京 都 大 学 防 災 研 究 所 年 報 第 50 号 C 平 成 19 年 4 月
Annuals of Disas. Prev. Res. Inst., Kyoto Univ., No. 50 C, 2007

A Comprehensive and Effective Earthquake Information System:
Contributions to Earthquake Hazard Mitigation for a Local Government (4)Kunihiko WATANABE and Manabu HASHIMOTO
Synopsis
So-called “Tottori project” has been carried out for these 3.5 years. As for this cooperative
project, the earthquake researchers provide the detailed earthquake information to theadministrative organs of Tottori local government. The outcomes obtained by utilizing
actually are then fed back to researchers. The purpose of this project is to improve
earthquake information to be more useful for actual society. Through the experience for 3.5
years, it was recognized that there were some discrepancies between the researcher side andthe administration one. As the 21COE project was finished, we started to distribute ahome-page of earthquake information experimentally.
Keywords: earthquake information, local government, earthquake disaster prevention

1. Introduction
As a research project of 21st century COE program,Research Center for Earthquake Prediction, D.P.R.I. of
Kyoto University put so-called " Tottori project " into
effect with Tottori prefecture. The origin of this project
was the M5.3 earthquake occurred in the central partof Tottori prefecture in September 2002.
When a remarkable earthquake occurred, a local
government was able to get seismic intensity
information quickly at that time. So, the disasterprevention measures were supposed to beaccomplished based on this information. But, it wasdifficult for a usual local government to get moredetailed information about the successive seismic
activity after that. Therefore, it was necessary to
execute the effective measure in the so-called grope
state after the occurrence of a remarkable earthquake.
The author and the director of the disaster protection
service of Tottori prefecture discussed and made thefollowing plan. First, the researcher side of theuniversity offers detailed seismic activity information
to the local government. The local government utilizes
this information in earthquake disaster prevention
program. By using those results of utilization, theuniversity and the local government execute the joint
research which improve earthquake information andcommunication technique to be more effective. This isso-called " Tottori project ".
This paper is a generalization of " Tottori project ".
2. Seismic activity in the western Japan and theearthquake of the central Tottori prefecture in 2002
At first, we look back to the historical major seismic
activity in the western Japan (Fig.1). M7 class large

Fig.1 The earthquake distribution of more than M5
in western Japan from historical days to recent (byJMA data). Red circles show M7 class earthquakes.

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earthquakes which appeared first in the area of Fig.1
were Harima earthquake (in 868 (Jogan 10), M>=7)
and Izumo earthquake (in 880 (Gankei 4), M7), both
after the chronological table of science. After them, forabout 1000 years, any M7 class large earthquake had
not occurred in the area of the figure until Hamada
earthquake in 1872 (M7.1).
Following the occurrence of Hamada earthquake,the seismic activity started to be active again in the
San-in coastal region. Tajima earthquake (1925, M6.8),
northern Tango earthquake (1927, M7.3) and Tottori
earthquake (1943, M7.2) successively occurred, andafter them, Tonankai earthquake (1944, M7.9) andNankai earthquake (1946, M8.0) which were theinterplate major earthquakes occurred in the Pacific
Ocean coastal area. These activity seemed to be the"Seismic activation in the southwestern Japan
preceding the Nankai interplate major earthquake".
After those two large interplate earthquakes, any M7class large earthquake has not occurred in the westernJapan for about 50 years.
Finally in 1995, southern Hyogo prefectureearthquake (M7.3) occurred, and in 2000, 5 years and9 months later, western Tottori prefecture earthquake(M7.3) followed. Repetition of these M7 inland
earthquakes makes us imagine the activation of inland
earthquakes preceding the next Nankai major
earthquake considered to occur in 21 mid-century.

Fig.2 The earthquake distribution of the southwesternJapan for these 30 years (after THANKS data of Kyoto
University and the JMA integration seismic catalogue)
In Fig.2, the seismic activity for these 30 years of
the region is shown. Considering the historical seismic
activity, the San-in coastal region is seismically active
in recent 150 years.

