Kikuchi Kayo stepped into her house. Muddy water covered the floor. Dishes and food had scattered everywhere. Nothing looked the way it used to. All around the house, she saw mud, mud, and more mud.

But then Kayo heard a familiar noise. Her dog Towa scratched at the door. Her other dog, Melody, started to bark. Kayo thought the dogs had died in the tsunami. Her face got red with excitement.

“I don't know how they survived,” Kayo’s father told the Wall Street Journal. On March 11, 2011, a magnitude-9 earthquake hit Japan. Just a few days had passed since then. The quake was one of the most powerful in recorded history. Soon after, a giant tsunami struck Japan’s coast. Towa and Melody were tied up outside during the disasters. How did they get free? If dogs could talk, these two would probably have a great story to tell!

They aren’t the only ones. A man named Hiromitsu Shinkawa was swept away in a wave. He was at sea for two days. He floated 10 miles from the coast. A rescue ship found him. Mr. Shinkawa was clinging to the roof of his house! With his left hand, he waved a self-made red flag. A helicopter lifted him to the hospital.

But many stories of the tsunami do not have happy endings. The terrible quake lasted for six whole minutes. People received text messages to warn them just a minute before the quake began. Still, many people died. Others lost loved ones. Even now, about 230,000 people still need new homes.

Many scientists did not know the horrible quake was coming. Some officials ignored the warning signs. Now people in Japan and around the world are starting to think differently. How can they better prepare for disasters like this one?