NHESS Natural Hazards and Earth System Sciences NHESS Nat. Hazards Earth Syst. Sci. 1684-9981 Copernicus Publications Göttingen, Germany 10.5194/nhess-9-1551-2009 A pre seismic radio anomaly revealed in the area where the Abruzzo earthquake (<i>M</i>=6.3) occurred on 6 April 2009 Biagi P. F. 1 2 Castellana L. 1 Maggipinto T. 1 Loiacono D. 1 Schiavulli L. 1 Ligonzo T. 1 Fiore M. 3 Suciu E. 4 Ermini A. 5 Department of Physics, University of Bari, Via Amendola 173, 70126 Bari, Italy Inter-Department Centre for the Evaluation and Mitigation of the Volcanic and Seismic Risk, University of Bari, Italy Elettronika s.r.l., Palo del Colle (Bari), Italy Elettronika Research, Brasov, Romania Department of Mechanical Engineering, University of Roma Tor Vergata, Via di Tor Vergata, 00133 Rome, Italy 08 09 2009 9 5 1551 1556 Copyright: © 2009 P. F. Biagi et al. 2009 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://nhess.copernicus.org/articles/9/1551/2009/nhess-9-1551-2009.html The full text article is available as a PDF file from https://nhess.copernicus.org/articles/9/1551/2009/nhess-9-1551-2009.pdf

On 6 April 2009 a strong (<i>M<sub>w</sub></i>=6.3) earthquake occurred in the Abruzzo region (central Italy). Since 1996, the intensity of CLT (<i>f</i>=189 kHz, Sicily, Italy), MCO (<i>f</i>=216 kHz, France) and CZE (<i>f</i>=270 kHz, Czech Republic) broadcast signals has been collected with a ten minutes sampling rate by a receiver operating in a place located about 13 km far from the epicenter. During March 2009, the old receiver was substituted with a new one able to measure, with one minute sampling rate, the intensity of five VLF signals and five LF signals radiated by transmitters located in different zones of Europe. The MCO and CZE transmitters mentioned above are included among them. From 31 March to 1 April the intensity of the MCO radio signal dropped and this drop was observed only in this signal. The possibility that the drop was connected to problems in the transmitter or in the receiver was investigated and excluded. So, the drop indicates a defocusing of the radiated signal. Since no particular meteorological situation along the path transmitter-receiver happened, the defocusing must be related to other causes, and a possibility is presented that it is a precursor of the Abruzzo earthquake.

 References Bella, F., Bella, R., Biagi, P. F., Della Monica, G., Ermini, A., Manjgaladze, P., Sgrigna, V., and Zilpimiani, D.: A digital recording system of electromagnetic emissions, Nuovo Cimento 12C, 251–259, 1989. Bella, F., Biagi, P. F., Della Monica, G., Zilpimiani, D., Manjgaladze, P., Pokhotelov, O., Sgrigna, V., Ermini, A., and Liperovsky, V.: Monitoring of natural electromagnetic emissions during moderate seismicity in Central Italy, Fizika Zemli, 112–119, 1992. Bella, F., Bella, R., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V.: Artificial and natural electromagnetic signals revealed during two years in the Amare cave (Central Italy), Annali di Geofisica, XXXVII, 41–46, 1994a. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V., Electromagnetic background and preseismic anomalies recorded in the Amare cave (Central Italy), in: Electromagnetic Phenomena Related to Earthquake Prediction, edited by: Hayakawa, M. and Fujinawa, Y., TERRAPUB, Tokyo 1994b. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V.: Normal and anomalous behaviour of electric, magnetic and seismoacoustic signals recorded in the Amare cave, Annali di Geofisica, XXXIX, 97–100, 1996. Bella, F., Biagi, P. F., Caputo, M., Cozzi, E., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V.: Field strenght variations of LF radiowaves prior to earthquakes in Central Italy, Phys. Earth Planet. Int., 105, 279–286, 1998a. Bella, F., Biagi, P. F., Caputo, M., Cozzi, E., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V.: Aquifer-induced seismicity in the Central Apennines (Italy), Pageoph, 153, 179–194, 1998b. Bella, F., Biagi, P. F., Caputo, M., Della