Cause of Human Damage by Typhoon No.0423 from October 20 to 21, 2004.
Motoyuki USHIYAMA
Iwate Prefectural University
ABSTRACT:A heavy rainfall caused by the typhoon No.0423 (Tokage) and a stationary front occurred inWestern Japan from October 20 to 21, 2004.

In this heavy rainfall, 96 persons were killed and serious

social capital damage was happened (GLIDE: TC-2004-000109-JPN).

It is the highest human damage by

heavy rainfall in Japan after the “Heavy rainfall on July 1983” (death persons: 117).
by flood.
1982.

32 people were killed

This is the largest number of death by flood since the Nagasaki heavy rainfall disaster in July

And 3/4 of them died while driving or walking out of their resident area.

It is difficult to transmit

of disaster prevention information such as flood forecast to them on actual forecasting and warning system.
28 persons were killed by sediment disaster and almost of them died in their houses.
actual disaster information could mitigate this type victim.
canal or river and died.

It is possible that the

20 persons slipped down to small irrigation

Almost of them were the aged and on patrol to their farmland.

In this study, thistype cause of death was called "Active accident".

It is difficult to mitigate this type victim because they had

accessed to dangerous area of their own free will.

If actual disaster information such as precipitation, flood

forecast and hazard map had used and understood completely, it had been possible that 35 victims had
mitigated.
KEYWORDS: Typhoon No.0423, heavy rainfall disaster, flood disaster, sediment disaster, disasterprevention information.
(FDMA, 2004a).

1. INTRODUCTION

This amount of damage was theworst in the past 10 years.

The number of humanThe heavy rainfall and strong winds of Typhoon No.

deaths in particular was the highest recorded since0423 (TOKAGE) caused widespread damage andthe "Sanin heavy rainfall in 1983", which had anumerous deaths on the Japanese archipelago fromdeath toll of 117.

October 20 to 21(Figs. 1, 2).

In addition, there wasan active stationary front north of the typhoon,

In the years prior to the typhoon No.0423, there

accompanied by heavy rainfall. The highest 1-hour

were fewer deaths caused by heavy rainfall in Japan,

precipitation in the last 25 years was recorded at one

with the average number of deaths caused by storms

observatory, and the highest 24-hour precipitation inor typhoons 76 persons per year (FDMA, 2004b).

the last 25 years was recorded at 30 observatories

There are several characteristics to the humanbased on the data of the Japan Meteorologicaldamage caused more recently by heavy rainfall in

Agency.

Japan.

The typhoon and stationary front caused

First, the major cause of death by heavy

record damage (GLIDE: TC-2004-000109-JPN).

rainfall was due to sediment disaster, which is

In western Japan, ninety-six persons were killed,

defined as death by debris flow, slope failure, or

11,839 houses damaged, and 62,528 houses flooded

landslide, and few people were killed by floods. The

Cabinet Office (2003) estimated that the number ofdecreased.

deaths by sediment disaster was about 50 percent of
the whole.

Second, in recent serious heavy rainfall

disaster events, the deaths occurred within a narrowarea.

The heavy rainfall disaster in Minamata in

2003 (19 persons dead) and the heavy rainfall
disaster in Izumi on 1997 (21 persons dead) are
typical examples.

In these events, the deaths

occurred in only a few municipalities.
of those who died were elderly.

Third, mostIn this study, thistype of disaster will be called a "local type heavy
rainfall disaster."Typhoon No.0423, however, had different
features from those listed above.
of deaths was very high.

First, the number

Fig. 1 The route of typhoon No.0423

The annual average

number of deaths in the past 10 years was exceededin only this one event.
wide area.

Second, persons died over a

Third, many persons were killed not by

sediment disaster but by floods, and fourth, elderly
people were not the only people killed.
Analyzing the causes of death in a natural
disaster is important for disaster prevention efforts.
There have been several studies on the causes ofdeath during earthquakes (Japan's National Land
Agency, 2000, Kobayashi, 1981).

There have also

been several studies on the human damage caused by

Fig. 2 24-hour precipitation distribution map atthe "Nagasaki heavy rainfall"(Matsui et al., 1984).

24:00, October 20, 2004

However, since those studies were published, little
attention has been paid to the causes of death byheavy rainfall disasters.

It is likely that the reason

2. METHODOLOGY

for this lack is that no events have occurred since theNagasaki event in which many people were killed.

The FDMA examined an outline of the humandamage] (2004a).

The purposes of this study are:Generally, disaster statistic

values change with time.

From the FDMA study,1) To analyze the characteristics of the humanthe value on November 29, 2004 was used.

damage caused by typhoon No.0423.

total number of deaths was 96 persons in 18

2) To gather disaster prevention information, and toprefectures.

propose ways in which human damage can be

as follows: Chiba; 2, Kanagawa; 1, Gifu; 8, Aichi; 1,

The

The number for every prefecture wasShiga; 1, Kyoto; 15, Oosaka; 1, Hyogo; 26,

Kochi prefecture, 3 persons were killed by highWakayama; 1, Tottori; 1, Okayama; 7, Tokushima; 3,waves.

Kagawa; 11, Ehime; 5, Kouchi; 8, Nagasaki; 1,were killed.

Ooita; 1, Miyazaki; 2.

Detailed information on therightly be called a "local type heavy rainfall disaster"dead was collected from the web pages of the

but rather a "wide area type heavy rainfall disaster".

prefectural offices, municipality offices, national

Some events known as serious heavy rainfall

newspapers, local newspapers and others.

disasters, such as the "Sainin heavy rainfall in 1983"

In the other localities, one or two persons
Thus, the present disaster event cannot(117 dead) and the "Nagasaki heavy rainfall in 1982"
A field survey and interview survey were(299 dead) were also considered "local type heavy

performed in areas that had been seriously damaged.

rainfall disasters".

Toyooka city in Hyogo prefecture, Maizuru city,area type heavy rainfall disaster" has not occurred

Miyazu City, and Ooe town in Kyoto prefecturesince the "heavy rainfall disaster caused by typhoon

were researched on October 24 and 25.

No.17 in 1976" (169 dead).

SumotoIt is likely that a serious "widecity, Tsuna town and Ichinomiya town in Hyogo
prefecture, and Sanuki city and Higashi-Kagawa cityin Kagawa prefecture were researched on November
8 and 9.

In addition, the questionnaire survey wassent to seriously damaged municipality offices.
Twelvequestionnaires

weremailed,and5municipalities completed them.

3. RESULTS
3.1 Identification of the location of the deadRough addresses of the places where the dead were
found were identified based on the data gathered andFig. 3 Distribution map of deaths

the field survey.

▲: Floods, ★: Sediment disaster, ●: High waves,

This address data was converted

into latitude and longitude data by use of the "Free▼: Strong winds, ■: Active accident

Address Geocoding service for CSV formatted fileon WWW" (Center for Spatial Information Science,
University of Tokyo, 2001).

3.2 Classification of causes of death
A method for classifying the deaths caused by heavy

Fig. 3 shows the distribution of deaths caused

rainfall disasters has not been established in Japan.

by the typhoon based on the latitude and longitude

In the "Japan Statistical Yearbook", printed by thedata.

The total number of deaths was 96 persons,

Ministry of Internal Affairs and Communications,as stated previously, and the dead were found in 78

deaths by natural disaster are classified into

places in 60 municipalities.

"typhoon", "storm", "strong winds", "high tide",

The largest number ofdeaths was in the area of Uno, in Tamano city,"earthquakes",

Okayama prefecture, where 5 persons were killed by

However, there are several problems with thissediment disaster.

classification.

At Murotosaki-cho, Muroto city,"volcanoes"

and"tsunamis".

One is that it is not clear what thedifference is between a "typhoon" and a "storm".

irrigation canal while patrolling a paddy field orClassifying by hazards, such as a flood or sediment

other area can be classified as "flood victims".

disaster, is needed.

In addition, in the deaths that

we have seen, there are not few such victims recently.

occurred in the most recent heavy rainfall disaster in

They must have known that a swollen irrigation

Japan, some people were killed due to carelesscanal could be dangerous, but still went to the

behavior.

dangerous area and died.

A classification that takes this into

account was also needed.

Therefore, in this study,

we made the following classifications:"active victims."

As

They are thus, so to speak,

Of course, there are various

reasons for their behavior, but the behavior of"passive victims" and "active victims" can be1) "High waves": death by sea waves along the coast, considered to differ.

Therefore, methods fore.g. , death caused when the person was inside a

preventing human damage must also differ.

Forhouse destroyed by high waves, or death caused bythese reasons, the classification "active accident"

being struck by a wave during work or when visiting

was made.

an area.
2) "Strong winds": death related to strong winds,

Fig. 4 shows the classification of causes of

e.g. , person who died because of being blown off adeath from the disaster.

Thirty-two persons died byroof by strong winds, or being crushed by a tree

"flood", and 20 by "active accident".

felled by strong winds.

"active accident" were included in the deaths caused

3) "Active accident": persons who died because theyby flood disaster in ordinal disaster statistics.

Deaths byThus,

approached the dangerous area instead of evacuating, in ordinal disaster statistics, the death toll by floodor persons who died after falling into an irrigation

would be considered 52. The numbers of deaths bycanal while patrolling a paddy field or irrigation

flood were far fewer in the latest disaster in Japan.

canal.

However, in this typhoon, the number of deaths by

4) "Flood": death by flood flow or inundation, e.g. ,flood was higher than that by sediment disaster.

drowning in their house, or being carried away by

Hyogo prefecture, which suffered the worst damage,floods while driving a car or walking.

15 of 26 deaths were by flood.

5) "Sediment disaster": death by debris flow, slope

prefecture, 10 of 15 deaths were caused by flood.

failure and landslide.

Table 1 lists the events since the 1980s in which theIn

Even in Kyoto

number of deaths was 50 persons or more, for"Active accident" is the classification that isoriginal to this study.

This classification wascomparison with the present event.

As the tableshows, since the 1980s, most of the deaths were

defined in order to distinguish it from "floods".

caused by sediment disaster.

Passive victims may be considered to be thoseflood in the "Nagasaki heavy rainfall disaster inpersons who, for example, stayed indoors, not1982" was the most serious (about 30 persons) ofrealizing that their houses would be flooded and thatthese events.

they would drown.

present event is the largest since 1982.

Moreover, people who drowned

The death toll byThus, the death toll by flood in
Manywhile driving their car or walking were attempting topersons were killed by flood in the "Niigata andrun away from the danger, and can also be

Fukushima heavy rainfall disasters", but the death

considered "passive" victims.

toll by flood in the present event exceeded thoseOn the other hand,

generally persons who died after falling into an

numbers.

Serious human damage caused by floods

has not occurred for about the past 20 years.

present event shows that there is a possibility that

However, this was evidently a matter of luck, as theserious damage will occur from now on.

Table 1 Heavy rainfalls causing the deaths of 50 or more persons since the 1980s
Date

Cause of heavy rainfall

1982. 7.10 - 26
1982. 8. 1 - 3
1983. 7.20 -27
1991. 9.24 - 10.1
1993. 7.31 - 8.7
2005. 7.13
2005.10.20 - 21

Death(persons)
Nagasaki heavy rainfall
299
Typhoon No10 and front
95
Sanin heavy rainfall
107
Typhoon No.19
62
Kagoshima heavy rainfall
49
Niigata and Fukushima heavy rainfall 16
Typhoon No.23 and front
96

Breakdown (persons)Sediment disaster: 263
Sediment disaster: 56, Flood: 15, unknown: 24
Sediment disaster: 91, Flood: 11
Most of death caused by strong wind.
Most of death caused by sediment disaster.
Flood: 12, Active accident: 2, Sediment disaster: 2
Flood: 32, Active accident: 20, Sediment disaster: 28

present disaster was higher than that in the
Unknown Strong,1
wind, 5"Nagasaki heavy rainfall disaster" and "Kagoshimaheavy rainfall disaster".

Sediment
disaster,
28

We can say with a fairamount of certainty that the "victims were unevenly
distributed among elderly people".

