The Nikkei 225 hit its post-earthquake low on March 15, down 17.53% from the close on March 10, the day before the quake occurred. The index closed the past week just below the interim post-quake high, down about 6.96% from March 10.
The first chart below shows the Nikkei 225 daily closes since 2007 with both the Financial Crisis of 2008 and the March 11 earthquake highlighted.
[Click all to enlarge]
The next chart shows the market behavior following the 1995 earthquake. The Nikkei fell 24.7% over about five-and-a-half months. It then rallied 52.2% over the next 10 months.
At this point, the ultimate economic and market impacts of the March 11 earthquake are simply unknown. For example, a piece published on April 2 in The New York Times gives some inking of how little we really know about the nuclear crisis at the Fukushima Daiichi power plant.