Earthquake   Disturbance Detection     Place Magnitude Date(s) Emission type Frequency range Instrumentation Method(s) Precursory time ED Reference Single events Chile 10 22/05/1960 Radio 18 MHz Radioastronomy receiver Visual observation b (6 days) Worldwide [34]   Hollister, California 5.2 28/11/1974 ULF magnetic   Array of 7 proton magnetometers Visual observation b(7week-several months) 11 km [35]   Tangshan, China 7.8 28/07/1976 Resistivity     Visual observation b(2-3 years) <150 km [36]   Tangshan, China 7.8 28/07/1976 Self potential, magnetotelluric     Visual observation b(3 months) <120 km [36]   Sungpan–Pingwu,China 7.2 16/08/1976 Telluric currents     Visual observation b(1month) <200 km [37]   Sungpan–Pingwu,China 6.8 22/08/1976 Telluric currents     Visual observation b(1month) <200 km [37]   Sungpan–Pingwu,China 7.2 23/08/1976 Telluric currents     Visual observation b(1month) <200 km [37]   Kyoto, Japan 7.0 31/03/1980 LF electric 81 kHz Electric antenna Visual observation b(1/2 h) 250 km [38]   Tokyo, Japan 5.3 25/09/1980 LF electric 81 kHz Electric antenna Visual observation b(1h) 55 km [38]   Tokyo, Japan 5.5 28/01/1981 LF electric 81 kHz Electric antenna Visual observation b(3/4h) 50 km [38]   Kalamata, Greece 6.2 13/09/1986 Electric     Visual observation b(3-5days) 200 km [39]   Spitak, Armenia 6.9 (Ms) 07/12/1988 ULF magnetic 0.01-1Hz 3-axis magnetometers Visual observation & Statistical analysis b(4h),a 128 km [6]   Spitak, Armenia 6.9 (Ms) 07/12/1988 ULF magnetic 0.005-1Hz   Visual observation & Statistical analysis b(4h).a 120 km, 200 km [40]   Loma Prieta, California 7.1 (Ms) 18/11/1989 ULF magnetic 0.01Hz   Visual observation & Statistical analysis b(3h),a 7  km [6]   Loma Prieta, California 7.1 (Ms) 19/11/1989 ELF-LF EM 0.01Hz-32kHz Ground-based magnetometers Visual observation b(3h),d 52 km [41]   Spitak, Armenia 6.9 (Ms) 23/01/89 ELF-LF EM 140Hz,450 Hz 800Hz, 4500 Hz, 15000 Hz COSMOS-1809 Satellite Visual observation&StatisticalAnalysis&FFT b(<3h) Δlong<6°Δlat 2°-4°[12 from the 13 satelite orbits for f<450 Hz] [42]   Upland, California 4.3 17/04/1990 ELF magnetic 3-4Hz Vertical magnetic sensor Statistical Analysis&PSD-FFT b(1d) 160 km [43]   Western Iran 7.5 20/06/1990 Ionospheric(radiowave) 0-8kHz,10-14kHz INTERCOSMOS-19 satellite Visual observation & Modelling b(16d) 250 km-2000 km [44]   Watsonville, California 4.3 23/03/1991 ELF magnetic 3.0–4.0 Hz North–south magnetic sensor Statistical Analysis&PSD-FFT b (data averaged over 2 days) 600 km [43]   Watsonville, California 4.3 23/03/1991 ELF magnetic 3.0–4.0 Hz Vertical magnetic sensor Statistical Analysis&PSD-FFT b (data averaged over 2 days) 600 km [43]   Coalinga, California 4.0 15/01/1992 ELF magnetic 3.0–4.0 Hz Vertical magnetic sensor Statistical Analysis&PSD-FFT b (data averaged over 2 days) 400 km [43]   Hokkaido, Japan 7.8 12/07/1993 foF2 ionospheric     Visual observation & Statistical analysis b (3 days) 290 km, 780 km, 1280 km [45]   Guam 7.1 (Ms) 8/8/1993 ULF magnetic 0.02–0.05 Hz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical) Fractal analysis with PSD-FFT b (1 month) 65 km [46-48]   Guam 8.3 (MJAM) 8/8/1993 ULF magnetic 0.02–0.05 Hz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical) MultifractalDetrended Fluctuation