Flood, 32

However, it isnecessary to examine this issue from another point ofHighwave, 10view.
Activeaccident,
20

Fig. 6 shows the relationship between cause of

Death or missing: 96 persons

Fig. 4 The number of deaths by cause

death and age in the present disaster event.

The

death rates of elderly people (over 65 years old)
were higher than half in the "active accident" and"sediment disaster" classifications.

However, the

3.3 Relationship between cause of death, age, sex

death rate by "flood", among non-elderly people

and location of the dead(under 65 years old) is higher than half.

First, the victims were totaled according to age.

of these victims were washed away by floods while

Forty-one victims were under age 65 and 54 overdriving or walking.

age 65, so called elderly people.

between the cause of death and sex.

When theAlmost all

Fig. 7 shows the relationship
It is not clear

threshold was set at 60 years old, there were 34

if there is a significant difference (significance level:

persons under age 60 and 61 persons over age 60.

5%) of sex in the "flood" and "sediment disaster"Thus, elderly people accounted for about 60 percent

classifications.

of the total victims.

"active accident" is higher than that of females.

Fig. 5 compares the death toll

But the death rate of males by
Fig.

of the elderly in the present event with other recent

8 shows the relationship between the cause of death

serious heavy rainfall disaster events.

and location of the dead.

In this figure

Almost all of the victims

only, "elderly people" are defined as over 60 years

who died by "sediment disaster" died indoors, andold in the data on the "Nagasaki heavy rainfall

most of the victims by "flood" died outdoors.

disaster".

The death rate of the elderly in theNagasaki heavy rainfall on 1982

191

Kagoshima heavy rainfall on 1993

33

Niigata and Fukushima heavy
rainfall on 2004

Activeaccident

61

6

Flood

39

2

20

Sediment
disaster

14

25
0%

Typhoon No.23 on 2004

34

0%

20%

25%

50%

3
75%

100%

61

IndoorLess than 60 years old
60 years old or more

26

40%

60%

Outdoor80% 100%

Fig. 8 The death toll by the location of the dead andFig. 5 The death toll of elderly and non-elderly people

causes of death.

in the resent serious heavy rainfall disasters.

3.4 Possibility of human damage mitigation by using
disaster prevention information
Activeaccident

6

14

In this section, it is estimated how much humandamage can be mitigated when disaster prevention

Flood

17

14

information, such as rainfall forecasts, real-time
precipitation data, hazard maps and other tools, isSediment
disaster

11

17

0%
25%
50%
Less than 65 years old
65 years old or more

used.

75%

100%

The objects of estimation are the victims of"flood" and "sediment disaster".
First, the victims by "flood" were classified
based on the location where they were killed.

Fig. 6 The death toll by age and cause of death.

Thelocations are as follows: (1) In their home, (2)Outdoors near their home, (3) Outdoors far fromtheir residence area.

It is possible that the victimsof (1) and (2) could be saved if the following
Activeaccident

15

5

Flood

15

16

Sediment
disaster

15

13

necessary conditions were satisfied.
(a) By viewing a hazard map, they understood that it
was dangerous near their house.

0%
Male

25%

50%

75%

(b) The real-time precipitation or river water level
100%

Famaleinformation was gathered and disseminated throughthe Internet, radio, and by other means.
(c) The present precipitation or water level wasunderstood to have reached dangerous levels for the

Fig. 7 The death toll by sex and the causes of death.

region.

system, not only using IT but all technology, toTheinformation

contained

in

(b)

is

disseminate information to people.

disseminated now in Japan, and hazard maps offloods are released partly rivers to public by printed
mater or web pages.

Of course, it is not easy for

Most of the 25 persons killed by "sedimentdisaster" were killed inside their homes.

Althoughthe three conditions listed above to be satisfied, but it

three persons were killed outdoors, two of them wereis not impossible.

killed beside their homes.

That is, 27 victims werethe (1) or the (2) type victims.

Therefore, it isHowever, four-fifths of the "flood" victims werepossible that the victims could have been saved if thetype (3) victims, and it would be very difficult tonecessary conditions (a), (b) and (c) listed above

save this type of victim as most were killed in awere satisfied.

place far from their residence area during a trip byof victims by "sediment disaster", 27 persons could

car or when walking for commuting purposes or on

have been saved by obtaining information.

