are compared with simulations using non-evolving friction. Compared to fixed R conditions, evolving properties result in a significantly increased variability in the system dynamics. We find that for a given set of weakening parameters the resulting seismicity patterns are sensitive to details of the restrengthening process, such as the healing rate b and a lower cutoff time, t c , up to which no significant change in the friction parameter is observed. For relatively large and small cutoff times, the statistics are typical of fixed large and small R values, respectively. However, a wide range of intermediate values leads to significant fluctuations in the internal energy levels. The frequency-size statistics of earthquake occurrence show corresponding non-stationary characteristics on time scales over which negligible fluctuations are observed in the fixed-R case. The progressive evolution implies that-except for extreme weakening and healing rates-faults and fault networks possibly are not well characterized by steady states on typical catalogue time scales, thus highlighting the essential role of memory and history dependence in seismogenesis. The results suggest that an extrapolation to future seismicity occurrence based on temporally limited data may be misleading due to variability in seismicity patterns associated with competing mechanisms that affect fault stability.

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Long-range Automaton Models of Earthquakes: Power-law Accelerations, Correlation Evolution, and Mode-switching

Cited by 30 publications

References 27 publications

Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction

Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction

The Role of Heterogeneities as a Tuning Parameter of Earthquake Dynamics

Seismicity in a model governed by competing frictional weakening and healing mechanisms

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