Tsunamis are a significant risk to rail operations. That’s the surprising conclusion of a recently released rail risk research report. http://www.nzta.govt.nz/resources/research/reports/632
The team concluded that a tsunami striking the Wellington to Petone transport corridor is one of the top rail risks in New Zealand.
The Navigatus research team, led by Navigatus director, Kevin Oldham, reached this conclusion after in-depth research. The team evaluated many of the types of safety events that can and do occur in the New Zealand rail industry.
It was initially a surprise to the research team that tsunami ranked near the top of the list. However the commuter line is busy at times, especially during morning and evening peaks. A tsunami could be caused by a large local earthquake such as a “megathrust” event from the Hikurangi fault. http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11948290
The Kaikoura earthquake, at just 7.8 magnitude shows what can happen. That event created a tsunami that was 7m high at Oaro, 22 km south of Kaikoura. https://www.stuff.co.nz/national/90773348/kaikoura-earthquake-tsunami-was-as-high-as-7-metres-at-one-spot
It is a little known fact that the world’s greatest railway disaster was the Boxing Day tsunami of 2004. http://www.dailymail.co.uk/wires/afp/article-2887339/Sri-Lanka-train-guard-mourns-tsunami-dead-10-years-on.html
That experience has led to improvements in warning systems, such as the Pacific Tsunami Warning Centre. http://ptwc.weather.gov/
The Ministry of Civil Defence and Emergency Management is taking the threat seriously. The Ministry recently tested a warning system that can warn the public directly through cell phones. https://www.stuff.co.nz/national/99271529/most-mobile-phones-didnt-receive-the-civil-defence-alert-test
It’s the so called “near field” tsunamis that are the concern for the Petone rail corridor. An earthquake could knock out power supply to electric trains, leaving them stranded alongside the sea. Once the power supply is knocked out by the shaking, the tsunami wave could be just minutes away.
This issue raises questions of risk tolerance, societal risk acceptance and responsibility. Other countries such as Japan and Mexico have installed early warning systems. These systems broadcast radio warnings ahead of the earthquake waves as they move through the earth. https://www.stuff.co.nz/national/nz-earthquake/99309556/how-other-countries-warn-people-a-disaster-is-on-its-way
The Japanese system can give warnings from just seconds to 1-2 minutes ahead. That brief period could be critical, if the receiver knows what to do. Often such systems are automated.http://content.time.com/time/world/article/0,8599,2059780,00.html
Such a system would bring a train safely to a halt, or potentially could allow the train to coast to a safe refuge. Such safe refuges might also provide for walkers, cyclists and others on the transport corridor.
Developing a comprehensive national early warning system would be an expensive undertaking. So would providing safe refuge or other solutions on this busy transport corridor. These are not just rail issues, but are societal matters that would benefit New Zealanders more widely.