More than two months after southern Japan was struck by two major earthquakes in a matter of days, hundreds of people are being diagnosed with “earthquake sickness”.
Also known as post-earthquake dizziness syndrome, the complaint is linked to a loss of balance and can cause a sufferer to feel that they are experiencing an earthquake.
As well as dizziness and disrupted equilibrium, the ailment can trigger bouts of nausea and panic that another earthquake is under way. Some say it is similar to an unpleasant bout of motion sickness, while some doctors suggest it is a manifestation of earthquake phobia.
Also known as “jishin-yoi”, which means “earthquake drunk”, more than 200 people in Kyushu have been diagnosed with the complaint since a magnitude 6.2 tremor struck on April 14.
Less than 48 hours later, a second quake, with a magnitude of 7.3, rocked central areas of the most southerly of Japan’s main islands.
Fifty people were killed in the two tremors, with thousands treated for injuries, many serious and most caused when buildings collapsed.
The tremors were the most violent since the 9.1 quake struck off north-east Japan in March 2011, causing a tsunami that killed more than 19,000 people.
Experts told the Asahi newspaper that survivors of the March 2011 disaster also reported suffering from “earthquake sickness”, but that it is proving to be longer-lasting in Kyushu because of the hundreds of aftershocks that continue to plague the region.
More than 1,600 aftershocks with a magnitude of at least 1 on the seven-stage Japanese scale have been reported since the initial earthquakes.
Physiological stress and anxiety are also believed to be contributing factors behind the complaint, with up to 50 per cent of the 214 people complaining of symptoms also reporting feeling depressed.
Women accounted for 80 per cent of the people diagnosed with “earthquake sickness”.
The experts say the condition tends to abate as the aftershocks tail off, although seismic activity in Kyushu shows no sign of halting.