Southern Hyogo prefecture earthquake in 1995 was
an extreme catastrophe. The system and the directionof Japanese earthquake investigation have changed
greatly taking advantage of this earthquake. On theother hand, each local government settled a disasterprevention plan for its own area and started to promote
the administration for disaster prevention based on thisplan. Under such conditions, a M5.3 earthquake
occurred in the central part of Tottori prefecture on
September 16th in 2002. Seismic intensity 4 wasrecorded in several points in the prefecture, and the
local government of Tottori prefecture took themeasures which appeared in the disaster prevention
plan. The largest aftershock of M3.9 occurred on 19th,
3 days later from the main shock. But the head quarterof the prefecture could not get enough information
about the aftershock activity, so the alert of Tottori
prefecture had been continued about one monthconsequently. The author exchanged views with thedirector of the Disaster prevention Department of
Tottori prefecture about the situation that it wasdifficult for a local government to get detailed seismic
information. This was the beginning of this joint
research project. Through such passage, thecooperative project described in the Introduction
paragraph has started.
3. Execution of 21COE plan, "Tottori project"
A project plan " Center of Excellence for Natural
Disaster Science and Disaster Reduction" was adopted
as a 21st century COE program for D.P.R.I., Kyoto
University. The Research Center for Earthquake
Prediction carried out the project titled "Study of thecomprehensive and effective earthquake informationand its transfer to contribute the countermeasure of thelocal governments to earthquake hazard" (deputy: Prof.
Yasuhiro Umeda, Director of R.C.E.P.) since fiscal
year 2002. This plan was proposed based on the
consultation with the author and the director of theDisaster prevention Department of Tottori prefecture
about an earthquake occurred at the central part of
Tottori prefecture in 2002. After we conferred withTottori-prefecture on embodiment of this plan, "Thewritten agreement about cooperation and coordination
which affects earthquake disaster prevention" isconcluded between the director of D.P.R.I. of Kyoto
University and the director of the disaster protection－ 52 －

service of Tottori prefecture on March 10th in 2003,
and this plan has begun to move for implementation.
There are three reasons that Tottori prefecture wassuitable as the counterpart of the above investigation
plan. Those will be described simply. First, the inland
seismic activity in San'in district has been active forthese 150 years, including several M7 order big
earthquakes. In particular, the Tottori earthquake
occurred in 1943 brought great damage to this area.
And the memory of the earthquake is still fresh among
the people of this district. Tottori prefecture and theresidence in this district are much interested about
earthquakes. We thought that this interest was
important and effective in execution of the plan. Next
reason is as follows. Since the establishment of the
Tottori microearthquake observatory in 1964, D.P.R.I.
of Kyoto University has carried out the routine
observation of seismic activity in the area from Kinki
to Eastern Chugoku for these 40 years. So, we have agreat knowledge about the seismic activity throughthis district. Finally, Tottori prefecture is always
aggressive about earthquake disaster prevention andinformation disclosure.
We thought these factors were important andindispensable as the co-investigator of our study. Joint
research project with Tottori prefecture was proposedby means of these reasons. We do not think that anyother local government is suitable to promote thisresearch. Because of the conditions described in theprevious and this sections, an earthquake information
system was installed in Tottori prefectural office andthe project study started.

Fig.3 Block diagram of the information system. The
equipments shown in the right part beyond the dottedline were established in the Tottori prefectural office.
the data of high-sensitivity seismic network deliveredby E.R.I. of University of Tokyo. The results obtainedby synthesizing both data received by the satellite andseismic information from D.P.R.I. of Kyoto University
received via internet can be seen on the display at the
Tottori prefectural office (Umeda et al.,2004, ).
Displayed contents of the system are as follows.
1. Seismic activity (by designating area and period byselecting on the menu). Hypocentral distribution (Anexample is indicated in Fig.4.), space-time distribution,
frequency distribution of earthquakes, accumulated
number of earthquakes and M-T distribution can beseen.

4. Earthquake information system
Seismic intensity information just after theoccurrence of a big earthquake triggers the disasterprevention plan execution at that area. Therefore, thisinformation should not include any indeterminacy nor
investigational element. The main purpose of theearthquake information system established in Tottori
prefectural office by this project is to indicate
information which explain the usual seismic activity of
the area, not to tell the urgent alarm in real time.
The block diagram of the system is shown in Fig.3.
The information system consists of the following
compositions. A satellite receiving antenna is installedon the roof of Tottori prefectural office and receives

Fig.4 An example of hypocentral distribution
2. Information of felt earthquakes. The informationfrom J.M.A. is indicated.
3. Monitor of ground motion (by designating theobservation point and the time ). Continuous record ofhigh sensitivity seismometer at any seismic station can－ 53 －

be indicated by an LTR (long-term recorder) image (anexample is indicated in Fig.5). Each line indicates theground motion of 1 minute. 60 lines (i.e. one hour
record) are shown in one page.