Analysis b (1 month) 65 km [49]   Hokkaido–Toho–Oki, Japn 8.1 (MW) 04/10/1994 LF electric   Borehole antenna Visual observation b (20 min) >1000 km [50]   Hyogo-ken Nanbu (Kobe), Japan 7.2 17/01/1995 DC geopotential, ELF magnetic,LF radio, MF–HF, FM-wave 223 Hzz, 1–20 kHz, 163 kHz, 77.1 MHz   Visual & statistical analysis b (<7 days) ≥ 100 km [51]   Hyogo-ken Nanbu (Kobe), Japan 7.2 (M0) 17/01/1995 LF radio 10.2 kHz LF Omega transmitter and receiver Statistical Analysis (TT method) & Modelling b (2 days) 70 km [6]   Hyogo-ken Nanbu (Kobe), Japan 7.2 17/01/1995 Electric 22.2 MHz Phase-switched interferometer with two horizontally-polarized antennas   b (1 h) 77 km [52]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 Electric, magnetic       b (2 weeks) 70 m, 200 km [53]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 HF electromagnetic E: 41 and 54 MHz M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas PSD-Wavelet Spestral Fractal analysis b (20 h) 284 km [10,12]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 HF electromagnetic E: 41 and 54 MHz M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas PSD-Wavelet Spestral Fractal analysis and Statistical methods. b (20 h) 284 km [13]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 HF electromagnetic E: 41 and 54 MHz M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas PSD-Wavelet Spestral Fractal analysis and Statistical methods. b (20 h) 284 km [14]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 HF electromagnetic E: 41 MHz Electric dipole antennas, magnetic loop antennas PSD-Wavelet Spestral Fractal analysis and Statistical methods. b (20 h) 284 km [15]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 HF electromagnetic E: 41 and 54 MHz M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Intermittent dynamics of critical fluctuations (IDCF)-model & Approximation of Power Spectral Density b (20 h) 284 km [55]   Kozani-Grevena, Greece 6.6 (MW) 13/05/1995 SES ≤1 Hz Electric dipole antennas, magnetic antennas Visual and mathematical analysis b (4 weeks) 70 km-80 km [56]   Kozani-Grevena, Greece 6.8 (Ms) 13/05/1995 SES ≤1 Hz Electric dipole antennas, magnetic antennas Visual and mathematical analysis b (24,25 days) 70 km-80 km [57]   Kozani-Grevena, Greece 6.8 (Ms) 13/05/1995 SES ≤1 Hz Electric dipole antennas, magnetic antennas Visual and mathematical analysis b (22 min-3min) 70 km-80 km [58]   Mid Niigata prefecture 6.8(MJMA) 16/08/2005 DC/ULF magnetic   HF/LF 0.02–0.05 Hz      40 kHz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical)  Discon-type antenna (from 25 MHz to 1300 MHz) with IC-RF75 HF reciever Signal analysis with FFT b (17-21 days & 5-7 days) <220 km, 550 [59]   Miyagi-ken oki Japan 7.2 (MW) 16/08/2005 HF electromagnetic 49.5 MHz Discon-type antenna (from 25 MHz to 1300 MHz) with IC-RF75 HF reciever (Spectral slope estimation, multi-fractal detrended fluctuation analysis & multi-fractal wavelet transform modulus maxima method. b (2-3 weeks & few days-Kunimi station only) 90 km -140 km [60]   Akita-ken Nairiku-nanbu, Japan 5.9 11/08/1996 HF electric 10 kHz- 1MHz Vertical-dipole ground electrodes Visual analysis and analysis of related parameters b (6 days) <100 km [51]   Chiba-ken Toho-oki, Japan 6.6 11/09/1996 HF electric 