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Worst-Case Scenario: The Tohoku-Pacific Ocean Earthquake

Commentary, 4 April 2011
Global Security Issues, Pacific
The complexities of responding to a disaster in a highly developed and technologically sophisticated country like Japan are testing humanitarian response strategies. Much of what has happened and continues to unfold is the realisation of multiple worst-case scenarios.

The complexities of responding to a disaster in a highly developed and technologically sophisticated country like Japan are testing humanitarian response strategies. Much of what has happened and continues to unfold is the realisation of multiple worst-case scenarios.

By Dr M H K Bulmer for RUSI.org

Japan Earthquake & Tsunami Damage (24RTR2JTXO)

As the impacts of the Japanese earthquake and tsunami continue to unfold, the complexities of responding to a disaster of this scale in a highly developed and technologically sophisticated country like Japan are testing humanitarian response strategies. Much of what has happened and continues to unfold is the realisation of many worse-case scenarios: earthquake, tsunami, nuclear emergency, mass casualties and injuries, national power crisis, industrial disruption, a perception of political weakness and a global financial crisis. Any one of these can stretch the response capability of the UK or the US, and in Japan they are all occurring at the same time, at various and varying rates and scales.

Additionally, 23.2 per cent of the population is aged sixty-five or older. Unlike other natural disasters in recent times, where the potency of the situation begins to diminish soon after the event, the dynamism of the physical environment - particular aspects of which are explored below - along with events at Fukushima continue to compound the complexities of the disaster.

Dynamic Physical Environment

Understanding the effects of the physical landscape on the humanitarian response is central to all natural disaster response and emergency management planning. Ground motion and shaking intensity data of the earthquake show that strong shaking [1] was experienced over large areas of Japan. The pattern of shaking appears to run parallel to the offshore subduction trench, with intensity decreasing east to west, more than north and south. Ground motions were more intense in coastal and riverine areas, where settlements are built on softer sediments and less bedrock. In the week after the main quake, there were 262 aftershocks of at least Magnitude (M) 5, according to JMA. Forty-nine of them were M6 or greater, and three were M7 or higher (the February 2011 Christchurch earthquake was M6.3). The aftershocks have been almost entirely offshore, in a zone stretching about 500 kilometers (300 miles) from Iwate to Ibaraki prefectures. At 07:23 local time on Monday, an M6.5 quake struck 109 km (sixty-seven miles) east of the badly-damaged port city of Sendai, prompting the authorities to issue another tsunami alert, which  has since been lifted.

The earthquake moved the main island of Japan across by 2.4 metres, but, on a smaller scale, the earthquake and tsunami deposits have fundamentally changed the topography of affected valleys and plains. This is of more than purely academic interest, for it will have a discernible effect on geo-positioning and all related navigation. Pre-earthquake mapping and geospatial databases are now inaccurate for finding and marking sites in the rescue and recovery. The earthquake has changed slope stability conditions and a significant volume of sediment was moved by the tsunami, which is now being remobilised by the winter conditions of wind, rain and snow. On 19 March, forecasts from Japan's Meteorological Agency predicted continuing cold temperatures along with rain or snow for much of the country over the next week. The forecast for Sendai included low temperatures and a high probability of rain. The risk of increased landslide activity remains high and sediment-laden valleys and estuaries are liable to flood. Offshore sediment run-off and continued aftershocks are liable to increase the likelihood of submarine landslides and damage to infrastructure.

Rescue and Recovery

Humanitarian responders have attempted to get to the disaster-affected areas as soon as possible. The time it takes is critical to meeting the intent of rescue or recovery. However, what do these teams need and over what period? Preliminary examination of the different ways that energy was released in the earthquake and tsunami suggests that there will be some differences in the nature of injuries and survivability associated with each. As more time since the 9.0 earthquake and tsunami elapses, the chances of survivors decreases (although survivability will vary depending on the nature and severity of any injury). Images of the tsunami traveling inland show its flow dynamics changing as the percentage of debris to water increases. As well as risking drowning, persons caught in the tsunami will have been subjected to major physical trauma and likely have sustained life threatening injuries with low survivability chances. These characteristics are similar to debris flow events, where victims often experience high rates of non-survivable crush injuries and amputations.[2] There is a higher likelihood of survivable spaces in areas only affected by the earthquake.

