>> mine safety officials say it appears that methane gas caused the explosion just as in the disaster four years ago. >> breaking news, a violent earthquake off japan's northeast coast has rocked the nation and the region. >> a tsunami has flooded coastal areas of japan with warnings in hawaii and as far away as chile and peru. >> the mission to kill bin laden was carried out by navy seals in a city not far from pakistan. >> president obama broke the news late last night to the world. t.j. winick has the details. >> it is amazing the awesome responsibility that comes with sitting at this desk. we have fun, but we have the world to cover. triumphs, tragedies. a small taste of it. what a ride it's been. we will lighten the news and laughs on "world news now" when we come right back.