Fig.5 : An example of continuous ground motion
4. Link
Among the contents above-mentioned, monitor ofground motion is a significant information. By thisdisplaying page, we can see a continuous groundmotion of any observation point in semi-real time. In
usual earthquake data processing, hypocenter
determination is carried out only about the triggered
events based on some standards. Therefore, those
events which deviated from triggering judgment, forexample, very small local earthquakes or peculiar
events or tremors, are not compiled usually. But themonitor of ground motion is the whole continuousrecord, so this includes all kinds of ground motion
information. By watching this record in detail, we canknow a slight change of aftershock activity and acharacteristics of seismic activity of the region andothers. But in order to comprehend these seismic
activity totally, seismological knowledge andexperience of some level are needed. So, to use thisinformation effectively, much appropriate explanationis needed. On the contrary, there is also an anxiety thatsuch explanation gives some kinds of prediction.
About this problem, we will describe later at the partof user questionnaire.
5. Situation of the practical use
Test practical use of the system started on March
18th in 2004 at Tottori prefectural office. As thesystem was in test use, the access right was permitted
only for the staffs of Tottori prefecture, Kyoto
University, Tottori University and several persons

concerned ( Turner,S.,2004 ).
For about 2 years and half period from the start ofthe system on March 18th in 2004 to the end on
November 20th in 2006, any big earthquake did notoccur around Tottori prefecture fortunately. Thismeans, in other words, that there was no chance toutilize this system effectively nor to get much requestfrom the administrative side about the contents of thisinformation system. After J.M.A., the number of felt
events at anywhere in Tottori prefecture during theabove-mentioned period are shown for every intensity.
Intensity 1 : 40 times
Intensity 2 : 15 times
Intensity 3 : 5 times
Intensity 4 : once,
any more seismic intensity was not recorded.
Seismic intensity 4 was recorded by the earthquake
at southeastern off Mie prefecture occurred at 23h57m
September 5th in 2004 with M7.4, whose hypocentral
depth was 44 km. This was a so-called distant big
earthquake from Tottori prefecture. In other cases,
there was not any influence to Tottori prefecture.
Therefore, there were few chances for this earthquake
information system to be utilized effectively.
We made a survey through questionnaire about thissystem on the staffs of Disaster Prevention & Crisis
Management Division of Tottori prefecture in the
period from December 2004 to January 2005, about 9months after the system began its operation. The
questionnaire was composed of 6 items and 1
additional question (Watanabe,K., 2005; Watanabe, K.,
2006). An addition one was about the propriety of
publication of earthquake prediction information. The
questions are as follows.
Q.1 : Have you ever seen the earthquake displaying
system installed at Tottori Office?
Q.2 : In what kind of situation do you see the system?
Q.3 : Do you have an interest in the contents of thesystem?
Q.4 : Are the displayed contents easy to understand?
Q.5 : Is the information useful for anything?
Q.6 : What kinds of additional information andimprovement are needed for earthquake disasterprevention of a local government?
Additional Question : Earthquake prediction ispractically difficult today. In this circumstances,
if the reseachers get some kinds of irregular but
indefinite phenomena, should they publish those－ 54 －

phenomena?
The number of answer was a few with about ten
names, so there was no statistical meaning. Therefore,
those answers are digested overall and the compiled
result is enumerated in the following.
٤About simplicity of the displayed contents:*It's concise. Contents are classified into some items,
so the required information can be picked out easily.
*Hypocentral distribution is easy to understand. The
graphs shown in three dimensions are convenient.
*There is a lot of English indications. So an additional
explanation page in Japanese may be useful.
*Comprehension of the ground motion monitoring isdifficult. Explanation is needed.
٤About the utility of information:*It can be used for communication of the outline ofseismicity with related organizations.
*As the seismically active area can be grasped, we canprovide the useful information. The occurrence
tendency, the seismically active area and the area
where attension is needed can be known.
*Temporal activity change can be understood.
*It is difficult how the information should be utilized.
٤About the point that should be improved:*The explaining site of general knowledge about
earthquakes is desirable. Interpretation of the pastearthquakes is also preferable.
*The information about the tendency of earthquake
occurrence in the area and the probability ofaftershock occurrence are useful.
*The plain explanation by Japanese is expected.
*A local government often requires the information
expressed numerically and in written form. The
information contents illustrated both in tabular andgraphical forms are desirable.
*It is preferable to list up the installed points ofseismometers and intensity meters.
*It is useful to indicate the results of long-term
prediction, the future's activity and suggestions foreach active fault.
*The estimated information about the aftershockmagnitude and place, as much as possible, is alsopreferable.
*After dividing the damaged area into small meshes, it
is also useful to send detailed information ( directions
or recommendation of refuge etc) to each meshedarea.
٤Additional question : If some kind of information

