[jp] JR-Maglev and major earthquakes

[Miss Maglev]

The Linear train is running on an active fault line, there's a major earthquake, it's the middle of winter in the Southern Alps, what will happen to the passengers? JR Tokai stresses safety.

Source: Translated info form Diamond editorial office, Mrs. Eiko Hamane: Reporter https://diamond.jp/articles/-/336548 Accessed 2023-12-26


The "Heated Discussion! In #3 and #4 of the "What will happen to the Linear Shinkansen?" feature, Akira Ikegami explained that the Southern Alps are mountains with intense mountain-building activity, and that two major active faults, the Median Tectonic Line and the Itoigawa-Shizuoka Tectonic Line, run directly beneath them, and that there are many active volcanoes and the Fossa Magna, where earthquakes and landslides can easily occur, runs through the area. Concerns were raised about the risk of earthquakes, as well as the evacuation routes in the event of a train stopping in the tunnel, and the impact of fault displacement on the tunnel.


We asked JR Tokai for their views on safety.
In the Southern Alps in mid-winter
If a major earthquake occurs while the tunnel is in operation

--If the Linear Central Shinkansen were to make an emergency stop in a tunnel due to an earthquake or fire, would there be any way for passengers to escape? If the Linear Shinkansen stops directly under the Southern Alps in mid-winter, will passengers have to escape through the mountains while preparing to freeze to death as the emergency exit is at an altitude of 1,300-1,500 metres?

　In general, even in winter, the annual temperature change in the tunnel is less than that outside, so it is safer for passengers to stay in the tunnel than to go outside, but in an emergency we will promptly instruct them to evacuate the area.

　In the South Alps Tunnel, an advanced shaft, which has been excavated parallel to the mainline tunnel to test the geology, will be used as an emergency evacuation route. This advanced shaft will be used for maintenance once the tunnel is operational, allowing maintenance and other vehicles to pass through.

　As a result, passengers can safely evacuate to the surface by vehicle or on foot, depending on the situation, via the nearest station at Hayakawa-cho, Yamanashi Prefecture, or Oshika-mura, Nagano Prefecture, or via a nearby emergency exit. The route to the emergency exits is similar to that of other Shinkansen trains travelling through mountainous areas, using existing roads or roads built during construction to ensure safe evacuation even in winter.

- Japan is an earthquake-prone country and the Linear Shinkansen will cross active faults such as the Fossa Magna, a huge rift valley prone to earthquakes and landslides, and the Itoigawa-Shizuoka Tectonic Line. What are the safety measures?

　To protect the Linear Central Shinkansen from earthquakes, the main stations in Tokyo, Nagoya and Osaka and much of the line will be built in tunnels or underground. In general, underground spaces are less subject to seismic shaking, a characteristic that makes them more resistant to disasters. As far as the civil engineering structures are concerned, they are designed to be sufficiently earthquake resistant according to the latest national standards. In past major earthquakes, such as the Great East Japan Earthquake and the Kumamoto Earthquake, Shinkansen structures built and reinforced according to these and other standards did not suffer significant damage.

　In addition, the superconducting linear vehicles run contactlessly, floating about 10 cm in the U-shaped guideway. The magnetic force of the levitating guide coils keeps the vehicle in the centre of the guideway and prevents it from derailing in the event of an earthquake.
Fig_Structure of the Linear Central ShinkansenThe vehicle is held at the centre of the guideway by the action of powerful magnetic springs Source: Tokai Railway "Key Points for Responding to Abnormalities" Enlarge this image

　In addition, the "Terrace" earthquake early warning system used on the Tokaido Shinkansen will also be introduced on the Linear Central Shinkansen. This system will enable trains to slow down or stop early in the event of an earthquake, thereby increasing safety. The system will also use data from the JMA's Tonankai submarine earthquake observation network and is expected to be able to detect earthquakes occurring in the presumed epicentre area of the sea in question up to 10 seconds earlier than conventional systems.

[...]

In addition to seismometers along the coast (50 sites), remote seismometers (21 sites) and seismometers for earthquake early warning (about 1,000 sites), the submarine earthquake observation network will also be used. Data from JMA's Tonankai submarine earthquake observation network will also be used.

[...]

-In the past, the Tanna Tunnel was hit by the North Izu earthquake (1930) during excavation, and the tunnel's front wall shifted by 2 metres. Can the tunnel be made safe even if the fault is significantly shifted by an earthquake at a speed of 500 km/h?

　Regarding the point where the tunnel crosses the fault, topographical and geological surveys have been carried out at the point where the tunnel crosses the fault by JNR since 1974 (Showa 49) and by the Company and the Railway Construction Corporation since 1990 (Heisei 2). Over a long period of time, we have carried out extensive and detailed borehole and other surveys to fully understand the status of active faults in the areas concerned.

　Japan's trunk transport networks (major transport networks), such as the Shinkansen and motorways, cover large areas and long distances, making it practically difficult to avoid all active faults. Therefore, in selecting the route of the Chuo Shinkansen, based on the results of previous surveys, it is important to (1) avoid active faults as much as possible, (2) if a fault is crossed, keep the distance as short as possible, and (3) after detailed surveys of the shape of the active fault, provide appropriate reinforcement according to its characteristics. --The design plans are carefully formulated from these points of view.

[...]

--Governor Kawakatsu told the Shizuoka Prefectural Assembly (12 December) that his solution to the "linear problem" was "to open the line from the parts that are ready to be opened, based on the current route, which I believe will be an operational result and a solution". He said. In other words, he clearly stated that partial opening was the solution. What is the view of JR Tokai, the party concerned, on the governor's proposal for partial opening?

　As for partial opening, as we have said before, we have no intention of implementing it. This is because even if we were to open a limited section of the line, from Kanagawa to Yamanashi, we would need a lot of equipment. Everything has to be in place, including a depot to store the rolling stock and a control centre to manage train operations. There are also a number of considerations that need to be taken into account, such as trial runs before the trains are actually put into service and the establishment of a system for operating the trains, which is not considered realistic.

　In addition, the Linear Shinkansen was planned in response to the ageing of the existing Tokaido Shinkansen and to cope with major disasters such as an earthquake in the Nankai Trough. The plan aims to maintain transportation functions in the event of a disaster by doubling major transportation routes. For this reason, partial opening of the line is not considered, as this goal cannot be achieved by opening only the section from Kanagawa Station to Yamanashi Station.

　Many residents along the Shinkansen line have expressed their expectation that the Shinkansen will be opened as soon as possible. In order to meet these expectations, we believe it is essential to start construction of the section through Shizuoka Prefecture. We are doing our utmost to ensure that this important construction work can begin. Under these circumstances, we have decided that a partial opening is not a realistic option.


Source: Translated info form Diamond editorial office, Mrs. Eiko Hamane: Reporter https://diamond.jp/articles/-/336548 Accessed 2023-12-26