Japan has experienced a large number of aftershocks since the initial 9.0 earthquake in March. The USGS has recorded 726 aftershocks so far and according to a recent report affected areas are very much in need of aid as 15,077 people have been reported missing and around 500,000 people have been displaced. There are also large amounts of debris from damage caused by the earthquake and tsunami. This tragic scenario, combined with the risks posed by leaked radiation from the damaged nuclear reactors, makes this one of the worst disasters Japan has ever faced in history.
This Google Earth Map from USGS gives some idea of the large range of aftershocks that have taken place in the region:
USAID provides a map of the most affected in Japan including parts of the country where flooding damage has occurred:
There are a number of other resources online that give real-time data on the disaster including the ‘Earthquake Viewer’ from Texas Tech University: http://mapserver.gis.ttu.edu/japanquake/ and Relief Web provides updates on aid efforts and donations as they come in.