Ionospheric electron enhancement preceding the 2011 Tohoku-Oki earthquake

A new paper by K. Heki in GRL seems to confirm what could become a tool for large earthquake prediction:

I reproduce the abstract of the paper:
The 2011 March 11 Tohoku‐Oki earthquake (Mw 9.0) caused vast damages to the country. Large events beneath dense observation networks could bring breakthroughs to seismology and geodynamics, and here I report one such finding. The Japanese dense network of Global Positioning System (GPS) detected clear precursory positive anomaly of ionospheric total electron content (TEC) around the focal region. It started ∼40 minutes before the earthquake and reached nearly ten percent of the background TEC. It lasted until atmospheric waves arrived at the ionosphere. Similar preseismic TEC anomalies, with amplitudes dependent on magnitudes, were seen in the 2010 Chile earthquake (Mw 8 .8), and possibly in the 2004 Sumatra‐Andaman (Mw 9.2) and the 1994 Hokkaido‐Toho‐Oki (Mw 8.3) earthquakes, but not in smaller earthquakes.

Reference: Heki, K. (2011), Ionospheric electron enhancement preceding the 2011 Tohoku‐Oki earthquake, Geophys. Res. Lett., 38, L17312, doi:10.1029/2011GL047908.

PD: Check this paper questioning the results by Heki.


  1. A part from the coincidence of the two phenomenon, is there any explanation why crustal movements should influence the ionosphere??

  2. According to the authors:

    "Electromagnetic earthquake precursors have been often attributed to positively charged aerosols [Tributsch, 1978]. Several hypotheses have been proposed for their sources. For example, experiments demonstrated that stresses mobilize positive holes in igneous rocks [Takeuchi et al., 2006]. Alpha decay of radon released from the crust can also ionize the atmosphere. They may change the electric resistivity of the lower atmosphere, which could disturb the global electric circuit and redistribute ionospheric electrons [Pulinets and Ouzounov, 2011]."