Smart Digital Futures 2014
R. Neves-Silva et al. (Eds.)
IOS Press, 2014
© 2014 The authors and IOS Press. All rights reserved.
doi:10.3233/978-1-61499-405-3-293

293

Will Mail-Based Disaster Information
Systems Work Well?:A Case Study in Japan
Kota TOMOYASU 1 , Yuanyuan WANG, Reo KIMURA and Kazutoshi SUMIYA
University of Hyogo, Japan
E-mail: {nd13y015, ne11u001}@stshse.u-hyogo.ac.jp,{rkimura, sumiya}@shse.u-hyogo.ac.jp
Abstract. Japan’s recent disaster response management planning efforts have focused on non-structural measures. Many local governments often disseminate evacuation information through mail-based disaster information systems. Local governments make evacuation announcements based on their best judgment, and after that,they disseminate these announcements further using e-mails. However, there are
no format of mail-based disaster information systems, and it has proven difﬁcult todisseminate the appropriate evacuation information at the right time. Further, there
are no current studies focused on developing a more suitable and effective management of mail-based disaster information system. We intend to analyze problems
associated with current disaster information systems?with the objective of being
able to recommend improvements?by focusing on actual evacuation information
dissemination processes of mail-based disaster information systems. We begin witha survey of the actual content and timing of text messages issued by local governments. In this way, we are able to identify differences between text messages andtime delays in the dissemination of evacuation information by local governments.
Our case study is based on a survey of the evacuation information dissemination
processes used in the case of Typhoon Man-yi (2013).
Keywords. disaster response, evacuation information, dissemination processes, email

Introduction
Japan’s recent disaster response management planning efforts have focused on nonstructural measures. Many local governments often disseminate evacuation information
through mail-based disaster information systems, and local governments are responsible
for helping residents decide whether to evacuate [1]. The communication of evacuation
information is a stepwise process, made up of phases. These phases are implemented
according to the severity of the disaster; speciﬁcally, local governments implement different phases as needed, to keep residents informed of the severity and potential dangersof the unfolding disaster. As depicted in Figure 1, there are three phases: ﬁrst, dissemi1 Corresponding Author: Kota Tomoyasu, University of Hyogo, Shinzaike-honcho 1–1–12, Himeji, Hyogo
670–0092, Japan; E-mail: nd13y015@stshse.u-hyogo.ac.jp.

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Figure 1. Evacuation information phasenate evacuation preparation information; second, issue an evacuation advisory; and third,
issue an evacuation order. Many local governments issue their evacuation information
using e-mails. Currently, many residents use mobile devices, so they can receive information wherever they are. For that reason, optimal dissemination processes have becomea necessary component of disaster management measures. However, there are no guidelines outlining how a mail-based evacuation information system should operate. As aresult, mail-based evacuation information systems are managed differently in each local
government. To date there has not even been any discussion about what the components
of an appropriate evacuation information system would be, and consequently most local
governments do not manage their mail-based evacuation information systems very well.
The objective of this paper is to break down the problems associated with these information systems, so that we can understand them better, and suggest improvements.
We begin by analyzing existing mail-based evacuation information dissemination processes. We survey the case of Typhoon Man-yi 2013 ﬁrst. Using our survey results, weanalyze the evacuation information systems that were used, focusing on the timing ofdissemination and the contents of the text messages sent.
While some studies have focused on evacuation information systems, no studies
have been based on surveys and analyses of actual evacuation dissemination processes.
Kodama examined different evacuation information phases and found them to be effective [2]. Yabe reviewed evacuation information related to the speciﬁc characteristics ofregional ﬂooding [3], and Katada analyzed residents’intentions to acquire disaster information in the event of ﬂooding [4]. Ohta investigated a heavy rainfall disaster using non
mail-based information that had been provided by local governments [5].
In the next section, we summarize our survey of existing mail-based evacuation information dissemination processes. Section 2 explains how we analyzed these processes
by focusing on the timing of the dissemination and the contents of the text messages sent.
Section 3 suggests improvements to the mail-based evacuation information systems. Finally, Section 4 concludes this paper with suggestions for future research.