10 kHz- 1MHz Vertical-dipole ground electrodes Visual analysis and analysis of related parameters b (3 days) 320 km, 430 km [51]   Umbria–Marche, Italy 5.5 26/03/1998 LF radio 0.006 Hz Radio wave vertical antenna   b (1.5 months) 818 km [61]   San Juan Bautista, California 5.1 (MW) 12/08/1998 UHF magnetic 0.01–10 Hz 3-component magnetic field inductor coils Statistical analysis and Power spectrum analysis (MA indices) b (2 h) 3 km [62]   Athens, Greece 5.9 (MW) 07/09/1999 LF electromagnetic M: 3 & 10 kHz Magnetic loop antennas Delay Times Method, Approximate Entropy, Spectral Fractal Analysis b (12-17 h) 247 km [63]   Athens, Greece 5.9 (MW) 07/09/1999 LF electromagnetic M: 3 & 10 kHz Magnetic loop antennas Wavelet Power Spectrum analysis b (12-17 h) 247 km [64]   Athens, Greece 5.9 (MW) 07/09/1999 LF electromagnetic M: 3 & 10 kHz Magnetic loop antennas Symbolic Dynamics b (12-17 h) 247 km [64]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic E: 41 and 54 MHz  M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Wavelet Power Spectrum analysis b (12-17 h) 247 km [10,12]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic M: 10 kHz Electric dipole antennas, magnetic loop antennas Block Entropy, Kolmogorov-Sinai Entropy, Conditional Entropy b (12-17 h) 247 km [65]   Athens, Greece 5.9 (MW) 07/09/1999 LF electromagnetic M: 3 & 10 kHz Magnetic loop antennas Symbolic Dynamics b (12-17 h) 247 km [64]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic E:154 MHz M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Intermittent dynamics of critical fluctuations (IDCF)-model &Approximation of Power Spectral Density b (20 h) 247 km [55]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic E: 135 MHz   M:10 kHz Electric dipole antennas, magnetic loop antennas Intermittent dynamics of critical fluctuations (IDCF)-model & Hurst Analysis b (>3 h) 247 km [55]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic M: 10 kHz Electric dipole antennas, magnetic loop antennas Tsallis Entropy b (12-17 h) 247 km [31]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic M: 10 kHz Electric dipole antennas, magnetic loop antennas Statistical Analysis b (12-17 h) 247 km [66]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic M: 10 kHz Electric dipole antennas, magnetic loop antennas Tsallis Entropy & Fisher Information (10 kHz) b (12-17 h) 247 km [24]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic M: 10 kHz Electric dipole antennas, magnetic loop antennas T-Entropy & R/S analysis & wavelet spectral fractal analysis b (12-17 h) 247 km [23]   Athens, Greece 5.9 (MW) 07/09/1999 HF & LF electromagnetic 10 kHz Electric dipole antennas, magnetic loop antennas Fisher Information, Approximate Entropy b (<3h) 284 km [67]   Chi-Chi, Taiwan 7.6 (MW) 20/09/1999 foF2 ionospheric   IPS-42 ionosonde Visual observation b (3-4 days) 120 km [68]   Chia-Yii, Taiwan 6.4 (MW) 22/10/1999 foF2 ionospheric   IPS-42 ionosonde Visual observation b (1-3 days) 179 km [68]   L'Aquila, Italy 6.3 06/04/2009 HF & LF electromagnetic E: 41 and 54 MHz  M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Wavelet Power Spectrum analysis,Block Entropy, Kolmogorov-Sinai Entropy, Conditional Entropy, Entropy of the source, approximate entropy, Tsallis