The object of this study is to make sure of the availability of aerial photographs in investigating the damages the typhoon 7513 did to the Island Hachijo.
From the result of the photo interpretation, a multiple regression equation to induce the damage rates from combinations of the topographical factors was worked out by multiple regression analysis.
As the result of this, aerial photos were recognized as useful to the investigation of storm damages as well as to the recognition of the damage distribution in view of the fact that as the photos show, the damages were mostly primary ones due to the sheer verocity of the wind and that the indirect damages from secondary causes, such as pebbles, scraps of sheet zinc, etc. were comparatively few. Hence their usefulness to the analysis of the damage distribution.
Moreover it became clear that the damage distribution chart based on the photo interpretation and the multiple regression equation show the damage distribution have been influenced by the differences of the topographical factors.
Among factors which control the damage distribution, the sea rate, i. e. the percentage of the sea space in an area is most dominating in the case of the Island of Hachijo.
The regional discrepancy between the multiple regression equation and the results of the aerial photographs is supposed to be due to some local terrain factors, such as a windbreak forest, hillocks, etc.

抄録全体を表示

In part 1, we certified that it is useful to use aerial photos to investigate damage distribution of houses hit by a storm. In the former report, we induced regression equation, which can approximately estimate a damage ratio of the houses hit by a storm, by means of multiple regression analysis with combination of some topographical factors. Then we made clear the effects of every factor with residual analysis of which manner was to analyse the discrepancy of real damages and evaluated results. From the results, we found out that so long as to discuss the effects of topographical factors on damages of houses hit by a storm, there were some particular points which may be influenced by more local factors, such as hill, slope, foot of mountain. Those were too difficult to incorporate into the analysis numericaly. Thus, in this paper, we analysed the effects of every topographical factor by means of the combination of regression equation deviced from both quantification analysis and residual analysis. Where, quantification analysis is the method to be able to analyse the effects of every factor without estimate them numerically. By this way, we found out that it is necessary to take account of more limited factors than we chose in our former paper. In conclusion, we proposed a new manner to analyse the relationships between topographical factors and damages of houses hit by a storm.

抄録全体を表示