Development of GIS-Based Building Damage Database for the 1995 Kobe Earthquake
Koichiro Umemura, Osamu Murao, and Fumio Yamazaki
Institute of Industrial Science, University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505
Tel: (81)-3-5452-6388 Fax: (81)-3-5452-6389
E-mail: umemura@rattle.iis.u-tokyo.ac.jp
JAPAN
Keywords
the 1995 Kobe Earthquake, Building Damage Database, GIS, Digitized Data
Abstract
After the 1995 Kobe Earthquake, local governments and an organization consisted of Architectural Institute of Japan (AIJ) and City Planning Institute of Japan (CPIJ) carried out building damage surveys. Each organization made the damage database according to its own criteria. In this study, a more detailed database of damaged buildings in Nishinomiya City was developed by matching two different data sets. One of them is the building damage data surveyed by Nishinomiya City Government in Hyogo prefecture, and other one is conducted by the organization of AIJ and CPIJ and digitized by Building Research Institute (BRI). By the matching, it would be possible to utilize the detailed inventory by the former survey and the unified standard of damage assessment in the wide damaged area by the latter. This database can be used to analyze the building damage in regard to the structural type and construction period. As a result, using the damage ratio in each district and the ground motion distribution, better fragility curves can be constructed.
1. Introduction
After the 1995 Kobe Earthquake, local governments and an organization consisted of AIJ and CPIJ, carried out many building damage surveys for different purposes. They made summary reports of those surveys, and BRI and Nishinomiya City Government digitized the spatial data with the result of building damage assessment. The digitized data in the damaged area can be used effectively for the researches on urban safety planning or earthquake engineering, and the recent computer technology enables us to deal with various GIS data. The structure of the digitized GIS data is different according to the organization. Besides, each of the conducted survey has own characteristics and the databases were constructed accordingly. In this study, a more detailed database of building damage in Nishinomiya City was developed by matching two different data sets. One of them is the building damage data surveyed by Nishinomiya City Government in Hyogo prefecture. Another one is conducted by the organization of AIJ and CPIJ, and digitized by BRI. Using the results from this study, the fragility curves for buildings can be constructed more accurately comparing the two data sets.
2. Building Damage Data
The two data sets of building damage in Nishinomiya City were used in this study. One of them was the building damage data that had been investigated by Nishinomiya City Government, and another one was surveyed by the organization of AIJ and CPIJ and digitized by BRI (BRI 1996).
2.1 Building Damage Data by Nishinomiya City Government
This data set was investigated by the Nishinomiya City Government just after the Kobe Earthquake. The main purpose of the damage survey was its use for the property tax reduction. The result of the survey was also used for the distribution of the donated money from people to the victims, and for grasping the damaged area. Therefore, the standard of the damage assessment was intended for the residents. Two staff members of the local government examined and judged how much buildings were damaged by visual observation from inside and outside. This survey was carried out for two weeks after the earthquake. The classification of building damage was divided into three levels, i.e., "heavy damage", "moderate damage", and "slight damage" including "no damage". According to the damage levels, the property tax was reduced by 100%, 50%, and 10%, respectively (Murao and Yamazaki, 1999). Table 1 shows the comparison of the building data by Nishinomiya City Government and by BRI. Remarkable characteristics of the Nishinomiya data set are more detailed "structural type", including "roof type" and "construction period". These factors are very significant to construct fragility curves. The center of each building is shown as point data (Figure 1). The coordinate system is fifth of JPN.
Table 1: Comparison of the Building Data by Nishinomiya City and by BRI
Figure 1: Point Data of Buildings by Nishinomiya City
