Abundant evidence indicates that such a new volcano exists at L'ihi, a seamount (or submarine peak) located about 20 miles off the south coast.
In 2011, a 9.0-magnitude earthquake -- one of the worst ever to hit Japan -- killed more than 20,000 people and caused tsunamis of up to 12 meters (40 feet) which swamped the Fukushima Daiichi nuclear power plant, triggering a nuclear meltdown. Fukushima resident: We live in fear.
How does the earthquake compare with others? This was the sixth largest earthquake in the world since 1900, when seismological records began. The most devastating earthquake to strike Japan was in 1923, when a magnitude 7.9 tremor devastated Tokyo and Yokohama and killed an estimated 142,800 people. The Kobe earthquake in 1995 was a magnitude 6.9 and caused more than 5,000 deaths and injured 36,000 others. The earthquake that wrecked Christchurch in New Zealand last month was a magnitude 6.3 event. Around 30 times more energy is released as the magnitude of an earthquake increases one unit, for example from magnitude 8 to 9. Why is the area so prone to earthquakes? The Pacific plate moves fast in tectonic terms, at a rate of 9cm (3.5 inches) a year.