We know the scale of death and destruction that can be wrought by a tsunami generated by a massive earthquake under the ocean floor. The Boxing Day, 2004, Asian tsunami that devastated several countries following a 9.2 magnitude undersea quake taught us that. But such are the primeval forces unleashed that nothing can steel us against the sheer scale of human helplessness, tragedy and suffering that is inevitable when land stands in the way of a speeding, towering wall of water.
No one who, from the security of their homes and offices all over the world, saw the replays of live aerial footage of the horror in Japan on Friday afternoon will ever forget them. Our hearts and sympathies go out to the people in the northeast of the country who are just beginning to count the cost of the catastrophe that overwhelmed them so swiftly, and with so little warning. Any material or moral support that this city can give must follow quickly, in the spirit of the immediate offer of practical help from China and many other countries, and the international rescue and aid effort following the Christchurch quake disaster in New Zealand. There is no word yet of any need to be concerned about the welfare of Hong Kong tourists or businesspeople, but we must remain prepared for the worst.
Were the casualties and damage confined to the effects of the earthquake alone, or for that matter a tsunami of manageable proportions, there are few if any nations as well prepared as Japan to protect lives and property, and for rescue and reconstruction. So much are quakes part of everyday life that it will soon be 100 years since Japanese schoolchildren were first formally taught what to do when one strikes. Regular earthquake drills are the rule for schools, industry and offices.
That it was all to little avail in the face of the combined fury of the sea and the earth after Japan's biggest recorded earthquake is testament to the threat of tsunami, and a reminder of the need for sophisticated international warning systems and public education - promised, yet still a work in progress, for nations at risk after the Indian Ocean tsunami.
It is fortunate, if that is the right word, that the clash of tectonic plates on the so-called ring of fire that delineates earthquake risk in the region did not occur closer to Tokyo, one of the world's biggest cities. As it is, the capital and a large surrounding area were severely shaken by a 7.9 magnitude shock - a big one even by Japan's standards - that damaged buildings and triggered a public transport shutdown, leaving hundreds of thousands of workers stranded.
Amid efforts to rescue and get medical help to survivors in the wreckage and rubble, the authorities have fought fires and floods from cities to villages. They were quick to shut down nuclear power reactors and huge oil refineries that might have been affected - although one refinery caught fire - and commendably transparent about the risk of a radioactive leak from one plant and the need for immediate evacuation to ensure public safety.
Life must go on, as evidenced by the guarded speculation about the impact of the catastrophe on Japan's debt-laden and underperforming economy. But we would be foolish not to reflect for some time on the humbling power of nature, as we did after the 2008 Sichuan earthquake that left more than 80,000 dead. Our thoughts remain with the victims.