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

More documents

Recommendations

Info

2012 tsunami drills (Johnson, 2011). There is also no specific advice around the actions of parents following an earthquake – i.e. collection of students from school, or organised rendezvous at a specified safe location. In the United States, FEMA advice states: “If the school evacuation plan requires you to pick your children up from school or from another location. Be aware telephone lines during a tsunami watch or warning may be overloaded and routes to and from schools may be jammed.” (FEMA, 2011) This advice makes no mention of the potential that parents may have to travel through potential inundation zones to get to or from the school. Education in Washington encourages parents to travel to the schools designated assembly point rather than collecting children directly from school. 2.5.5 Necessary relocation from evacuation refuges It has been reported in the media that over 100 evacuation centres were inundated on March 11 th 2011 (Unknown, 2011a). In Kamaishi, nine of a total of 96 refuges were inundated. It should be noted that these refuges were not vertical evacuation facilities designed to provide refuge above the inundation height within the inundated area; rather they were evacuation centres which had been incorrectly perceived to be outside of the tsunami hazard zone. In Tarō, evacuation centres had been located outside of the 1896 and 1933 inundation extent, believed to be the maximum possible inundation (Figure 8). Unfortunately one of these refuges was inundated, killing people who had travelled there. The case of Unosumai has already been discussed, where evacuating school staff and pupils were required to reassess their situation and evacuate to a different place according to the evolving hazard. In this case, they evacuated further uphill several times (I. Matsuo, pers. comm., October 20 th 2011). In Ishinomaki, people left the Kadonowaki Elementary School when the school building became inundated. They were able to exit to the rear of the school and immediately climb to higher land, due to the location of the school. This school later caught fire while inundated with tsunami water. The response of evacuees in these cases shows that judging the evolving situation and being able to make further decisions is a worthwhile education strategy, although this should not be at the expense of ensuring that any evacuation centres are certainly outside of the maximum tsunami inundation, and any vertical evacuation buildings are designed to remain safe in the worst tsunami. 2.5.6 Leaving evacuation refuges too early In Tarō, a town with high awareness of tsunami risk and a history of tsunami education, many residents died on returning to the town a short time after arriving at a refuge, because they had seen no wave eventuate. This occurred in spite of local government advice that once a tsunami advisory or warning is issued, people should remain on high ground until that advisory or warning is lifted. The disaster prevention official noted that there is no legal recourse for not following the advice, so people are legally entitled to return to low-lying areas at any time. The Ishinomaki City disaster prevention official also reported deaths which occurred when people had successfully evacuated to uphill refuges, only to leave the refuge when the JMAestimated time of wave arrival had passed with no apparent realisation of the tsunami. Some GNS Science Report 2012/17 35
2012 people who had stayed at high ground while inundation occurred returned to low-lying areas around 17:00, when tsunami waters receded, only for the fourth and fifth waves to inundate parts of the city and kill many more people. A similar effect was observed during the event in Yuriage, Natori City, where people who were in evacuation buildings left those buildings after the first waves receded. Subsequent waves resulted in the deaths of many of these people. The occurrence of deaths in this manner can be seen as an issue for education and understanding of uncertainty in i) arrival times, ii) the time of first t wave versus the largest waves, and iii) education of people in the fact that tsunami are a series of waves often occurring over many hours. In New Zealand, language broadcast in a National Warning: Tsunami Threat to New Zealand is as follows, including a brief statement to clarify the uncertainty of arrival time: “If a tsunami has been generated, the first wave may arrive in