An explosion shook a quake-damaged Japanese nuclear power plant today. Japan’s nuclear safety agency said the blast, at the number 3 reactor at the Fukushima No 1 plant, is believed to be caused by hydrogen. Also an offshore quake of 5.8-magnitude struck 140 kilometres northeast of Tokyo on Monday morning, shaking tall buildings in Japan’s capital, but authorities did not issue a tsunami alert. There are no immediate reports of damage or casualties.

Alarm bells also rang in southwestern Japan yesterday where the 1,421-metre Shinmoedake volcano erupted, shooting ash and rocks up into the sky.

In a televised statement, Prime Minister Naoto Kan said Japan is experiencing its biggest crisis since World War II. Kyodo news agency quoted the Miyagi police as saying the toll is likely to cross 10,000.

Japanese authorities scrambled to control overheating reactors and fresh radiation threats at the quake-hit Fukushima nuke reactor as the risk of a second explosion grew. Fukushima shut down three reactors after the tsunami.

With the cooling systems at the Fukushima plants not functioning, frantic efforts are underway to stop fuel rods from overheating. If not controlled, it can lead to an explosion, resulting in radioactive material being released into the atmosphere.

BBC in the meantime reported that Japan’s nuclear agency declared a state of emergency at another nuclear facility at Onagawa after excessive nuclear radiations were reported there.

Thousands of military personnel and civilians joined hands in a massive search and rescue operation. Over 1.80 lakh people have been evacuated from a 20 kms radius from the nuke plant joining over 3.5 lakhs who have already moved out.

More than 215,000 people are said to be living in 1,350 temporary shelters in five prefectures in quake-hit areas. One report said four trains had disappeared following the quake and still have not been located. An official sources told PTI that 30 Indians in Tanida, centre of Tsunami area, found safe in the rehabilitation camp being shifted to hotel.