As people across Japan were preparing to take their annual mid-August "Bon" holidays, the government issued a surprise alert. Officials said a magnitude-7.1 earthquake off Miyazaki Prefecture had increased the chance of a devastating mega-quake striking in the Nankai Trough, off the country's southwestern coast. The mega-quake advisory stayed in place for one week, but during that time many people in affected areas were no clearer about exactly what it meant or how they should respond. The confusion meant that some municipalities closed off tourist areas, causing huge financial losses for local businesses, while others pressed ahead with summer festivities as usual. NHK asked an expert to explain Japan's mega-quake information system and offer some tips on the best way to respond to a potential disaster.