Upper-5 Tokyo quake an opportunity to rethink preparation for ‘Big One’

The strong temblor that struck the greater Tokyo area late Thursday night was a jolting reminder that earthquakes can occur anywhere at any time. Serious consideration must be given to how to prepare for a possible earthquake originated directly below the Tokyo metropolitan area.

The Thursday quake registered upper 5 on the Japanese seismic intensity scale of 7 in parts of Tokyo and Saitama Prefecture. It was the first time since the Great East Japan Earthquake that tremors of this intensity were recorded within the 23 wards of Tokyo, and many people must have been reminded of that time.

The area above the earthquake’s focus in the northwestern part of Chiba Prefecture, where the Earth’s surface plates push against each other, is the site of frequent tectonic activity. A similar scale quake may occur in the next few days, so vigilance must be maintained.

In Adachi Ward, Tokyo, a train in the Nippori-Toneri Liner transit system derailed and three passengers were injured. If things had gone further, it could have led to a catastrophe. The transit system must be restored speedily.

Major JR lines suspended operations, and local governments opened emergency facilities to accommodate those who could not return home. Timetables were disrupted until the following morning, and trains and stations were crowded during commuting hours. It can be said that the fragility of urban areas in the face of earthquakes was exposed.

It is essential for railway companies to examine their earthquake preparedness and whether their response was appropriate. They must regularly make plans for earthquakes and practice drills so that they can reduce confusion as much as possible in the case of an emergency.

On this occasion, there were also a number of power outages and broken water pipes. To avoid interruptions to the functioning of urban infrastructure, it is important to constantly make efforts to inspect and repair.

Telecommuting has become popular as a way to prevent coronavirus infections. Companies should try to switch to telecommuting flexibly and avoid commuting disruptions.

It is forecast that there is a 70% probability of a magnitude-7-class earthquake directly below the greater Tokyo area within the next 30 years, which is much larger than the magnitude-5.9 earthquake that struck this time. If a massive earthquake were to actually occur, chaos would be inevitable.

It is predicted that up to 8 million people will have difficulty returning home and 23,000 people will die in the case of such a massive earthquake. In order to reduce the damage as much as possible, each person needs to start checking for furniture that might fall over indoors and think about what to do if he or she becomes unable to return home from work or school.

Japan is also at risk of an earthquake in the Nankai Trough, which could cause strong tremors and tsunamis over a wide area on the Pacific Ocean side. Major cities such as Osaka and Nagoya are concentrated in this area. It is important to share a sense of crisis.

The central and local governments must take lessons from Thursday’s earthquake and identify issues to be addressed to see if the current plans and stockpiles of goods can deal with a future “Big One.”

— The original Japanese article appeared in The Yomiuri Shimbun on Oct. 9, 2021.