Failure Knowledge Database / 100 Selected Cases

The Hanshin Awaji Great Earthquake (Hyogo Prefecture Southward Earthquake)[On 17th January in 1995, Hanshin and Awaji district]Masahiko Kunishima, Mariko Abe（Note１）
The earthquake, which hit the city early in the morning, brought about great damage
such as the burning and collapse of buildings in the Hanshin and Awaji region. A large
number of casualties occurred, and the city functions were paralyzed for a long time. In
particular, a large number of casualties were caused by the collapse of houses.
Furthermore, the fires that broke out just after the earthquake increased themagnitude of the disaster, which became the largest earthquake disaster in the postwarera.
A great number of fundamental infrastructures, such as expressways, railways,
harbors and lifelines, were damaged.
1. Event
Early in the morning on 17th January 1995, a M7.3 earthquake whose hypocenter
was below Akashi Channel occurred and brought great damage to the Hanshin Awaji
district. Over 6,400 people died and over 41,500 people were injured, and the monetaryamount of the damage is estimated to have been over 9.6 trillion yen. Especially, in theregion that is called the "band of the earthquake disaster" (→Figure 1, 2) located on thealluvial plain of the base of Mt. Rokkosan where a seismic intensity of 7 was registered,many old wooden houses with tiled roofs fell down, and many people who were buried
under the houses died. The bridge with single pillars of Hanshin Expressway collapsed
over a length of 630m (→Figure 3), and the viaduct bridges made of RC rigid frame ofthe Shinkansen also collapsed (→Figure 4). Part of the structure of the subway wasdestroyed for the first time in the world (→Figure 5). In the reclaimed land of "PortIsland", the cranes in the harbor dipped due to the liquefaction of the ground (→Figure6).

1

Failure Knowledge Database / 100 Selected Cases

Figure 1 "The band of the earthquake disaster" in Hanshin district(From the field study of Meteorological Agency) (Source: Architectural Institute of Japan)

Fault

Akashi Strait

Osaka Bay

Figure 2 Fault distribution chart of Hanshin district (Source: Architectural Institute of Japan)

2

Failure Knowledge Database / 100 Selected Cases

Figure 3 Collapse of the Pilz elevated bridge of Hanshin Expressway Kobe Line
(Source: Architectural Institute of Japan Picture: YomiuriNewspaper)

3

Failure Knowledge Database / 100 Selected Cases

Figure 4 Collapse of the Hansui elevated bridge of the Sanyo Shinkansen(Source: Architectural Institute of Japan, Picture: NikkeiBP Co)

Figure 5 Crushing of the central pillar of Daikai Station of Kobe Express Railway andcollapse of the upper floor panel (Source: Architectural Institute of Japan, Picture: Prof. Iwadate)4

Failure Knowledge Database / 100 Selected CasesFigure 6: Collapse of the RC3-4 crane at Rokko Island(Only one crane totally collapsed.) (Source: Japan Society of Civil Engineers)
2. Course
There were four foreshocks that occurred on 16th January 1995, the night before theearthquake, with magnitudes of M3.6, M2.5, M1.5, and M2.1. These earthquakes
occurred just below Akashi Channel where the main shock occurred.
At 5:46 on 17th January 1995, the M7.3 earthquake whose hypocenter was below
Akashi Channel occurred. The quaking motion due to this earthquake was observed
from the southern Tohoku area in the north to southern Kyushu in the south, and theseismic intensity of 7 was applied for the first time near the hypocenter. A region ofseismic intensity 7, which was 1km in width and 20km in length and called the "band of
the earthquake disaster", appeared from Kobe City to Nishinomiya City.
Due to the earthquake, approximately 6400 people died, about 512,880 residential
houses collapsed, 285 buildings caught fire, and many infrastructures were damaged.
The total amount of the damage came to over 9.6 trillion yen.
As the large earthquake occurred early in the morning, many people who weresleeping in their houses were killed due to the collapse of the house and the falling of
the furniture. Furthermore, the people who did not die due to the collapse of the house
could not escape since they were buried under the collapsed house, and many of themwere killed by the fire.
3. Cause
Before the Hyogo Prefecture Southward Earthquake occurred, there was a general,almost superstitious, belief that "a large earthquake will not occur in the Kansai area",
5Failure Knowledge Database / 100 Selected Cases

