Detection of ultra-low-frequency emissions connected with the Spitak earthquake and its aftershock activity, based on geomagnetic pulsations data at Dusheti and Vardzia observatories

Kopytenko, Yu. A.; Matiashvili, T. G.; Voronov, P. M.; Kopytenko, E. A.; Molchanov, O. A.

doi:10.1016/0031-9201(93)90035-8

Cited by 208 publications

(132 citation statements)

References 12 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…If, on the other hand, the charge carriers are positive holes, generated in the stressed rock and capable of propagating at speeds comparable to those determined from the impact experiments described here, rapid fluctuations in the charge carrier density are expected to occur between different parts of the rock volume. The fluctuations and the currents that they produce are expected to generate a wideband EM noise or discrete pulsations as observed during the December 7, 1988, M•=7 Spitak, Armenia, earthquake [Kopytenko et al, 1993]. With the knowledge that positive holes may be generated in rocks we can go one step further and address the phenomenon of earthquake lights.…”

Section: Application To Electrical Phenomena Related To Earthquakesmentioning

confidence: 99%

Time‐resolved study of charge generation and propagation in igneous rocks

Freund¹

2000

J. Geophys. Res.

187

137

View full text Add to dashboard Cite

Abstract. Electrical resistivity changes, ground potentials, electromagnetic (EM), and luminous signals preceding or accompanying earthquakes have been reported many times, in addition to ground uplift and tilt and other parameters. However, no concept exists that would tie these diverse phenomena together into a physically coherent model. Using low-to medium-velocity impacts to measure electrical signals with microsecond time resolution, it is observed that when gabbro and diorite cores are impacted at relatively low velocities, --100 m/s, highly mobile charge carriers are generated in a small volume near the impact point. They spread through the rocks, causing electric potentials exceeding +400 mV, EM, and light emission. As the charge cloud spreads, the rock becomes momentarily conductive. When a granite block is impacted at higher velocity, --1.5 km/s, the propagation of the P and S waves is registered through the transient piezoelectric response of quartz. After the sound waves have passed, the surface of the granite block becomes positively charged, suggesting the same charge carriers as observed during the lowvelocity impact experiments, expanding from within the bulk. which all nominally anhydrous minerals incorporate when crystallizing in H20-laden environments. The fact that positive holes can be activated by low-energy impacts, and their attendant sound waves, suggests that they can also be activated in the crust by microfractures during the dilatancy phase. Depending on where in the stressed rock volume the charge carriers are activated, they will form rapidly moving or fluctuating charge clouds that can account for earthquake-related electrical signals and EM emission. Wherever such charge clouds intersect the surface, high fields are expected, causing electric discharges and earthquake lights.

show abstract

Section: Application To Electrical Phenomena Related To Earthquakesmentioning

confidence: 99%

Time‐resolved study of charge generation and propagation in igneous rocks

Freund¹

2000

J. Geophys. Res.

187

137

View full text Add to dashboard Cite

show abstract

“…Ramírez-Rojas (arr@correo.azc.uam.mx) 1996, 2002Eftaxias et al, 2004;Hayakawa et al, 1999Hayakawa et al, , 2000Hayakawa and Timashev, 2006;Smirnova et al, 2001;Telesca et al, 2001Telesca et al, , 2003Telesca et al, , 2005aTelesca et al, , 2005bTelesca et al, , 2007Ida et al, 2005;Ida and Hayakawa, 2006;Ida et al, 2007;. Furthermore, the presence of precursory signatures of EQs has been clearly identified in the ULF range for large magnitude (Ms>6) EQ's (Fraser-Smith et al, 1990;Molchanov et al, 1992;Kopytenko et al, 1993Flores-Marquez et al, 2007). In a previous work we performed a statistical analysis of the spectral exponent and the correlation time of geoelectrical signals associated to the Guerrero-Oaxaca EQ (Ms=7.4) occurred on 14 September 1995 in southern Mexico (Ramirez-Rojas et al, 2004).…”

Section: Introductionmentioning

confidence: 98%

Statistical features of seismoelectric signals prior to M7.4 Guerrero-Oaxaca earthquake (México)

Ramírez-Rojas¹,

Márquez²,

Guzmán‐Vargas³

et al. 2008

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. In this paper a statistical analysis of seismoelectric ULF signals prior to the M7.4 Guerrero-Oaxaca earthquake (EQ) occurred at the Mexican Pacific coast on 14 September 1995, has been performed. The signals were simultaneously recorded at three monitoring stations from the last months of 1994 until July of 1996. The nonlinear time series methods of Higuchi fractal dimension (HFD) and detrended fluctuation analysis (DFA) have been used. In the three data sets we found some complex dynamical behaviors that seemingly reflect a relaxation-EQ preparation-main shock-relaxation process. In particular, clear spike-like anomalies in both DFAand HFD-exponents some months before the main shock are revealed.

