Lessons Learnt For Tsunami Early Warning Systems from Japan

This article was published in the Aberystwyth University News Letter Issue 5, 2011. For full illustrated article please click here and see p10 in the PDF.

 
 

The magnitude 9.0 Tohoku earthquake on March 11, 2011 is one of the most documented disasters in history with video footage, photographs, and TV documentaries providing rapid insights into the devastation following the quake. Like millions around the globe, I viewed this footage with horror and a sense of disbelief; the destruction and trauma witnessed are difficult to rationalise. Yet, the early warning system in place saved the lives of at least 50,000 to 100,000 people demonstrating that the devastation could have been far worse; as it currently stands the Japanese National Police Agency has confirmed 14,755 deaths.

The 2004 Sumatra-Andaman tsunami in the Indian Ocean was particularly devastating killing over 230,000 people across fourteen countries, partly because there was no early warning system in place and tsunami awareness was generally very low. Despite this absence a number of people who felt the earthquake in Indonesia and the Andaman Islands moved to high ground, in response to local or traditional knowledge passed down through many generations of those rooted in the area. For these people simple knowledge of tsunamis and understanding their warning signs of an earthquake and a receding ocean proved an effective early warning system by self-evacuating to high ground demonstrating the value of simple education and knowledge.

There appears to be a recurring trend following recent earthquakes greater than magnitude 8.8 that generate tsunamis that inundate coastal communities located near to the epicentre with less than 30 minutes warning. The residents of the Sanriku coast and Sendai in Japan only had 10-30 minutes of warning time before the leading main wave of the tsunami hit, and the earthquake lasted in the region of six minutes, leaving little time to recover and evacuate to higher ground. In 2004, the Indian Ocean tsunami struck Sumatra within 20 minutes of the earthquake killing 168,000 people, when many people were still confused and disorientated by the earthquake. The 8.8 earthquake off the coast of Chile in 2010 generated a tsunami that arrived within 30 minutes in the Valparaiso-Concepcion-Temuco coastline and is responsible for a proportion of the 521 people killed during the event. These instances pose a challenging problem; that even with a sophisticated warning system using the latest technology that can detect an earthquake in seconds and provide a tsunami warning within a couple of minutes, there is often not enough time for potentially affected communities to fully evacuate the tsunami inundation zone. 

Two months on from the devastating Tohoku earthquake it has been demonstrated that in most locations the tsunami early warning system was largely effective; mortality rates in the populations in inundation zones in the worst affected areas of Miyagi and Iwate prefectures was less than 10% compared to over 30% for corresponding areas of Arche in 2004. Areas outside the worst impacted areas e.g. northern Iwate, Aomori and Hokkaido the inundation zones were largely evacuated and casualties were very low, with only a few per town, in contrast to the 10% mortality rates as far away as Thailand and Sri Lanka in 2004, demonstrating the preparedness and effectiveness of the tsunami early warning system. It is clear that we cannot fully rely on early warnings to give enough time for everyone to evacuate (including the young, senior, ill, or disabled), however the Japanese tsunami has proved that the most sensible method of coping with rapid onset tsunamis is to focus on being prepared.

It is becoming increasingly possible to forecast where large scale earthquakes may occur and potentially generate a destructive tsunami. By taking preparedness actions such as good land-use planning can be highly effective, for example high schools in towns along the Sanriku coast built on higher ground had high survival rates. In areas of flat terrain where there was not time to evacuate to safety, especially when a tsunami wave is travelling at high speed, tall strong tower buildings (vertical evacuation sites) need to be built that people can get to in time, albeit a costly solution. Whilst some buildings (e.g. port facilities) and their workforces need to be located by the shore, it may be recommended that populations be located on higher grounds, where possible, including the vulnerable populations of a community. 

The solution therefore is to work on a case by case basis, understanding the local geography, social and cultural contexts, and economic capabilities to prepare for and respond to rapid onset tsunamis for each and every town, city, or region. This requires significant political will, as to standardise preparedness and warning procedures is the easiest and most cost-effective approach. For rapid onset tsunamis there is no time for hesitation, everything needs to be considered because that ten minutes warning needs to be as effective as possible, otherwise, well you have seen some of the footage.

Do emergency plans really need scientists?

