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Friedemann Freund - One of the best experts on this subject based on the ideXlab platform.
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Earthquake precursors in the light of peroxy defects theory: Critical review of systematic observations
'Springer Science and Business Media LLC', 2021Co-Authors: Friedemann Freund, Guy Ouillon, John Scoville, Didier SornetteAbstract: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 (revealing the build-up of stress deep below) and on prior seismic events (past Earthquakes may be related to or even trigger future Earthquakes). Since the results have been less than convincing, there is a general consensus in the seismology community that Earthquake forecasting on time scales comparable to meteorological forecasts is still quite far in the future, if ever attainable. The starting point of the present review is to acknowledge that there are innumerable reports of other types of precursory Phenomena observable on the ground or in near-Earth space ranging from the emission of electromagnetic waves from ultralow frequency (ULF) to near-infrared (NIR) and visible (VIS) light, electric field and magnetic field anomalies of various kinds (see below), all the way to widely reported but never fully understood unusual animal behavior. These precursory signals are intermittent and seem not to occur systematically before every major Earthquake. As a result they are not widely accepted, because no one could fully explain their origins. In addition, the diversity of these signals makes them look unrelatable, hampering any progress. In the first part, we review evidence for a solid-state mechanism based on decades of research bridging semi-conductor physics, solid state chemistry and rock physics, that is capable of providing explanations for the diversity of reported pre-Earthquake Phenomena. In fact, it appears that all pre-Earthquake Phenomena might be traceable to a single fundamental process on the atomic scale: the rupture of peroxy bonds via activation of electronic charges, electrons and positive holes, in rocks subjected to tectonic stresses prior to seismic activity. The positive holes are defect electrons in the O2- sublattice. They are unusual inasmuch as they are able to flow out of the stressed rock volume, into and through the surrounding unstressed or less stressed rocks. They form electric currents that travel fast and far, causing along the way a wide range of physical and chemical follow-on processes: electrical ground potentials, stimulated infrared emission, massive air ionization, radon emanation, increased levels of ozone, toxic levels of carbon monoxide (CO) and more. In the second part, we critically examine satellite and ground station data, recorded before a selection of past large Earthquakes. Some of the Phenomena can be directly related to the peroxy defect theory, namely, radon gas emanations, corona discharges, thermal infrared emissions, air ionization, ion and electron content in the ionosphere, and electro-magnetic anomalies. Of course there is a need for further systematic investigations, continuing statistical examination of the relevance and confidence levels of the observable precursors. Only then will the scientific community be able to assess and eventually improve the performance of Earthquake forecasts
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changes in animal activity prior to a major m 7 Earthquake in the peruvian andes
Physics and Chemistry of The Earth, 2015Co-Authors: Rachel A Grant, Friedemann Freund, J P RaulinAbstract:Abstract During Earthquake preparation geophysical processes occur over varying temporal and spatial scales, some leaving their mark on the surface environment, on various biota, and even affecting the ionosphere. Reports on pre-seismic changes in animal behaviour have been greeted with scepticism by the scientific community due to the necessarily anecdotal nature of much of the evidence and a lack of consensus over possible causal mechanisms. Here we present records of changes in the abundance of mammals and birds obtained over a 30 day period by motion-triggered cameras at the Yanachaga National Park, Peru, prior to the 2011 magnitude 7.0 Contamana Earthquake. In addition we report on ionospheric perturbations derived from night-time very low frequency (VLF) phase data along a propagation paths passing over the epicentral region. Animal activity declined significantly over a 3-week period prior to the Earthquake compared to periods of low seismic activity. Night-time ionospheric phase perturbations of the VLF signals above the epicentral area, fluctuating over the course of a few minutes, were observed, starting 2 weeks before the Earthquake. The concurrent observation of two widely different and seemingly unconnected precursory Phenomena is of interest because recently, it has been proposed that the multitude of reported pre-Earthquake Phenomena may arise from a single underlying physical process: the stress-activation of highly mobile electronic charge carriers in the Earth’s crust and their flow to the Earth’s surface. The flow of charge carriers through the rock column constitutes an electric current, which is expected to fluctuate and thereby emit electromagnetic radiation in the ultralow frequency (ULF) regime. The arrival of the charge carriers can lead to air ionization at the ground-to-air interface and the injection of massive amounts of positive airborne ions, known to be aversive to animals.
