During the Mw9 Tohoku-Oki earthquake, gradual increases in both ionosphere total electron content (TEC) and geomagnetic declination signals were observed, starting from ~40 minutes before the mainshock, followed by impulsive enhancements ~10 minutes after the mainshock. There have been many studies on pre-seismic TEC enhancements, including their characteristics, debates regarding whether TEC anomalies are real signals or artefacts, and the explainable models, and many studies have reported that the impulsive TEC enhancement was caused by a tsunami-induced neutral atmospheric gravity wave. Since TEC and geomagnetic declination anomalies were synchronized so that their origin should be attributed to the same seismic activities, any models must explain both anomalous phenomena, but not the case considered herein. Compared with the corresponding TEC anomalies, we re-examined the characteristics of geomagnetic variation just before and after the mainshock, focusing on the generation process of the impulsive enhancement immediately after the mainshock. We showed that the observed anomaly could be explained if there are quasi-static electric currents of 20 - 30 kA generated near the epicentre area. The possible mechanism of the current generation is discussed in terms of the ionization process in the atmosphere near the sea surface.
References
[1]
Heki, K. (2011) Ionospheric Electron Enhancement Preceding the 2011 Tohoku-Oki Earthquake. Geophysical Research Letters, 38, L17312. https://doi.org/10.1029/2011GL047908
[2]
Saito, A., Tsugawa, T., Otsuka, Y., Nishioka, M., Iyemori, T., Matsunuma, M., Saito, S., Chen, C.H., Goi, Y. and Choosakul, N. (2011) Acpistoc Resonance and Plasma Depletion Detected by GPS Total Electron Content Observation after the 2011 off Pacific Coast of Tohoku Earthquake. Earth and Planetary Science Letters, 63, 863-867. https://doi.org/10.5047/eps.2011.06.034
[3]
Tsugawa, T., Saito, A., Ohtsuka, Y., Nishioka, M., Maruyama, T., Kato, H., Nagatsuma, F. and Murata, K. (2011) Ionospheric Disturbance Detected by GPS Total Electron Content Observation after the 2011 off the Pacific Coast of Tohoku Earthquake. Earth Planets Space, 63, 875-879. https://doi.org/10.5047/eps.2011.06.035
[4]
Kakinami, Y., Kamogawa, M., Tanioka, Y., Watanabe, S. Gusman, A.R., Liu, J.Y., Watanabe, Y. and Mogi, T. (2012) Tsunamigenic Ionsphere Hole. Geophysical Research Letters, 39, L00G27. https://doi.org/10.1029/2011GL050159
[5]
Kamogawa, M., Orihara, Y., Tsurudome, C., Tomida, Y., Kanay, T., Ikeda, D., Gusman, A.R., Kakinami, Y., Liu, J.Y. and Toyoda, A. (2016) A Possible Space-Based Tsunami Early Warning System Using Observations of the Tsunami Ionosphere Hole. Scientific Reports, 6, 37989. https://doi.org/10.1038/srep37989
[6]
Heki, K. and Enomoto, Y. (2013) Preseismic Ionospheric Electron Enhancements Revisited. Journal of Geophysical Research, 118, 1-9. https://doi.org/10.1002/jgra.50578
[7]
Utada, H. and Shimizu, H. (2014) Comment on “Preseismic Ionospheric Electron Enhancements Revisted”. Journal of Geophysical Research: Space Physics, 119, 6011-6015. https://doi.org/10.1002/2014JA020044
[8]
Heki, K. and Enomoto, Y. (2014) Reply to Comment by K. Heki and Y. Enomoto on “Preseismic Ionospheric Electron Enhancement Revisited”. Journal of Geophysical Research: Space Physics, 119, 6016-6018. https://doi.org/10.1002/2014JA020223
[9]
Wyss, M. (1991) Evaluation of Proposed Earthquake Precursors. American Geophysical Union, Washington DC, Volume 302, 94 p. https://doi.org/10.1029/SP032
[10]
Heki, K. and Enomoto, Y. (2015) Mw Dependence of the Preseismic Ionospheric Electron Enhancements. Journal of Geophysical Research: Space Physics, 120, 7006-7020. https://doi.org/10.1002/2015JA021353
[11]