Judging from the above, in the casebusiness and there were only a few persons who
were evacuated to a shelter.

Therefore, it is likely

As we have seen, the victims who died by anthat knowledge would not be useful to them, even if"active accident" were defined as "persons who diedthey could see the hazard map for their residence

because they approached the dangerous area by

area.

themselves

It is not impossible to pass information

insteadofevacuating".

They

gathered about real-time rainfall and river water

approached the dangerous area of their will.

levels by mobile phone and other methods.

But itprobable that their decision would not have been

is not easy for non-experts to use this information,changed only by receiving disaster information.

because most people don't know how gather

Therefore, it is unlikely that these victims could haveinformation on real-time rainfall and river water

been saved, even if all necessary conditions were inlevels, or how to use this information to help themplace.

remain safe.

In addition, the present information on

often considered "support to elderly people".

flood forecasts does not show the inundation depths

However, 14 of the 20 victims who died from aninland (out of river).

"active accident" were elderly people.

It is

Refuge guidance at the time of a disaster is

It is possiblethat this number cannot be reduced, even if an
Judging from the above, in the case of victims

evacuation guiding system for elderly people isby "flood", the number of victims who could be

developed.

saved by additional information was estimated at 8with information and support so that they do not

persons.

become victims of an "active accident".

It was the sum of the (1) type victims (6persons) and the (2) type victims (2 persons).
were elderly, over 65 years old.

It is important to provide the elderlyAll

However, it wasFig. 9 shows the conclusion of the above

estimated that it would be difficult to save the (3)estimation.

type victims, 24 persons, using this information.

disaster prevention information.

Seventeen of them were not elderly people.

The thick line is a connector related to
The number

That is, classified into the lower side of the connectors is 35

people become vulnerable to disasters regardless of

persons.

age when they are taking a trip.

prevention information had been used, 35 persons

It is necessary todevelop an information transmission method or

It is possible that if the present disastermaximum would have been saved.

All death toll
96 persons

Strong wind,High wave: 16

Indoorout of analysis

Flood: 32

6

Place

Near

Others: 80
OutdoorResidence
area
Distant

Passive

2

24

Indoor25

Passive
Approach todangerous area

Sediment
disaster: 28

Place

Near
2

ActiveOutdoorResidence
area

Active accident: 20

1
Distant

Fig. 9 Flow chart analysis of causes of death in the disaster

4. CONCLUSIONS(3) The awareness among residents of the dangers ofIn this heavy rainfall disaster, 96 persons were killed, natural disasters is decreasing.
the highest death toll by heavy rainfall in Japan since(4) The danger of underground spaces flooding is

the “Heavy rainfall in July 1983” (117 persons dead). increasing.
Several heavy rainfall disasters occurred in 2004 in
Japan, including the "Niigata and Fukushima heavy

The above points need to be further discussed.

rainfall in 2004", in which 16 persons died, theAs we have seen, one of the most important points to"Fukui heavy rainfall disaster in 2004" (5 persons),

note about the disaster studied here is that 32 of the"Typhoon No. 0416" (17 persons), "Typhoon No.

96 victims were killed outdoors by floods.

0418" (45 persons), and "Typhoon No. 0421" (27was a very rare circumstance when other recent

persons).

heavy rainfall disaster events are considered.

These disasters had a strong impact on

This
They

the Japanese government, and several committees

are not only elderly people, and it is also difficult tofor heavy rainfall disaster prevention policy weresave them by mutual help, the point (2), andformed.

For example, the Ministry of Land,

improvement in awareness for disaster, the point (3).

Infrastructure and Transport (MLIT, 2005) made the

Further research and analysis into the causes of deathfollowing points about the recent heavy rainfall

by heavy rainfall disaster would clarify the issues

disasters.

that need to be addressed.

(1) The damage was unevenly distributed among"people vulnerable to disasters", such as the elderly
and handicapped persons.

NOTE(2) Mutual help of resident community at the time ofThis paper is a revision of an earlier study bydisaster became inactive.

Ushiyama (2005, in Japanese).

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Fire and Disaster Management Agency (FDMA),
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