Biggest volcanic eruption in 100 years went unnoticed 

The biggest underwater eruption of the last century took place 600 miles (1,000km) off the coast of New Zealand, scientists have found.The discovery was made after an airline passenger saw a strange substance spreading across the Pacific Ocean in 2012.At the time, scientists identified the material as pumice, a volcanic substance which floats.However, it has taken six years for researchers to understand the scale of the eruption with the help of remotely-operated deep search robots.The findin...