There's a remarkably active underwater volcano in the Indian Ocean, close to the French overseas department of Mayotte, part of the Comoros island group.

A team of researchers from the Global Physics Institute here in Paris has just completed a mission to the site, mainly with a view to finding the cause of the earthquakes recorded last year on the Indian Ocean island.

As Dhananjay Khadilkar reports, the expedition turned up a few surprises.