It is a very sad day for the people of Japan. My heart goes out to all those who are suffering from the 8.9 earthquake and the tsunami that followed it.
Google has created a Person Finder tool to help the earthquake victims locate their friends and family.
Google did this for the New Zealand Christchurch earthquake.
Now, they have added this tool in English and Japanese so you can use it to find someone or share information about someone you know.
I have embedded this tool in this page right here.
You can also get to the Person Finder: 2011 Japan Earthquake here.