G. Ouillon

G. Ouillon
Lithophyse

Dr

About

89
Publications
19,396
Reads
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2,117
Citations
Additional affiliations
January 2001 - September 2006
University of California, Los Angeles
Position
  • Researcher
January 1992 - September 2006
University of Nice Sophia Antipolis
Position
  • Researcher

Publications

Publications (89)
Article
Full-text available
Fundamentally related to the ultraviolet (UV) divergence problem in Physics, conventional wisdom in statistical seismology is that the smallest earthquakes, which are numerous and often go undetected, dominate the triggering of major earthquakes, making accurate forecasting of the latter difficult if not inherently impossible. Using the general cla...
Preprint
Full-text available
Conventional wisdom in seismology is that the smallest earthquakes, which are numerous and often go undetected, dominate the triggering of major earthquakes, making accurate forecasting of the latter difficult if not inherently impossible. Here, we demonstrate that a significant fraction of large events is triggered by previous large events. Being...
Article
There are several long-term statistical researches using the Molchan diagram (MD) to prove the relation between thermal infrared (TIR) anomalies and earthquakes in different regions, however, these studies are flawed: 1) the original MD is based on the spatially uniform Poisson model, but it will offer wrong evaluations for inhomog-enous systems wi...
Conference Paper
Full-text available
Nature is scary. You can be sitting at your home and next thing you know you are trapped under the ruble of your own house or sucked into a sinkhole. For millions of years we have been the figurines of this precarious scene and we have found our own ways of dealing with the anxiety. It is natural that we create and consume prophecies, conspiracies...
Preprint
Full-text available
Fundamentally related to the ultraviolet (UV) divergence problem in Physics, conventional wisdom in seismology is that the smallest earthquakes, which are numerous and often go undetected, dominate the triggering of major earthquakes, making accurate forecasting of the latter difficult if not inherently impossible. By developing a rigorous validati...
Presentation
Full-text available
This is the 2 minute pitch slide for the EGU 2021 Education and Outreach session (EOS 7.10), for the presentation "How prediction statistics can help us cope when we are shaken, scared and irrational". Watch the full presentation here: https://www.youtube.com/watch?v=So4c9GnfHi0 Read the abstract here: https://meetingorganizer.copernicus.org/EGU2...
Article
Full-text available
Seismicity and faulting within the Earth’s crust are characterized by many scaling laws that are usually interpreted as qualifying the existence of underlying physical mechanisms associated with some kind of criticality in the sense of phase transitions. Using an augmented epidemic-type aftershock sequence (ETAS) model that accounts for the spatial...
Article
We describe the process of pairing M4 + earthquakes reported in the routine catalogues of two seismic networks in Turkey and present the resulting products: (i) hypocentre locations and magnitudes; (ii) minimum 1D velocity model with station delays for the combined station network. The two networks are the Kandilli Observatory (KOERI) and the Natio...
Article
Full-text available
Predictability of earthquakes has been vigorously debated in the last decades with the dominant -albeit contested -view being that earthquakes are inherently unpredictable. The absence of a framework to rigorously evaluate earthquake predictions has led to prediction efforts being viewed with scepticism. Consequently, funding for earthquake predict...
Article
Full-text available
We conclude this special issue on the Global Earthquake Forecasting System (GEFS) by briefly reviewing and analyzing the claims of non-seismic precursors made in the present volume, and by reflecting on the current limitations and future directions to take. We find that most studies presented in this special volume, taken individually, do not provi...
Article
Full-text available
We present rigorous tests of global short-term earthquake forecasts using Epidemic Type Aftershock Sequence models with two different time kernels (one with exponentially tapered Omori kernel (ETOK) and another with linear magnitude dependent Omori kernel (MDOK)). The tests are conducted with three different magnitude cutoffs for the auxiliary cata...
