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Liperovskaya, E. V.; Parrot, M.; Bogdanov, V. V.; Meister, C.-V.; Rodkin, M. V.; Liperovsky, V. A. (2006)
Publisher: Copernicus Publications on behalf of the European Geosciences Union
Journal: Natural Hazards and Earth System Sciences
Languages: English
Types: Article
Subjects: [SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, G, GE1-350, Geography. Anthropology. Recreation, QE1-996.5, Environmental technology. Sanitary engineering, Environmental sciences, Geology, TD1-1066
The statistical analysis of the variations of the dayly-mean frequency of the maximum ionospheric electron density foF2 is performed in connection with the occurrence of (more than 60) earthquakes with magnitudes M>6.0, depths h<80 km and distances from the vertical sounding station R<1000 km. For the study, data of the Tokyo sounding station are used, which were registered every hour in the years 1957–1990. It is shown that, on the average, foF2 decreases before the earthquakes. One day before the shock the decrease amounts to about 5%. The statistical reliability of this phenomenon is obtained to be better than 0.95.

Further, the variations of the occurrence probability of the turbulization of the F-layer (F spread) are investigated for (more than 260) earthquakes with M>5.5, h<80 km, R<1000 km. For the analysis, data of the Japanese station Akita from 1969–1990 are used, which were obtained every hour. It is found that before the earthquakes the occurrence probability of F spread decreases. In the week before the event, the decrease has values of more than 10%. The statistical reliability of this phenomenon is also larger than 0.95. Examining the seismo-ionospheric effects, here periods of time with weak heliogeomagnetic disturbances are considered. For the foF2 analysis, the Wolf number is less than 100 and the index ΣKp is smaller than 30, and in case of the F-spread study a Wolf number less than 80 and ΣKp smaller than 17 are chosen.

  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • Hobara, Y. and Parrot, M.: Ionospheric perturbations linked to a very powerful seismic event, J. Atmos. Terr. Phys., 67, 677-685, 2005.
    • Liperovsky, V. A., Pokhotelov, O. A., and Shalimov, S. L.: Ionospheric precursors of earthquakes, Nauka, Moscow, 1992.
    • Liu, J. Y., Chen, Y. I., Chuo, Y. J., and Chen, C. S.: A statistical investigation of preearthquake ionospheric anomaly, J. Geophys. Res., 111, A05304, doi:10.1029/2005JA011333, 2006.
    • Ondoh, T.: Seismo-ionospheric phenomena, Adv. Space Res., 26(8), 1267-1272, 2000.
    • Pulinets, S. A. and Boyarchuk, K. A.: Ionospheric precursors of earthquakes, Springer, Berlin, 2004.
    • Rios, V. H., Kim, V. P., and Hegai, V. V.: Abnormal perturbations in the F2 region ionosphere observed prior to the great San Juan earthquake of 23 November 1977, Adv. Space Res., 33, 323-327, 2004.
    • Singh, B., Kushwah, V., Singh, O. P., Lakshmi, D. R., and Reddy, B. M.: Ionospheric perturbations caused by some major earthquakes in India, Phys. Chem. Earth, 29, 537-550, 2004.
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  • Discovered through pilot similarity algorithms. Send us your feedback.

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