Below is a link to an interactive map of the Japanese Earthquake and it's Aftershock Sequence.
There are a number of interactive tools enabling a close examination of what took place . . . ie; you can speed up the sequence and select various periods of activity. You can also pause the sequence and hover the pointer over specific Quakes to determine depth, magnitude etc.
The map will open beginning with day one . . . the main Earthquake occurs around 14:40 JST on the clock at the top.
It's a very interesting and informative site for those with an interest in Seismology. but also very informative for all, as to what the Japanese people have had to endure in recent times. All of the aftershocks from mid-4's upwards will have been felt on the East Coast at least.
Speaking from experience . . . aftershock sequences such as this are extremely frightening and have a cumulative effect over time.
Anyone from Japan who has been experiencing this . . . our hearts are with you, you haven't been forgotten . . . we would love for you to comment. Others may wish to contribute also.