In Japan, fears mount of a massive 2011-style earthquake on disaster anniversary

As Japan marks the anniversary of the earthquake and tsunami that devastated large areas of the country’s northeast in 2011, experts have warned that the seismic conditions in an underwater trench off Hokkaido hint at another powerful tremor.

A five-year study of the Chishima Trench, which runs parallel to the east coast of Hokkaido about 150km (93 miles) offshore, has determined that the two plates are not slipping past each other. Instead, sections of the plates appear to be joined together but that when they do inevitably break free, a huge amount of seismic energy will be unleashed.

Experts at the Japan Agency for Marine-Earth Science and Technology have been studying the trench with scientists from Tohoku University and Hokkaido University and believe the plates may have been fused together since the last major earthquake in the region in the 17th century.

A separate report released by the government has stated that the likelihood of a quake with a magnitude of at least 8.8 in the trench within the next 30 years stands at between 7 per cent and 40 per cent.

That might sound like an inexact likelihood and timescale, said Fumiaki Tomita, assistant professor at Tohoku University’s research centre for the prediction of earthquakes and volcanic eruptions, but he pointed out that predicting seismic activity was notoriously difficult.