Tsunami evacuation: Lessons from the Great East Japan earthquake ...

2012
Generally maps appear quite crowded with a range of topographic, cultural as well as
tsunami evacuation related content. In some cases additional historic event lines are present
as well as coloured zones. However, the location of at least one tsunami hazard zone stands
out well in all maps.
All of the evacuation maps that we observed show refuge locations although, the symbols
used are inconsistent between maps. Definitions of refuges vary and include generic ‘safe
refuge’, ‘tsunami-specific refuge’, ‘vertical evacuation building’ (Figure 11) or ‘welfare
location’s, with some maps using different symbols to define refuge type. Many of the
refuges shown on maps were designated based on community function and capacity and
were typically schools or community centres. During the evacuation on March 11th many
people evacuated directly to designated shelters.
There is limited illustration of evacuation routes on the maps. Ōfunato (Figure 10) and
Kesennuma (Figure 11) use arrows indicating the approximate best route out of the
inundation zone, but there is no prescriptive route marked. Other maps do not include any
graphical indication of evacuation route.
Text-based evacuation or preparedness information is provided on most maps, but the
content of this information varies. The Tarō Town map includes information on previous
tsunami events, while the maps for Ōfunato and Natori have advice on preparedness and
space for residents to fill out important information.
The interviews carried out in this study did not provide sufficient insight into the impact of
inconsistent evacuation maps on evacuation on March 11 th 2011. This requires further
research as Japan amends and enhances its hazard modelling and evacuation mapping in
light of the Tōhoku tsunami. Recent work by Kurowski et al. (2011) highlighted that some
similar inconsistencies occur in evacuation mapping in Washington and Oregon (see Section
1.5), and any research in Japan into the impacts of variable evacuation maps on the
response of transient populations or different levels of risk perception in Japanese coastal
communities could provide additional guidance as to enhancing the approach taken in
Washington. Consistency in evacuation mapping is already recognised as an issue in the
United States and all maps produced after January 1st 2012 are subject to guidelines set out
by the NTHMP Mitigation and Education Subcommittee (2011) to ensure minimum
requirements in evacuation mapping. Updating of current maps to ensure consistency is
expected to be complete by the end of 2012 (J. D. Schelling, personal communication,
March 9th 2012).
Consistent evacuation mapping in New Zealand is being achieved by following the
guidelines set out in MCDEM (2008a). Some variation still exists in terms of the delineation
of the location of evacuation zone boundaries, where local CDEM group members are
responsible for producing their own mapping of zones from hazardous wave heights e.g.
Hawke’s Bay CDEM Group (2011). In New Zealand there is a strong emphasis on simple
maps showing zones, routes and safe locations, and as concise as possible messaging
focussing on the required response to natural and informal warnings (evacuate all zones) vs.
official warnings (the warning will state the zone(s) to evacuate). One community group, in
conjunction with Wellington Emergency Management Office, has delineated the beginning of
the mapped safe zone with a blue line painted across roads throughout the suburb. This has
generated very high public awareness and is planned to be rolled out city-wide.
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