Notes From UNU Synopsis on 3.11 Tsunami

Japan -UNESCO-UNU International Symposium 16-17th Feb 2011:The Great Eastern Tsunami and The Tsunami Warning
Systems: Policy Perspective
Notes: Samantha Ueno

STATISTICS FROM 3.11
-15850 dead 3281 still missing (as of 15th Feb 2012)
-65% victims over 60 years old
-Most Japanese houses became dislodged when water levels reached 2m and over.
-Some Coastal areas subsided up to 1.2m and there was Eastward displacement of max of 5m
-Sea did not pull back before Tsunami because sea trench facing Japanese coast lifted not sank
-Initial wavefront was not as high as subsequent wave because upward displacement of seabed started gradually then jumped.

TIMELINE FOR THE TSUNAMI
– 3mins after the Earthquake JMA issued Tsunami warning
– 4mins after the Earthquake NHK announce Tsunami Warning on TV
– 28mins after the Earthquake Tsunami begun to hit the coast


How long did it take people to evacuate from their homes?
Surveys show the average time for the survivors to evacuate their homes was between 10- 19mins in East Japan (Tohoku)
***In West Japan especially Shizoka there would be a short time perhaps only 5 minutes between the Quake and Tsunami reaching the coast because the sea trench is closer to the coast – so people especially in those areas will need to move much quicker***


How and why did people die?

Approx 10% died due to Collapsed buildings/Fire from Earthquake
Approx 90% people drowned. Reason they where caught in Tsunami were;
-Did not evacuate (estimated 70% of drowned victims)
-Obstacles and traffic jams blocking evacuation route.
-Evacuated then returned before it was safe
-Looking for family members
-Evacuated to a Evacuation centres that was not safe – due to hazard map inaccuracy


Why didn't more people Evacuate?

• Normalcy bias – People assuming Tsunami wouldn't reach them because of existing sea wall, hazard map info, low initial wave warning, or didn't get warning due to power cut and didn't think a Tsunami would accompany the Earthquake. So just started cleaning up their home or returned to work.

• Helping behavior – People went looking for Family, relatives, also many Civic people and Emergency people died in danger areas trying to alert others to risk rather than evacuating.

• Conformity bias – If people didn't see others evacuate they tended no to. Also many evacuated by car and queued in Traffic Jams rather than taking back-routes or going by foot and were washed away.

• Self Abandonment – Depressed/elderly people could not be convinced to go.


Why where many of the Hazard Maps wrong and Sea walls not high enough?

Hazard maps and levee where made based on historical data and simulation of Earthquake, Tsunami and high tidal data. They use estimates and assumptions from events considered highly probably. But Historical records are relatively short compared to geological time so their was not much information about the frequency of Mega-events. M7-8 events along the Pacific trench facing Tohoku every 35 years the last mega M9 event similar to 3.11 was in AD869 and as there was no data on it having occurred before the frequency was not known so it was not considered likely to occur.

Hazard Maps should be updated to consider worst case – but in some cases historical record might not provide data to give an accurate worst case so:

*People should not over-rely on Hazards Maps or Sea walls but understand these are made on assumptions*


Why did so many people evacuate by car when they are taught to go on foot?

Approximately 60% of survivor evacuated by car the reasons were:
-Felt car was quicker.
-Elderly thought walk was too far.
-Easier to collect family members/young children/disabled.
-Were already in car at time of incident
-It was cold/snowing and car had heater
Japanese government is now considering how they can make evacuation areas more accessible by car for rural areas


Why did the Japan Meteorological Agency (JMA) Warning underestimated the Tsunami size?

JMA will always issue Tsunami alerts in 3mins – this is based on measured Magnitude from it's 1400 GEONET sensors across Japan and previously simulated wave size calculations.

The reason JMA underestimated the size of the 3.11 Tsunami in the initial warning was their early warning equipment was not able to measure accurately Earthquakes above M7.4. They had been expecting a M7.9 in the area from previous simulations so they based the first warning on the M7.9 data which meant the mean Tsunami size prediction of 3-6meter were given to many areas in Tohoku (substantially lower than the actual size).

As power was lost in many areas many people did not receive the Tsunami information and some only got the first low warning and assumed they would be safe with the local sea walls and hazard maps.

A more accurate prediction of the Earthquake magnitude should have been generated 15mins after the disaster but the secondary sensors and calculation where overwhelmed so attempt were made to gauge height from the Tsunami monitoring system which did mean the JMA raised their warning estimates to 6m-10m. However many of the sensors were too close to the coast to provide accurate enough data in time and some were damaged by the wave

JMA did try to get an accurate Magnitude data from international monitoring centers but this data was only fully processed in 54minute after the earthquake (too late).


How will JMA be improved the system?

From now on if they get data of events above M7.4 they will use worst case prediction data for initial 3minute warning and focus on provide Tsunami arrival time data more general warning of scale than exact size.

Obtain better equipment for measuring large scale events. Deploy more robust and real-time transmitting Tsunami monitor equipment offshore.


How the Japanese government aim to improves peoples Evacuation response?

Change the policy of planning for not only high probability disasters but also consider measures for large 1 in 1000 year mega events. Also adopt a Kaizen (continuous improvement) approach to regularly updating and training for Emergency plans as new scientific information is learned and population distribution/demographic changes.

Consider effect of car evacuation on evacuation planning and more robust civic buildings (Schools/Town Hall). Update planning laws for coastal areas to restrict rebuilding of housing in low areas.

Encourage people to 'Save your life by yourself' 自分の命は自分で守る! and not over-depend on civic instructions.

Educate children and the community more to evaluate risk.

Provide more redundancy and low technology emergency systems to Local governments to cope with disaster situation when there is no power
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The original Synopsis Program can be seen http://isp.unu.edu/tsunami-symposium

Earthquake Technology Expo Yokohama Feb 2012

Here are some of the highlights of interesting developments in the Japanese Emergency Equipment world on display at the Earthquake Technology Expo Feb 2012 www.exhibitiontech.com/etec

Starting with the most extreme here is the Capsule NOAH a waterproof capsule for couple to survive in during a Tsunami see http://newcosmopower.com/menu2.html 

Then there is 'Wood Luck' a hard wood frame bed area to ensure occupants are not crushed should the house collapse:

One of the ideas I liked most was this simple corner elevator seat which converts into a toilet and store emergency goods as it is predicted in the next Big Tokyo earthquake 1500 people could end up trapped in old Elevators for up to 8hours...

Another interesting item which is unique to Japan is their PHS communication system - this system frequency was origianally used by the Japanese for their mobiles but has now been left mostly empty.  So therefore offers an alternate option for emergency communication with phones being sold on a pay as you go 3year system  see http://phs.rescueplus.jp/


The cutie award goes to this Kids Emergency bag which is shaped like a catfish: www.namazun.com

An interesting idea - although I am not sure how practicle is that of the Emergency towel which provides you with information on how to make an emergency kit etc: http://www.bousainugui.com/

There was also lots of Emergency food sellers and life Jacket sellers there:

I am hope the reason they have arrows in the Rubber dingy in the background is to prove its toughness rather than imply you might get shot at while evacuating...

 Then of course the fireservice where showing off their bits: