Abstract
We present evidence of unusual Very Low Frequency (VLF) signal amplitude variation during the devastating earthquake of magnitude 9.0 which occurred at Honshu, in Japan on 11 March, 2011. We use the SoftPAL very low frequency receiver placed at Ionospheric and Earthquake Research Centre of Indian Centre for Space Physics, located at Sitapur (Lat. 22°30′N, Long. 87°47′E). We observe significant changes in signal amplitude from JJI (Lat. 32°05′N, Long. 131°51′E) station transmitting at a frequency of 22.2 kHz prior to the earthquake. We analyze signal amplitude for almost 2 weeks to establish a possible seismo–ionospheric correlation. We observe significant shift of the sunrise terminator time up to 2 days before the earthquake and the shift is found to be maximum on the day of the earthquake. In addition, we observe unusual increase of the D-layer disappearance time during the earthquake and the value becomes maximum on the day of the earthquake. These findings generally agree with our previous findings reported elsewhere.
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References
B A Bolt Nature 202 1095 (1964)
B M Gokhberg, I R Gufeld, A A Rozhnoy, V F Marenko, V S Yampolsky and E A Ponomarev Phys. Earth Planet. Inter. 57 64 (1989)
I L Gufeld, A A Roznoi, S N Tyumentsev, S V Sherstyuk and V S Yampolskiy Phys. Solid Earth 3 267 (1992)
M Hayakawa, R Kawate, O A Molchanov and K Yumoto Geophys. Res. Lett. 23 241 (1996)
O A Molchanov and M Hayakawa J. Geophys. Res. 103 17489 (1998)
O A Molchanov, M Hayakawa, T Ondoh and E Kawai Phys. Earth Planet. Inter. 105 239 (1998)
A M Clilverd, C J Rodger and N R Thomson J. Geophys. Res. 104(A12) 28171 (1997)
M Hayakawa, O A Molchanov, N Shima, A V Shvets and N Yamamoto TERRAPUB Tokyo 223 (2002)
S Maekawa et al. Ann. Geophys. 24 2219 (2006)
A Rozhnoi et al. Nat. Hazards Earth Syst. 9 1727 (2009)
S K Chakrabarti, M Saha, R Khan, S Mandal, K Acharyya and R Saha, Indian J. Radio Space Phys. 34 314 (2005)
S Sasmal and S K Chakrabarti Nat. Hazards Earth Syst. Sci. 9 1403 (2009)
S Ray and S K Chakrabarti Nat. Hazards Earth Syst. Sci. 13 1501 (2013)
S Sasmal, S K Mondal, S K Chakrabarti and S Ray J. Earth Sys. Sci. (Communicated) (2014)
S Chakrabarti, S Sasmal, M Saha, R Khan, D Bhowmik and S K Chakrabarti Indian J. Phys. 81 531 (2007)
S Sasmal, S K Chakrabarti and S Chakrabarti AIP Conf. Proc. 1286 270 (2010)
S K Chakrabarti, S Sasmal and S Chakrabarti Nat. Hazards Earth Syst. Sci. 10 1751 (2010)
S Ray, S K Chakrabarti, S Sasmal and A K Choudhury AIP Conf. Proc. 1286 298 (2010)
S Ray, S K Chakrabarti, S K Mondal and S Sasmal Nat. Hazards Earth Syst. Sci. 11 2699 (2011)
S Ray, S K Chakrabarti and S Sasmal Indian J. Phys. 86 85 (2012)
I P Dobrovolsky, I S Zubkov and V I Myachkin Pure Appl. Geophys. 57 64 (1989)
Acknowledgments
S Sasmal acknowledges the financial support from a ISRO RESPOND and MOES project. S Ray acknowledges ISRO RESPOND project. The authors thank D Bhowmick and S K Mondal for technical supports at IERC, Sitapur.
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Sasmal, S., Chakrabarti, S.K. & Ray, S. Unusual behavior of Very Low Frequency signal during the earthquake at Honshu/Japan on 11 March, 2011. Indian J Phys 88, 1013–1019 (2014). https://doi.org/10.1007/s12648-014-0520-8
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DOI: https://doi.org/10.1007/s12648-014-0520-8