show abstract

“…Recently, an increasing number of ground-based observing ULF electromagnetic emissions related to strong earthquakes have been recorded at a distance of several, hundreds, and even several thousands of kilometers. Some notable examples include the Loma Prieta M S 7.1 earthquake on 17 October 1989 (f = 0.01-10 Hz, D = 7 km, A = 1.5 nT; FraserSmith et al, 1990;Bernardi et al, 1991), as well as the Spitak M S 6.9 earthquake on 7 December 1988 (f = 0.005-1 Hz, D = 200 km, A = 0.2 nT; Molchanov et al, 1992;Kopytenko et al, 1993). In addition, the geo-electric potential enhance-M. Li et al: Ionospheric influence on the seismo-telluric current ment appeared 1-19 days before five of all six earthquakes (EQs) with a magnitude > 5, which occurred within 75 km in Japan and its duration and intensity were several minutes to 1 h with an amplitude of 0.01-0.02 mV m −1 (Uyeda et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Ionospheric influence on the seismo-telluric current related to electromagnetic signals observed before the Wenchuan MS 8.0 earthquake

Tan

Cao

2016

Solid Earth

View full text Add to dashboard Cite

Abstract. A three-layer (Earth-air-ionosphere) physical model, as well as a two-layer (Earth-air) model, is employed in this paper to investigate the ionospheric effect on the wave fields for a finite length dipole current source co-located at a hypocenter depth and along the main fault of an earthquake when the distance between the epicenter and an observing station is up to 1000 km or even more. The results show that all electrical fields are free of ionospheric effects for different frequencies in a relative short range, e.g., ∼ 300 km for f = 1 Hz, implying the ionospheric influence on electromagnetic fields can be neglected within this range, which becomes smaller as the frequency increases. However, the ionosphere can give a constructive interference to the waves passing through and make them decay slowly when an observation is out of this range; moreover, the ionospheric effect can be up to 1-2 orders of magnitude of the electrical fields. For a ground-based observable 1.3 mV m −1 electric signal at f = 1 Hz 1440 km away from the Wenchuan M S 8.0 earthquake, the expected seismo-telluric current magnitude for the Earth-air-ionosphere model is of 5.0 × 10 7 A, 1 magnitude smaller than the current value of 3.7 × 10 8 A obtained by the Earth-air model free of ionospheric effects. This indicates that the ionosphere facilitates the electromagnetic wave propagation, as if the detectability of the system were improved effectively and it is easier to record a signal even for stations located at distances beyond their detectability thresholds. Furthermore, the radiating patterns of the electrical field components |E x | and |E y | are complementary to each other, although any two-dimensional (2-D) power distribution of these components shows strong power areas as well as weak ones, which is advantageous to register a signal if the observing system is designed to measure both of them instead of only one.

show abstract

Detection of ultra-low-frequency emissions connected with the Spitak earthquake and its aftershock activity, based on geomagnetic pulsations data at Dusheti and Vardzia observatories

Cited by 208 publications

References 12 publications

Time‐resolved study of charge generation and propagation in igneous rocks

Time‐resolved study of charge generation and propagation in igneous rocks

Statistical features of seismoelectric signals prior to M7.4 Guerrero-Oaxaca earthquake (México)

Ionospheric influence on the seismo-telluric current related to electromagnetic signals observed before the Wenchuan <i>M</i><sub><i>S</i></sub> 8.0 earthquake

Contact Info

Product

Resources

About

Detection of ultra-low-frequency emissions connected with the Spitak earthquake and its aftershock activity, based on geomagnetic pulsations data at Dusheti and Vardzia observatories

Cited by 208 publications

References 12 publications

Time‐resolved study of charge generation and propagation in igneous rocks

Time‐resolved study of charge generation and propagation in igneous rocks

Statistical features of seismoelectric signals prior to M7.4 Guerrero-Oaxaca earthquake (México)

Ionospheric influence on the seismo-telluric current related to electromagnetic signals observed before the Wenchuan &lt;i&gt;M&lt;/i&gt;&lt;sub&gt;&lt;i&gt;S&lt;/i&gt;&lt;/sub&gt; 8.0 earthquake

Contact Info

Product

Resources

About

Ionospheric influence on the seismo-telluric current related to electromagnetic signals observed before the Wenchuan <i>M</i><sub><i>S</i></sub> 8.0 earthquake