More volcanic blasts likely

Japan disaster:

Japan which was devastated by an earthquake measuring 8.9 on the richter scale and tsunami leaving thousands dead, followed by possible meltdown of nuclear power reactors, is in danger of experiencing more volcanic eruptions, said experts at the Centre of Earth Sciences (CES), Indian Institute of Science (IISC).

As if confirming their prediction, two earthquakes of 6.1 on Richter scale hit the northeast of Honshu, Japan at 3.30 p.m. and at 7.20 pm on Tuesday. The region has been rocked by 42 earthquakes over the first 15 days of the current month including the disastrous quake on March 11.

Different clusters of volcanoes form the Japan Trench, the country’s eastern coastline, as it is close to subduction zone. Subduction is a geological process in which one edge of crustal plate is forced sideways and downward into the mantle below another plate. A subductive earthquake is caused when a tectonic plate pushes the denser one beneath after intense grinding and friction, causing a volcanic eruption, says Dr Kusala Rajendran of CES.

After every devastating earthquake, like the one that hit Japan on Friday, volcanic eruptions can be expected, she said. Subductive earthquakes trigger volcanoes to become active, as the shift in land mass disturbs the whole chamber.

“In the Japan earthquake, heat and mass got mixed with water and the resulting stress created underneath the land led to volcanic eruptions. There were volcanic eruptions after the Chile earthquake as well,” Dr Kusala said.

Tsunami prediction

At present, Dr Kusala Rajendran is working on a project to find out the occurrence of the last tsunami and its periodicity. As predicting an earthquake is difficult, most of the scientists have diverted their efforts on predicting tsunami, she said.

"The Indian National Centre for Ocean Information Services, Hyderabad, is the centre that sends out tsunami warning. It sends out warning when an earthquake is felt in Sumatra or Indonesia, as it impacts India. However, all earthquakes would not cause tsunami," she added.