The government's updated earthquake probability map — showing the area-by-area likelihood of a quake registering lower 6 or above on the Japanese seismic scale of 7 taking place within 30 years — points to the high probability of powerful temblors striking across wide areas of the Pacific coast, including eastern Hokkaido, where the quake risk was significantly raised from the last annual update. The government warns people and local authorities to be prepared for a powerful quake to hit anytime, anywhere in this seismically active country — a risk highlighted by the earthquake that rocked northern Osaka Prefecture on June 18. Naoshi Hirata, head of the government panel that compiled the map, states there is "no place with zero probability" of an earthquake with an intensity of lower 6 or more.

The Osaka earthquake also showed that while we may not be able to predict when or where a quake will hit, we can at least take steps to contain the damage caused by them by addressing foreseeable risks beforehand, particularly when it comes to big cities. That should be one of the lessons we learn from the June 18 earthquake that left five people dead, hundreds injured and more than 10,000 houses damaged in Osaka and neighboring prefectures.

The magnitude 6.1 quake that hit during the morning rush hour, registering an intensity of lower 6 in the northern parts of Osaka Prefecture, was indeed a medium-scale temblor, but one that still caused extensive damage to critical urban lifelines and infrastructure — most of which were quickly restored. The disruptions to train services and expressway networks, as well as the water, gas and electricity supply, once again exposed the vulnerability of densely populated big cities to powerful quakes.