Keywords: Urban Safety, GIS, Image of the City, Environmental Design, Disaster
Abstract
In Japan, where earthquakes occur frequently, it is important to carry out urban
planning considering natural disasters. However, it appears that Japanese cities have not been
designed with any definite visions of urban safety based on previous research concerning natural
disasters in Japan, except for a few cases. It is necessary for people in Japan, which has been
plagued with many earthquakes throughout history, to propose a future vision of a city from the
viewpoint of urban safety. On the other hand, recent computer technology enabled the
improvement of real-time monitoring systems after the 1994 Northledge Earthquake and the
1995 Kobe Earthquake. In this paper a method of analyzing and designing a city, based on the
viewpoint of urban safety, is proposed. This method, named MUSE (Method of Urban Safety
Analysis and Environmental Design), is based on the theory of The Image of the City by Lynch
(1961), and some urban physical elements are defined as parts of an organic system. Using the
MUSE with Arc/View 3D analyst, we can easily and visually simulate the city as a
three-dimensional world, a task which previously required much time to express by models, on a
monitor. The authors constructed vulnerability functions (Murao and Yamazaki, 1999) and
proposed the Method for Building Collapse Risk Assessment (Murao and Yamazaki, 2000).
Applying these methods of urban safety assessments to the MUSE should make it useful for
early damage assessment systems. Moreover, by combining it with recent technology the MUSE
will be realized for urban safety in the future.
1. Introduction
In Japan, where earthquakes occur frequently, it is important to carry out urban planning
considering natural disasters. However, it appears that Japanese cities have not been designed
with any definite visions of urban safety based on previous research concerning natural disasters
in Japan, except for a few cases. It is necessary for people in Japan, which has been plagued with
many earthquakes throughout history, to propose a future vision of a city from the viewpoint of
urban safety. The proposed vision must also be useful for other countries in which earthquakes
often occur. On the other hand, the recent computer technology enabled the improvement of
real-time monitoring systems after the 1994 Northledge Earthquake and the 1995 Kobe
Earthquake. Using future technology, it will become possible to easily simulate urban visions
according to various situations. The authors constructed vulnerability functions for buildings
based on actual damage data of the 1995 Kobe Earthquake (Murao and Yamazaki, 1999) and
proposed the Method for Building Collapse Risk Assessment (Murao et al., 1999, Murao and
Yamazaki, 2000). The use of future technology and the proposed method of urban safety
assessment should be useful for early damage assessment systems. This paper focuses on urban
physical environments, and we propose a method named MUSE (the Method of Urban Safety
Analysis and Environmental Design) to analyze a city from the viewpoints of urban safety.
2. Image of a City
It might be difficult for us to recognize differences among cities with physical elements.
Lynch (1960) proposed the method called “The Image of the City” to consider the differences
between Boston, Jersey City and Los Angeles. In his theory, Lynch classified physical elements
of cities into five types and analyzed the cities using the idea called imagability, as shown in
Figure 1. These five types of elements which were “paths”, linear elements on which people can
pass, such as like streets; “edges”, other linear elements which people cannot cross, like coasts;
“districts”, areas that people recognize to be identical; and “nodes”, important intersections and
symbolized “landmarks” in the city. The proposed method was an experimental attempt to
analyze cities visually using urban physical elements.
3. Method of Urban Safety Analysis and Environmental Design
3.1 City as an organic system
After World War II, large-scale development for new towns was carried out worldwide. In
those days, some new methods for designing cities were considered by many architects to deal
with the social situation. Tange (1961) in Tokyo Project 1960 and Smithon and Smithon (1967)
in Urban Structuring tried to design cities in analogy to living organisms (structure of human
body, trunks or leaves of trees, etc.), as shown in Figure 2. These theories or an organic city can
be applied for urban safety planning. Referring to The Image of the City” by Lynch (1960) and
considering the city to be an organic system, the MUSE is proposed.
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| (a) Boston |
(b) Los Angeles |
Figure 1
Images of cities by Lynch (1960)
 |
 |
| Opened System and Closed System |
Axis of Possibility for Urban Development |
| (a) Tokyo 1960 by Tange (1961) |
(b) Cluster City by Smithon and Smithon (1967) |
Figure 2
City as an organic system
