A recent EOS transactions AGU Research Highlights reports on a paper by Heki in Geophysical Research Letters that total electron content (TEC) of the ionosphere increased 40 minutes before the M9 Tohoku quake (east Honshu Japan). This was from analysis of the Japan GPS network. The increase of TEC was greatest over the epicenter. The author also reports similar anomalies before the M8.8 Chile quake and maybe the M9.2 Sumatra quake.

It will be interesting to see how this paper holds up under scrutiny and I imagine other researchers trying to duplicate it. But, it passed peer review and is published. A lot of what is published is wrong, however (I know, snarky and vague statement). We'll see what John V. has to say.

Chris