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. 2015 Apr 1;10(4):e0121443. doi: 10.1371/journal.pone.0121443

Fig 7. Number of whole tweets per minute from March 11 to 17 in 2011 (top).

Fig 7

Number of tweets per second with ground acceleration at the very moment of the quake on March 11 (middle) and 15 (bottom). Red colored areas in the top figure are enlarged in the lower figures, which depict the very moment of the quakes. There are two big earthquakes on March 11 and 15 in 2011. One is the Great East Japan earthquake that registered 9.0 on the Richter scale in the Tohoku area on March 11, and the other hit Shizuoka area (middle-eastern Japan) on March 15, with 6.4 on the Richter scale. The ground acceleration data are obtained from the Japan Meteorological Agency (http://www.seisvol.kishou.go.jp/eq/kyoshin/jishin/index.html).