looks as if something underneath the water may have collapsed
http://earthquake.usgs.gov/earthquakes/recenteqsww/Maps/10/140_40.php MAG UTC DATE-TIME LAT deg LON deg DEPTH km Region
MAP 5.5 2011/03/11 10:45:46 38.466 143.591 41.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/11 10:35:35 37.044 141.298 25.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 10:28:44 39.447 143.531 29.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 10:20:27 36.966 142.289 21.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.0 2011/03/11 10:10:34 39.248 142.779 28.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:59:56 36.703 142.207 41.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 09:47:01 39.685 142.938 29.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:42:22 39.438 142.749 30.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 09:37:08 35.877 141.585 29.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 09:09:14 37.717 143.267 36.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 09:04:10 37.299 142.655 30.5 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/11 09:00:19 37.056 141.966 20.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/11 08:52:26 36.763 141.910 35.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 08:46:47 37.421 142.453 37.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 08:40:56 37.465 141.122 38.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 08:31:07 37.428 141.200 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.5 2011/03/11 08:19:24 36.200 142.000 19.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 08:15:40 37.034 144.612 27.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.2 2011/03/11 08:12:04 36.606 141.557 19.8 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.5 2011/03/11 08:10:30 36.394 140.631 30.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 08:01:58 37.071 142.734 22.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/11 07:56:15 37.130 142.305 34.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/11 07:54:44 37.742 141.565 45.3 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 07:42:55 36.406 141.919 29.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 07:38:26 39.250 142.783 29.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 07:28:12 36.802 141.911 24.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/11 07:25:33 37.916 144.621 15.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 07:14:59 36.648 141.811 25.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.9 2011/03/11 07:13:47 36.051 142.347 28.5 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.8 2011/03/11 07:10:59 37.899 142.734 30.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 06:57:14 35.758 140.992 30.2 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.3 2011/03/11 06:48:47 37.993 142.764 22.3 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 7.1 2011/03/11 06:25:50 38.106 144.553 19.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.8 2011/03/11 06:15:40 36.186 141.192 35.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.4 2011/03/11 06:07:21 36.401 141.862 35.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.4 2011/03/11 06:06:11 39.025 142.316 25.1 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 8.9 2011/03/11 05:46:23 38.322 142.369 24.4 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/10 22:44:25 38.844 143.006 34.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.7 2011/03/10 21:49:46 38.590 143.086 26.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/10 16:54:45 38.053 143.253 4.7 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/10 11:21:08 38.611 143.049 17.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/10 09:02:21 38.652 143.146 21.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/10 08:59:19 38.547 143.295 19.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/10 08:08:20 38.630 143.304 17.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/10 07:33:04 38.954 142.458 20.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.6 2011/03/10 04:14:00 38.406 143.427 31.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/10 01:20:23 38.408 143.033 25.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/09 23:57:41 38.308 143.275 20.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.4 2011/03/09 23:37:00 38.438 143.185 32.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/09 21:22:18 38.385 142.642 23.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/09 21:00:57 38.267 142.580 22.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 6.0 2011/03/09 18:44:35 38.502 143.199 23.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 6.1 2011/03/09 18:16:14 38.378 142.506 22.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/09 14:24:05 38.589 143.226 10.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.7 2011/03/09 12:03:17 38.358 143.119 13.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/09 11:27:51 38.529 143.040 28.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.7 2011/03/09 10:13:39 38.721 143.090 27.2 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/09 08:55:38 38.667 143.055 15.6 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/09 08:02:36 38.606 143.103 15.4 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/09 07:56:27 38.849 142.929 10.7 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/09 07:13:48 38.246 143.108 9.9 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.1 2011/03/09 06:25:12 38.299 143.067 10.8 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.9 2011/03/09 06:12:13 38.681 143.022 10.0 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.3 2011/03/09 04:45:54 38.543 142.740 27.0 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.7 2011/03/09 04:37:03 38.666 142.991 25.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/09 04:32:10 38.727 143.001 32.1 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/03/09 04:15:39 38.857 142.658 12.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/09 04:05:53 38.870 142.420 10.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.0 2011/03/09 03:19:00 38.795 142.962 19.9 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 5.2 2011/03/09 03:08:35 38.339 143.097 24.4 OFF THE EAST COAST OF HONSHU, JAPAN
MAP 5.6 2011/03/09 02:57:16 38.402 142.825 17.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 7.2 2011/03/09 02:45:20 38.424 142.836 32.0 NEAR THE EAST COAST OF HONSHU, JAPAN