京 都 大 学 防 災 研 究 所 年 報 第 49 号 C 平 成 18 年 4 月Annualsof Disas. Prev. Res. Inst., Kyoto Univ., No. 49 C, 2006


A Comprehensive and Effective Earthquake Information System:Contributions to Earthquake Hazard Mitigation for a Local Government (3)Kunihiko WATANABE, Manabu HASHIMOTO, Tatsuya NOGUCHI㧖
Norio HIRANO and James J. Mori㧖

Civil Engineering, Tottori University

Synopsis
When significant earthquakes occur, local governments execute disaster prevention
procedures, however, the administration staff often have little detailed information about theearthquake. As a result of a questionnaire survey, some discrepancies are recognized between theadministration side and research side for the use of the earthquake information. The administrativeside would like to have " accuracy " and the research side emphasizes " diversity ". What should bedone to diminish this essential difference? As a convenient and effective method, a home pagesystem is proposed.
     Keywords: earthquake information, local government, earthquake disaster prevention

1.

Main Purpose

This investigation has been carried out since 2003 as apart of the 21st century Centers of Excellence project for
Natural Disaster Science and Disaster Reduction, and this is
the 3rd annual report of the same title. We have reported
on the previous progress in the two previous reports
㧔 Umeda et al.,2004 ; Watanabe et al.,2005).
Noguchi(2004) also mentioned about the database for thisproject.
In this section, the past results of this investigation aresummarized. When a significant earthquake occurs,
disaster prevention procedures are usually executed by localgovernments. Using the experience of the Hyogo-kenNanbu earthquake, the Central Disaster Prevention Council
settled on a disaster prevention program. Each local
government studied this program and made their own
appropriate disaster prevention plans. When a large
disaster occurs, the local government acts according to themanual of the plan. In this paper, only the aspects of aearthquake disaster are considered.
Usually, a local government initiates its disasterprevention plan at seismic intensity 4 or greater. The
seismic intensity information that is the basis of their actions
are provided to the local government through the Japan
Meteorological Agency and its related institutions. Also,
information from mass media is sometimes used.
Recently, the rapid earthquake information systems havealso been developed.
The local government establishes a headquarters fordisaster prevention and begins to execute countermeasureactions according to the scale of the earthquake intensity
and the damage situation.
Although the initial information about the earthquake istransmitted to the local government quickly, there is little
detailed information about the total amount of the seismic
activity. The local government is obliged to collect suchinformation on its own. Such information includes, thespatial expansion of aftershock area, decay of aftershock
activity, prospect of future activity, and other earthquake
related phenomena. Usually, there are many locally felt
earthquakes in the focal region, but smaller events may
not be reported sufficiently and the headquarters may not be
fully aware of the activity. Lack of information may cause㧙㧙anxiety for the residents.
We considered that providing detailed seismic
information to the local government immediately after amajor earthquake occurrence should be useful for executing
a meaningful disaster prevention program. In providing
this data, we want to know what practical information thatthe local government and residents truly desire. In
addition, we want to consider how the information shouldbe transferred. By conveying those requests to theearthquake researcher side, we will be able to improve thequality and quantity of information and the method ofinformation transfer.
There are three reasons that Tottori prefecture waschosen as a cooperating local government of this joint
research, as follows;
1) In Japanese historic times, the San’in district has been
seismically active for the past 100 years with occurrences
major earthquakes of Magnitude 7 or larger.
The Hamada earthquake (M7.1,1872), Northern Tango
earthquake (M7.3,1927), Tottori earthquake (M7.2,1943)
and Western Tottori-prefecture earthquake (M7.3,2000)
have occurred causing great damage. So the local
residents in this district have a great interest in the possiblelevels of seismic damage.
2) Kyoto University established the Tottori
microearthquake observatory in 1964 and started
microearthquake routine observation in the surroundingarea. Since then, we have accumulated much knowledge
about the seismic activity in the San’in district for more than
40 years.
3) It is well-known that Tottori prefecture provided effective
correspondence for the Western Tottori-prefectureearthquake in 2000. Tottori prefecture also retains a
positive posture for information disclosure.
For these reasons, Tottori prefecture and the Disaster
Prevention Research Institute of Kyoto University made anagreement, and this investigation plan has been started.
Two years has passed and we realize that the reason
why this project has been well developed is mainly due tothe accommodation of the conditions mentioned above.
2.

Current Progress

An information terminal was installed at the Tottori
prefecture office in March 2004, and practical use of thesystem started. Tottori prefecture and Kyoto University
entered into an agreement about the usage of the system.
The system configuration is shown in Fig.1. The display

Fig. 1 Block diagram of the Tottori system (Umeda et al,2004)
terminal of the system shows the earthquake information,
including seismic activity information (hypocentral
distribution, the number of earthquakes and spatio-temporaldistribution), felt earthquake information and seismic
waveforms. The seismic waveforms can be shown by useof a parabolic antenna installed on the roof of the prefectural
office that receives the data. Other information aretransmitted by phone line from the Research Center ofEarthquake Prediction, D.P.R.I., Kyoto University.
The system is in practical test use at present, so there are
domain restrictions on the system. Access is allowed to
Kyoto University, Tottori prefecture, Tottori University anda few personal addresses of related persons.
Since the beginning of the practical use of the system,no significant earthquakes have occurred around the Tottori
region, so Tottori prefecture has not initiated any cautionstates for the past two years. There are no cases yet for
which this system was used for an actual emergency
procedure , and there have been no evaluations of thesystem from actual practical use.
After a questionnaire survey of the members of Tottori
prefecture was taken, several opinions from theadministrative side were summarized. The results showedthat there was an essential discrepancy between
administration and research points of view.
Administrative side:
Accurate and guaranteed information (the informationnecessary for initiating action) are needed. The judgment
about the information should not differ depending on theperson. The information should be written in sentences
and also digitized.
The research side:
The view of researchers is to offer as much informationas possible. They often think that it is better not to hide㧙㧙any information, even if the judgement is left to the users .
The information from the research side generally lack
explanations.
A summary of the accesses to this information as
determined by the statistical software “Analog”(Turner,2004) is described below. Fig.2 is the monthly
number of accesses. This is the total number of all access,so the differences between domains cannot be identified.

as follows;
2004. 9. 5. Off Kii peninsula M7.1 seismic intensity 3
2004. 9. 5. Off Kii peninsula M7.4 seismic intensity 4
2004. 9. 7. Off Tokaido
M6.5 seismic intensity 3
2004.10.13. East Shimane-pref. M3.3 sismici ntensity 3
2005. 3. 20. Western Off Fukuoka-pref. M7.0 intensity 3.
Except for the fouth event, these were all large distantearthquakes. The 4th event on October 13, 2004 occurredin eastern Shimane prefecture and had a seismic intensity 3in Tottori (Yonago city), but the hypocenter was inneighboring prefecture of Shimane. Emergency responseby the Tottori local government was not needed for any ofthese cases. An extreme increase of the access number
was not recognized for all of these cases. It can be
anticipated that the accesses from the local government will
increase when a large earthquake occurs in the prefecture.

Fig. 2 Number of accessed files per 1 month. The
system was settled at March 2004 and a questionnaire wascarried out from December 2004 to January 2005. Twopeaks can be explained by those circumstances.
First, the number of accesses was highest in March
2004, because of the establishment of the system. There
were 1151 accesses during the 14 day interval until the endof March after the system was established on March 18th.
This is equivalent to 82 accesses per day. This seems tohave reflected the interest of the persons in charge. There
were no access from Tottori University at this stage. Oneof our co-investigators moved to Tottori University in Juneof 2004, so access from Tottori University started at thattime. The next peak was recognized in the period fromDecember in 2004 to February in 2005.
Thequestionnaire survey was distributed during this time, so theaccesses by concerned persons, including prefecture staff,
seem to have increased.
After that period, the number of accesses generally
tends to decrease. Table 1 shows the access numbers forevery period. The length of period varied, so the numberof accesses per day is listed. This is the result for
approximately 2 years. The statistical periods overlaps,
but the number of accesses is decreasing gradually.
Earthquakes with seismic intensity 3 or greater wererecorded 5 times in Tottori prefecture during these 2 years

Table 1 Number of accessed files according to theinstitution. Total number of accessed files in the period
indicated in the left is shown in the upper row and thenumber per 1 day in the lower.
3.

New Problems

The purpose of this system is to offer the informationthat the university can obtain to the local government inorder to be utilized for the disaster prevention program.
Usually the earthquake information collected by theuniversity are regarded as data only for research work, notfor commercial nor civic use. So, the stability over a long
period is not expected as a primary requirement. The
contents of the information and the system itself are oftenchangeable due to the circumstances of the communities ofuniversities and other research institutions.
The present system of data transmission uses satellite
telemetry, but this satellite system may be abolished by the㧙㧙end of 2006. After the end of the satellite system, it isplanned that the earthquake information network of theuniversity group will be shifted to JGN2, which is a highqualifty terrestrial network system . The satellite system
will no longer be used by the university group, but changeof the system is a big problem for administration. For theTottori system, the satellite transmissions will no longer beavailable. Furthermore, the 21st COE project is going tofinish in this fiscal year. We would like the information
system to remain as a contribution to society after the end of
this project and Tottori prefecture also wants to continue toutilize this system. However, currently there are nospecific plans nor funds for this from the university side.
As an alternative idea for data dissemination, we would liketo propose the home page system described in the nextchapter.
4.