although the documents for historical earthquakes prove that this belief was false.
Therefore, it can be said that the consciousness of disaster prevention in the entire
society of that region was low and that the disaster prevention countermeasures were
not advanced.
"Many more people might have been saved, if a mechanism which stipulated that theSelf-Defense Forces could be dispatched without waiting for the request of the governor
had been prepared." "The damage could have been reduced if the prime minister had
dealt with this situation earlier." Although a lack of the follow up measures was pointed
out, the biggest reason for the large number victims caused by this earthquake was thecollapse of houses, which occurred instantly after the earthquake. Of the approximately
5500 people who were killed by direct damage, 77% of them (4224 people) died from
suffocation or traumatic asphyxiation, and 9.2% of them (504 people) died from burns
suffered by the fires.
Autopsies of about 2400 bodies were done by the medical examiners in Hyogo
Prefecture and the doctors from the Japanese Society of Legal Medicine in the localitiesof their responsibilities (Kobe City except for Nishi Ward and Kita Ward), and autopsiesof another 1200 bodies were done by the clinicians who were asked by the Hyogo
Prefectural Police. The totals for the cause of death reported on the 3651 postmortem
certificates from the autopsies are shown in Table 1 (Nishimura, 1997).

Death
Number Percentage
Suffocation
1967
53.9%
Crush
452
12.4%
Shock of injury
82
2.2%
Head
124
3.4%
Internal organ
55
1.5%
Neck
63
1.7%
Burned444
12.2%
Insufficiency
150.4%
Depresson/Frozen
70.2%
300
8.2%
BruiseUnknown
116
3.2%
Other
26
0.7%
Sum
3651
100.0%
Table 1: The distribution of the causes of death(Source: Architectural Institute of Japan, The report of interdisciplinary symposium on the death factors from theviewpoint of forensic medicine and casualties problems in the earthquake" (edited by Akira Nishimura ／ humansuffering workshop, 1997)

Another report showed that 90 percent of the places where victims were injured were
their own houses, including apartment buildings. The most of these victims lived inwooden houses, but not all because some RC apartment buildings also collapsed. The
reconstruction of the old wooden houses had not advanced in the downtown area where6

Failure Knowledge Database / 100 Selected Cases

the number of victims was large. This lack of reconstruction resulted from the physicalfactor that there were many houses built in a terrace style making it difficult toreconstruct the houses individually the economical factor that the reconstruction costs
could not paid because there were many elderly people, and the legal factor that there
were many small house sites.
4. Immediate Action
As a political response to the situation, the countermeasures headquarters wereestablished in each of the ministries concerned, the local authorities, the government
corporations, and the government financial corporations.
About four hours after the earthquake, "the emergency center of Hyogo PrefectureSouthward Earthquake in 1995" led by the Director-General of the National Land
Agency was established by the decision of the cabinet. This center made the decision tocarry out precautions against aftershocks, assessment of the damage, search and rescue
operations for missing people, aid measures for the disaster victims, extinguishing offires at the early phase, and early emergency recovery of the damaged facilities such as
roads, railways and lifeline utilities.
Staff members of the fire defense authorities who gathered in the area damaged by
the earthquake engaged in fire fighting and emergency rescue efforts. The total numberof the volunteer fire fighters who engaged in the emergency rescue effort was estimatedto be 71,000. Furthermore, many inhabitants joined self-organized disaster prevention
organizations such as community associations engaged in fighting fires in the earlyphase, rescue efforts and preparation of hot meals.
Disaster investigating teams from academic societies such as civil engineering,architecture,earthquake,machineandgeotechnology,

weredispatchedandinvestigation committees were established.
Because of the great scale of the disaster that involved many organizations, thecorrespondence was examined in the entire field.
5. Countermeasure
Various countermeasures were taken for restoration and reconstruction, including
price stabilization measures, emergency rehabilitation, assessment and restoration ofthe damaged lifeline facilities, execution of the disaster garbage disposal, support forsmall and medium enterprises, guarantee of employment for the victims, development
and improvement of the system, and so on. There are many countermeasures that are ineffect even now in 2004.