1. Survey Overview
We surveyed the case of Typhoon Man-yi that formed on September 13, 2013, and struck
Japan on September 16 (see Figure 2). Several regions suffered serious damage from thistyphoon. It resulted in 6 deaths, 1 missing person, and the destruction of 11,739 residences. Kyoto Prefecture, Shiga Prefecture, and Fukui Prefecture announced heavy rain
Emergency Warnings. Emergency Warnings are weather bulletins issued by the Japan
Meteorological Agency (JMA) [6], to alert people to the signiﬁcant likelihood of catastrophes associated with natural phenomena of extraordinary magnitude.

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Figure 2. Tracks of Typhoon Man-yi in 2013

We collected three types of disaster response data from each of the three local governments, and studied the contents of text messages sent from Kyoto and Shiga Prefectures. The three types of data collected were: what weather information had been announced and when (the JMA announces weather information to help local governments
judge whether they should issue evacuation notices [6]); what evacuation information
had been issued and when; and what mailings local governments had disseminated andwhen.
We concluded that the local governments that had provided us with their evacuation information dissemination dates quickly and correctly were the governments mostcapable of disseminating evacuation information. Other local governments did not provide their dates, and did not summarize their evacuation response records as requested.
Even worse, one local government tampered with its data. It was apparent that evacuation information dissemination problems existed even among otherwise capable local
governments.

2. Analysis of the Evacuation Information Dissemination Processes
In this study, we analyzed evacuation information dissemination processes with a focus
on their timing and message contents. Timing of the dissemination allowed us to judge
whether residents obtained information quickly and so were better able to decide when
to begin evacuating; message content allowed us to assess whether residents were able
to assess their levels of risk accurately. By analyzing the data we had collected, we wereable to document on-going problems with the dissemination processes.

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2.1. Timing of Evacuation Information Dissemination
The ﬁrst point to be discussed is whether local governments disseminated evacuation
and weather information within suitable time frames. As depicted in Figures 3 and 4, weused the results of our survey to summarize the evacuation information dissemination
processes of each local government. Weather information consisted of JMA announcements that had been used by local governments to decide whether to issue evacuation notices [7]. Evacuation announcements that had been disseminated and were subsequently
cancelled were entered into the timetable, if the information had been disseminated bye-mail. Evacuation information consisted of local governments’announcements providing on weather information and the actual conditions in each region. As with the JMA
announcements, local government announcements that had been subsequently cancelledwere entered into the timetable if the information had been disseminated by e-mail. Maildissemination consisted of local governments’distribution of information, mainly withregard to evacuation. The arrows in the ﬁgures reﬂect the paths linking disaster response
activities. There are three path patterns. The blue paths represent weather information
being transmitted into evacuation information, and reﬂect the time lapse between timingof the issuance of weather information and the issuance of corresponding evacuation notices. The black paths represent the transformation of evacuation information (whether
evacuation preparation notices, advisories, or orders) to mail communication, and show
the time delays between the issuance of evacuation bulletins and their dissemination by
mail. The green paths represent the time between the issuance of weather information to
the time this information was disseminated by mail, and they show the delays between
the time the weather information was announced to the time the corresponding mailings
were disseminated. The relative slopes of the different paths represent the relative timedelays between the various activities; that is, as the slopes increased, the delays weregreater.
2.1.1. Case 1: Fukuchiyama
Fukuchiyama is a city in Kyoto Prefecture (see Figure 2) where evacuation information dissemination followed all of the patterns described. The path slopes from receiving
the weather information to issuing this information as evacuation advisories or orders
were not large on average, which suggests that Fukuchiyama’s evacuation dissemination processes were timely. However, some large differences were noted. For example,
JMA announced a Level 3 ﬂood forecast that triggered an evacuation advisory at 2:15
(JST) on September 16, and Fukuchiyama announced an evacuation advisory at 2:20
(JST) on the same day. In contrast, a Level 2 ﬂood forecast that should have triggered anevacuation preparation advisory was announced at 23:50 (JST) on September 15, but thecorresponding evacuation preparation advisory was not announced until 1:10 (JST) on
September 16. Thus, there were lengthy delays with regard to some disaster responses.
This indicates that weather information is not an absolute trigger for issuing evacuation
advisories. This response was common in other cases.
The slopes of the paths from issuance of the evacuation advisory to mail dissemination of that advisory were very small, that is, there was virtually no delay between the two
activities. Based on this fact, Fukuchiyama disseminated evacuation advisory mailings
very quickly. Their dissemination coincided with the decision to issue the evacuation
advisory.

