Statistical Analysis of the Effectiveness of Seawalls and Coastal Forests in Mitigating Tsunami Impacts in Iwate and Miyagi Prefectures

The Pacific coast of the Tohoku region of Japan experiences repeated tsunamis, with the most recent events having occurred in 1896, 1933, 1960, and 2011. These events have caused large loss of life and damage throughout the coastal region. There is uncertainty about the degree to which seawalls reduce deaths and building damage during tsunamis in Japan. On the one hand they provide physical protection against tsunamis as long as they are not overtopped and do not fail. On the other hand, the presence of a seawall may induce a false sense of security, encouraging additional development behind the seawall and reducing evacuation rates during an event. We analyze municipality-level and sub-municipality-level data on the impacts of the 1896, 1933, 1960, and 2011 tsunamis, finding that seawalls larger than 5 m in height generally have served a protective role in these past events, reducing both death rates and the damage rates of residential buildings. However, seawalls smaller than 5 m in height appear to have encouraged development in vulnerable areas and exacerbated damage. We also find that the extent of flooding is a critical factor in estimating both death rates and building damage rates, suggesting that additional measures, such as multiple lines of defense and elevating topography, may have significant benefits in reducing the impacts of tsunamis. Moreover, the area of coastal forests was found to be inversely related to death and destruction rates, indicating that forests either mitigated the impacts of these tsunamis, or displaced development that would otherwise have been damaged

Immigrants’ “Role Shift” for Sustainable Urban Communities: A Case Study of Toronto’s Multiethnic Community Farm

As the ongoing health crisis has recently revealed, disparities and social exclusions experienced by immigrants in cities are now critical urban issues that can no longer be overlooked in the process of building sustainable urban communities. However, within the current practices aiming for social inclusion of immigrants, there has been an underlying assumption that immigrants are permanent “recipients” of their host society’s support, rather than potential “hosts” with abilities to support others in their society in the long-term. To question that assumption, this paper aims to identify immigrants’ degree of involvement by taking a multiethnic community farm in Toronto, Canada, as a case study to discuss the scope of the long-term inclusion of immigrants. Conducting a set of 15 life story interviews with participants of the Black Creek Community Farm (BCCF), the study identified what roles immigrants played within the group using the longitudinal analysis of individuals’ role-taking processes between 2010–2018. The paper identified three types of roles—recipient, assistant, and facilitator—taken by the participants during their involvement. The timeline of individual role types by year showed that more than half of the immigrants at the BCCF underwent a “role shift” to take an assistant and facilitator role that required higher engagement. The findings suggest immigrants’ orientations towards the BCCF have shifted from being the ones to be included to the ones including others in the local community over time, which confirms our hypothesis

Roles of Urban Agriculture for Fostering Social Inclusion of Immigrants : Case Study of Black Creek Community Farm in Toronto, Canada

University of Tokyo(東京大学

Out-of-sample predictive accuracy across different models.

<p>Out-of-sample predictive accuracy across different models.</p

Partial dependence plots of maximum tsunami height, coastal forest area, and flooded areas with mean destruction rate.

<p>The red lines represent bootstrapped confidence intervals around model estimates.</p

Plot of observed versus fitted values of destruction rate for methods of RF (correlation 0.96) together with the normal Q-Q plot.

<p>The red dashed lines in the QQ-plot represent 95% confidence intervals.</p

Plot of observed versus fitted values of death rate for methods of RF.

<p>The red dashed lines in the QQ-plot represent 95% confidence intervals.</p

Conditional density plots for death and damage rates versus maximum seawall heights.

<p>Here the response variables are binary, representing whether death and damage rates are above or below their median values. For a given seawall height, a greater proportion of red means lower death or damage rates, while a greater proportion of gray means higher death or damage rates.</p

Boxplots of maximum tsunami height, max seawall height, death and damage rates for the years of 1896, 1933, 1960, 2011.

<p>Boxplots of maximum tsunami height, max seawall height, death and damage rates for the years of 1896, 1933, 1960, 2011.</p