IWAKI: With a moment of silence, prayers and anti-nuclear protests, Japan on Thursday mourned about 20,000 victims of the massive earthquake and tsunami that struck Japan 10 years ago, destroying towns and triggering nuclear meltdowns in Fukushima.

Huge waves triggered by the 9.0-magnitude quake - one of the strongest on record - crashed into the northeastern coast, crippling the Fukushima Dai-ichi power plant and forcing more than 160,000 residents to flee as radiation spewed into the air.

The world's worst nuclear disaster since Chernobyl and the tremor have left survivors struggling to overcome the grief of losing families and towns to the waves in a few frightening hours on the afternoon of March 11, 2011.

About 50 kilometres (31 miles) south from the plant, in the gritty coastal city of Iwaki, which has since become a hub for labourers working on nuclear decommissioning, restaurant owner Atsushi Niizuma prayed to his mother killed by the waves.

"I want to tell my mother that my children, who were all close to her, are doing well. I came here to thank her that our family is living safely," said Niizuma, 47.

Before setting off for work, he quietly paid his respects at a stone monument at a seaside shrine with carvings of his mother's name, Mitsuko, and 65 others who died in the disaster.

On the day of the earthquake, Mitsuko was looking after his children. The children rushed into a car but Mitsuko was swept away by the waves as she returned to the house to grab her belongings. It took a month to recover her body, Niizuma said.

The Akiba shrine has become a symbol of resilience for the survivors, as it was barely damaged by the tsunami while houses nearby were swept away or burned down.

About two dozen residents gathered with Niizuma to decorate it with paper cranes, flowers and yellow handkerchiefs with messages of hope sent by students from across the country.

"It was sleeting 10 years ago, and it was cold. The coldness always brought me back to the memory of what happened on the day," said Hiroko Ishikawa, 62.

"But with my back soaking up the sun today, we are feeling more relaxed. It's as if the sun is telling us that 'It's okay, why don't you go talk with everyone who came back to visit their hometown?'"

REMEMBERING THE DEAD

Emperor Naruhito and Prime Minister Yoshihide Suga were slated to honour the dead at a commemorative anniversary ceremony in Tokyo while several other events were planned across northeastern Japan, which was most badly hit by the tremor.

The government has spent about $300 billion (32.1 trillion yen) to rebuild the region, but areas around the Fukushima plant remain off-limits, worries about radiation levels linger and many who left have settled elsewhere. Decommissioning of the crippled plant will take decades and billions of dollars.

Some 40,000 people are still displaced by the disaster.

Japan is again debating the role of nuclear power in its energy mix as the resource-poor country aims to achieve net carbon neutrality by 2050 to fight global warming. But an NHK public TV survey showed 85% of the public worries about nuclear accidents.

The mass demonstrations against nuclear power seen in the wake of 3/11 have faded, but distrust lingers. Some antinuclear activists are planning demonstrations in front of the operator of the plant, Tokyo Electric Power, for Thursday night.

Only nine of Japan's 33 remaining commercial reactors have been approved for restarts under post-Fukushima safety standards and only four are operating, compared with 54 before the disaster.

Nuclear power supplied just 6% of Japan's energy needs in the first half of 2020 compared with 23.1% for renewable sources - far behind Germany's 46.3% - and nearly 70% for fossil fuels.