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Contrary to the path slopes describing a path from the issuance of evacuation advisories to mail dissemination, the path slopes from weather information to mail dissemination were very large. The JMA called off a heavy rain emergency warning at 9:55
(JST) on September 16, and Fukuchiyama disseminated a mailing of this information at
22:15 (JST) on the same day, 12 hours and 20 minutes later. In contrast, a heavy rain
warning was called off at 19:15 (JST) on September 15, and Fukuchiyama disseminatedthe mailing of this information at 19:45 (JST) on the 15th. The delay in this case, wassmall. It is evident from these data that no mail-based information management system
had been established, and this lack of consistent management practices led to problems.
2.1.2. Case 2: Ayabe
Ayabe is a city in Kyoto Prefecture (see Figure 2) that issued both evacuation preparation
notices and evacuation advisories. The slopes of the paths representing the issuance ofevacuation preparation notices to their dissemination by mail are small, meaning that thedelays were short. However, there are some comparisons to be made with Fukuchiyama.
The short delays were always of the same length?roughly 10 minutes. This tendency
is characteristic of Ayabe . The delays in disseminating mail were an obvious problem, compared to the delays in issuing evacuation notices. It is not necessarily appropriate to suggest that the issuance of evacuation notices was delayed by the timing of
the announcement of weather information. Issuing evacuation notices is based not only
on weather information, but also on each region’s actual situation. However, mailings
should be disseminated without delay, following the issuance of evacuation notices. Although the delays were not great, when disaster severity is known early, delays in issuing
evacuation information, notices, or advisories can lead to serious damage.
Disaster responses differ among local governments, depending on the delays between issuing evacuation preparation information, notices or advisories, and the time atwhich this information is disseminated by mail. Local governments have no format of
mail-based evacuation information dissemination process, nor does such a process exist.
Moreover, in Fukuchiyama the local government’s approach to mail dissemination of
weather information is inconsistent. There is no national or local government format for
managing this information.
2.2. Contents of Text Messages
The following discussion regards the evacuation preparation information, notices, andadvisories sent by text messaging. We analyzed the contents of the disseminated text
messages for suitability. “The Guidelines for Producing a Decision and Dissemination
Manual for Evacuation Advisories and Orders” [1] itemizes the information that should
be provided to residents as follows:• Time of the announcement• Who is sending the announcement• Who should evacuate• Why they are being asked to evacuate• How dangerous the situation is• In what order the evacuation will be conducted• When the evacuation will commence

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Figure 3. Timetable of Fukuchiyama• Where the evacuation areas are located• What the evacuation route is• Required behavior of evacuees• Person in charge of dissemination
In addition to this information, we consider that the following information must also be
provided:• Continued updates regarding how hazardous the situation is• Continued updates on evacuation information as new information becomes available
These additional points are important because it is necessary to communicate how muchthe hazard is increasing (or decreasing), and for people to understand the meaning of theevacuation information being provided, in order to perceive the risks correctly. Especiallywith regard to evacuation information, many residents do not understand the different
meanings inherent in each of the three evacuation information phases [7]. In Japanese,
evacuation advisories are called Hinan (evacuation), Kankoku (advisory), and evacua-

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Figure 4. Timetable of Ayabetion orders are called Hinan (evacuation) Shiji (order). Residents ﬁnd Kankoku morecompelling than Shiji, which is one of the reasons that residents do not understand thedifferent evacuation information phases. However, there was nothing that explained these
two matters in the data we collected.
Now, we would like to examine actual text messages. Figure 5 shows excerpts from
actual text messages disseminated by local governments, i.e., Fukuchiyama and Ayabe.
2.2.1. Case 1: Fukuchiyama
Fukuchiyama disseminated all types of evacuation information. In all of its messages,
the evacuation information was explained, including who should evacuate, as in the following example: This siren announced evacuation preparation information to the Yurariver valley area. Nevertheless, apparent inconsistencies in the evacuation information
were not explained. In brief, the messages providing evacuation information were noteasy to understand. Moreover, it was unclear when the evacuation preparation information had been announced.ʠ This siren ʡindicated that Fukuchiyama rang the siren when
they announced the evacuation preparation information. Thus, the residents who had not