entropy, normalisedTsallis entropy, T-entropy, DFA, R/S analysis, Hurst analysis, b(<3h) 816 km [21,22] Multiple Events Greece                 (3 events) 6.0     [NW Crete] 5.0      [SE Crete]  5.0      [NE Samos] 21/11/1992    29/07/1995    07/05/1995 HF electromagnetic E: 41 and 53 MHz Electric dipole antennas Visual observation b (1-3 days) 20-150 km [69]   Greece    (2 events) 6.6(MW)[Kozani-Grevena]    6.6 (MW)[Athens] 13//05/1995   07/09/1999 ULF,    HF & LF electromagnetic SES 1Hz    E: 41, 54  and 135 MHz   M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Wavelet Power Spectrum analysis, Symbolic Dynamics,  T-Entropy, Approximate Entropy, normalisedTsallis Entropy, b (<3 h) 284km, 247 km [18]   Greece    (4 events) 6.6(MW)[Kozani-Grevena] 5.9 (MW)    [Egio-Eratini]6.6 (MW)[Athens]  5.9 (MW)   [Lefkas] 13//05/1995  15/06/1995  07/09/1999    14/06/2003 HF & LF electromagnetic E: 41 and 54 MHz  M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Wavelet Power Spectrum analysis, Symbolic Dynamics,  T-Entropy, Approximate Entropy, normalisedTsallis Entropy, b (12-17 h) <300 km [17]   Japan (4 events)       (swarm earthquakes of depth~10km) 6.4 (MJMA)   [Izu-Peninsula]  6.1 (MJMA)    [Izu-Peninsula]   6.3 (MJMA)    [Izu-Peninsula]   6.0 (MJMA)    [Izu-Peninsula] 01/07/2000    09/07/2000    15/07/2000    18/08/2000 ULF geomagnetic 0.001-1 Hz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical) Fractal analysis with FFT, Higuchi and Bulgara-Klein  methods b (<1 month) 80 km-1160 km [70]   Japan (5 events) 8.3 (MJMA)   [Guam]  6.4 (MJMA)   [Izu-Peninsula]  6.1 (MJMA)    [Izu-Peninsula]   6.3 (MJMA)    [Izu-Peninsula]   6.0 (MJMA)    [Izu-Peninsula] 08/08/1993 01/07/2000    09/07/2000    15/07/2000    18/08/2000 ULF geomagnetic 0.001-1 Hz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical) Fractal analysis with FFT, Fractal Dimension b (<1 month) 80 km-1160 km [71]   Greece    (2 events) 5.2 (ML) & 5.8 (ML) 18/01/200& 03/02/2007 SES ≤1 Hz Electric dipole antennas & Magnetic antennas Natural time analysis b (22min),a(3min) <150 km [58]   Greece Synthetic& 6.4 (MW) 08/06/2008 SES ≤1 Hz Electric dipole antennas & Magnetic antennas Natural time analysis   <30 km [32]   Japan 7.8 (MJMA)   [SW offshore Hokkaido]   8.2 (MJMA) [E offshore Hokkaido]   7.6 (MJMA)   [far-offshore Hokkaido]   8.0 (MsMA)  [offshore Tokachi] 7.8 (MJMA) [Near Chichi-jima] 9.0 (MsJMA) [Tohoku] 07/12/1993& 04/10/1994& 28/12/1994& 26/09/2003& 22/10/2010& 11/3/2011 SES ≤1 Hz Electric dipole antennas& Magnetic antennas Natural time analysis b(1 month)   [for Tohoku and remaining 6 major EQs with MJMA≥7.6, depth <400 km] ΔLat<3°Δlong<3° [33]   Sumatra, Indonesia 9.0 (Mw)    [Sumatra-Andaman]   8.7 (Mw)    [Sumatra-Nias] 26/12/2004    28/3/2205 ULF geomagnetic 1 Hz 3-axis ring–core-type fluxgatemagnetometer (NS, EW, Vertical) Spectral density ratio analysis and transfer functions analysis based on wavelet transform method, fractal dimension. b (<1.5 monhs) <750 km [72]   Sumatra, Indonesia 9.3 8.7 26/12/2004    28/3/2205 Geomagnetic 1 Hz CHAMP satellite vector magnetic antennas Wavelet Power Spectrum analysis b(few hours),a(2 hours) 700 km region [25] Seismic Periods Worldwide      (325 events) > 5 (Ms) 1981 (Oct)-1983 (Dec) ELF-LF EM 140 Hz, 450Hz 800Hz, 4500Hz