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nature of pre Earthquake Phenomena and their effects on living organisms
Open Access Journal, 2013Co-Authors: Friedemann Freund, Viktor StolcAbstract:Earthquakes occur when tectonic stresses build up deep in the Earth before catastrophic rupture. During the build-up of stress, processes that occur in the crustal rocks lead to the activation of highly mobile electronic charge carriers. These charge carriers are able to flow out of the stressed rock volume into surrounding rocks. Such outflow constitutes an electric current, which generates electromagnetic (EM) signals. If the outflow occurs in bursts, it will lead to short EM pulses. If the outflow is continuous, the currents may fluctuate, generating EM emissions over a wide frequency range. Only ultralow and extremely low frequency (ULF/ELF) waves travel through rock and can reach the Earth surface. The outflowing charge carriers are (i) positively charged and (ii) highly oxidizing. When they arrive at the Earth surface from below, they build up microscopic electric fields, strong enough to field-ionize air molecules. As a result, the air above the epicentral region of an impending major Earthquake often becomes laden with positive airborne ions. Medical research has long shown that positive airborne ions cause changes in stress hormone levels in animals and humans. In addition to the ULF/ELF emissions, positive airborne ions can cause unusual reactions among animals. When the charge carriers flow into water, they oxidize water to hydrogen peroxide. This, plus oxidation of organic compounds, can cause behavioral changes among aquatic animals.
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stimulated mid infrared luminescence experiment contribution to the study of pre Earthquake Phenomena and uv absorption by interstellar dust
2004Co-Authors: Friedemann Freund, Minoru M Freund, Sichee Tsay, Dimitar OuzounovAbstract:The work performed under this proposal is based on the experimentally supported observation - or inference - that a small fraction of the oxygen anions in silicate minerals in igneous and high-grade metamorphic rocks on Earth may not be in the usual 2- oxidation state, O(sup 2-), but in a higher oxidation state, as O(sup -). If this is true, the same would likely apply to the fine dust that fills the diffuse interstellar medium. An (sup -) in a matrix of O(sup 2-) represents a defect electron in the valence band, also known as positive hole or p-hole for short. When two O(sup -) combine, they undergo spin-pairing and form a positive hole pair, PHP. Chemically speaking a PHP is a peroxy bond. In an oxide matrix a peroxy bond takes the form of a peroxy anion, O2(sup 2-). In a silicate matrix it probably exists in the form of peroxy links between adjacent [SiO4] tetrahedral, O3Si00\SiO3. From a physics perspective a PHP is an electrically inactive point defect, which contains dormant electronic charge carriers. When the peroxy bond breaks, p-hole charge carriers are released. These p-holes are diffusively mobile and spread through the O 2p-dominated valence band of the otherwise insulating mineral matrix.
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rocks that crackle and sparkle and glow strange pre Earthquake Phenomena
2003Co-Authors: Friedemann FreundAbstract:Seismic waves are the most dramatic and most intensely studied manifestations of Earthquakes. However, we also know of non-seismic Phenomena, which precede large Earthquakes. Some of them have been reported for centuries, even millennia. The list is long and diverse: bulging of the Earth's surface, changing well water levels, ground-hugging fog, low frequency electromagnetic emission, Earthquake lights from ridges and mountain tops, magnetic field anomalies up to 0.5% of the Earth 's dipole field, temperature anomalies by several degrees over wide areas as seen in satellite images, changes in the plasma density of the ionosphere, and strange animal behavior. Because it seems nearly impossible to imagine that such diverse Phenomena could have a common physical cause, there is great confusion and even greater controversy. This explains why reports on non- seismic pre-Earthquake Phenomena are regarded with suspicion in the scientific community. This may change with the recent discovery that igneous and metamorphic rocks, which make up a major portion of the Earth 's crust, contain electric charge carriers, which have been overlooked in the past. These charge carriers are defect electrons in the valence band, i.e., positive holes. Under normal conditions they are dormant, but when they ''wake up'', the rocks begin to sparkle and glow. This paper describes the physical and chemical nature of these positive holes, how they are introduced into minerals and rocks, and how they become activated. Evidence will be presented that, once the positive holes are generated, currents propagate through the rocks leading to electromagnetic emission, to positive surface potentials, to corona discharges, to positive ion emission, and to mid-infrared radiation. These Phenomena are expressions of the same fundamental process: the ''awakening'' of dormant positive hole charge carriers that turn rocks momentarily into p-type semiconductors.
Christopher H. Scholz - One of the best experts on this subject based on the ideXlab platform.
