Omori law for foreshocks and aftershocks in a realistic earthquake model

2019 ◽  
Vol 126 (4) ◽  
pp. 49001
Author(s):  
O. M. Braun ◽  
M. Peyrard
Keyword(s):  
2015 ◽  
Vol 31 (1) ◽  
pp. 19-45 ◽  
Author(s):  
Jonathan P. Stewart ◽  
John Douglas ◽  
Mohammad Javanbarg ◽  
Yousef Bozorgnia ◽  
Norman A. Abrahamson ◽  
...  

Ground motion prediction equations (GMPEs) relate ground motion intensity measures to variables describing earthquake source, path, and site effects. From many available GMPEs, we select those models recommended for use in seismic hazard assessments in the Global Earthquake Model. We present a GMPE selection procedure that evaluates multidimensional ground motion trends (e.g., with respect to magnitude, distance, and structural period), examines functional forms, and evaluates published quantitative tests of GMPE performance against independent data. Our recommendations include: four models, based principally on simulations, for stable continental regions; three empirical models for interface and in-slab subduction zone events; and three empirical models for active shallow crustal regions. To approximately incorporate epistemic uncertainties, the selection process accounts for alternate representations of key GMPE attributes, such as the rate of distance attenuation, which are defensible from available data. Recommended models for each domain will change over time as additional GMPEs are developed.


1994 ◽  
Vol 84 (6) ◽  
pp. 1940-1959 ◽  
Author(s):  
Steven G. Wesnousky

Abstract Paleoearthquake and fault slip-rate data are combined with the CIT-USGS catalog for the period 1944 to 1992 to examine the shape of the magnitude-frequency distribution along the major strike-slip faults of southern California. The resulting distributions for the Newport-Inglewood, Elsinore, Garlock, and San Andreas faults are in accord with the characteristic earthquake model of fault behavior. The distribution observed along the San Jacinto fault satisfies the Gutenberg-Richter relationship. If attention is limited to segments of the San Jacinto that are marked by the rupture zones of large historical earthquakes or distinct steps in fault trace, the observed distribution along each segment is consistent with the characteristic earthquake model. The Gutenberg-Richter distribution observed for the entirety of the San Jacinto may reflect the sum of seismicity along a number of distinct fault segments, each of which displays a characteristic earthquake distribution. The limited period of instrumental recording is insufficient to disprove the hypothesis that all faults will display a Gutenberg-Richter distribution when averaged over the course of a complete earthquake cycle. But, given that (1) the last 5 decades of seismicity are the best indicators of the expected level of small to moderate-size earthquakes in the next 50 years, and (2) it is generally about this period of time that is of interest in seismic hazard and engineering analysis, the answer to the question posed in the title of the article, at least when concerned with practical implementation of seismic hazard analysis at sites along these major faults, appears to be the “characteristic earthquake distribution.”


2015 ◽  
Vol 42 (4) ◽  
pp. 277-289
Author(s):  
Miodrag Zigic ◽  
Nenad Grahovac

We study the seismic response of two adjacent structures connected with a dry friction damper. Each of them consists of a viscoelastic rod and a rigid block, which can slide without friction along the moving base. A simplified earthquake model is used for modeling the horizontal ground motion. Energy dissipation is taken by the presence of the friction damper, which is modeled by the set-valued Coulomb friction law. Deformation of viscoelastic rods during the relative motion of the blocks represents another way of energy dissipation. The constitutive equation of a viscoelastic body is described by the fractional Zener model, which includes fractional derivatives of stress and strain. The problem merges fractional derivatives as non-local operators and theory of set-valued functions as the non-smooth ones. Dynamical behaviour of the problem is governed by a pair of coupled multi-valued differential equations. The posed Cauchy problem is solved by use of the Gr?nwald-Letnikov numerical scheme. The behaviour of the system is analyzed for different values of system parameters.


1975 ◽  
Vol 65 (2) ◽  
pp. 351-357
Author(s):  
John Filson ◽  
Tom Simkin

abstract The Kolomogorov model of event occurrence as developed by Knopoff in earthquake model studies has been applied to a volcanic earthquake swarm. It is shown that in this case, where the rate of seismic energy release was nearly constant in time, the model adequately relates the various seismicity statistics of the swarm.


Author(s):  
John F. Schneider ◽  
Jephraim Oro ◽  
Anselm Smolka ◽  
Peter Suhadolc ◽  
Zhongliang Wu
Keyword(s):  

2019 ◽  
Vol 105 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Alexey A. Ostapchuk ◽  
Kseniya G. Morozova ◽  
Dmitry V. Pavlov

Presented are the results of laboratory experiments on investigating manifestations of acoustic emission (AE) of a gouge-filled fault during stick-slip. The laboratory experiments were held at the slider-model setup, when a granite block slides along a rough granite base under normal and shear loads. In the course of experiments we altered the structure of the two-component filler of the fault and focused on variations of the AE parameters. The kinematic parameters of fault slip events in all the realizations remained approximately the same. The eff ect of gouge structure on the statistics of AE has been revealed. An alteration of proportion of quartz sand / glass beads in the filler of the fault was accompanied by an alteration of the b-value of frequency-energy distribution from 0.53 to 0.85, and the p-value of Omori law from 1.00 to 2.06. Also, it has been demonstrated that the nucleation of a slip event is accompanied by an alteration of the mechanism of AE generation – at the initial stage the 'tensile crack' signals prevailed, while at the final stage – the 'shear crack' signals did. The alteration of AE genesis manifested vividly in a corresponding alteration of the emitted waveforms for all the realizations.


2019 ◽  
Vol 525 ◽  
pp. 1463-1471 ◽  
Author(s):  
Gui-Qing Zhang ◽  
Jordi Baró ◽  
Fang-Yin Cheng ◽  
He Huang ◽  
Lin Wang

Fractals ◽  
2004 ◽  
Vol 12 (02) ◽  
pp. 243-273 ◽  
Author(s):  
K. EFTAXIAS ◽  
P. FRANGOS ◽  
P. KAPIRIS ◽  
J. POLYGIANNAKIS ◽  
J. KOPANAS ◽  
...  

We introduce a new model of the generation of pre-seismic electromagnetic emissions, which explains the observed phenomenology in terms of its geometry and fractal electrodynamics. Accumulated evidence indicates that an earthquake can be viewed as a critical phenomenon culminating in a large event that corresponds to a type of critical point. The principle feature of criticality is the fractal organization in both space and time. Earthquakes display a complex spatio-temporal behavior: in addition to the regularity in the rate of occurrence (e.g. Gutenberg-Richter law, Omori law), the spatial distribution of epicenters is fractal and earthquakes occur on a fractal structure of faults. Thus, the hypothesis that the fault develops as a fractal is reasonable. A mounting body of laboratory evidence suggests that micro-fracturing of rocks are associated with the appearance of spontaneous charge production and transient electromagnetic emissions (EME). The emitting, diffusing and recombination charge accompanying the micro-fracturing, can act as current generated during the crack opening. In this view, an active crack or rupture, can be simulated by a "radiating element." The idea is that a fractal geo-antenna (FGA) can be formed as an array of line elements having a fractal distribution on the ground surface as the critical point is approached. We test this idea in terms of fractal electrodynamics: we argue that the precursory VLF-VHF EM signals associated with recent earthquakes in Greece are governed by characteristics (e.g. scaling laws, temporal evolution of the spectrum content, broad band spectrum region and accelerating emission rate) predicted by fractal electrodynamics.


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