Regional Workshop on Total Disaster Risk Management

7-9 August 2002________________________________________________________________________________________________The Successful Experience in Disaster Risk Managementin Japan: Focus on Earthquake Disaster
Mr. Hideki Kaji
Professor, Faculty of Policy Management, Keio University, Japan

Introduction
In recent years, the argument that damage caused by natural disasters cannot
be prevented but only mitigated has become popular among scientists andengineers engaged in research on natural disasters. This argument implies thefollowing two factors that have been noted from the characteristics of recent
natural disasters.
First, people assume that there are technological and engineering limits to fully
preventing natural disasters and therefore damages caused by them might beunavoidable up to a certain level.
Second, recent natural disasters have proved that damage caused by disasters
vary greatly according to social and institutional factors rather than physicaland engineering ones. They strongly depend on preparedness, relief and rescuearrangements, and quick recovery and reconstruction measures. Thus,
currently, the concept of disaster management rather than disaster prevention
is widely accepted and its importance is gradually being recognized. A typicalexample is the Hanshin-Awaji Earthquake in Kobe, which occurred on 17
January 1995.
After the earthquake, a heated argument about overall crisis management
including natural disasters took place among politicians, scientists, and thegeneral public in Japan. In fact, the Japanese central government as well as the
local governments that were directly affected by the earthquake obviously failed
in taking appropriate response actions immediately after the quake.
Then Prime Minister Murayama did not receive a prompt report of the full extent
of the quake, and, therefore, did not realize the extent and severity of the1Regional Workshop on Total Disaster Risk Management

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damage until about noon that day, that is, more than six hours after theearthquake had occurred. Hyogo Prefectural Governor Kaibara did not make arequest for the Self Defense Agency (SDA) to dispatch a rescue team to theaffected area until 10:00 a.m., that is, four hours after the occurrence of thequake, while the SDA just waited for the request by the Governor without taking
any action on its own initiative.
As shown by this example, many instances of miscommunication created asituation that allowed the disaster to remain out of control. Needless to say,quick responses, or crisis management must be an essential part of disastermanagement.
This paper aims at discussing the disaster management measures in Japan,
which is partially successful, but not all, by focusing on earthquakes in line with
one of the risk components.
How can earthquakes be defined as a risk?
Before discussing the practical earthquake disaster measures in Japan, theconcept of risk in terms of earthquake disasters has to be examined. In
particular, the discussion focuses on usefulness of the risk concept as a target
indicator for measures against disasters.
A theoretical discussion on risk concept itself was actively conducted during the1950s among members of the American Risk and Insurance Association (ARIA).
According to Prof. Morimiya,(1) the definition of risk can be roughly classified
into the following three groups:(a) Chance of loss,(b) Uncertainty of loss, and(c) Variance or deviation of loss.
The loss in this classification implies not only direct and primary but also
indirect and secondly damage.

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Regional Workshop on Total Disaster Risk Management

7-9 August 2002________________________________________________________________________________________________The term chance in definition (a) has the same meaning as probability. The
chance of loss thus implies two probabilities. One is the probability ofoccurrence of an event that causes a loss. It is identical with the probability ofearthquake occurrence itself. The other is the probability of loss generation
under the condition that the event has happened. Then the chance of loss canbe calculated as a product by multiplying these two probabilities.
From the viewpoint of risk management, since the probability of earthquake
occurrence cannot be controlled, the probability of loss generation might
depend on social vulnerability, including structural and nonstructural frame.
In general, the frequency of small earthquake occurrence is high, while that oflarge earthquake occurrence that causes severe damage is quite low.
Accordingly, when proper earthquake measures are taken, almost no damage
might be caused by small earthquakes, and thus, the risk, which is the chanceof loss, becomes equal to the probability of large earthquakes which seldom
happen.
This definition, however, does not take into account the volume of loss itself.
Therefore, whatever severe damage is anticipated, the risk itself is recognized
to be very small, since it may rarely happen. To cover up this fault, Shah andDavidson, Stanford University, proposes the Earthquake Disaster Risk Index(EDRI), which is defined as a linear combination of probability of hazard,
vulnerability of structures, volume of exposure, and emergency response andrecovery capability. (2)With regard to definition (b), there is a discussion about subjective andobjective uncertainties, the details of which are omitted in this paper.
The relationship between a probability and an uncertainty can be illustrated infigure 1. As seen in the figure, uncertainty is highest when the probability of anevent occurrence is 0.5.
- Figure 1 -3Regional Workshop on Total Disaster Risk Management