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heard the siren did not know the exact time of the announcement. Local governments
should show exactly when the siren had been sounded. Without understanding what wasmeant by the different types of evacuation information, residents could not respond appropriately, even after they had received explanations regarding the speciﬁc evacuation
information being announced.
However, Fukuchiyama explained the risks more clearly, with its evacuation information dissemination process. For example, one evacuation advisory message stated,ʠ A
disaster may occur. ʡ, while on the other hand, in a subsequent message about the evacuation advisory, it was stated thatʠ A serious disaster may occur. ʡ. Risks were emphasizedin the evacuation order message. We concluded that these types of messages promoted
accurate risk perceptions.
Additionally, hazard levels at the time were highlighted in all messages as the reasons to evacuate. For instance, ʠ The water level has exceeded 4m, and it may continue
to rise. ʡ However, implications of the hazard conditions were not explained. In brief,
messages mentioned the current hazard conditions, but did not mention how the conditions had changed, or what the conditions implied in terms of risk. It was difﬁcult forresidents to understand the seriousness of the risks when they were told only what the
speciﬁc hazard conditions were, such asʠ The water level has exceeded 4m. ʡorʠ The
water level has exceeded 5m. ʡ.
2.2.2. Case 2: Yasu
Yasu is a city in Shiga Prefecture (see Figure 2). Yasu disseminated evacuation preparation information, and then issued an evacuation order, which was later replaced byan evacuation advisory. In common with Fukuchiyama, the differences in hazard conditions were not explained. In addition, there were particular problems in the case of Yasu.
Yasu notiﬁed residents as the situation moved from one evacuation phase to another, forexample,ʠ The evacuation order was shifted to an evacuation advisory at 12:10. ʡ.
Differences between different types of evacuation information were mentioned, butwhat the differences meant was not clariﬁed. Therefore, without understanding the evacuation information they had received, residents could not understand the information
they had been given regarding the differences between the three evacuation phases. Even
further complicating matters, Yasu did not disseminate any messages regarding its evacuation order.

3. Suggested Improvements of Mail-based Systems Operation
The results of our analysis clearly show that there are a number of problems in local
governments ʟ mail-based systems operation. We would like to propose a number of
improvements from two points of view, namely, the timing of the dissemination of evacuation information, and the content of the evacuation-related text messages. We show
the proposal format of the mails for improvement(see Figure 6) and discussed in detailbelow.
3.1. Timing of Dissemination
In circumstances of disaster, the timing of evacuation information announcements andmail dissemination can have signiﬁcant implications. Therefore, it is necessary to estab-K. Tomoyasu et al. / Will Mail-Based Disaster Information Systems Work Well?

