A digital recording system of electromagnetic emissions

Bella, Francesco; Monica, Giuseppe Della; Ermini, A.; Sgrigna, Vittorio; Bella, R; Biagi, P. F.; Mandjgaladze, P.; Zilpimiani, D.

doi:10.1007/bf02523794

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…Near the mouth of the cave a natural spring, named Pietà spring is located. Since 1985, in order to investigate possible earthquakes precursors, some of the authors have installed: a) electromagnetic and acoustic equipments (Bella et al, 1989) near the bottom of the cave, b) a level meter in the De Marchi pool, c) a receiver able to measure the intensity of three LF radio signals: CLT P. F. Biagi et al: The Abruzzo earthquake on 6 April 2009 (f =189 kHz, Sicily, Italy), MCO (f =216 kHz, France) and CZE (f =270 kHz, Czech Republic), in the mouth of the cave. In addition the flow rate of the Pietà spring has been sampled systematically.…”

Section: Introductionmentioning

confidence: 99%

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009

Biagi

Castellana

Maggipinto

et al. 2009

Nat. Hazards Earth Syst. Sci.

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Section: Introductionmentioning

confidence: 99%

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009

Biagi

Castellana

Maggipinto

et al. 2009

Nat. Hazards Earth Syst. Sci.

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“…We selected the LF broadcasting station MCO located in France. The monitoring equipment is detailed in Bella et al (1989). At the beginning of 1993, we put into operation receivers at two sites in central Italy, named AS and PE, located at a distance of 60 km from each other.…”

Section: Introductionmentioning

confidence: 99%

Possible earthquake precursors revealed by LF radio signals

Biagi

Piccolo

Ermini

et al. 2001

Nat. Hazards Earth Syst. Sci.

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Abstract. Among radio signals, low frequency (LF) radio signals lie in the band between 30-300 kHz. Monitoring equipment with the ability to measure the electric strength of such signals at field sites, were designed and assembled in Italy. From 1993 onwards, the electric field strength of the MCO (216 kHz, France) broadcasting station has been collecting measurements at two sites in central Italy that were chosen according to very low noise levels. At the end of 1996, radio signals from the CLT (189 kHz, Italy) and CZE (270 kHz, Czech Republic) broadcasting stations were included in the measurements. Meteorological data from central Italy were also collected over the same time period in order to study the influence of weather conditions on the experimental measurements. During the monitoring period, we observed some evident attenuation of the electric field strength in some of the radio signals at some of the receivers. The duration of the attenuation observed was several days, so it could possibly be related to particular meteorological conditions. On the other hand, this phenomenon might represent precursors of moderate (3.0 ≤ M ≤ 3.5) earthquakes that occurred near the receivers (within 50 km) along the transmitter-receiver path. In this case, it is possible that the pre-seismic processes could have produced irregularities in the troposphere, such as ducts, reflecting layers and scattering zones, so that some local troposphere defocusing of the radio signals might have occurred. These observations were related only to moderate earthquakes and in these cases, suitable meteorological conditions were probably needed to observe the effect. Between February -March 1998, we observed at one measuring site, a significant increase in the CZE electric field strength. Unfortunately, we could not use the data of the other receiver in this case, due to frequent interruptions in the data set. The increase might have been a precursor of the strong seismic sequence (M = 5.0-6.0) that Correspondence to: P. F. Biagi (biagi@fisica.uniba.it) occurred during March -May 1998 in Slovenia at a location over 400 km from the receiver, but lying in the middle of the transmitter-receiver path. In this case, it is possible that an ionospheric disturbance, produced by the pre-seismic processes, might have occurred.

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“…The monitoring equipment is composed of a 1‐m‐long vertical antenna and a data recording system consisting of (1) analogue units with an amplifier module with a five‐step selectable amplification, a frequency filter with an uncertainty of 1%, and an analog‐to‐digital (A/D) converter and (2) a digital unit with a divider, a decade scaler, and an exponent counter. The A/D converter and the digital unit are detailed by Bella et al [1989]. A 12‐V battery connected to solar cells supplies the power.…”

Section: Receiver and Radio Stationsmentioning

confidence: 99%

Electric field strength analysis of 216 and 270 kHz broadcast signals recorded during 9 years

et al. 2006

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[ 1] The electric field strength analysis of Czech Republic (CZE) ( 270 kHz) and Monte Carlo (MCO) ( 216 kHz) broadcast signals, collected with a 10 min sampling frequency by a receiver located in central Italy from 1996 to 2004, is presented. The distance from transmitter to receiver ranges from 515 km ( MCO) to 818 km ( CZE). The daytime data and the nighttime data were extracted and then in the daytime data the data collected in winter ( 21 December to 21 March) were separated from the data collected in summer ( 21 June to 21 September). Under the hypothesis that the simple addition of the ground wave and sky wave contributions holds, at first, the analysis was focused on the comparison between the experimental and theoretical values of these waves. The theoretical values were calculated by the ground wave (GRWAVE) algorithm and the wave hop theory, respectively. Ratios between the experimental and theoretical values ranging from a few tenths of decibels to some decibels were obtained. Then the analysis of the sunspots' influence on the sky wave propagation mode was performed, and the electric field strength of the two radio signals reveals a reduction of some decibels in sunspot maximum years with respect to the values during the sunspot minimum years. In addition, an influence of the sunspots also was recognized for the ground wave propagation mode

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A digital recording system of electromagnetic emissions

Cited by 9 publications

References 5 publications

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009

Possible earthquake precursors revealed by LF radio signals

Electric field strength analysis of 216 and 270 kHz broadcast signals recorded during 9 years

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A digital recording system of electromagnetic emissions

Cited by 9 publications

References 5 publications

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (&lt;i&gt;M&lt;/i&gt;=6.3) occurred on 6 April 2009

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (&lt;i&gt;M&lt;/i&gt;=6.3) occurred on 6 April 2009

Possible earthquake precursors revealed by LF radio signals

Electric field strength analysis of 216 and 270 kHz broadcast signals recorded during 9 years

Contact Info

Product

Resources

About

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009

A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009