So far today, 21 December 2013, we've had two earthquakes we could feel in Tokyo, four in total in Japan at the time of writing (13:45 JST). The first was at 01:20 JST, detail courtesy of the Japan Meteorological Agency (JMA).
Sounds big, but by the time it works its way through 70km of the Earth's crust and makes its way to here (Tokyo) it was magnitude 2.
The second quake we felt at 10:37 JST, detail in the following image.
On the surface in Tokyo this felt like a magnitude 1.
The Japan Times article estimates up to 23,000 people would perish should a magnitude 7.0 quake strike directly beneath the 23 wards which comprise Tokyo; with a 70% chance such a quake would occur in the next 30 years. Sounds bad right, but if you consider the population of Tokyo is 13.23 million as at 1 April 2013, the number is actually quite small. I think this is potentially the strength of Japan's building standards and emergency response capability, who have been "ready" for this big quake for some time.
Out of interest, below is an animation of all of the earthquakes in Japan recorded by JMA since 10 December 2013 until the time of writing this post. The images are available from the weather/earthquakes section of the JMA site.