New Zealand in the areas around [insert place] at [insert NZDT/NZST on insert date]. The first wave may arrive later and may not be the largest” (MCDEM, 2010a) Recommended text for warning and evacuation information covers the other issues, stating: “There may be multiple waves separated by up to an hour, or more. Large waves may come after a series of smaller waves. The largest waves from distant sources may take many hours to arrive.” (MCDEM, 2008a) “Stay OUT of evacuation zones until given the official ‘all-clear’ from Civil Defence Emergency Management. Stay away from the Red Zone for at least 24 hours after any tsunami warning – even small waves can create dangerous currents.” (MCDEM, 2008a) In Washington, advice in evacuation brochures give consistent advice to wait for an ‘all-clear’ message before returning to the shore. Washington Military Department Emergency Management Division (1999) states: “Do not return to shore after the first wave. Wait for Emergency Management officials to give the “All Clear” before you return.” A later map for Ocean Shores published by Washington State Department of Natural Resources covers several points in this statement: “The first wave is often not the largest; successive waves may be spaced many minutes apart and continue to arrive for several hours. Return only after emergency officials say it is safe” (Washington State Department of Natural Resources, 2007) 2.6 Impacts of coastal defence on warning response and evacuation Japan spends a significant amount of resource on ‘hard’ coastal defence, and some of the most formidable sea walls and breakwaters of the Tōhoku region were adversely affected during the tsunami of March 11 th . It is recognised that these substantial defences can prevent damage in small to moderate events, and may allow extra time for evacuation in such extreme tsunami. The breakwaters at Kamaishi are estimated to have reduced inundation height by 40%, and delayed onshore arrival by approximately 6 minutes (Takahashi et al., 2011). Despite the physical benefits, our interviews also indicate some GNS Science Report 2012/17 36
Page 1 and 2: Tsunami evacuation: Lessons from th
Page 3 and 4: 2012 CONTENTS ABSTRACT ............
Page 5 and 6: 2012 Figure 18 Tsunami evacuation r
Page 7 and 8: 2012 TABLES Table 1 Human perceptio
Page 9 and 10: 2012 congestion in some areas, when
Page 11 and 12: 2012 Table 1 Human perception and i
Page 13 and 14: 2012 • Factors affecting emergenc
Page 15 and 16: 2012 1.4 Tsunami preparedness in th
Page 17 and 18: 2012 Municipality governments are t
Page 19 and 20: 2012 Figure 2 Excerpt from the tsun
Page 21 and 22: 2012 Currently there are no early w
Page 23 and 24: 2012 project, in which the communit
Page 25 and 26: 2012 Figure 8 Extract from Tarō ts
Page 27 and 28: 2012 Figure 11 Excerpt from Kesennu
Page 29 and 30: 2012 Figure 14 Natori City hazard m
Page 31 and 32: 2012 Figure 21 A sign in Matsushima
Page 33 and 34: 2012 location in the 1960 Chile tsu
Page 35 and 36: 2012 when an earthquake occurs or w
Page 37 and 38: 2012 “Warnings from friends, othe
Page 39 and 40: 2012 The original broadcast point o
Page 41 and 42: 2012 Figure 33 Building damage and
Page 43: 2012 vehicle, drive as far as possi
Page 47 and 48: 2012 Section 2.1 introduces the Pro
Page 49 and 50: 2012 Figure 37 The Hotel Horaikan a
Page 51 and 52: 2012 structures that met the 2005 g
Page 53 and 54: 2012 Figure 49 The large open car p
Page 55 and 56: 2012 Following experiences of March
Page 57 and 58: 2012 There was widespread use of bu
Page 59 and 60: 2012 Figure 64 Locations of designa
Page 61 and 62: 2012 Figure 68 Official vertical ev
Page 63 and 64: 2012 3.0 RECOMMENDATIONS This secti
Page 65 and 66: 2012 Communications channels can be
Page 67 and 68: 2012 Motivating people not to use v
Page 69 and 70: 2012 Where ‘hard’ defences are
Page 71 and 72: 2012 3.8 Additional recommendations
Page 73 and 74: 2012 International Tsunami Informat
Page 75 and 76: 2012 Ozaki, T. (2011). Outline of t
Page 77 and 78: 2012 APPENDICES APPENDIX 1 INTERVIE
Page 79 and 80: 2012 APPENDIX 2 INTERVIEW QUESTIONS
Page 81 and 82: 2012 12. 人々はどこに避
Page 83 and 84: 2012 APPENDIX 3 SUMMARY OF KEY POIN
Page 85 and 86: 2012 Earthquake and tsunami Tarō T
Page 87 and 88: 2012 APPENDIX 4 SUMMARY OF VERTICAL
Page 89 and 90: 2012 City/town Building Constructio
Page 91: Principal Location Other Locations

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

Create successful ePaper yourself

Delete template?

Save as template?