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Useful discussion about earthquake prediction, which is currently being
undertaken for the anticipated Tokai Earthquake in Japan, can be drawn fromthe application of this definition. That is, the risk of earthquake loss becomes
highest when no information about it is available. When earthquake prediction
is successfully made in such a way that an earthquake of a given magnitude canbe anticipated within a week or so in a certain region, uncertainty will be
reduced.
In fact, if this kind of warning is announced by an authority, the whole
population within a region can take preparatory actions for the earthquake sothat railways might halt operations, traffic might lower its driving speed,
industries might stop operations, schools would be closed, and so on. In thisway, earthquake loss might be drastically reduced.
This definition implies that losses are suffered due to uncertainties rather thanprobabilities. Because, if the occurrence of events which cause losses is certain
or perfectly predictable, actions must be taken beforehand to avoid them.
In case of earthquake losses, however, there is again some questions as to thisdefinition whether the predictable loss is a risk or not, and that unavoidable
loss due to lack of proper preventive measures cannot be regarded as a risk.

Questions also arise regarding ignorance of the size of loss in this definition.
Definition (c) is proposed in many ways. In this paper, the definition by Robert
Mehr and Bob Hedges will be examined. (3) They say that risk is a possibility incases where a loss exceeds the one normally anticipated.
Figure 2 shows this definition by taking the probability of earthquake4Regional Workshop on Total Disaster Risk Management

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occurrence in a horizontal axis.
- Figure. 2 -In this definition, risk depends on the normally anticipated losses. In otherwords, the higher the losses are anticipated, the lower the risk becomes. This
argument can be met with an insurance contract, because the risk is normallyreduced by insurance benefits that are determined based on the beneficiary’s
anticipation.
However, in case of public disaster management policy by governments, thisdefinition may not be applicable. As shown in figure 3, governmental measures
have the effect of shifting down the curve of loss occurrence.

- Figure. 3 -5Regional Workshop on Total Disaster Risk Management

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According to this definition, the original risk of (x) has theoretically been
reduced to the new risk of (y) by the measures. The difference between tow
risks at the same level of anticipated loss clearly implies the effect of risk
management program by governments. The next step for the government,
however, must be to replace the original anticipate loss (a) with a new one (b)because it must have already been achieved for the same risk of (x). Thus, therisk itself is kept as it was and therefore cannot be the target indicator ofearthquake measures, but reduction of anticipated loss is. In other words, theefforts of governments to disaster are normally made to reduce an anticipatedloss at the same level of risk.
Thus, Morimiya(1) proposes a new definition, i.e., that a risk is the extent ofvariance between an unwished state and the current normal one, which isobserved as a potential gap. When it is applied to disasters, the variance is
identical to the estimated damage to the present properties of society, resulting
from earthquakes.
In figure 3, the volume of anticipated loss (b) that is reduced by earthquake
measures is the index of a risk, which may vary with the magnitude ofearthquakes, i.e., the risk of a large earthquake is high, and that of small
earthquakes is low regardless of their probability of occurrence.
Risk management for earthquake disaster in Japan
Since Japan is one of the most earthquake-prone countries in the world, thegovernments, private sectors and citizens have taken intensive measuresagainst earthquakes, to mitigate the damage caused by them, in particular, interms of the technological and engineering fields.
However, very few efforts have been made so far to reduce earthquake damage