The recent evaluation of the UK Government's response to a number of crises in 2010 has been published in British media recently. Given my research on volcano early warning systems I have taken particular interest in the review of the Eyjafjallajökull eruption response that generated quite possibly one of the most economically costly volcanic disasters in history. One thing to note upfront, is that the enquiry has not been sufficient at all, and barely scratched at the surface at an issue that is likely to affect the UK and Europe in the future. So already the Government have failed to adequately prepare for the low-probability but high-impact events it has expressed a specific mandate to do by not even taking time to learn from our past mistakes. Interestingly the aviation sector seems to show little interest in investing in further research to understand the impact of ash on jet engines.

An article by BBC News caught my recent attention (http://www.bbc.co.uk/news/science-environment-12623089). It is reasonable that the Commons Science and Technology Committee highlighted 'last April's volcanic ash cloud - which grounded thousands of flights - as an example of poor risk assessment'. Indeed it was poor risk assessment - but not because scientists were unaware that Icelandic volcanic ash could cause trouble for aviation. Professor Sir John Beddington said ash should have been considered given the 'relative frequency of volcanic events in Iceland'. This is interesting given that in only 2004 the volcanic eruption of the Icelandic subglacial Grimsvotn volcano in the Vatnajokull ice cap generated an eruption plume detected on satellite images showing ash drifting into large parts of the North Atlantic, reaching Scandinavia. Air traffic was disrupted with an area of 311,000 square kilometres closed for flights from the beginning of the eruption (November 1) until the morning of November 4. In 2000 a NASA DC-8 airplane suffered significant damage to its engines when inadvertently flying through volcanic ash generated by Hekla volcano in February 2000 (see: http://www.skybrary.aero/bookshelf/books/1161.pdf for full paper and analysis. This paper shows two things: first, volcanic ash from Icelandic volcanoes has been a nuisance to aviation in the past and therefore is not an unidentified risk; second, that volcanic ash can have lasting impact on aircraft that may not be immediately apparent. Clearly this is worrying as many aircraft may have flown through low concentrations of ash ain 2010 and may currently be accumulating wear and tear - like the NASA DC plane - but I digress. Scientists and the aviation sector were well aware of the possibility of volcanic ash affecting European airspace because it has happened before, numerous times. Poor risk assessment took place in understanding the interaction of ash and jet engines, and their sustained impacts.

The result of this enquiry is to generate another independent committee to advise the government on risks. The article states that during the ash ban 'research had to be hurriedly carried out to find out when it might be safe for planes to fly'. I am not sure what research was actually conducted - certainly there was a huge effort to monitor the ash using a variety of new techniques including LIDAR, but in terms of determining safe concentrations of ash, which led to the CAA amending its protocols three times, it seems no new research was done. After 30 years of research into the impact of volcanic ash on engines, I find it hard to see how in 6 days any significant advancement could have been made, other than looking at data from other parts of the world, where the physical and social contexts differ greatly. The Commons Science and Technology Committee examined the use of scientific advice and evidence in national emergencies resulting in MPs stating that the Iceland volcano was a 'stark example' of the lack of scientific input in risk assessment, which seems fair however, they also go on to say that 'the government should take more notice of scientists when deciding how to respond to emergencies'. In some respects I agree; the risk assessment conducted is dependent on scientists who are connected with the Government and able to voice their opinions - of which I was not one, despite the useful research I had conducted that may have helped to have managed the crisis better. However, I fundamentally disagree with this statement. It is precisely because we only have scientists providing a perspective that we are missing out on the expertise of many other stakeholders that could provide valuable insights on how to prepare for such high-impact low-probability events, and react better during a crisis. If the Government wants to make crisis response better then perhaps then need to have a process whereby any specialist or expert (scientist or not) can easily request to be involved and shake this notion that the scientific expert is the only way forward. Almost any resident in Anchorage, Alaska could have told the UK Government about volcanic ash and its impacts, some with startling detail. But to 'flip' this statement around, the Government needs to act on what scientists (and other experts/stakeholders) say, and not just have more or better information to provide ample accountability for identifying and taking reasonable steps to mitigating against an environmental risk. Action is needed: investment is needed, but both go beyond the typical political term. It therefore may be the political system that needs to be reformed if we are to take environmental risks seriously to make sure that a Government can sustain its people, businesses and nation during a crisis. It did not do well with a tiny bit of ash, what happens if another Laki fissure opens in Iceland, like it did in 1783-1784, that would impact agriculture, aviation, trade, and cause significant health hazards for over a year? We are totally unprepared, and tragically the UK Government, like many around the World, are not taking notice of the warning signs that the Eyjafjallajökull eruption really demonstrated rather well.