Fig. 2

Ship distributions derived from AIS data during the 2011 Tohoku tsunami. Distributions at a 0 min, b 2 min, c 24 min, and d 45 min after the earthquake occurrence are shown. In c and d, the right panel enlarges the rectangular area in the left panel, and blue lines trace ship tracks of 13 offshore vessels during 0–45 min after the earthquake occurrence (Table 1). Dashed isobaths of 100 and 500 m are added