01662685

Component

Using data from a survey of survivors of the 2011 Great East Japan Earthquake and Tsunami, this article evaluates quantitatively the effect of seawalls on evacuation departure time. A mixed effect Cox proportional hazard model is estimated, using time dependent covariates to account for the changing nature of tsunami risk. Findings suggest that on average, presence of an effective seawall (defined as a seawall higher than the forecast tsunami height at any given time) delays evacuation by 29.8%. Furthermore, irrespective of forecast tsunami height, higher seawalls were associated with 11.6% and 15.2% delays in departures for walls of 4 to 8 meters and over 8 meters, respectively. These results provide quantitative evidence of the existence of a false sense of security deriving from the presence of seawalls, a hypothesis that to the best of the authors’ knowledge has only been discussed qualitatively. Given that timely evacuation is one of the main factors affecting survival probability, the effect of seawalls on evacuation delay or non-evacuation is an important policy consideration. In particular, results suggest that more work is needed in pre-disaster education and training, as well as in the content of tsunami warnings, to ensure that residents do not view seawalls as a guarantee of survival, and promote prompt evacuations.

This paper was sponsored by TRB committee ABR10 Standing Committee on Critical Transportation Infrastructure Protection.

18-01014

English

0000-0002-7581-774X

14p

2018

Transportation Research Board 97th Annual Meeting

Digital/other

Figures; Maps; References; Tables

Case studies; Departure time; Disaster preparedness; Evacuation; Sea walls; Surveys; Tsunamis

Great East Japan Earthquake, 2011

Japan

Bridges and other structures; Planning and Forecasting; Security and Emergencies; Transportation (General)

Transportation Research Board Annual Meeting 2018 Paper #18-01014

TRIS, TRB, ATRI

Jan 8 2018 10:15AM