Pulinets, S. and Ouzounov, D. (2011) Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) Model—An Unified Concept for Earthquake Precursors Validation. Journal of Asian Earth Sciences, 41, 371-382. https://doi.org/10.1016/j.jseaes.2010.03.005
[12]
Ouzounov, D., Pulinets, S., Romanov, A., Romanov, A., Tsubuly, K., Davidenko, D., Kafatos, M. and Taylor, P. (2011) Atmosphere-Ionosphere Response to the M9 Tohoku Earthquake Revealed by Multi-Instrument Space-Borne and Ground Observations: Preliminary Results. Earthquake Science, 24, 557-564. https://doi.org/10.1007/s11589-011-0817-z
[13]
Hayakawa, M., Kasahara, Y., Nakamura, T., Hobara, Y., Rozhnoi, A., Solovieva, M., Molchanov, O.A. and Korepanov, Y.V. (2011) Atmospheric Gravity Waves as a Possible Candidate for Seismo-Ionospheric Perturbations. Journal of Atmospheric Electricity, 31, 129-140. https://doi.org/10.1541/jae.31.129
[14]
Enomoto, Y. (2012) Coupled Interaction of Earthquake Nucleation with Deep-Earth Gases: A Possible Mechanism for Seismo-Electromagnetic Phenomena. Geophysical Journal International, 191, 1210-1214. https://doi.org/10.1111/j.1365-246X.2012.05702.x
[15]
Kuo, C.L., Lee, L.C. and Huba, J.D. (2014) An Improved Coupling Model for the Lithosphere-Atmosphere-Ionosphere System. Journal of Geophysical Research: Space Physics, 119, 3189-3205. https://doi.org/10.1002/2013JA019392
[16]
Freund, F. (2010) Toward a Unified Solid State Theory for Pre-Earthquake Signals. Acta Geophysica, 58, 719-766. https://doi.org/10.2478/s11600-009-0066-x
[17]
Kelley, M.C., Swartz, W.S. and Heki, K. (2016) Apparent Ionospheric Total Electron Content Variation Prior to Major Earthquakes Due to Electric Fields Created by Tectonic Stresses. Journal of Geophysical Research, 122, JA023601. https://doi.org/10.1002/2016JA023601
[18]
Kumagai, H., Pulido, N., Fukuyama, E. and Aoi, S. (2012) Strong Localized Asperity of the 2011 Tohoku-Oki Earthquake, Japan. Earth Planes Space, 64, 649-654. https://doi.org/10.5047/eps.2012.01.004
[19]
Brown, L., Wang, K. and Sun, T. (2015) Static Stress Drop in the Mw9 Tohoku-Oki Earthquake: Heterogeneous Distribution and Low Average Value. Geophysical Research Letters, 42, 10595-10600. https://doi.org/10.1002/2015GL066361
[20]
Goddin, O.A. (2004) Air-Sea Interaction and Feasibility of Tsunami Detection in the Open Ocean. Journal of Geophysical Research, 109, C05002. https://doi.org/10.1029/2003JC002030
[21]
Rolland, L.M., Longnonnè, P., Astafyeva, E., Kherani, E.A., Kobayashi, N., Mann, M. and Munekane, H. (2011) The Resonant Response of the Ionosphere Imaged After the 2011 off the Pacific Coast of Tohoku Earthquake. Earth Planets Space, 63, 853-857. https://doi.org/10.5047/eps.2011.06.020
[22]
Utada, H., Shimizu, H., Ogawa, T., Maeda, T., Furumura, T., Yamamoto, T., Yamazaki, N., Yoshitake, Y. and Nagamachi, S. (2011) Geomagnetic Field Changes in Response to the 2011 off the Pacific Coast of Tohoku Earthquake and Tsunami. Earth and Planetary Science Letters, 311, 11-27. https://doi.org/10.1016/j.epsl.2011.09.036
[23]
Maeda,T., Furumura, T., Sakai, S. and Shinohara, M. (2011) Significant Tsunami Observed at Ocean-Bottom Pressure Gauges during the 2011 off the Pacific Coast of Tohoku Earthquake. Earth Planets Space, 63, 803-808. https://doi.org/10.5047/eps.2011.06.005
[24]
Tappin, D., Grilli, S.T., Harris, J.C., Geller, R.J., Masterlark, T., Kirby, J.T., Shi, F., Ma, G., Thingbaijam, K.K.S. and Mai, P.M. (2014) Did Submarine Landslide Contribute to the 2011 Tohoku Tsunami? Marine Geology, 357, 344-361. https://doi.org/10.1016/j.margeo.2014.09.043
[25]
Utada, H. (2014) Kyodai tsunami ni tomonau jiba-hendo: English Translation; Magnetic Disturbances Associated with Huge Tsunami. JISIN Journal, No. 58, 21-26. (In Japanese)
[26]
Johnston, M.J.S., Mueller, R.J. and Sasai, Y. (1994) Magnetic Field Observations in the Near-Field the 28 June 1992 Mw7.3 Landers, California, Earthquake. Bulletin of the Seismological Society of America, 84, 792-798.