Article
Full-text available
We examine the precursory behavior of geoelectric signals before large earthquakes by means of a previously published algorithm including an alarm-based model and binary classification [H.-J. Chen, C.-C. Chen, Nat. Hazards 84, 877 (2016)]. The original method has been improved by removing a time parameter used for coarse-graining of earthquake occu...
Article
Full-text available
Recently, researchers have conducted long-term statistical studies to prove the correspondence between earthquakes and thermal infrared (TIR) anomalies. Upon obtaining relatively high true positive rates (TPR), it was concluded that TIR anomalies are closely related to earthquakes. However, the temporal-spatial clustering of earthquakes and overly...
Article
Full-text available
We introduce the first fully self-consistent numerical model combining seismic micro-ruptures, occurring within a generalized Burridge-Knopoff spring-block model, with the nucleation and propagation of electric charge pulses within a coupled mechano-electrokinetic system. This model provides a general theoretical framework for modeling and analyzin...
Article
Full-text available
In this paper we introduce a method for fault network reconstruction based on the 3D spatial distribution of seismicity. One of the major drawbacks of statistical earthquake models is their inability to account for the highly anisotropic distribution of seismicity. Fault reconstruction has been proposed as a pattern recognition method aiming to ext...
Preprint
Full-text available
We present rigorous tests of global short-term earthquake forecasts using Epidemic Type Aftershock Sequence models with two different time kernels (one with exponentially tapered Omori kernel (ETOK) and another with linear magnitude dependent Omori kernel (MDOK)). The tests are conducted with three different magnitude cutoffs for the auxiliary cata...
Preprint
Full-text available
Seismicity and faulting within the Earth crust are characterized by many scaling laws that are usually interpreted as qualifying the existence of underlying physical mechanisms associated with some kind of criticality in the sense of phase transitions. Using an augmented Epidemic-Type Aftershock Sequence (ETAS) model that accounts for the spatial v...
Preprint
Full-text available
In this paper we introduce a method for fault network reconstruction based on the 3D spatial distribution of seismicity. One of the major drawbacks of statistical earthquake models is their inability to account for the highly anisotropic distribution of seismicity. Fault reconstruction has been proposed as a pattern recognition method aiming to ext...
Article
Full-text available
The flow behavior of soft materials below the yield stress can be rich and is not fully understood. Here, we report shear-stress-induced reorganization of three-dimensional solid-like soft materials formed by closely packed nematic domains of surfactant micelles and a repulsive Wigner glass formed by anisotropic clay nano-discs having ionic interac...
Article
Full-text available
Currently, one of the best performing earthquake forecasting models relies on the working hypothesis that the “locations of past background earthquakes reveal the probable location of future seismicity.” As an alternative, we present a class of smoothed seismicity models (SSMs) based on the principles of the epidemic‐type aftershock sequence (ETAS)...
Preprint
Full-text available
We introduce the first fully self-consistent model combining the seismic micro-ruptures occurring within a generalized Burridge-Knopoff spring-block model with the nucleation and propagation of electric charge pulses within a coupled mechano-electrokinetic system. This model provides a general theoretical framework for modeling and analyzing geoele...
Preprint
Full-text available
We examine the precursory behavior of geoelectric signals before large earthquakes by means of an algorithm including an alarm-based model and binary classification. This algorithm, introduced originally by Chen and Chen [Nat. Hazards., 84, 2016], is improved by removing a time parameter for coarse-graining of earthquake occurrences, as well as by...
Article
Full-text available
Forecasting the full distribution of the number of earthquakes is revealed to be inherently superior to forecasting their mean. Forecasting the full distribution of earthquake numbers is also shown to yield robust projections in the presence of surprise large earthquakes, which in the past have strongly deteriorated the scores of existing models. W...
Preprint
Full-text available
Forecasting the full distribution of the number of earthquakes is revealed to be inherently superior to forecasting their mean. Forecasting the full distribution of earthquake numbers is also shown to yield robust projections in the presence of "surprise" large earthquakes, which in the past have strongly deteriorated the scores of existing models....
