Electromagnetic

 

Earthquakes with Reported Electomagnetic Precursors

earthquake mag. date type of emmission before/during/after? freq. range(Hz) signal level background level SNR distance from epicenter instrumentation reference
Armenia, Spitak 6.9 Ms 12/7/1988 ULF magnetic b (4hours), a 0.01 - 1 0.2 nT 0.02 nT 10 128 km 3-axis high-sensitivity magnetometers 3
Armenia, Spitak 6.9 Ms 12/7/1988 ULF magnetic b (4 hours), a 0.005 - 1 0.1 - 0.2 nT 0.03 nT 6.67 120 km and 200 km - 6
Guam 7.1 Ms 8/8/1993 ULF magnetic b (1 month) 0.02 - 0.05 0.1 nT not reported - 65 km 3-axis ring-core-type fluxgate magnetometer 4
Loma Prieta, CA 7.1 Ms 11/19/1989 ELF/VLF EM b (3 hours), d 0.01 5 - 60 nT Hz-1/2 ~1 nT Hz-1/2 - 52 km ground-based magnetometers 8
Loma Prieta, CA 7.1 Ms 11/18/1989 ULF magnetic b (3 hours), a 0.01 4-5 nT not reported - 7 km - 3
Loma Prieta, CA 7.1 Ms 11/18/1989 ULF magnetic a 0.01 - 10 1 nT not reported - 7.3 km proton magnetometers 5
Armenia region - 1989 ELF/VLF EM b (3 hours) 140 Hz 10 mγ not reported - 6 deg. in long, 2 - 4 in latitude COSMOS-1809 satellite 7
Armenia region - 1990 ELF/VLF EM b (3 hours) 450 Hz 3 mγ not reported - 6 deg. in long, 2 - 4 in latitude COSMOS-1809 satellite 7
worldwide (325 eq's) Ms > 5 - ELF/VLF EM b (0-4 hours) 140 Hz 3.28E-5 γ Hz-1/2 1.53E-5 γ Hz-1/2 2.14 ∆ long < 10 deg. ARCAD 3 aboard AUREOL 3 satellite 2
worldwide (325 eq's) Ms > 5 - ELF/VLF EM b (0-4 hours) 800 Hz 9.08E-5 γ Hz-1/2 1.57E-5 γ Hz-1/2 5.78 ∆ long < 10 deg. ARCAD 3 aboard AUREOL 3 satellite 2
- Ms > 5.5 - LF radiowave - - 102-103 V m-1 - - 60 deg. in long, 2 in latitude Intercosmos 19 satellite 2
Upland, CA 4.7 4/17/1990 ULF magnetic b (1 day) 3.0 - 4.0 - 40 dB - 46.8 dB - 160 km vertical magnetic sensor 1
Watsonville, CA 4.3 3/23/1991 ULF magnetic b (data averaged over 2 days) 3.0 - 4.0 - 43 dB - 47.6 dB - 600 km north-south magnetic sensor 1
Watsonville, CA 4.3 3/23/1991 ULF Magnetic b (data averaged over two days) 3.0 - 4.0 - 44 dB - 46.8 dB - 600 km vertical magnetic sensor 1

References

  1. Dea, J.Y., P.M. Hansen, and W.M. Boerner. Long-term ELF Background Noise Measurements, the Existence of Window Regions, and Applications to Earthquake Precursor Emission Studies
      Physics of the Earth and Planetary Interiors, Vol. 77, pp.109-125, 1993
  2. Parrot, M. Statistical Study of ELF/VLF Emissions Recorded by a Low-Altitude Satellite During Seismic Events.
      Journal of Geophysical Research, Vol. 99, No. A12, pp.23,339-23,347, 12/1/94
  3. Molchanov, O.A., et al. Results of ULF Magnetic Field Measurements Near the Epicenters of the Spitak (Ms = 6.9) and Loma Prieta (Ms = 7.1) Earthquakes: Comparative Analysis
      Geophysical Research Letters, Vol. 19, No. 14, pp.1495-1498, 7/24/92
  4. Hayakawa, M., et al. Results of Ultra-Low-Frequency Magnetic Field Measurements During the Guam Earthquake of 8 August 1993.
      Geophysical Research Letters, Vol. 23, No. 3, pp.241-244, 2/1/96
  5. Mueller, R.J., and M.J.S. Johnston. Seismomagnetic Effect Generated by the October 18, 1989, ML 7.1 Loma Prieta, California, Earthquake
      Geophysical Research Letters, Vol. 17, No. 8, pp.1231-1234, 7/90
  6. Kopytenko, Y.A., et al. 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
      Physics of the Earth and Planetary Interiors, Vol. 77, pp.85-95, 1993
  7. Serebryakova, O.N., et al. Electromagnetic ELF Radiation from Earthquake Regions as Observed from Low-Altitude Satellites
      Geophysical Research Letters, Vol. 19, No. 2, pp.91-94, 1/24/92
  8. Fraser-Smith, A.C., et al. Low-Frequency Magnetic Field Measurements Near the Epicenter of the Ms 7.1 Loma Prieta Earthquake
      Geophysical Research Letters, Vol. 17, No. 9, pp.1465-1468, 8/90