Overall, the environment is not proving hospitable. Substantial damage to roads, bridges, communication and power facilities has limited access to many areas, particularly those in the mountains. There are real complexities that come with conducting rescue and recovery operations in areas that used to have high density housing and highly developed infrastructure. Hurricane Katrina highlighted the difficulties associated with disaster debris contaminated with household and industrial hazardous or toxic materials. In Japan, much of this debris cannot be left since it will pose a future hazard to reconstruction and livelihoods. It therefore requires disposal and possible decontamination. Incineration is problematic due to the unknown scale and types of toxins, and burial in landfill sites is complicated by the mix of metamorphic, granitoid and sedimentary rocks in the region. Additionally, water that travels over or through disaster debris may become contaminated and need treatment before safe drinking.

In areas within the fallout zone of the Fukushima plant, additional decontamination measures are required. On 30 March, Police dressed in full radiation suits retrieved nineteen corpses from the rubble. Work stops any time a radiation detector alarms goes off. Disposal of bodies, which by custom is by cremation, is raising concerns about the spread of radiation. The Health Ministry is recommending that bodies be cleaned requiring those undertaking this task to be dressed in suits, gloves and masks. The total amount of radioactivity that could theoretically be released is linked to the total amount of radioactive material in the damaged reactor cores and spent fuel pools. Dose rates of a few hundred milliSieverts per hour (mSv/h) have been reported close to the reactors, and the government has reported recording 150 microSieverts per hour (µSv/h) thirty kilometres from the plant. Official details on the type of radiation released have been few, but some inference can be made from the advice issued in certain prefectures not to eat or drink particular products and to stay indoors, measures often undertaken to minimise exposure to alpha and beta radiation.[3] Workers at the power station trying to control the reactors have been exposed to gamma and neutron radiation, whichcan penetrate the body and cause long-term health problems.

Emergency Response Planners

Attempts to respond to an earthquake and tsunami disaster in a highly developed and technologically sophisticated society have revealed the need to examine, plan and resource not just response to the first order, but also the likely second and third order consequences, how their characteristics differ, diverge and link. Multiple worst-case events have occurred together, the impacts of which continue to evolve. Co-ordination has been required through all branches of government, civil society and the international community. When future,[4] emergency response teams plan their logistical and medical resilience, they must bear the Japanese experience in mind. Any teams working in disaster response in Japan will need to be checked for contamination, as will all their equipment. This requires planning where any decontamination will occur, who will monitor it and who will sign off the cleaning as effective. This verification will need to be acceptable and agreed upon by all nations and organisations through which personnel and equipment transit. This may mean that highly trained teams and their specialist equipment may not be available for redeployment for some time.

Contamination has already spread with the arrival of aircraft, ships, persons, possessions and cargo from Japan in repatriation efforts (e.g. UK and US). On 29 March, atmospheric traces of radioactive iodine were found in Glasgow and Oxfordshire. On March 16, travelers arriving from Japan triggered radiation detectors at O'Hare and Dalles International airports in the US. Tests on a plane that landed at Dallas-Fort Worth showed traces of radiation on passengers luggage and in the filtration system of the aircraft cabin. While there has been no detection of hazardous levels each events requires response, verification and reporting. Controlling and limiting points of entry can allow decontamination, tagging and verification to be co-ordinated and a clear information campaign to be conducted. The GoJ continues to seek international assistance and those wishing to travel to Japan need to be informed of repatriation considerations.

Dr M H K Bulmer is a Research Associate Professor and Director at the Geophysical Flow Observatory, Joint Center for Earth Systems Technology, University of Maryland Baltimore County. He is also a Visiting Scientist at the Aon Benfield UCL Hazard Research Centre, Department of Earth Sciences, University College London.

Main and thumbnail images courtesy of Kordian

NOTES

[1] Shades of pale yellow represent the lowest intensity and deep red represents high intensity. The ground shaking data is overlaid on a map of population density provided by Oak Ridge National Laboratory. A shaking intensity of VI (orange) is considered 'strong' and can produce 'light damage', while a IX (red) on the scale is described as 'violent' and likely to produce 'heavy damage'.

[2] Ongoing research by Bulmer working with emergency medicine physicians in UK, US, NZ.

[3] Radioactive iodine (Radioiodine-131) Strontium-90 and Plutonium-238 have half-lives of ~8 days,  28.8and 88 years respectively.

[4] Lord Ashdown's Humanitarian Emergency Response Review published on 28 March 2011.

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