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Earthquakes and friction laws
Nature, 1998Co-Authors: Christopher H. ScholzAbstract:The traditional view of tectonics is that the lithosphere comprises a strong brittle layer overlying a weak ductile layer, which gives rise to two forms of deformation: brittle fracture, accompanied by earth- quakes, in the upper layer, and aseismic ductile flow in the layer beneath. Although this view is not incorrect, it is imprecise, and in ways that can lead to serious misunderstandings. The term ductility, for example, can apply equally to two common rock deformation mechanisms: crystal plasticity, which occurs in rock above a critical temperature, and cataclastic flow, a type of granular deformation which can occur in poorly consolidated sediments. Although both exhibit ductility, these two deformation mechanisms have very different rheologies. Earthquakes, in turn, are associated with strength and brittleness—associations that are likewise sufficiently imprecise that, if taken much beyond the generality implied in the opening sentence, they can lead to serious misinterpretations about Earthquake mechanics. Lately, a newer, much more precise and predictive model for the Earthquake mechanism has emerged, which has its roots in the observation that tectonic Earthquakes seldom if ever occur by the sudden appearance and propagation of a new shear crack (or 'fault'). Instead, they occur by sudden slippage along a pre-existing fault or plate interface. They are therefore a frictional, rather than fracture, phenomenon, with brittle fracture playing a secondary role in the lengthening of faults 1 and frictional wear 2 . This distinction was noted by several early workers 3 , but it was not until 1966 that Brace and Byerlee 4 pointed out that Earthquakes must be the result of a stick-slip frictional instability. Thus, the Earthquake is the 'slip', and the 'stick' is the interseismic period of elastic strain accumula- tion. Subsequently, a complete constitutive law for rock friction has been developed based on laboratory studies. A surprising result is that a great many other aspects of Earthquake Phenomena also now seem to result from the nature of the friction on faults. The properties traditionally thought to control these processes— strength, brittleness and ductility—are subsumed within the over- arching concept of frictional stability regimes. Constitutive law of rock friction In the standard model of stick-slip friction it is assumed that sliding begins when the ratio of shear to normal stress on the surface reaches a value ms, the static friction coefficient. Once sliding initiates, frictional resistance falls to a lower dynamic friction coefficient, md, and this weakening of sliding resistance may,
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the mechanics of Earthquakes and faulting
1991Co-Authors: Christopher H. ScholzAbstract:This essential reference for graduate students and researchers provides a unified treatment of Earthquakes and faulting as two aspects of brittle tectonics at different timescales. The intimate connection between the two is manifested in their scaling laws and populations, which evolve from fracture growth and interactions between fractures. The connection between faults and the seismicity generated is governed by the rate and state dependent friction laws - producing distinctive seismic styles of faulting and a gamut of Earthquake Phenomena including aftershocks, afterslip, Earthquake triggering, and slow slip events. The third edition of this classic treatise presents a wealth of new topics and new observations. These include slow Earthquake Phenomena; friction of phyllosilicates, and at high sliding velocities; fault structures; relative roles of strong and seismogenic versus weak and creeping faults; dynamic triggering of Earthquakes; oceanic Earthquakes; megathrust Earthquakes in subduction zones; deep Earthquakes; and new observations of Earthquake precursory Phenomena.
Gregory C Beroza - One of the best experts on this subject based on the ideXlab platform.
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temporal variation in the magnitude frequency distribution during the guy greenbrier Earthquake sequence
Geophysical Research Letters, 2015Co-Authors: Yihe Huang, Gregory C BerozaAbstract:The recent increase in Earthquake activity in the central U.S. has led to concerns about the hazard posed by induced Earthquakes. Understanding Earthquake Phenomena and monitoring in all settings can be improved by the detection of small events; however, the catalog of induced Earthquakes is incomplete for small events due to the sparse instrumentation. This is particularly true in settings of low background seismicity, like the central U.S. We apply single-station template matching to detect small Earthquakes during the Guy-Greenbrier sequence in central Arkansas and find over 100 times more Earthquakes than are registered in the Advanced National Seismic System catalog between July 2010 and October 2011. A complete catalog over nearly 4 units of magnitude enables us to analyze the magnitude-frequency distribution of induced Earthquakes. We find that Earthquakes deviated from the Gutenberg-Richter statistics during the operation of nearby injection wells but returned to Gutenberg-Richter statistics after the wells were shut in.