Plans for Improvement

We talked with Tottori prefecture staff about future
prospects of this system.
The administration siderecognizes that the earthquake information is useful for theirdisaster prevention program. It is the obligation for theresearch side to propose ideas for the future possibility ofdata information to the administration side.
Considering some problems which the present system
involves, we concluded that a convenient homepage systemwith much more content would be preferable. In general,the homepage system can be easily and widely used. The
information sent by satellite are not used in the system,
therefore the maintenance becomes much easier. We hopeto start the experimental practical use of this homepage infiscal year 2006. The conditions that the system should
satisfy are the following.
1) A homepage should be appealing and frequently
accessed.
Ordinarily when large earthquakes are not occuring, thefrequency of accesses to the earthquake information system
are low. If there are few accesses, the earthquake
information is not of great interest. Therefore, thepotential of the earthquake information for theadministrative persons does not increase. Furthermore,
the administrative persons often change positions within inseveral years, and it is common that new members will
cover this project. In general, the administrative person
has many duties and does not concentrate on earthquake
disaster prevention program. In order to raise the potential
for earthquake prevention, it is necessary to increase theaccess frequency to the homepage.
To achieve more frequent accesses, the homepage
should contain other attractive information related toearthquake disaster prevention and mitigation, in addition to
the purely seismic information.
2) The home page should contain both attractive andspecialized information.
At present, the seismic wave data are transmitted by thesatellite as described above,. so, the maintenance of thesystem by members of the prefectural office side requires
technical expertise and time. But, there was little use of
the seismic wave monitoring. There may be two reasons
why the seismic wave monitoring is not used. One is thatthe understanding seismic wave is a little difficult for
non-seismologists, and the other is that there was not
sufficient explanation about the seismic waves. So, the
new homepage excludes the seismic wave monitoring thatare currently being receiving satellite data at the prefectureoffice. When the wave monitoring is needed, it will beavailable by accessing the homepage of the university.
Then, the maintenance on the prefecture side becomes moresimple.
The information displayed on this new web site isclassified into 3 types.
a) Accurate information which can be used for the disasterprevention program :This information is offered by the Japan Meteorological
Agency, and related institutions. This is authorized by theJapanese government and can be formally utilized for thedisaster prevention program.
b) Added information (reference information) :These are the data to assist and understand theauthorized information mentioned above. Explanations
about the authorized information are also included in thiscategory.
c) Descriptions and comments :These are the general descriptions about earthquake
phenomena and seismic hazards, which include comments
about various earthquake related problems. Geochemicaland geomagnetic data, seismic activity in the past andinformation related the area are helpful for understanding
the seismic activity. These are useful to improve thepotential about earthquake information for theadministrative persons in charge and the general users.
5.

㧙㧙

The Way to the Future
In this project, only Tottori prefecture was a cooperator

for this earthquake information system. The investigation
system is to be studied jointly by a local government and a
research institute, and is not a one-way street. The systemneeds the positive posture of the administration toward
information disclosure. On the other hand, we researchers
have accumulated knowledge about the past seismic
activity in this district. Therefore, as the co-investigator,
any local government might not be appropriate for this kindof project.
When considering the broad use of a system, easy
utilization becomes possible by adopting a homepage
system. There are some problems in the contents of
information in this homepage system. For example, theutilization of the real-time seismic waveform becomes alittle difficult. On the other hand, the merit is that manyusers can easily obtain the information.
As a result of the 2 year trial, the home page systemdescribed above is proposed as an effective information
system. Since the system does not have exclusive lines
and equipment, the congestion of the internet circuit may
arise when a large earthquake occurs, but, usual accessbecomes much easier. Use from a wide area can beexpected, and this must be effective to improve the potential
use for earthquake disaster prevention. We plan toconstruct the model homepage during the last year of the
21st COE project.
Acknowledgements
We would like to express our appreciation to the Tottori
prefectural office for all their efforts in this project, withspecial thanks Katsunori Kinugasa, Moriaki Johira,

Sadanori Hamada and Ryoji Kobayashi. Prof. Ryohei
Nishida of Tottori University provided valuable advoses inmany fields. We received much help regarding thesatellite system from the Earthquake Research Institute,
University of Tokyo and the Japan Meteorological Agency.
We also received valuable information from National
Research Institute for Earth Science and DisasterPrevention. We thank the many people of thoseorganizations for their support and cooperation.
References
Noguchi,T.,Watanabe,K.,Itaba,S., Nishida,R. and Umeda,Y.
(2004) : Preparation and Distribution of Earthquake
Information for the Disaster Prevention Program ofTottori prefecture – Oreparation of a Database Using GIS- , Annuals, Disas. Prev. Res.Inst., Kyoto univ., Vol.47C,
pp.139-147.
Turner,S.(2004) : Analog (The most popular logfileanalyzer in the world), web-site.
Umeda,Y., Oshiman,N., Hashimoto,M., Ito.K., Mori,J.J.,
Watanabe,K., Ohmi,S., and Shibutani,T.(2004) : A
Comprehensive and Effective Earthquake Information
System : Contrbution to Earthquake Hazard Mitigation
for a Local Government, Annuals, Disas. Prev. Res.Inst.,
Kyoto univ., Vol.47C, pp.71-76.
Watanabe,K. Umeda,Y. Ito,K., Hashimoto,M. Mori,J.J.,
Shibutani,T. and Noguchi,T.(2005) : A Comprehensive
and Effective Earthquake Information System :Contrbution to Earthquake Hazard Mitigation for a LocalGovernment, Annuals, Disas. Prev. Res.Inst., Kyoto univ.,Vol.48C, pp.25-29.

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