03/14/2012 10:11 EDT | Updated 05/14/2012 05:12 EDT

New earthquake rattles Tokyo

A strong earthquake hit the Tokyo region, just hours after a magnitude-6.8 tremblor struck northern Japan, causing small tidal changes on the country's Pacific coastline but no damage or injury.

The new quake was centred in Chiba prefecture, east of Tokyo, on Wednesday, and gave the Japanese capital a strong jolt, the CBC's Craig Dale reported.

Seismologists have said Tokyo is long overdue for a strong quake. Some studies suggest there's a 70 per cent chance a big quake could hit under Tokyo Bay within the next four years, he said. The chance of such an event within the next 30 years rises to 98 per cent.

After the earlierquake in northern Japan on Wednesday, several towns issued evacuation orders or advisories to residents nearest the coast. A rise of about 20 centimetres was observed in the port of Hachinohe in Aomori, northern Japan, about one hour after the quake struck the region. Smaller changes were also reported in several locations on Hokkaido island and Aomori prefecture.

The agency lifted all tsunami advisories about an hour and a half later.

The Japan Meteorological Agency said the tremor was magnitude 6.8. A magnitude-5.9 aftershock followed about two hours later.

Sombre anniversary passes

The town of Otsuchi in Iwate prefecture, where more than 800 died in last year's tsunami, issued an evacuation order to all households along the coast as a precaution, said prefectural disaster management official Shinichi Motoyama. No damage or injury has been reported so far from the quake, he said.

Iwate was heavily damaged by last year's earthquake and tsunami. Thousands of aftershocks have shaken the region since then, nearly all of them of minor or moderate strength.

The magnitude-9.0 earthquake and tsunami on March 11, 2011, left some 19,000 people dead or missing.

Japan marked the first anniversary of the disasters on Sunday, as the country still struggles to rebuild.

Wednesday's tremor was centred about 235 kilometres south of Kushiro, Japan, on Hokkaido island. It was a relatively shallow 10 kilometres below the sea surface.

The quake was not felt in Tokyo, and there was no threat of a Pacific-wide tsunami.