The 2020 Olympics has been announced for Tokyo, one of the most earthquake prone megacities on the planet. The 2011 Sendai quake has also upped the chances of a big quake in the Tokyo area.

Despite extensive disaster preparedness for earthquakes Tokyo still has many vulnerabilities, and the clean-up of the Fukushima disaster will still be ongoing as the games get underway.

Plenty of Olympics have been held in disaster prone cities: Beijing, Athens, Los Angeles, Montreal, Mexico City and Rome all have high earthquake hazards, but fortunately a major natural disaster has not been visited on an Olympic Games. The 1908 games were originally going to be held in Rome, but were moved to London after the 1906 eruption of Mt Vesuvius led to financial pressures on the Italian Government. The worst olympics disaster in history was the terrorist attack on the 1972 Summer Games in Munich, and with billion dollar security budgets terrorism has been foremost in the minds of games’ organisers in recent years.

Although risk management has become a new priority for the IOC, assessment of disaster and emergency preparedness, particularly for natural disasters appears to be brief.

With the influx of athletes, officials and visitors Japan will need to put in place special measures to ensure that they are as prepared as the rest of the population, upgrade emergency response units and ensure that construction for the games is specially hardened – and that’s just for starters. A disaster ready games will be expensive and for a nation already faced with the recovery bill of the 2011 quake and tsunami and the clean-up of Fukushima it will be difficult for it to face up to the challenge. But the costs of not being prepared can be far greater.