Common dependence on stress for the two fundamental laws of statistical seismology

Narteau, C.; Byrdina, Svetlana; Shebalin, P.; Schorlemmer, Danijel

doi:10.1038/nature08553

Cited by 137 publications

(87 citation statements)

References 27 publications

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“…Furthermore, the role of the parameter b variations is critical. Strong variations of b across different stress regimes imply that this parameter acts as a stress meter that depends inversely on differential stress (e.g., Schorlemmer et al, 2005;Narteau et al, 2009, and references therein). Observations of seismic sequences have shown that b usually drops and becomes significantly lower in foreshocks than in aftershocks or in background seismicity (Papazachos, 1975;Jones and Molnar, 1979;Main et al, 1989;Molchan et al, 1999;Enescu et al, 2001;Nanjo et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Foreshocks and short-term hazard assessment of large earthquakes using complex networks: the case of the 2009 L'Aquila earthquake

Daskalaki

Spiliotis

Siettos

et al. 2016

Nonlin. Processes Geophys.

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Abstract. The monitoring of statistical network properties could be useful for the short-term hazard assessment of the occurrence of mainshocks in the presence of foreshocks. Using successive connections between events acquired from the earthquake catalog of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) for the case of the L'Aquila (Italy) mainshock (M w = 6.3) of 6 April 2009, we provide evidence that network measures, both global (average clustering coefficient, small-world index) and local (betweenness centrality) ones, could potentially be exploited for forecasting purposes both in time and space. Our results reveal statistically significant increases in the topological measures and a nucleation of the betweenness centrality around the location of the epicenter about 2 months before the mainshock. The results of the analysis are robust even when considering either large or off-centered the main event space windows.

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Section: Discussionmentioning

confidence: 99%

Foreshocks and short-term hazard assessment of large earthquakes using complex networks: the case of the 2009 L'Aquila earthquake

Daskalaki

Spiliotis

Siettos

et al. 2016

Nonlin. Processes Geophys.

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“…This can result in short-term variations of M c , which, if ignored, can lead to spurious results and misinterpretations (Kagan, 2004;Hainzl, 2013). Thus, a temporal resolution of M c is necessary to get unbiased parameter estimations of seismicity models such as the epidemic-type aftershock sequence (ETAS) model (Ogata, 1988;Zhuang et al, 2012) and to evaluate variations of statistical parameters such as the b-value (e.g., Imoto, 1991;Hainzl and Fischer, 2002;Mallika et al, 2013;Schurr et al, 2014;Huang and Beroza, 2015) or Omori c-value (e.g., Shcherbakov et al, 2004;Narteau et al, 2009;Davidsen et al, 2015). Both are important for physical interpretations and seismic-hazard estimations.…”

Section: Introductionmentioning

confidence: 99%

Rate‐Dependent Incompleteness of Earthquake Catalogs

Hainzl

2016

Seismological Research Letters

129

114

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Important information about the earthquake generation process can be gained from instrumental earthquake catalogs, but this requires complete recordings to avoid biased results. The local completeness magnitude M c is known to depend on general conditions such as the seismographic network and the environmental noise, which generally limit the possibility of detecting small events. The detectability can be additionally reduced by an earthquake-induced increase of the noise level leading to shortterm variations of M c , which cannot be resolved by traditional methods relying on the analysis of the frequency-magnitude distribution. Based on simple assumptions, I propose a new method to estimate such temporal excursions of M c solely based on the estimation of the earthquake rate resulting in a high temporal resolution of M c . The approach is shown to be in agreement with the apparent decrease of the estimated Gutenberg-Richter b-value in high-activity phases of recorded data sets and the observed incompleteness periods after mainshocks. Furthermore, an algorithm to estimate temporal changes of M c is introduced and applied to empirical aftershock and swarm sequences from California and central Europe, indicating that observed b-value fluctuations are often related to rate-dependent incompleteness of the earthquake catalogs.Online Material: MATLAB code to compute rate-dependent completeness magnitude, and figures showing variation in the estimated M c values in equalized time scale.

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“…It is possible that the result is more important, because it allows us to correlate the variation in the character of the aftershock activity with the maximum load because such a correlation is used [7] in the algorithm of earthquake prediction. However, our data require additional confirmation by tests on various materials that have different strengths, structures, and tendency to occurrence of aftershocks.…”

Section: Materials and Methods Of Researchmentioning

confidence: 99%

Time dependences of acoustic signal characteristics during fracture of metal samples

Ботвина

Petersen²,

Soldatenkov

et al. 2015

Dokl. Earth Sc.

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Analysis of time dependences of the amount of acoustic emission signals during the fracture processes is important for both the diagnosis and forecast of breaking at various stages of the process and also for the investigation of the influence of different factors on the fracture process. It was shown in [1-3] that the time dependences of the acoustic emission signals observed at the final stage of the breaking of rock sam ples are similar to the time dependences of the number of seismic events (aftershocks) during the develop ment of processes in the Earth's crust after the main event, an earthquake. They are described by the Omori-Ursu relation [4]:where n(t) is the rate of aftershocks; t is the time from the moment of the main event; K is the number of aftershocks; p is the exponent; and c is the time delay before the beginning of the realization of the power dependence of the aftershock rate.The similarity between the time dependences of the number of acoustic emission signals preceding the crack jump during fracture of metal samples and the number of seismic events before an earthquake (fore shocks) was found in [5]. This allows us to suppose that a similarity between time dependences of acoustic sig nals in metal samples and seismic signals might be found at the stage of the aftershock activity described by the Omori-Utsu law. If such a similarity exists, experiments with metal samples should give us the possibility to study the influence of stress on the parameters of this relation. With this in mind, we con ducted the study reported here. MATERIAL AND METHODS OF RESEARCHThis study was performed using double cantilever bend (DCB) specimens (Fig. 1a) made of low carbon steel (0.3-0.35 C, 0.17-0.37 Si, 1.1-1.35 Mn) with embrittlement that resulted from keeping the samples in a hydrogen sulfide environment.Testing of samples was performed using the Instron 1195 tension testing machine in the conditions of eccentric tension: the tension load was applied through the holes in the samples and the main crack developed from the tip of a preliminarily made fatigue crack at the notch mouth (Fig. 1a). Signals of acoustic emission (AE) in the frequency range 50-500 kHz were recorded during the tension using piezo electric receivers with a resonance at 250 kHz. The data were digitized with a frequency of 1 MHz (the gray circle in Fig. 1 denotes the location of the AE sensor). The amplitude threshold of recording was set equal to 35 dB. Eight parameters separated from each AE signal exceeding the threshold were recorded, as well as the digitized signal form. The load applied to the sample was recorded as an external parameter. Informative indicators of the signal were used to distinguish the useful signal.The following characteristics of the process were estimated: acoustic activity , time intervals τ between the arrival of sequential acoustic signals, and distributions of signal amplitudes for different time moments of loading the sample. All characteristics listed were described by functional dependences. The function ...

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Common dependence on stress for the two fundamental laws of statistical seismology

Cited by 137 publications

References 27 publications

Foreshocks and short-term hazard assessment of large earthquakes using complex networks: the case of the 2009 L'Aquila earthquake

Foreshocks and short-term hazard assessment of large earthquakes using complex networks: the case of the 2009 L'Aquila earthquake

Rate‐Dependent Incompleteness of Earthquake Catalogs

Time dependences of acoustic signal characteristics during fracture of metal samples

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