7Failure Knowledge Database / 100 Selected Cases

6. Generalization
It is important to foresee the situation that could occur in an earthquake and toprepare appropriate countermeasures before an earthquake occurs. It goes without
saying that the appropriate response after an earthquake is important, but it can besaid that degree of preparation for earthquakes is the biggest factor for saving lives.
The Great Hanshin Earthquake caused such a large effect on Japanese society that it
forced people to reconsider the basic social system.
In order to assure that the tremendous sufferings caused by the Kobe earthquake
would result in an opportunity to create a safe and comfortable city, it is necessary to
face up to the damages, to understand the problems precisely and to try to solve them.
7. Knowledge
The following lessons for the general public are mentioned.
◎Training to imagine the situation that could occur in the case of earthquake○Reinforcement of buildings should be done.
○Furniture such as sideboards should be fixed to the wall.
○It is better to sleep in the second floor when living in a detached house.
The following countermeasures are mentioned.
The protection of the lives of yourself and the people you know should be the highest
priority since there is no lifesaver just after a big earthquake. It is important to foresee
the situation that could occur in an earthquake and to prepare appropriate
countermeasures before an earthquake occurs.
The following lessons for all the people who participate in the infrastructure
investment are mentioned.
◎ It should be kept in mind that if you leave existing structures that do not meet thestandards in a state of disrepair, even though the academic advance has revealed
that that is a problem, your action could be considered to be a crime of omission. In
the guidelines for "nonconformance to the standard", the buildings that had met thestandards at the time when they were constructed could be legally released from therequirements of the current standards, even if the standards are revised. However,
because this standard was established on a firm scientific basis, if the retroactive
application of the revised standard is not taken for the existing buildings, theywould remain dangerous.
○ You cannot say that anything is safe "absolutely" if a big earthquake occurs. Inengineering, a humble attitude towards nature is important.
○ It is a duty of the specialists to enlighten the general public so that they would not8

Failure Knowledge Database / 100 Selected Cases

think that "vows made in a storm are forgotten in the calms".
8. BackgroundThe general belief was that "a large earthquake will not occur in the Kansai district."
Actually, it was noted that "if a large earthquake occurs, it will bring great damage" inthe newspaper in previous decades, but this warning had been forgotten by the generalpublic. To maintain countermeasures continuously against earthquakes which only
occur every 10 to 100 years is difficult because it runs against basic aspects of humannature, such as "to get bored", "to forget" and "to give up." This catastrophic earthquakedisaster has led to the realization that countermeasures have to be taken andmaintained in order not to lose important things, however difficult that is.
There are some problems for which no countermeasures had been taken in spite of thefact that they should not be left, such as the problem of city blocks crowded with wooden
dwellings. Countermeasures must be examined from a broad viewpoint that goesbeyond the field of disaster prevention.
＜Reference＞"The report of the Great Hanshin Earthquake -roundup edition-" (edited byArchitectural Institute of Japan, 2003)"Dictionary of the earthquake disaster prevention" (Tsuneo Okada and Kenzo Toki,
2000)"The report of interdisciplinary symposium on the death factors from the viewpoint offorensic medicine and casualties problems in the earthquake" (edited by Akira
Nishimura ／ human suffering workshop, 1997)------------------------------------------------------------------------------------------------------------------------(Note 1) The department of civil engineering, the University of Tokyo

9