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a scaling law for slow Earthquakes
Nature, 2007Co-Authors: Satoshi Ide, Gregory C Beroza, David R Shelly, Takahiko UchideAbstract:With the availability of the Global Positioning System and other technical advances, a growing number of unusual Earthquake Phenomena occurring at relatively long periods have been recognized. They include deep episodic tremor, low-frequency Earthquakes, slow slip events and 'silent' Earthquakes. Based on data chiefly from western Japan, Ide et al. report that these 'slow' seismic events follow a unified scaling relationship that clearly differentiates their behaviour from that of 'regular' Earthquakes. A diverse array of unusual Earthquake Phenomena occurring at relatively long periods, 'slow' events, follow a unified scaling relationship that clearly differentiates their behaviour from that of regular Earthquakes, indicating that they comprise a new Earthquake category. Recently, a series of unusual Earthquake Phenomena have been discovered, including deep episodic tremor1, low-frequency Earthquakes2, very-low-frequency Earthquakes3, slow slip events4 and silent Earthquakes5,6,7,8,9. Each of these has been demonstrated to arise from shear slip, just as do regular Earthquakes, but with longer characteristic durations and radiating much less seismic energy. Here we show that these slow events follow a simple, unified scaling relationship that clearly differentiates their behaviour from that of regular Earthquakes. We find that their seismic moment is proportional to the characteristic duration and their moment rate function is constant, with a spectral high-frequency decay of f-1. This scaling and spectral behaviour demonstrates that they can be thought of as different manifestations of the same Phenomena and that they comprise a new Earthquake category. The observed scale dependence of rupture velocity for these events can be explained by either a constant low-stress drop model or a diffusional constant-slip model. This new scaling law unifies a diverse class of slow seismic events and may lead to a better understanding of the plate subduction process and large Earthquake generation.
Takahiko Uchide - One of the best experts on this subject based on the ideXlab platform.
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a scaling law for slow Earthquakes
Nature, 2007Co-Authors: Satoshi Ide, Gregory C Beroza, David R Shelly, Takahiko UchideAbstract:With the availability of the Global Positioning System and other technical advances, a growing number of unusual Earthquake Phenomena occurring at relatively long periods have been recognized. They include deep episodic tremor, low-frequency Earthquakes, slow slip events and 'silent' Earthquakes. Based on data chiefly from western Japan, Ide et al. report that these 'slow' seismic events follow a unified scaling relationship that clearly differentiates their behaviour from that of 'regular' Earthquakes. A diverse array of unusual Earthquake Phenomena occurring at relatively long periods, 'slow' events, follow a unified scaling relationship that clearly differentiates their behaviour from that of regular Earthquakes, indicating that they comprise a new Earthquake category. Recently, a series of unusual Earthquake Phenomena have been discovered, including deep episodic tremor1, low-frequency Earthquakes2, very-low-frequency Earthquakes3, slow slip events4 and silent Earthquakes5,6,7,8,9. Each of these has been demonstrated to arise from shear slip, just as do regular Earthquakes, but with longer characteristic durations and radiating much less seismic energy. Here we show that these slow events follow a simple, unified scaling relationship that clearly differentiates their behaviour from that of regular Earthquakes. We find that their seismic moment is proportional to the characteristic duration and their moment rate function is constant, with a spectral high-frequency decay of f-1. This scaling and spectral behaviour demonstrates that they can be thought of as different manifestations of the same Phenomena and that they comprise a new Earthquake category. The observed scale dependence of rupture velocity for these events can be explained by either a constant low-stress drop model or a diffusional constant-slip model. This new scaling law unifies a diverse class of slow seismic events and may lead to a better understanding of the plate subduction process and large Earthquake generation.
Chie Yoshino - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal characteristics of the geomagnetic diurnal variation anomalies prior to the 2011 tohoku Earthquake mw 9 0 and the possible coupling of multiple pre Earthquake Phenomena
Journal of Asian Earth Sciences, 2016Co-Authors: Peng Han, Katsumi Hattori, Qinghua Huang, Shinji Hirooka, Chie YoshinoAbstract:Abstract Xu et al. (2013) and Han et al. (2015) have reported unusual behaviors of geomagnetic diurnal variation (GDV) in the vertical component prior to the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0). To make a better understanding of this phenomenon, temporal-spatial analyses of GDV have been applied in this study. Geomagnetic data of long-term observations at 17 stations in Japan have been analyzed using the same method in Han et al. (2015). Ratios of diurnal variation range between the reference station KAK and the target stations have been computed. After removing seasonal variations, the 15-day backward running mean values of the ratios in the vertical component shows a clear anomaly exceeding the statistical threshold about 2 months before the mega event at both ESA and MIZ stations in the Tohoku Region. Locations of anomalies in spatial distribution show a good correlation with the epicenter of the Mw 9.0 Earthquake. These spatiotemporal results are consistent with those obtained from other independent observations such as groundwater level and GPS displacements. The coupling of multiple pre-Earthquake Phenomena may help to understand the preparation process of a mega Earthquake in the subduction zone.