Monica, G., Ermini, A., Plastino, W., and Sgrigna, V.: Anomalies in different parameters related to the <i>M</i>{=}3.9 Gran Sasso earthquake (1992), Phys. Chem. Earth, 23, 959–963, 1998c. Biagi, P. F., Piccolo, R., Ermini, A., Martellucci, S., Bellecci, C., Hayakawa, M., Capozzi, V., and Kingsley, S. P.: Possible earthquake precursors revealed by LF radio signals, Nat. Hazards Earth Syst. Sci., 1, 99–104, 2001a. Biagi, P. F., Ermini, A., and Kingsley, S. P.: Disturbances in LF radiosignals and the Umbria-Marche (Italy) seismic sequence in 1997–1998, Phys. Chem. Earth, 26, 755–759, 2001b. Biagi, P. F., Piccolo, R., Ermini, A., Martellucci, S., Bellecci, C., Hayakawa, M., and Kingsley, S. P.: Disturbances in LF radio-signals as seismic precursors, Annali di Geofisica, 44(5/6), 1011–1019, 2001c. Biagi, P. F., and Hayakawa, M.: Possible premonitory behaviour of LF radiowaves on the occasion of the Slovenia earthquakes (<i>M</i>{=}5.2–6.0–5.1) occurred on March–May 1998, in Seismo Electromagnetics, edited by: Hayakawa, M. and Molchanov, O., TERRAPUB, Tokyo, 2002. Biagi, P. F., Ermini, A., Piccolo, R., Loiacono, D., and Kingsley, S. P.: Electromagnetic signals related to micromovements of limestone blocks: a test in karst caves of Central Italy, in: Seismo Electromagnetics, edited by: Hayakawa, M. and Molchanov, O., TERRAPUB, Tokyo, 2002. Biagi, P. F., Piccolo, R., Castellana, L., Ermini, A., Martellucci, S., Bellecci, C., Capozzi, V., Perna, G., Molchanov, O., and Hayakawa, M.: Variations in a LF radio signal on the occasion of the recent seismic and volcanic activity in Southern Italy, Phys. Chem. Earth, 29, 551–557, 2004. Biagi, P. F., Castellana, L., Maggipinto, T., Piccolo, R., Minafra, A., Ermini, A., Martellucci, S., Bellecci, C., Perna, G., Capozzi, V., Molchanov, O. A., and Hayakawa, M.: LF radio anomalies revealed in Italy by the wavelet analysis:Possibile preseismic effects during 1997–1998, Phys. Chem. Earth, 31, 403–408, 2006a. Biagi, P. F., Castellana, L., Maggipinto, T., Ermini, A., Perna, G., and Capozzi, V.: Electric field strength analysis of 216 and 270 kHz broadcast signals recorded during 9 years, Radio Sci., 41, RS4013, https://doi.org/10.1029/2005RS003296, 2006b. Biagi, P. F., Castellana, L., Maggipinto, T., and Ermini, A.: An overview on preseimic anomalies in LF radio signals revealed in Italy by wavelet analysis, Annals of Geophysics, 51, 237–246, 2008. CCIR: Effects of tropospheric refraction on radio-wave propagation, Propagation in non-ionized media, Annex to Vol. V, Report 718-3, 149–188, 1990a. CCIR: Attenuation by hydrometeors, in particular precipitation, and other atmospheric particles, Propagation in non-ionized media, Annex to Vol. V, Report 721-3, 226–245, 1990b. CCIR: Scattering by precipitation, Propagation in non-ionized media, Annex to Vol. V, Report 882-2, 246–250, 1990c. Hayakawa, M., Molchanov, O. A., Ondoh, T., and Kawai, E.: The precursory signature effect of the Kobe earthquake on subionospheric VLF signals, J. Comm. Res. Lab., 43, 169–180, 1996. Hayakawa, M., Ohta, K., Maekawa, S., Yamauchi, T., Ida, Y., Gotoh, T., Yonaiguchi, N., Sasaki, H., and Nakamura, T.: Electromagnetic precursors to the 2004 Mid Niigata Prefecture earthquake, Phys. Chem. Earth, 31, 356–364, 2006. INGV: National Institute of Geophysics and Volcanology, online available at: <a href="http://www.ingv.it">http://www.ingv.it</a>, 2009. Molchanov, O. A. and Hayakawa, M.: Subionospheric VLF signal perturbations possibly related to earthquakes, J. Geophys. Res., 103, 17489–17504, 1998. Rozhnoi, A. A., Solovieva, M. S., Molchanov, O. A., Hayakawa, M., Maekawa, S., and Biagi, P. F.: Anomalies of LF signal during seismic activity in November–December 2004, Nat. Hazards Earth Syst. Sci., 5, 657–660, 2005. Rozhnoi, A. A., Solovieva, M., Molchanov, O., Chebrov, V., Voropaev, V., Hayakawa, M., Maekawa, S., and Biagi, P. F.: Preseismic anomaly of LF signal on the wave path Japan-Kamchatka during November 2004, Phys. Chem. Earth, 31, 422–427, 2006.