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Common dependence on stress for the statistics of granular avalanches and earthquakes.

Hatano T, Narteau C, Shebalin P - Sci Rep (2015)

Bottom Line: The faulting style dependence may be related to the magnitude of the differential stress, but no model so far has been able to reproduce this behaviour.Here we investigate the statistical properties of avalanches in a dissipative, bimodal particulate system under slow shear.These results are consistent with recent seismological observations of earthquake size-distribution and aftershock statistics.

View Article: PubMed Central - PubMed

Affiliation: Earthquake Research Institute, University of Tokyo, 113-0032 Tokyo, Japan.

ABSTRACT
Both earthquake size-distributions and aftershock decay rates obey power laws. Recent studies have demonstrated the sensibility of their parameters to faulting properties such as focal mechanism, rupture speed or fault complexity. The faulting style dependence may be related to the magnitude of the differential stress, but no model so far has been able to reproduce this behaviour. Here we investigate the statistical properties of avalanches in a dissipative, bimodal particulate system under slow shear. We find that the event size-distribution obeys a power law only in the proximity of a critical volume fraction, whereas power-law aftershock decay rates are observed at all volume fractions accessible in the model. Then, we show that both the exponent of the event size-distribution and the time delay before the onset of the power-law aftershock decay rate are decreasing functions of the shear stress. These results are consistent with recent seismological observations of earthquake size-distribution and aftershock statistics.

No MeSH data available.


Related in: MedlinePlus

The declustering method to select mainshock and aftershocks.We consider two non-overlapping magnitude ranges for mainshocks  and aftershocks . A magnitude  event occuring at time tM is selected as a mainshock if there is no larger event in the time interval [tM − ΔT; tM + ΔT]. All magnitude  events in the time window [tM, tM + ΔT] are selected as aftershocks (see also the Methods section.)
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f5: The declustering method to select mainshock and aftershocks.We consider two non-overlapping magnitude ranges for mainshocks and aftershocks . A magnitude event occuring at time tM is selected as a mainshock if there is no larger event in the time interval [tM − ΔT; tM + ΔT]. All magnitude events in the time window [tM, tM + ΔT] are selected as aftershocks (see also the Methods section.)

Mentions: Second, we can also study time series of avalanches from our simulations to take them as analogues for mainshock-aftershocks sequences. Unlike the magnitude-frequency distribution, and despite the systematic occurrence of aftershocks in seismogenic areas, there are only few examples of such mainshock-aftershocks sequences in amorphous systems914. Triggered events may be difficult to distinguish from other events or simply too rare in individual sequences to exhibit a specific decay rate. Here, we use stacks of aftershocks to capture signals over more than two decades in time. Following geophysical studies53435, the definitions of mainshocks and aftershocks as well as the declustering technique are described in Fig. 5 and in the Methods section.


Common dependence on stress for the statistics of granular avalanches and earthquakes.

Hatano T, Narteau C, Shebalin P - Sci Rep (2015)

The declustering method to select mainshock and aftershocks.We consider two non-overlapping magnitude ranges for mainshocks  and aftershocks . A magnitude  event occuring at time tM is selected as a mainshock if there is no larger event in the time interval [tM − ΔT; tM + ΔT]. All magnitude  events in the time window [tM, tM + ΔT] are selected as aftershocks (see also the Methods section.)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508663&req=5

f5: The declustering method to select mainshock and aftershocks.We consider two non-overlapping magnitude ranges for mainshocks and aftershocks . A magnitude event occuring at time tM is selected as a mainshock if there is no larger event in the time interval [tM − ΔT; tM + ΔT]. All magnitude events in the time window [tM, tM + ΔT] are selected as aftershocks (see also the Methods section.)
Mentions: Second, we can also study time series of avalanches from our simulations to take them as analogues for mainshock-aftershocks sequences. Unlike the magnitude-frequency distribution, and despite the systematic occurrence of aftershocks in seismogenic areas, there are only few examples of such mainshock-aftershocks sequences in amorphous systems914. Triggered events may be difficult to distinguish from other events or simply too rare in individual sequences to exhibit a specific decay rate. Here, we use stacks of aftershocks to capture signals over more than two decades in time. Following geophysical studies53435, the definitions of mainshocks and aftershocks as well as the declustering technique are described in Fig. 5 and in the Methods section.

Bottom Line: The faulting style dependence may be related to the magnitude of the differential stress, but no model so far has been able to reproduce this behaviour.Here we investigate the statistical properties of avalanches in a dissipative, bimodal particulate system under slow shear.These results are consistent with recent seismological observations of earthquake size-distribution and aftershock statistics.

View Article: PubMed Central - PubMed

Affiliation: Earthquake Research Institute, University of Tokyo, 113-0032 Tokyo, Japan.

ABSTRACT
Both earthquake size-distributions and aftershock decay rates obey power laws. Recent studies have demonstrated the sensibility of their parameters to faulting properties such as focal mechanism, rupture speed or fault complexity. The faulting style dependence may be related to the magnitude of the differential stress, but no model so far has been able to reproduce this behaviour. Here we investigate the statistical properties of avalanches in a dissipative, bimodal particulate system under slow shear. We find that the event size-distribution obeys a power law only in the proximity of a critical volume fraction, whereas power-law aftershock decay rates are observed at all volume fractions accessible in the model. Then, we show that both the exponent of the event size-distribution and the time delay before the onset of the power-law aftershock decay rate are decreasing functions of the shear stress. These results are consistent with recent seismological observations of earthquake size-distribution and aftershock statistics.

No MeSH data available.


Related in: MedlinePlus