Less than one year after a devastating earthquake-tsunami struck Japan and precipitated the worst nuclear emergency in more than twenty years, scientists are predicting that another huge quake could hit the teeming metropolis of Tokyo within a few years.

A group of researchers at the Earthquake Research Institute of University of Tokyo warned that there is a 75 percent likelihood of at least a magnitude-7 quake striking the capital within the next four years.

The Japanese government earlier released a more conservative guess as to when the next large quake would strike the country – they have the odds at 70 percent over the next 30 years.

The chance that a magnitude-7 earthquake will happen (in the area) has increased since the March quake, said Shinichi Sakai, an associate professor at the institute in a statement.

According to reports, the last big earthquake to hit Tokyo was in 1923 when a 7.9-magnitude monster killed more than 100,000 people, perhaps as many 140,000, many of whom died in fires.

The tremor that smashed into Japan last March measured at 9.0-magnitude, striking the northeastern coast and killing at least 16,000 people, with many thousands more still missing. It also crippled the Fukushima nuclear power plant and forced a massive evacuation of people from the vicinity.

Indeed, the Tokyo researchers cited that the March 2011 has created unusually high number of after-effects in the capital – five times the usual number of tremors have struck metropolitan Tokyo region since last year’s devastation. The spike in tremors suggests more intense seismic activity in the Tokyo area, thereby greatly increasing the chance for a major earthquake – sooner than later.

The researchers warned that the government needs to prepare for such a catastrophe – the greater Tokyo area is home to more than 13-million people, one of the most populous urban environments in the world.

According to Reuters, a survey by the Japanese government estimated that a 7.3-magnitude quake centered in the northern part of Tokyo Bay would kill about 11,000 people and cause the destruction of about 850,000 buildings.

In 1995, a 7.3-magnitude quake struck Kobe in central Japan, claiming more than 6400 lives and causing about $100-billion in damage.