Preprint
Full-text available
Forecasting the full distribution of the number of earthquakes is revealed to be inherently superior to forecasting their mean. Forecasting the full distribution of earthquake numbers is also shown to yield robust projections in the presence of "surprise" large earthquakes, which in the past have strongly deteriorated the scores of existing models....
Preprint
Full-text available
Currently, one of the best performing and most popular earthquake forecasting models rely on the working hypothesis that: "locations of past background earthquakes reveal the probable location of future seismicity". As an alternative, we present a class of smoothed seismicity models (SSMs) based on the principles of the Epidemic Type Aftershock Seq...
Article
Full-text available
The driving concept behind one of the most successful statistical forecasting models, the ETAS model, has been that the seismicity is driven by spontaneously occurring background earthquakes that cascade into multitudes of triggered earthquakes. In nearly all generalizations of the ETAS model, the magnitudes of the background and the triggered eart...
Preprint
The driving concept behind one of the most successful statistical forecasting models, the ETAS model, has been that the seismicity is driven by spontaneously occurring background earthquakes that cascade into multitudes of triggered earthquakes. In nearly all generalizations of the ETAS model, the magnitudes of the background and the triggered eart...
Presentation
Full-text available
(This presentation is concerning my PhD thesis defense.) Abstract: Due to the lack of the physical mechanisms of rupture precursors, studies of earthquake precursors are still debated and skeptical. The purpose of this thesis is to verify correlations between pre-seismic anomalies of geoelectric fields and earthquakes. The thesis includes two main...
Poster
Full-text available
In rock fracture experiments, electromagnetic emission accompanying fracture is a common physical phenomenon. And in field observations, the anomalies of electromagnetic signals were found before large earthquakes [Chen and Chen, Nat. Hazards, 2016; Chen et al., Terr. Atmos. Ocean., 2017]. In this study, we conceptualize a completely novel model co...
Article
Full-text available
Forecasting earthquakes implies that there are time-varying processes, which depend on the changing conditions deep in the Earth's crust prior to major seismic activity. These processes may be linearly or non-linearly correlated. In seismology, the research has traditionally focused on mechanical variables, including precursory ground deformation (...
Article
Full-text available
The earthquake-alarm model developed by Chen and Chen [Nat. Hazards, in press] is investigated to validate its forecasting performances for the 2016/2/6, ML6.6 Meinong, Taiwan earthquake. This alarm model is based on anomalies of skewness and kurtosis of geoelectric fields. The parameters of the model, such as the detected range and the predicted t...
Article
Full-text available
Earthquake catalogs are fundamental cornerstones in the study of earthquake phenomena. They provide the origin time, location, and magnitude information that constitutes the basis for earthquake interaction analysis, as well as physics-and statistics-based earthquake forecasting models. In this article, we locate the southern California seismicity...
Article
Full-text available
The ETAS model is widely employed to model the spatio-temporal distribution of earthquakes, generally using spatially invariant parameters. We propose an efficient method for the estimation of spatially varying parameters, using the Expectation Maximization (EM) algorithm and spatial Voronoi tessellation ensembles. We use the Bayesian Information C...
Article
Full-text available
A likely source of earthquake clustering is static stress transfer between individual events. Previous attempts to quantify the role of static stress for earthquake triggering generally considered only the stress changes caused by large events, and often discarded data uncertainties. We conducted a robust two-fold empirical test of the static stres...
Article
Full-text available
We present the "condensation" method that exploits the heterogeneity of the probability distribution functions (PDF) of event locations to improve the spatial information content of seismic catalogs. The method reduces the size of seismic catalogs while improving the access to the spatial information content of seismic catalogs. The PDFs of events...
Conference Paper
Full-text available
We present the "condensation" method that exploits the heterogeneity of the probability distribution functions (PDF) of event locations to improve the spatial information content of seismic catalogs. The method reduces the size of seismic catalogs while improving the access to the spatial information content of seismic catalogs. The PDFs of events...