about earthquake prediction is recognized but notcompletely sure, should this information be released ornot?
*There are no reasons to be undisclosed. By
mentioning the specialist's opinion and also adding
the explanation how the judgement has been got,
disclosure of the information may be able to getgeneral understanding.
*Fact should not be hidden intentionally, but should be
published rather aggressively. It's a problem of
personal consciousness how to catch that.
*If an information is called after an earthquake
occurrence, it isn't useful any more.
*It would be significant to publish the considerationand explanation about the past earthquakes and about
those expected from now on*A local government is not a research institute, so it
should not release those research problems under thename of the local government. If there is a question,
the administration side can not reply any more.
The replied answers were those described above.
Generally speaking, the utility of the earthquake
information system might be admitted. But, someitems to be improved were proposed. Those were
improvement of explanation, clear expression,
digitization, tabular and written form etc.
It was shown clearly that the indeterminacy or
discretion should not be matched with theadministration side. There is consciousness among the
researchers (the data supplier side) that it is important
to offer the data resource without any prediction, in
which all kinds of information are involved. On theother hand, when there is no suitable interpretation andspecification about the information by a specialist, theadministration side can not allow to use nor accountthat.
There is also another problem. On the institutionside, one specific researcher is usually engaged overa long term. On the contrary, transfer of staffs isfrequent in the administrative agency. Therefore, alocal government requires a information which can beutilized without any specialist nor specific technology
and knowledge. The difference between these twoorganizations will be a big factor in considering theutilization and donation of information.
6. End of the project and the information service
in future－ 55 －

The 21st century COE project of a five-year plan, as
scheduled, has been ended in fiscal year 2006. The
satellite system that the researcher side had been used
for storing and transmitting of high-magnification
seismic data also ended its utilization at November,2006. Therefore, this joint research project with Tottori
prefecture also had no choice but to end with finishingof the satellite utilization. Looking back for these three
years experience, it is obvious that detailed earthquake
information is useful for the earthquake disasterprevention program of a local government. Both sides,
administration side and researcher one, also expressed
the expectation for effective utilization of the detailed
earthquake information in future through thediscussion held after being finished of the project. As aresult of the argument, the researcher side has begun to
produce a homepage with much contents beyond theformer system. But there may be another problem inpublishing the data circulated between researchers forinvestigation to polities and general public. Moreover,practical use of a home page is not accepted as ainvestigation at the university side, so there is also a
problem who takes charge of managing a system likethis. There are many factors still left in joint research
between variety organizations that can not be settled
by the personal effort.

widely. This is also the shortcut for information to be
utilized effectively.
Acknowledgements
In execution of this project, major staffs of Disaster
Prevention
Divisionof
Tottori
Prefectural
Government , Fumihiro Iwashita, Mitsuru Ogura,
Katsunori Kinugasa, Morio Johira, Sadanori Hamada
and Ryoji Kobayashi, contributed and cooperated verymuch. Prof. Kiyoshi Takano of University of Tokyo
helped us in getting allowance of utilization ofearthquake data. Those related staffs of E.R.I. of
University of Tokyo, of National Research Institute for
Earthscience and Disaster Prevention and Japan
Meteorological Agency taught us the instruction ofdata too. Prof. Ryohei Nishida and Dr. Tatsuya
Noguchi of Tottori University and Dr. Norio Hirano,
Mr. Sei Yabe and Ms. Yuka Oda of D.P.R.I. of Kyoto
University devoted thier services to install andmaintein the system at Tottori government office.
Profs. Yoshiaki Kawata and Haruo Hayashi and otherstaffs and secretaries of 21COE organization
extremely supported us in execution of the study.
Members of R.C.E.P. and E.Q.H. of D.P.R.I. of Kyoto
University helped us in various cases. .Especially, Dr.
Shiro Ohmi built and developed the receiving system
and indication software. This research should not berealized without his great effort. Being supported by
all people above, this research has been executed. The
authors express their great and sincere thanks to all ofthem.
References

Fig.6 Cover of the earthquake information home page
Level up of the social recognition about earthquake
is important to distribute earthquake information

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