Last week, the media was filled with reports on Tokyo’s latest projections regarding what residents could expect if a major earthquake struck the capital. The parameters used for the simulation were a 7.3M quake that occurred directly beneath the prefecture’s 23 wards, with a shindo reading of 6+ for the city center, and shindo 7 for riverbank and coastal areas. It would occur in the wintertime with wind speeds of 8m/second. For the most part, the news was relatively good in that the number of deaths (6,200) and amount of damage (194,000 structures) estimated were less than in past projections—30 percent less, as a matter of fact. 

In detail, 50 percent of the deaths would be caused by collapsed houses, and 40 percent the result of fires. In both cases, the houses involved would be older wooden structures that are densely concentrated, so the prefectural government has said—not for the first time—that it will work harder on providing subsidies for the rebuilding of such houses to make them less vulnerable to earthquakes. 

An important factor in the lower casualty and damage numbers estimated by the report is improved quake-proofing since the last report was compiled. The portion of houses that have been quake-proofed since 2010 increased by 10.8 percent, which means 92 percent of all homes in Tokyo have some form of quake-proofing. In addition, the total area of densely packed wooden houses has decreased by 46 percent since 2012. The government now estimates that 4.53 million workers who live outside the capital would not be able to return home on the day of a major earthquake, and of the city’s residents 2.99 million would have to evacuate their homes. But while these numbers sound high, they are down by 12 percent from the last report. 

However, there is one sector where matters have not improved: high-rise residential apartment buildings. As we’ve written in this blog numerous times in the past, so-called “tower mansions” have unique problems when it comes to earthquakes that have nothing really to do with their ability to withstand the tremor itself. All multi-story buildings in Japan, whether for commercial or residential use, are constructed to the world’s strictest quake-proofing standards, and are expected to maintain their integrity even during a catastrophic temblor. The problems occur after the shaking, and none have been solved in the past decade while at the same time there has been a 30 percent increase in the number of high-rise residential apartment buildings and condos during that time. At present, there are some 600 “tower mansions” in Tokyo, which are defined as multi-residence buildings that are at least 45 meters tall. 

A May 25 article in the Asahi Shimbun explained the disaster preparedness measures implemented by a 38-story condo in Shinjuku that contains 426 units and about 900 residents as a means of showing how people who live in such buildings have to prepare doubly for a quake. According to the building’s disaster action manual, which was drafted last September, when an earthquake occurs, each resident should check potential fire sources in their rooms and if they find no problems then they post a pre-distributed sticker saying “safe” on their entrance door. Predesignated floor leaders then check the door of each unit and knock on those where none are posted to make sure there are no injuries. If an evacuation is deemed necessary, all residents on the floor meet at the entrance to the emergency stairwell. The disaster HQ also compiles a list of healthcare workers who live in the building just in case emergency medical care is needed and injured people have to be transfered. In the case of injured or elderly residents, special equipment must be prepared to carry them down the stairwell.

All the above preparations are well and good, but as the article points out, the main problem for a high-rise in such a disaster is the loss of electricity. According to the simulation carried out by Tokyo, on average about 12 percent of buildings in the city will lose power in a quake and it will take 4 days to get it back on. Like many high-rises in the city, the Shinjuku condo mentioned above has an emergency generator, but due to fire laws the building can only keep so much fuel in reserve and the maximum amount of time the generator can provide electricity is 7 hours. The most pressing problem in that regard is the elevators. As we’ve mentioned before in this space, elevators in buildings automatically shut down in the event of a strong quake and can only be turned back on by a qualified technician. Some buildings, we’ve heard, have enabled their maintenance staff to be certified for such operations, but if there is no one who can turn the elevators back on then they have to wait, which could be a long time. In any case, if the electricity is out indefinitely, the elevators don’t move.

In addition, loss of electricity means loss of toilet functions and running water, so anyone who is stranded on an upper floor should have a portable toilet and lots of drinking water in their disaster preparation kit, which should also include enough food for an extended stay, especially if going up and down multiple stairways is a problem. 

A recent segment on TBS News brought up another point. Many tower condos contain more than 1,000 residents, so evacuation may not be practical. Especially in Tokyo, space in evacuation centers—usually public schools—does not take into consideration high-rise dwellers. That means residents will likely have to stay in their units, whether they want to or not and regardless of which floor they live on. Of course, people living on the ground whose buildings have withstood a quake will also be inconvenienced by power outages and loss of running water, but they have the freedom to go outside and obtain supplies if available. High-rise residents, especially the elderly, do not, and so may require assistance in the form of emergency deliveries if they run out of necessities. 

In news that was reported separately but which has a bearing on disaster preparedness, a March 10 report in NHK outlined Tokyo’s progress in burying its utility cables underground. The report opened by saying that some 28,000 utility poles fell down in the Tokyo Metropolitan area after the monster 2011 earthquake in northern Japan. Such a situation causes serious problems for rescue operations, since emergency vehicles cannot pass through neighborhoods with downed power lines. At the time, the Tokyo Metropolitan Government said it would accelerate the process of putting cables on poles underground. Even beyond the problem of fallen cables in a disaster, many of Tokyo’s narrow streets are lined with poles that make it difficult for drivers and pedestrians to pass even under normal circumstances. This project became part of the platform of Yuriko Koike when she first ran for governor in 2016, but progress has been slow. 

As it stands, Tokyo has one of the worst records among world-class cities in terms of buried cables—at present, only 8.2 percent of utility cables are underground in the 23 wards, compared to 100 percent in London and Hong Kong and even 49 percent in Seoul. (Osaka is even worse—5.6 percent.) The main problem is road width. When placed utilities underground, cables are enclosed in concrete boxes that are at least 2 meters wide. Many public roads in Tokyo are only 4 meters wide, thus making the work difficult and time consuming. NHK described the work of burying cables in Arakawa Ward, where houses are densely packed. In order to do the work properly, the city had to buy extra land in order to make the roads wider, and in many areas it took more than 10 years. Then a study has to be carried out before construction began. Consequently, while 20 kilometers of road in the ward was designated for construction, after 6 years only 3 kilometers could be confirmed as ready for the construction, but in the meantime only 630 meters of work has been carried out. In addition, ¥350 million per kilometer was earmarked for the construction, but that estimate has since doubled. It’s obvious that it will take many decades to place the cables underground, so Tokyo residents will have to live with them for a while.