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dĞǆƚDĞƐƐĂŐĞƐŽĨǇĂďĞǀĂĐƵĂƚŝŽŶWƌĞƉĂƌĂƚŝŽŶ/ŶĨŽĂŵĂƚŝŽŶ;ϵͬϭϲϭ͗ϭϬͿǀĂĐƵĂƚŝŽŶWƌĞƉĂƌĂƚŝŽŶ/ŶĨŽĂŵĂƚŝŽŶ;ϵͬϭϲϭϬ͗ϰϭͿdŚŝƐŝƐƚŚĞ&ƵŬƵĐŚŝǇĂŵĂ ĚŝƐĂƐƚĞƌǁĂƚĐŚŚĞĂĚƋƵĂƌƚĞƌƐ͘dŚŝƐƐŝƌĞŶŝŶĚŝĐĂƚĞƚŚĞŶĞĞĚĨŽƌĞǀĂĐƵĂƚŝŽŶƉƌĞƉĂƌĂƚŝŽŶŝŶĨŽƌŵĂƚŝŽŶŝŶƚŚĞzƵƌĂ ƌŝǀĞƌǀĂůůĞǇĂƌĞĂ͘dŚĞǁĂƚĞƌůĞǀĞůŚĂƐĞǆĐĞĞĚϰŵĂŶĚŵĂǇĐŽŶƚŝŶƵĞƚŽƌŝƐĞ͘ZĞƐŝĚĞŶƚƐ䠉ŝŶĂƌĞĂƐĂƚƌŝƐŬŽĨĨůŽŽĚĂŶĚƐĞĚŝŵĞŶƚĚŝƐĂƐƚĞƌ䠉ǁŚŽŵĂǇĨŝŶĚŝƚĚŝĨĨŝĐƵůƚƚŽƚƌĂǀĞů͕ƐƵĐŚĂƐƚŚĞĞůĚĞƌůǇĂŶĚƚŚŽƐĞǁŚŽĂƌĞŝůůƐŚŽƵůĚĞǀĂĐƵĂƚĞƚŽĂŶĞĂƌďǇƐŚĞůƚĞƌ͘WůĞĂƐĞďƌŝŶŐĞƐƐĞŶƚŝĂůŝƚĞŵƐƚŽƚŚĞƐŚĞůƚĞƌƐ͗ĨŽŽĚ͕ǁĂƚĞƌ͕ĂŶĚŵĞĚŝĐŝŶĞƐ͘WƌĞƉĂƌĞƚŽĞǀĂůƵĂƚĞĨƌŽŵƚŚĞƌĞĂŶĚŬĞĞƉĂďƌĞĂƐƚŽĨƚŚĞƐŝƚƵĂƚŝŽŶ͘dŚĞ&ƵŬƵĐŚŝǇĂŵĂ ĚŝƐĂƐƚĞƌǁĂƚĐŚŚĞĂĚƋƵĂƌƚĞƌƐĚŝƐƐĞŵŝŶĂƚĞƐĞǀĂĐƵĂƚŝŽŶƉƌĞƉĂƌĂƚŝŽŶŝŶĨŽƌŵĂƚŝŽŶ͘^ŝŶĐĞƚŚĞǁĂƚĞƌůĞǀĞůŽĨƚŚĞzĂƐƵ ƌŝǀĞƌĐƌŽƐƐĞĚƚŚĞĨůŽŽĚĐĂƵƚŝŽŶƐǁĂƚĞƌůĞǀĞůĂƚϵ͗ϭϳĂ͘ŵ͘ƚŽĚĂǇ͕ĞǀĂĐƵĂƚŝŽŶƉƌĞƉĂƌĂƚŝŽŶŝŶĨŽƌŵĂƚŝŽŶǁĂƐĂŶŶŽƵŶĐĞĚ͘dŚĞĞůĚĞƌůǇĂŶĚĐŚŝůĚƌĞŶŶĞĞĚŝŶƐƚƌƵĐƚŝŽŶƐĨŽƌĞǀĂĐƵĂƚŝŽŝŶ͘dŚĞŽďũĞĐƚƌĞŐŝŽŶŝƐĂƐĨŽůůŽǁƐ͘DŝŬĂŵŝ ƐĐŚŽŽůĚŝƐƚƌŝĐƚ͗KŵŝĨƵũŝ͕^ŚŝĐŚŝŬĞŶũŽ͕ĂŶĚƚŚĞĞǀĂĐƵĂƚŝŽŶƐŚĞůƚĞƌŝƐŽŵŵƵĐĞŶ DŝŬĂŵŝ͘zĂƐƵ ƐĐŚŽŽůĚŝƐƚƌŝĐƚ͗ĞǀĂĐƵĂƚŝŽŶƐŚĞůƚĞƌŝƐŽŵŵƵĐĞŶ zĂƐƵ͘<ŝƚĂŶŽƐĐŚŽŽůĚŝƐƚƌŝĐƚ͗/ĐŚŝŵŝǇĂŬĞ͕dĂŬĞũŽ ƐĐŚŽŽůĚŝƐƚƌŝĐƚ͕ĂŶĚƚŚĞĞǀĂĐƵĂƚŝŽŶƐŚĞůƚĞƌŝƐŽŵŵƵĐĞŶ <ŝƚĂŶŽ͘&ƌŽŵzĂƐƵ >ŝĨĞƐĂĨĞƚǇĚŝǀŝƐŝŽŶǀĂĐƵĂƚŝŽŶĚǀŝƐŽƌǇ;ϵͬϭϲϮ͗ϭϬͿdŚŝƐŝƐƚŚĞ&ƵŬƵĐŚŝǇĂŵĂ ĚŝƐĂƐƚĞƌǁĂƚĐŚŚĞĂĚƋƵĂƌƚĞƌƐ͘dŚĞƉƌĞƐĞŶƚƐŝƌĞŶĂŶŶŽƵŶĐĞĚĞǀĂĐƵĂƚŝŽŶĂĚǀŝƐŽƌǇƚŽƚŚĞzƵƌĂƌŝǀĞƌǀĂůůĞǇĂƌĞĂ͘dŚĞǁĂƚĞƌůĞǀĞůĞǆĐĞĞĚϱŵĂŶĚŝƚŵĂǇŐŽƵƉĨƌŽŵŶŽǁ͘ĚŝƐĂƐƚĞƌŵĂǇŽĐĐƵƌ͘dŚŽƐĞůŝǀŝŶŐŝŶƌĞŐŝŽŶƐĂƚƌŝƐŬŽĨĨůŽŽĚĂŶĚƐĞĚŝŵĞŶƚĚŝƐĂƐƚĞƌŶĞĞĚƚŽĞǀĂĐƵĂƚĞƚŽĂŶĞĂƌďǇƐŚĞůƚĞƌ͘ǀĂĐƵĂƚŝŽŶKƌĚĞƌ;ϵͬϭϲϱ͗ϰϬͿdŚŝƐŝƐƚŚĞ&ƵŬƵĐŚŝǇĂŵĂ ĚŝƐĂƐƚĞƌƌĞƐƉŽŶƐĞŚĞĂĚƋƵĂƌƚĞƌƐ͘dŚŝƐƐŝƌĞŶƉƌĞƐĞŶƚŝŶĚŝĐĂƚĞƐƚŚĞĞǀĂĐƵĂƚŝŽŶŽƌĚĞƌĨŽƌƚŚĞ&ƵŬƵĐŚŝǇĂŵĂ ǁŚŽůĞƌĞŐŝŽŶ͘EŽǁ͕ƚŚĞŚĞĂǀǇƌĂŝŶĞŵĞƌŐĞŶĐǇǁĂƌŶŝŶŐŝƐĂŶŶŽƵŶĐĞĚ͘ƐĞƌŝŽƵƐĚŝƐĂƐƚĞƌŵĂǇŽĐĐƵƌ͘dŚĞǁĂƚĞƌůĞǀĞůŽĨzƵƌĂ ƌŝǀĞƌŚĂƐĞǆĐĞĞĚϳŵͲͲ ƚŚĞǁĂƚĞƌůĞǀĞůĞǆĐĞĞĚϳŵĂŶĚĐŽŶƚŝŶƵĞƚŽƌŝƐĞ͘/ƚŝƐƵŶƐƵƌƉƌŝƐŝŶŐǁŚĞŶĞǀĞƌĂƐĞƌŝŽƵƐĚŝƐĂƐƚĞƌŽĐĐƵƌ͘ZĞƐŝĚĞŶƚƐŝŶƌĞŐŝŽŶƐĂƚƌŝƐŬƐŚŽƵůĚĐŽŵƉůĞƚĞĞǀĂĐƵĂƚŝŽŶŝŵŵĞĚŝĂƚĞůǇ͘,ŽǁĞǀĞƌ͕ǁŚĞŶǇŽƵƚĂŬĞĞǀĂĐƵĂƚŝŽŶ͕ďĞĨƵůůǇĐĂƌĞĨƵů͘ŽŶĚƵĐƚƚŚĞĞǀĂĐƵĂƚŝŽŶĐĂƌĞĨƵůůǇ͗ĚŽŶŽƚƵƐĞĨŽƌĐĞ͖ƚĂŬĞƚŚĞŵŝŶŝŵƵŵĂĐƚŝŽŶƌĞƋƵŝƌĞĚƚŽƉƌŽƚĞĐƚǇŽƵƌůŝĨĞ͕ƐƵĐŚĂƐŵŽǀŝŶŐƚŽƐĂĨĞƉůĂĐĞĂƐƋƵŝĐŬůǇĂƐƉŽƐƐŝďůĞ͘

