. Several electromagnetic signal types were observed prior to and immediately after 30 October 2007 (Local Time) M5.4 earthquake at Alum Rock, Ca with an epicenter ~15 km NE of San Jose Ca. The area where this event occurred had been monitored since November 2005 by a QuakeFinder magnetometer site, unit 609, 2 km from the epicenter. This instrument is one of 53 stations of the QuakeFinder (QF) California Magnetometer Network-CalMagNet. This station included an ultra low frequency (ULF) 3-axis induction magnetometer, a simple air conductivity sensor to measure relative airborne ion concentrations, and a geophone to identify the arrival of the P-wave from an earthquake. Similar in frequency content to the increased ULF activity reported two weeks prior to the Loma Prieta M7.0 quake in 1989 (Fraser-Smith, 1990, 1991), the QF station detected activity in the 0.01–12 Hz bands, but it consisted of an increasing number of short duration (1 to 30 s duration) pulsations. The pulsations peaked around 13 days prior to the event. The amplitudes of the pulses were strong, (3–20 nT), compared to the average ambient noise at the site, (10–250 pT), which included a component arising from the Bay Area Rapid Transit (BART) operations. The QF station also detected different pulse shapes, e.g. negative or positive only polarity, with some pulses including a combination of positive and negative. Typical pulse counts over the previous year ranged from 0–15 per day, while the count rose to 176 (east-west channel) on 17 October, 13 days prior to the quake. The air conductivity sensor saturated for over 14 h during the night and morning prior to the quake, which occurred at 20:29 LT. Anomalous IR signatures were also observed in the general area, within 50 km of the epicenter, during the 2 weeks prior to the quake. These three simultaneous EM phenomena were compared with data collected over a 1–2-year period at the site. The data was also compared against accounts of air ionization reported to be associated with radon emission from the ground (Ouzounov, 2007), and a series of laboratory rock stressing experiments (Freund, 2006, 2007a, b, c) to determine if field data was consistent either of these accounts. We could not find a data set with pre-earthquake radon measurements taken near the Alum Rock epicenter to compare against our field data. However, based on the Alum Rock data set example and another data set at Parkfield, the field tests are at least consistent with the lab experiments showing currents, magnetic field disturbances, air conductivity changes, and IR signatures. This is encouraging, but more instrumented earthquake examples are needed to prove a repeating pattern for these types of pre-earthquake EM signatures. For more information on QuakeFinder please view http://www.quakefinder.com .

https://nhess.copernicus.org/articles/9/585/2009/nhess-9-585-2009.pdf

Investigation of ULF magnetic pulsations, air conductivity changes, and infra red signatures associated with the 30 October Alum Rock M5.4 earthquake

The widespread belief that animals can anticipate earthquakes (EQs) is poorly supported by evidence, most of which consists of anecdotal post hoc recollections and relates to a very short period immediately before such events. In this study, a population of reproductively active common toads Bufo bufo were monitored over a period of 29 days, before, during and after the EQ (on day 10) at L'Aquila, Italy, in April 2009. Although our study site is 74 km from L'Aquila, toads showed a dramatic change in behaviour 5 days before the EQ, abandoning spawning and not resuming normal behaviour until some days after the event. It is unclear what environmental stimuli the toads were responding to so far in advance of the EQ, but reduced toad activity coincides with pre-seismic perturbations in the ionosphere, detected by very low frequency (VLF) radio sounding. We compare the response of toads to the EQ with the reported responses to seismic activity of several other species.

Predicting the unpredictable; evidence of pre‐seismic anticipatory behaviour in the common toad

A systematic multi-parameter and multi-platform approach to study the slow process of earthquake preparation is fundamental to gain some insights on this complex phenomenon. In particular, an important contribution is the integrated analysis between ground geophysical data and satellite data. In this paper we review some of the more recent results and suggest the next directions of this kind of research. Our intention is not to detect a particular precursor but to understand the physics underlying the various observations and to establish a reliable physical model of the preparation phase before an impending earthquake. In this way, future investigation will search for suitable fore-patterns, which the physical model of multi-layers coupling predicts and characterizes by quasi-synchronism in time and geo-consistency in space. We also present alternative explanations for some anomalies which are not actually related to earthquakes, rather to other natural or anthropic processes.