ARCAD-3, AUREOL aboard Statistical Analysis&Modelling b(0-4h) [component BZ at 140Hz] ΔLong<20° [73]   Japan (26 events) 5.0-6.6 1985-1990 LF electric 82 kHz Loop Antennas Statistical Analysis b(up to 2 days) 2 km-895 km [74]   Greece (47 events) 3.4–6.8 1983 SES ≤1 Hz Electric dipole antennas& Magnetic antennas Visual observation b 10 km-160 km [75,76]   Central Italy 3.0-4.3 1991–1994 LF radio waves 216 kHz Electric field strength receivers Visual analysis and analysis of related parameters b (6–10 days) <100 km [77]   Crete, Greece (19 events) ≥5.0 (Ms) 1992-1995 HF electromagnetic 3 and 10 kHz, 41 and 53 MHz Electric dipole antennas, magnetic loop antennas Visual observation b(up to 6 days) 300-350 km [78]   Crete, Greece (19 events) ≥5.0 (Ms) 1992-1995 HF electromagnetic 41 and 53 MHz Electric dipole antennas, magnetic loop antennas Visual observation and Modelling b(up to 6 days) 300-350 km [69]   Mexico (Pacific Coast) ≥6.0 1993–1994 ULF electric 0–0.125 Hz Pair of unpolarized  electrodes FFT analysis b(2-3months) <200 km [79]   Chi-Chi Taiwan ≥ 6.0 1994–1999 ULF magnetic   IPS-42 ionosonde Visual observation & Statistical analysis b (1,3,4 days) 3 signals <400 km [80]   Vrancea, Romania > 3.9 (M0) 1997–1998 ULF electromagnetic 3 kHz 3-axis fluxgate magnetometes Visual observation b (1-12 days) 100 km [81]   Greece    (291 events) >4.6 1999-2001 HF & LF electromagnetic E: 41 and 54 MHz  M: 3 & 10 kHz Electric dipole antennas, magnetic loop antennas Visual analysis & Decision Algorithm b <150 km [82]   Japan (29 events) ≥4.8 04/09/2001–08/04/2003 HF electromagnetic   Two 5-element Yagi antennas Statistical Analysis b (up to 5 days) Δlat, Δlong<3° [83]   West Greece-South Greece & Greece (whole) 6.1 (Ms)-6.9 (Ms) 18/10/2005-08/01//2006 & 18/09/2005-08/01/2006 SES ≤1 Hz Electric dipole antennas, magnetic antennas Visual & Natural time analysis b (1 month),a (77 events) 22 kmx22 km region around epicentre [84]   Greece >3.5 (ML) 2006-2007 SES ≤1 Hz Electric dipole antennas & Magnetic antennas Natural time analysis b(22min),a(3min) <150 km [58]   Greece    (4 events) >5.0 (ML) 2008-2009 HF  electromagnetic E: 41 and 46 MHz Magnetic loop antennas Wavelet Power Spectrum analysis b (<1 month) <200 km [27]   Japan E:25°-46°, N: 125°-148° All events 1984-11/03/2011 SES ≤1 Hz Electric dipole antennas& Magnetic antennas Natural time analysis b(1 month) 7 major EQs with MJMA≥7.6, depth <400 km b(3 months) for 139 EQs with MJMA≥6.4, depth<400 km   [33]   California N:31.7-45.7,W:112.1-127.5 ≥2.5 01/01/1979-01/01/2004 SES ≤1 Hz Electric dipole antennas & Magnetic antennas Natural time analysis b(2-7 months)   [58]

Table 1: Earthquake precursory data: Earthquake data, type of electromagnetic precursor detected and related instrumentation, method of detection with precursory time and effective distance (ED) from the epicenter of the earthquake and literature data. The symbol b refers to disturbances detected prior to the earthquake(s) and the symbol a to those detected after the event(s). PSD refers to Power Spectral Density, FFT is the abbreviation of the Fast Fourier Transform and Greek delta (Δ) points to a difference in latitude or longitude. SES is the international abbreviation of the VAN method for the Seismic Electrical Signals.