Evacuaon Order → Evacuaon Advisory(9/16 12:53)
KŵŝĨƵũŝ͕^ŚŝĐŚŝŬĞŶũŽ ŽĨƚŚĞDŝŬĂŵŝ ƐĐŚŽŽůĚŝƐƚƌŝĐƚ͕ƚŚĞzĂƐƵƐĐŚŽŽůĚŝƐƚƌŝĐƚ͕KŚĂƚĂ͕zĂƐƵ͕ƚŚĞ<ŝƚĂŶŽƐĐŚŽŽůĚŝƐƚƌŝĐƚ͕/ĐŚŝŵŝǇĂŬĞ͕dĂŬĞũŽ͕ĂŶĚdĂŬĞŐĂŽŬĂ ĐĂŶĐĞůůĞĚĞǀĂĐƵĂƚŝŽŶƉƌĞƉĂƌĂƚŝŽŶŝŶĨŽƌŵĂƚŝŽŶĂŶŶŽƵŶĐĞĚŝŶƚŚĞƐĞƌĞŐŝŽŶƐĂƚϭϮ͗ϭϬ͘DŽƌĞŽǀĞƌ͕ƚŚĞ^ŚŝŶŽŚĂƌĂƐĐŚŽŽůĚŝƐƚƌŝĐƚ͕/ƌŝŵĂĐŚŝ͕dĂŬĂŐŝ͕EĂŐĂƐŚŝŵĂ͕<ŽŵŝŶĂŵŝ͕ĂŶĚĨƌŽŶƚŽĨ^ŚŝŶŽŚĂƌĂ^ƚĂƚŝŽŶ͕ƚŚĞĞǀĂĐƵĂƚŝŽŶŽƌĚĞƌǁĂƐƌĞǀŝƐĞĚĂƐĞǀĂĐƵĂƚŝŽŶĂĚǀŝƐŽƌǇĂƚϭϮ͗ϭϬ͘^ŝŶĐĞƚŚĞǁĂƚĞƌůĞǀĞůŽĨ,ŝŶŽZŝǀĞƌŝƐŚŝŐŚ͕ƐŝŶĐĞŝƚŝƐŚŝŐŚ͕ĐĂƵƚŝŽŶƐĂƌĞďĞĨŽƌĞƌĞƋƵŝƌĞĚĞŶŽƵŐŚ͘&ƌŽŵzĂƐƵ >ŝĨĞƐĂĨĞƚǇĚŝǀŝƐŝŽŶ

