Information analysis and risk management by cartography

Keiichi ISHIDA

ABSG Consulting Inc. Tokyo Japan


By the Central Disaster Management Council: The Cabinet Office of Japanese government, the earthquake risk is extremely high in Japan. Consequently, the necessity of effective risk control to minimize the influence of such an earthquake is rising. Thus, studies to assess the vulnerability to earthquake are required. When a great earthquake causes extensive damage to the headquarters of a company, it is difficult to continue business same as usual. Therefore it is natural that a company wants to have a backup data centre or a backup office in the light of the risk management.

In this paper, the validity of the analysis by cartography is discussed taking the case of choosing a backup data centre. A quantitative analysis of PML (Probable Maximum Loss), for example, is effective for the evaluation of risk. PML represents the percent of the restoration cost of building after earthquake. Then, it is desirable to choose a building whose numerical value of PML is low. The resultant of PML shows us if it is a high risk or not. However, the problem is the case where there are similar PML for some candidate buildings. In what way are those building similar? For this question, I propose to use cartography for information analysis. Especially, I introduce the Ordonnable Matrix that makes us possible to show, all at once, a ensemble information and low end information.

I evaluate 9 candidate sites for the backup data centre which escapes disaster at the same time as the Headquarter on assumption that we are hit by 19 great earthquakes.

The value in each cell indicates the seismic intensity based on the JMA seismic intensity scale (This is a scale used in Japan. JMA 7 is maximum.). Let the candidate sites be the horizontal axis, and the earthquake sources the vertical axis. The candidate sites are arranged in order of the distance from the Headquarter. The earthquake source ID is arranged by number. From Table 1, it is difficult to sort useful information, compare the candidate sites, and select better one. Then, I propose the analysis by Ordonnable Matrix. This is the illustration of the numerical value of each cell of a tabulation. The Table 2 shows that the darker of the colour of the cell becomes, the greater the earthquake is. In this analysis, the understanding of the whole table will be easy by the use of the six visual effects equivalent to the JMA. And I take, other information, the solidness of the ground and add it into Ordonnable Matrix as the width of each column of matrix. The solidness is given in terms of 3 levels; firm, average, and soft. The softer the ground is, the easier it is to quake, and I make the matrix wider so that it seems to do more harm. After making the matrix in visual, in order to grasp the whole image, lines of matrix are exchange to improve the visual effect.

The candidate site A, which is located only 4 km away from the headquarter, has almost the same earthquake hazard as that of the Headquarter against the expected 19 earthquakes. That is, there is a strong correlation of the risk between the Headquarter and the site A. The candidate site H or J is far away from the Headquarter, so the possibility of a simultaneous damage by the same earthquake is low among them. But the earthquake hazard is high. (The column widths are wide. This means that these sites are easy to quake.) The site F is possible to take a better candidate as a backup data centre. Because site F dont have simultaneous disaster with Headquarter and where the earthquake hazard in the site is low.

As this example, it is often important to use appropriate information effectively in the aggregation of information. In that case, the integration information will be important. I want to propose the cartography is a distinguishing method of information.


BERTIN Jacques. Sémiologie graphique. Paris: Mouton, 1966, 432p.

BERTIN Jacques. La graphique et le traitement graphique de linformation (japanese)Tokyo: Heibon-sha, 1982, 277p.

STEINBRUGGE Karl V. Earthquakes, Volcanoes, and Tsunami; An Anatomy of Hazards. NY: Skandia america group, 1982, 392p