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from the viewpoint of risk management except for an earthquake insurance
system, which has not enjoyed popularity due to the limited indemnity percontract for a high premium.
Table 1-(a) indicates the percentage of households that insure their homes andproperties against earthquakes. As shown in the table, its average ratio wasabout 7 per cent until the Hanshin-Awaji Earthquake occurred on 17 January
1995. The ratio jumped to 9 per cent just after the quake and to 11.6 per cent in1996 as the limit of indemnity per contract was increased from 10 million yen
to 50 million yen for buildings and from 5 million yen to 10 million yen forcontents (Note: 13.3% in 1997, unofficial figure).
It is also noted that earthquake insurance contract ratios vary among regionsthat are classified into four groups on the basis of potentiality of earthquake
occurrence (See Table 1-(b)).
In class 4, which comprises the most earthquake-prone regions including
Tokyo, the contract ratio is a record 20.1 per cent, while in class 1, lowest
potential regions of earthquake occurrence, only 7.6 per cent of the households
carry earthquake insurance.
As such, the earthquake insurance system does not seem to be recognized as
an effective earthquake risk management policy among the Japanese people.
Table 1-(a) Ratio of Earthquake Insurance Contact by Year
Year. Month

Ration Average insured amount

1996.3

11.6%

5,614 yen

1995.3

9.0%
7.0%

5,007
4,462

1993.3

7.0%

4,233

1992.3

7.1%

4,026

1994.3

1991.3

7.3%

3.812

Table 1-(b) Ratio of Earthquake Insurance Contact by Risk Class

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Regional Workshop on Total Disaster Risk Management

7-9 August 2002________________________________________________________________________________________________Class

Percent

Area

1st.(Lowest)

7.6

Hokkaido, Kagoshima, Hiroshima,etc.

2nd.

7.7

Niigata, Miyagi, Nagasaki, etc.

3rd.

11.2

Osaka, Hyogo, Kyoto, Aichi, etc.

4th (Highest)

20.1

Total

11.6

Tokyo, Kanagawa, Shizuoka(As of March l996)
With regard to the risk management measures by the government, most of local
governments have been conducting periodical surveys on potential danger on
earthquake disaster of their region.
For example, the Tokyo Metropolitan Government conducts two types ofsurveys periodically every five years. One is a survey on damage estimation inTokyo in an event of the anticipated Second Kanto Earthquake, and the other isvulnerability assessment by district in Tokyo.
The damage estimation survey measures to what extent the loss of buildings
and lives in a given area could be attributable to the Second Kanto
Earthquake.(4) On the other hand, vulnerability assessment measures how
vulnerable each district in Tokyo is, from overall points of view without
specifying any particular earthquake .(5)The survey of vulnerability assessment does not examine the damage itself but
the relative degree of magnitude of possible/probable damage which may vary
according to district. In the case of Tokyo, vulnerability assessment isrepresented here by five ranks in the smallest administrative units (figure 4).

- Figure.4 -8Regional Workshop on Total Disaster Risk Management

7-9 August 2002________________________________________________________________________________________________The results of damage estimation naturally reveal that regions subject toextensive damage also rate high in the vulnerability assessment, while, on theother hand, regions with little damage are safe and vulnerability assessment islow. Obviously, they are in direct proportion to each other.
In general, the relationship between damage estimate and vulnerability
assessment can be formulated as follows.
L(i,j)=∫∫P(k,t)・D(i,j,k)dtdk
k t∫L(i,j)dj
V(i)=∫∫L(i,j)djdi
i j
P (k, t) =Probability of occurrence of the earthquake k.
during the period of t

D (i, j, k) =The extent of damage (or loss) in aspect j causedby the earthquake k in district Aspect j includes
human loss and property loss

L (i, j) =Total damage (or loss) of aspect j in district i

V (i) =

Vulnerability to earthquake in district i during the period of t

As seen in this formula, a damage estimation study covers those cases ofdamage occurring under certain conditions, while a vulnerability assessment
study examines the possibility/probability of damage. If this were to be
described literally, it would have the meaning of “the mean value of various
suppositions of damage under varying circumstances.”