[27]
Sasai, Y. (2001) Tectonomagnetic Modelling Based on the Piezomagnetism: A Review. Annals of Geophysics, 44, 361-368.
[28]
Mizutani, H. and Ishido, T. (1976) A New Interpretation of Magnetic Field Variation Associated with the Matsushiro Earthquakes. Journal of Geomagnetism and Geoelectricity, 28, 179-188. https://doi.org/10.5636/jgg.28.179
[29]
Enomoto, Y., Yamabe, T. and Okumura, N. (2017) Causal Mechanisms of Seismo-EM Phenomena during the 1965-1967 Matsushiro Earthquake Swarm. Scientific Reports, 7, 44774. https://doi.org/10.1038/srep44774
[30]
Rycroft, M.J., Israelsson, S. and Price, C. (2000) The Grobal Atmospheric Electric Circuit, Solar Activity and Climate Change. The Journal of Atmospheric and Solar-Terrestrial Physics, 62, 1563-1576. https://doi.org/10.1016/S1364-6826(00)00112-7
[31]
Tajima, F. and Kennett, B.L.N.L. (2012) Interlocking of Heterogeneous Plate Coupling and Aftershock Area Expansion Pattern for the 2011 Tohoku Mw9 Earthquake. Geophysical Research Letters, 39, L05307. https://doi.org/10.1029/2011GL050703
[32]
Ichihara, H., Hamano, Y., Baba, K. and Kasaya, T. (2013) Tsunami Source of the 2011 Tohoku Earthquake Detected by an Ocean-Bottom Magnetometer. Earth and Planetary Science Letters, 382, 117-124. https://doi.org/10.1016/j.epsl.2013.09.015
[33]
Sugioka, H., Hamano, Y., Baba, K., Kasaya, T., Tada, N. and Suetsugu, D. (2014) Tsunami: Ocean Dynamo Generator. Scientific Reports,.4, 3596. https://doi.org/10.1038/srep03596
[34]
JAMSTEC (2011) Photos from the 2011 Tohoku Earthquake Source Area Captured by Deep-Sea Submersible Shinkai 6500. https://www.jamstec.go.jp/e/about/press_release/20110815/
[35]
Blanchard, D.C. (1963) The Electrification of the Atmosphere by Particles from Bubbles in the Sea. Progress in Oceanography, 1, 73-202. https://doi.org/10.1016/0079-6611(63)90004-1
[36]
Enomoto, Y., Yamabe, T., Sugiura, S. and Kondo, H. (2019) Possible Mechanism for the Tsunami-Related Fires That Occurred at Aonae Harbour on Okushiri Island in the 1993 Hokkaido Nansei-Oki Earthquakes. Geosciences, 9, 253. https://doi.org/10.3390/geosciences9060253
[37]
Enomoto, Y. (2002) A Tornado-Type Cloud Observed on January 9, 1995 Prior to the Kobe Earthquake. In: Hayakawa, M. and Molchanov, O.A., Eds., Seismo Electromagnetics: Lithosphere-Atmosphere-Ionosphere Coupling, TERRAPUB, Tokyo, 267-273.
[38]
Kakinuma, T. (2011) Watashi ga mita Ohtsunami: English Translation, The Big Tsunami I Saw, Kahoku-Shinpo. http://memory.ever.jp/tsunami/shogen_natori.html
[39]
Kamiyama, M., Sugito, M., Kuse, M., Schekotov, A. and Hayakawa, M. (2016) On the Precursors to the 2011 Tohoku Earthquake: Crustal Movements and Electromagnetic Signatures. Geomatics Natural Hazards and Risk, 7, 471-492. https://doi.org/10.1080/19475705.2014.937773