Conference Paper
Full-text available
Earthquake catalogs are the single most essential element in the study of earthquake phenomena. They provide the origin time, location and magnitude information that constitutes the basis for earthquake interaction analysis as well as physics and statistics based earthquake forecasting models. The information quality of earthquake catalogs has been...
Article
Full-text available
[1] We introduce the anisotropic clustering of location uncertainty distributions (ACLUD) method to reconstruct active fault networks on the basis of both earthquake locations and their estimated individual uncertainties. After a massive search through the large solution space of possible reconstructed fault networks, we apply six different validat...
Article
Full-text available
We present a method to estimate the multifractal spectrum of point distributions. The method incorporates two motivated criteria (barycentric pivot point selection and nonoverlapping coverage) in order to reduce edge effects, improve precision, and reduce computation time. Implementation of the method on synthetic benchmarks demonstrates the superi...
Article
Full-text available
We introduce the Anisotropic Clustering of Location Uncertainty Distributions (ACLUD) method to reconstruct active fault networks on the basis of both earthquake locations and their estimated individual uncertainties. After a massive search through the large solution space of possible reconstructed fault networks, we apply six different validation...
Article
Full-text available
This introductory article presents the special Discussion and Debate volume "From black swans to dragon-kings, is there life beyond power laws?" published in Eur. Phys. J. Special Topics in May 2012. We summarize and put in perspective the contributions into three main themes: (i) mechanisms for dragon-kings, (ii) detection of dragon-kings and stat...
Article
Full-text available
We report new tests on the Taiwan earthquake catalog of the prediction by the Multifractal Stress Activation (MSA) model that the p-value of the Omori law for the rate of aftershocks following a mainshock is an increasing function of its magnitude Mm. This effort is motivated by the quest to validate this crucial prediction of the MSA model and to...
Conference Paper
Full-text available
Active fault zones are the causal locations of most earthquakes, which release tectonic stresses. Yet, identification and association of faults and earthquakes is not straightforward. On the one hand, many earthquakes occur on faults that are unknown. On the other hand, systematic biases and uncertainties in earthquake locations hamper the associat...
Article
Full-text available
We present a new method of data clustering applied to earthquake catalogs, with the goal of reconstructing the seismically active part of fault networks. We first use an original method to separate clustered events from uncorrelated seismicity using the distribution of volumes of tetrahedra defined by closest neighbor events in the original and ran...
Article
Based on statistical physics and rock mechanics, the Multifractal Stress-Activated (MSA) predicts that the exponent p of the Omori law for aftershocks is linearly increasing in the magnitude M of the main shock. This prediction has been supported by empirical tests on Californian, Japanese and worldwide catalogs. We further test the prediction p(M)...
Article
Full-text available
We present a new method of data clustering applied to earthquake catalogs, with the goal of reconstructing the seismically active part of fault networks. We first use an original method to separate clustered events from uncorrelated seismicity using the distribution of volumes of tetrahedra defined by closest neighbor events in the original and ran...
Article
Full-text available
The Multifractal Stress-Activated model is a statistical model of triggered seismicity based on mechanical and thermodynamic principles. It predicts that, above a triggering magnitude cut-off M0, the exponent p of the Omori law for the time decay of the rate of aftershocks is a linear increasing function p(M) = a0M + b0 of the main shock magnitude...
Article
We propose a new pattern recognition method that is able to reconstruct the three-dimensional structure of the active part of a fault network using the spatial location of earthquakes. The method is a generalization of the so-called dynamic clustering (or k means) method, that partitions a set of data points into clusters, using a global minimizati...
Article
Full-text available
We propose a new pattern recognition method that is able to reconstruct the 3D structure of the active part of a fault network using the spatial location of earthquakes. The method is a generalization of the so-called dynamic clustering method, that originally partitions a set of datapoints into clusters, using a global minimization criterion over...