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These two studies are being conducted with different aims. The purpose ofdamage estimation is to formulate emergency measures during the response
phase, while a vulnerability assessment contributes to preventive measuresamong the pre-disaster phase from the viewpoint of urban planning.
Now, how can the results of these two surveys be utilized in an assessment ofrisk management for earthquake disaster mitigation? The damage estimate
obviously indicates Morimiya’s definition of a risk, although it is not used for
purposes of reducing direct damage but for preparing for relief activities during
the response phase.
As mentioned earlier, quick response is vital to control the extent of damage byrescuing the injured at an early stage thereby resulting in reduction in theoverall death toll. In this sense, the damage estimate survey should definitely
be considered as a component of risk assessment.
As to the measurement in the vulnerability assessment survey, no definition ofa risk discussed so far has matched it, since it reflects neither probability nor
volume of loss. Nevertheless, the vulnerability assessment survey is useful for
identifying districts where high priority should be given to intensive urban
planning and therefore provides an effective guideline for risk management.
In this regard, more detailed discussion about risk definition is urgently
required, in a practical sense.
The strengthening community capability to disasters is another aspect thatevery local government makes its effort expecting as an important risk

management measure. It is really true that the best resources for rescue andrelief after a disaster are the affected peoples themselves (Eisnar). In every
disaster, it is generally observed that public relief assistance cannot start justafter the disaster but delays for a couple of hours or more, and sometimes does
not reach to the affected area due to over relief demand. The affected people,
therefore, must help themselves until the public assistance reach to them.
Based on this recognition, Japan Disaster Countermeasure Basic Act provides
people’s responsibility for self-aid to natural disasters. Thus Japanese10Regional Workshop on Total Disaster Risk Management

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Government

has

been

encouraging

to

form

Self-Defense

Community

Organization to Natural Disasters. As a result, 93,000 organizations have been
formed and 55 per cent of households of the nation join this organization as ofyear 2000. The capability of the respective organizations, however, is still
unknown, though local governments provide certain amount of subsidy forthem to buy rescue and relief equipment for their capacity building. If we canmeasure their capability of risk reduction in a quantitative way, it should be
definitely important component of risk concept.
Concluding remarks
The idea of disaster risk management implies to reduce the risk of damage
caused by disasters. In this sense, the concept of risk works as a target or
objective indicator, by which the effect of disaster measures should be
evaluated. However, such risk indicator has not been clearly defined yet, or atleast is not shared as a common operational term for disaster management byrelated bodies such as politicians, administrators, enterprises, and citizens.
To meet this requirement, it seems to me that the definition of risk needs tosatisfy the following conditions:a.

The body who run a risk and therefore take measures to avoid it, should
be clarified,b. The event that causes a risk should happen with probability or
uncertainty to the body,c.

To serve as an objective indicator for the body to achieve,d. The period and spatial boundary applicable should be clarified,e. To be defined with clear dimension of scale.

Even though the concept of risk is vague, an idea of risk management is quite
attractive. It is because it implies an expectation for subjective and positiveefforts of human beings, which is an opposite attitude of passive resistance tounavoidable destiny. The progress of the idea is strongly expected.

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References(1)(2)

Morimiya, Y., What is Risk?, Yobo-jiho, Japan Association of Fire andMarine Insurance, No. 168, 1992

Shah H. and Davidson R.A., Risk Classification of Megacities, Proceedingsof The First International Earthquake and Megacities Workshop,
September 11, 2002 1-4,1997, Seeheim, Germany(3)Mehr, R.I. and Hedges B. A., Risk Management: Concepts and(4)Tokyo Metropolitan Government, The Survey on Damage Estimate caused(5)

Applications, Richard, Irwin Inc., 1974
by an Earthquake in Tokyo, 1991

Bureau of City Planning, Tokyo Metropolitan Government, The Survey on
Area Vulnerability Assessment of Earthquakes, 1993____________________________________________________________________________
This paper was prepared for the key speech of The Regional Conference on
Total Disaster Risk Management, organized by Asian Disaster Reduction Center,
held on 7-9 August 2002, Kobe, Japan, by rewriting the original paper
published in Planning Administration, Vol.20, No.3, 1997.

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