Geospace perturbations induced by the Earth: The state of the art and future trends

. Space-time fluctuations of Earth's emitted Thermal Infrared (TIR) radiation have been observed from satellite months to weeks before earthquakes occurrence. The general RST approach has been proposed in order to discriminate normal (i.e. related to the change of natural factor and/or observation conditions) TIR signal fluctuations from anomalous signal transient possibly associated to earthquake occurrence. In this work RST approach is applied to the Abruzzo 6 April 2009 event (ML=5.8) by using for the first time MSG-SEVIRI (Meteosat Second Generation -Spinning Enhanced Visible and Infrared Imager) thermal infrared observations. A validation/confutation analysis has been performed in order to verify the presence/absence of anomalous space-time TIR transients in the presence/absence of significant seismic activity. March–April 2009 has been analyzed for validation purposes. Relatively unperturbed periods (no earthquakes with ML≥5) have been taken for confutation. A specific TIR anomalies space-time persistence analysis as well as a cloud coverage distribution test have been introduced in order to eliminate artifacts and outliers both in the validation and confutation phases. Preliminary results show clear differences in TIR anomalies occurrence during the periods used for validation and confutation purposes. Quite clear TIR anomalies appear also to mark main tectonic lines related to the preparatory phases of others, low magnitude (ML~4) earthquakes, occurred in the area.

https://nhess.copernicus.org/articles/9/2073/2009/nhess-9-2073-2009.pdf

RST analysis of MSG-SEVIRI TIR radiances at the time of the Abruzzo 6 April 2009 earthquake

This paper reviews modeling of the influence of earthquake (EQ) preparation processes on the ionosphere through the electric field and electric current occurring in the global atmosphere–ionosphere electric circuit. Our consideration is based on the satellite-and ground-based experimental data of electric fields, plasma and electromagnetic perturbations obtained for several days before an EQ. We have ruled out the models which are not consistent with the experimental data on the electric fields in the ionosphere and also on the ground surface. There has then been proposed a new model of the generation of electric field on the basis of injection of charged aerosols into the atmosphere, and we discuss the mechanism of lithosphere-atmosphere-ionosphere coupling. It is then shown that such changes in the electric field within the ionosphere induce a variety of plasma and electromagnetic phenomena associated with an impending EQ.

/pdf/generation-of-seismic-related-dc-electric-fields-and-5d03lo704k.pdf

Generation of Seismic-Related DC Electric Fields and Lithosphere-Atmosphere-Ionosphere Coupling

. We present a general concept of mechanisms of preseismic phenomena in the atmosphere and ionosphere. After short review of observational results we conclude: 1. Upward migration of fluid substrate matter (bubble) can lead to ousting of the hot water/gas near the ground surface and cause an earthquake (EQ) itself in the strength-weakened area; 2. Thus, time and place of the bubble appearance could be random values, but EQ, geochemistry anomaly and foreshocks (seismic, SA and ULF electromagnetic ones) are casually connected; 3. Atmospheric perturbation of temperature and density could follow preseismic hot water/gas release resulting in generation of atmospheric gravity waves (AGW) with periods in a range of 6–60min; 4. Seismo-induced AGW could lead to modification of the ionospheric turbulence and to the change of over-horizon radio-wave propagation in the atmosphere, perturbation of LF waves in the lower ionosphere and ULF emission depression at the ground.

/pdf/lithosphere-atmosphere-ionosphere-coupling-as-governing-1hci79j660.pdf

Lithosphere-atmosphere-ionosphere coupling as governing mechanism for preseismic short-term events in atmosphere and ionosphere

Model of earthquake triggering due to gas-fluid "bubble" upward migration. II. Finite-automation model

Model of earthquake triggering due to gas-fluid "bubble" upward migration. I. Physical rationale

Surface charge distribution on aircraft windshields and front head shields of missiles is highly inhomogeneous and it may cause creeping discharge appearance The discharge produces strong electromagnetic emission, which get into the bodies through apertures A fractal model based on a cellular automaton network reproducing the dynamics of surface electrical charge distribution is proposed The model allows us to obtain both integrated characteristics of the discharge and its local properties The latter is of extremely importance for EMC applications

D.I. Iudin

Papers

Lithosphere-atmosphere-ionosphere coupling as governing mechanism for preseismic short-term events in atmosphere and ionosphere

Model of earthquake triggering due to gas-fluid "bubble" upward migration. II. Finite-automation model

Model of earthquake triggering due to gas-fluid "bubble" upward migration. I. Physical rationale

Cellular automaton modelling of surface discharge dynamics for EMC problems