HONG KONG – Major tsunami struck China’s southern coast in 1076 causing “drastic cultural decline,” Chinese researchers say in a study with implications for a densely populated region that now boasts multiple coastal nuclear power plants.

There is a growing body of scientific evidence suggesting that an earthquake in the Manila Trench sent a wall of water coursing into what is now China’s Guangdong province around 1,000 years ago.

Now scientists believe they have narrowed down the date to an exact year — 1076 — and say the new data should set alarm bells ringing over whether enough is being done to defend against future tsunami.

“This study confirms the risk of tsunamis in…