At 10:41 on the evening of Oct. 7, an earthquake estimated at a magnitude of 5.9 at its epicenter rattled the greater Kanto region. While damage was minimal, it was the strongest to hit Japan’s capital since the earthquake and aftershocks of the temblor that devastated the Tohoku region on March 11, 2011.
Kyodo News Agency reported that many late-night train passengers were stranded, with services on bullet trains and 16 local lines canceled or delayed. Normal service on some lines was not restored until 3 p.m. the next day.
On the JR Tokaido Line, several hundred passengers were forced to evacuate by escape ladder from a train after being stranded for more than two hours. East Japan Railway Co. alone estimated that around 368,000 passengers were affected.
A 42-year-old man told Aera (Oct. 25) that he gave up trying to hail a taxi after seeing long lines of people at Shinagawa Station. And with rooms at nearby hotels fully booked, he was left with no other means but to walk home to Ota Ward, arriving some time after 2 a.m.
To assist commuters who have become temporarily stranded in the city center in the aftermath of a natural disaster, the Tokyo government has prepared 232 temporary shelters around the capital. But because the Oct. 7 quake was below magnitude 6, only three facilities — in Adachi, Arakawa and Minato wards — opened their doors to take in people.
Shukan Taishu (Nov. 1) was among several magazines that asked whether the recent quake may be a harbinger of a shuto chokka jishin (earthquake directly beneath the capital) — the dreaded “big one” that has so far defied earlier predictions.
If Tokyo and its surrounding prefectures of Kanagawa, Chiba and Saitama are included, such an earthquake would affect an area accounting for roughly one-quarter of Japan’s entire population, and in the government’s worst-case projection would result in as many as 23,000 dead and missing, and economic losses of ¥47 trillion or more.
“The Japanese archipelago is presently in a period of seismic activity, which is the reason why earthquakes are occurring frequently,” explains Kyoto University professor Yasuhiro Umeda. “But the Oct. 7 quake is unlikely to trigger a quake beneath Tokyo.”
This, says Umeda, is because the capital region sits atop the North America plate, beneath which are the Philippine and Pacific plates — essentially a three-layered configuration. The Oct. 7 quake, which occurred 75 kilometers below the Earth’s surface, was a reverse fault-type quake centered near the boundary of the Philippine and Pacific plates.
“A ‘direct quake’ would be more likely to occur at a shallower depth, at an active fault on the North America plate,” Umeda says.
Kyoto University professor Hiroki Kamata, writing in Sunday Mainichi (Nov. 14), advised that three things should be attended to without hesitation at the very least. First, secure enough bottled water for three days per person (seven days would be even better). Second, install metal brackets or other devices in bedrooms and living rooms to prevent furniture or shelves from tipping over. Third, reinforce the house. These proactive measures will help protect from both building collapse and fire damage.
Perhaps the most sensible expert advice — and also the most impractical — came from professor Nobuo Fukuwa of Nagoya University. An authority on disaster management, Fukuwa told Aera (Oct. 25) that to mitigate damage from a major quake “it will be necessary for Tokyo to become smaller.” How small? Would you believe 2 million? That would be around one-fifth of its current population.
A nervous Friday (Nov. 19) showed a map, based on data from the Meteorological Agency, indicating the locations of 10 earthquakes of magnitude 4 or greater from the start of this year, up to a Nov. 1 temblor in northern Ibaraki Prefecture measuring 5.2.
Finally, I contacted British science journalist Peter Hadfield, a former geologist who in 1992 published a controversial work titled “Sixty Seconds That Will Change The World: The Coming Tokyo Earthquake.” Three decades on, I asked him if anything had happened to change the views presented in his book?
“If I were going to change anything, I think I would take out some of the potential earthquake dates, which I felt pressured to put into the book,” said Hadfield in an email. “I did warn at the time that they were nothing more than estimates based on past earthquake activity. But the danger of saying, ‘The most likely time for chokkagata (direct) earthquakes is around 2002 onwards’ is that when nothing happens, people think it’s a false alarm. It isn’t a false alarm, it just means the stress on fault lines continues to build.”
While conceding he would “need to do a lot of research to see what’s been newly discovered in the last 30 years,” Hadfield pointed out that certainly the basic geology hasn’t changed.
“Geologists are still expecting a major earthquake in the Suruga Bay area (on the coast of Shizuoka Prefecture),” he said. “The other area under watch is the potential of a swarm of chokkagata earthquakes below Tokyo itself. Again, nothing has changed — the plates beneath Tokyo continue to build up stress.
“One thing that I hope has changed is Tokyo’s preparedness,” he continued. “My book was heavily criticized by Japanese engineers because I warned about bad building practices, inadequate standards and regulation in earthquake-proofing buildings, complacency and tenuki (slipshod construction). But after the 1995 Kobe earthquake when exactly those malpractices were exposed, one of those critics — a professor at a major Tokyo university — apologized to me, and said he had felt humbled by what had happened.
“It would be nice to think that if I were writing the book today, I could report that lessons have been learned and things have improved. We’ll see.”
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