Figure 5. Examples of collected text messages

lish criteria that must be met in order to ensure the timely announcement and dissemination of evacuation information. It should be noted that relaxing the criteria for announcements would not be an effective strategy. Relaxing the criteria would lead to declining
public trust in the evacuation information provided, because of an increase in the numberof cases in which a serious disaster did not occur, even though evacuation information
announced the possibility of a disaster. For example, one criterion for announcing evacuation preparation information occurs when a heavy rain advisory is issued, but heavy
rain advisories are announced frequently, even when heavy rains do not lead to serious
disasters. Therefore, in most cases using relaxed criteria, residents do not suffer any damage even though evacuation preparation information has been announced. This confusion
leads residents to think that they are not in danger, even though evacuation information
has been announced. Therefore, it is important not to relax the criteria too readily.
Moreover, if there are delays in mail dissemination, local governments should tellresidents what the length of the delay will be, because it is possible that residents will not
realize that the disseminated announcement has been delayed. In these cases, residents
may make mistakes in the timing of their evacuations. For example, a message such asʠ announcement time 19:15; dissemination time 19:45; delay is 30 minutes ʡwould help
residents judge the timing of their evacuations because they clearly know of the delay.

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K. Tomoyasu et al. / Will Mail-Based Disaster Information Systems Work Well?
䠘dŝŵŝŶŐ䠚䠘ŶŶŽƵŶĐĞŵĞŶƚdŝŵĞ䠚䠘ŝƐƐĞŵŝŶĂƚŝŽŶdŝŵĞ䠚䠘ĞůĂǇ䠚䠘ŽŶƚĞŶƚƐŽĨĞǀĂĐƵĂƚŝŽŶŝŶĨŽƌŵĂƚŝŽŶ䠚䠘ŝĨĨĞƌĞŶĐĞĨƌŽŵWƌĞǀŝŽƵƐDĂŝů䠚䠘,ĂǌĂƌĚWƌŽŐƌĞƐƐŝŽŶ䠚䠘ǀĂĐƵĂƚŝŽŶWŚĂƐĞ䠚䠘KďũĞĐƚŝǀĞZĞŐŝŽŶ䠚Ğ͘Ő͘Ϳ

Figure 6. Proposal format

3.2. Contents of Text Messages
As mentioned above, we consider that the particularly important aspects of text message contents are information on changing conditions and what the implications of thosechanges are. However, in our analysis, these points were not mentioned in all messages.
With regard to weather information, residents may not understand the speed at which thehazard is progressing. We propose to explain and highlight the changing hazard levels
and their meanings. For example: ʠ The water level exceeds 5m. It has risen 1m since
the previous mail was disseminated. Its speed is very dangerous. ʡ Messages like thiscan help residents understand the details of hazardous conditions. Similarly, concerning
evacuation information, many residents may not understand the context of evacuation
information messages without some explanation. We propose to provide information explaining whether evacuation phases are progressing or receding, for example,ʠ The evacuation phase has advanced from evacuation preparation to evacuation advisory. ʡ Thisadditional information will help residents understand the increasing or decreasing levelsof risk they face.Moreover, it is consideredthat showing objective region of evacuation
information is effective.
Finally, we consider that it is important to express the risks emphatically, as in thecase of Fukuchiyama, because this lets the residents know that the situation is unusual.
When disasters occur, people often have mistaken perceptions because of normalcy bias
[8][9]. Normalcy bias leads to an underestimation of risk, which in turn tends to cause
people to consider that conditions are normal. Thus, expressing the risks emphaticallywill cause people to understand them better, and will help to eliminate normalcy bias
[10]. For that reason, we propose to add emphatic expressions of the level of risk inmessages, as does Fukuchiyama.

4. Conclusions and Future Works
In this paper, we analyzed evacuation information dissemination processes by focusing
on their timing and content, using cases from Typhoon Man-yi in 2013. We clariﬁed the
problems that we had identiﬁed by analyzing our data. Moreover, we identiﬁed necessary

K. Tomoyasu et al. / Will Mail-Based Disaster Information Systems Work Well?

303

improvements using our analyses. Concerning the timing of evacuation information dissemination, we concluded that it is important to establish criteria for announcing and disseminating evacuation information, and to clearly explain long delays in dissemination.
Furthermore, concerning the contents of text massages, we concluded that it is importantto provide explanations concerning the changing weather conditions, and to clarify what
the evacuation information means for the recipients, including the meanings of terms
used in the message. The clariﬁcation of risk should also be improved.
In future research, we will study the effectiveness of the improvements that we haveproposed, and examine the timing delays in more detail. Several factors may contributeto the delays. For instance, there is the relationship between the delay in announcing
evacuation information and the evacuation information phase. The more difﬁcult the decision to make an announcement is, the more serious the evacuation information phasebecomes. Delays in making evacuation information announcements may occur as a result. It will also be necessary to perform quantitative analysis on more cases, in order toclarify the factors related to delays. Conducting a survey with local governments will be
important.

Acknowledgment
The data for this investigation were provided by local governments in Aiso, Ayabe,
Fukuchiyama, Hikone, Kyoto, Omihachiman, Oyamazaki, Uzi, and Yasu.

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