資料 新総２－（７）消防庁の地震に関する総合的かつ基本的な施策の検討に向けたヒアリング資料

（様式１ 関係府省用）

地震に関する総合的かつ基本的な施策の検討に向けたヒアリング調査
担当機関

消防庁・消防研究センター

以下の項目に沿って、自由にご意見を記入してください。その際、特に（１）及び（４）②、（４）③については、適宜、関係資料（具体的な成果や施策の図表等）を添付してください。

（１）推進本部の方針の下での、これまでの地震調査研究の主な実施内容及び成果
長周期地震動に着目した，調査，観測，解析に基づき，地震時の石油タンクのスロッシングに係わる設計水平震度の見直しを行った.
以下，概略を述べる．
１．2003 年十勝沖地震での石油タンク被害の調査
半年に及ぶ現地調査を行い，被害の状況把握，火災原因の解明を行った．その結果は以下のように纏められる(図 1)．
(1) １例を除いて全てシングルデッキ浮屋根式タンクである．
(2) スロッシング固有周期は 7 秒以上である．
(3) 周期 12 秒付近のタンクを除き，最大波高は 2m 以上である．
(4) 周期 12 秒付近のタンクについては，2 次モード（周期 5.6 秒）が卓越したことが，沈没の原因となったと考えられた．
(5) 上記以外のタンクの浮屋根の沈没は，大きな波高によるポンツーン部分への過大な荷重による破断が原因と考えられた．
(6) 地震時の火災については，大きな波高のため浮屋根と上部付属設備とが衝突，着火したものと考えられた．
(7) 2 日後の火災に関しては，大きな波高によりポンツーンが破断したため浮屋根が沈没し，その対応として行ったシールのための泡が水溶液となって油中に沈降する際に帯電し，浮島状に油面にあった泡に電荷が蓄積されたことが原因と考えられた．
甚大な被害はいずれも大きな波高が原因となっており，周期 7 秒以上のタンクの波高予測，即ち地震動予測，および超大型タンクの2 次モードでの地震動予測が極めて重要であることが指摘された．

（様式１）1/5

（様式１ 関係府省用）

450

地震時のタンク火災

地震2日後のタンク火災
CRT Damaged

400

鎮火後のタンクとその周辺（浮屋根沈没）

CRT None

Maximum Wave Height (cm)350

CFRT Damaged

300

CFRT None250

FRT(S) Damaged

200

FRT(S) None
FRT(W) Damaged

150

FRT(W) None

100
50
0
0

1

2

3

4

5

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Natural Period of Liaquid Sloahing (sec)

地震応答解析による最大波高（苫小牧地区）

超大型タンク（浮屋根沈没，ドレインからの油流出）

図 1 2003 年十勝沖地震における苫小牧での石油タンク被害とスロッシング波高（屋根形式・被害別）（様式１）2/5

（様式１ 関係府省用）

２．長周期地震動の予測
東京湾岸での長周期地震動観測，約 10000 成分の気象庁 1 倍強震計記録記録の収集・数値化・解析，および FDM，経験的グリーン関数法などによる予測結果の収集から，地震地体構造区分の考慮し，全国の石油コンビナートで期待される長周期地震動を予測することによって，地域，周期の関数として設計水平震度に相当する速度応答スペクトルを提案した．このスペクトルは平成 17 年改正の消防

Correction Coefficient

Correction Coefficient

Correction Coefficient

法に盛り込まれた(図２)．

Natural Period of Sloshing(s)地域1-1 苫小牧，酒田，新潟

Natural Period of Sloshing(s)地域1-2 東京湾岸

Natural Period of Sloshing(s)地域1-3 上磯，秋田，清水，名古屋、四日市，大阪，尼崎，石狩北

図２ 速度応答スペクトル105cm/sに乗ずる係数

添付資料：Zama, S.: REVISION OF DESIGN SPECTRA FOR LIQUID SLOSHING OF OIL STORAGE TANK IN JAPAN, 9th Canadian Conf. Earthq.
Eng. pp.359-369, 2007

（様式１）3/5

（様式１ 関係府省用）（２）推進本部（政策委員会、地震調査委員会及びこれらの下に置かれている部会・委員会等）のこれまでの活動に対する評価
Seismology，Geophysicsの分野での稠密な観測，活断層調査，地震ハザードマップ作成等の活動は大いに評価できる．また，シナリオ地震による強震動予測波形の公開など，自治体等ユーザーから有用な情報の提供は評価できる．
一方,兵庫県南部地震での甚大な被害が契機になって設置された経緯からすると，すぐにでも社会の防災，住民の安全確保に繋がる
応用的な調査，研究開発は殆ど取り上げられてきていないように見える．サイエンスとして発展させることも国の使命であるが，同時に国民の生命，財産を守ることもそれ以上に重要な使命であることを忘れてはならない．

（３）今後、推進本部に期待する役割（２）に述べたように，地震のサイエンスに関する調査研究の継続的推進を図ることは重要である．また，その成果を社会に還元するための応用開発研究も欠く事ができない．さらに，地震防災に係わる総合的な研究，即ちソース，パスの検討と共に，構造物，都市，
ライフライン，人間等への影響，応急対応，復旧・復興，教育システム等々の，地震防災に向けての一体的な取り組みが必要であり,
その推進・調整を期待する．

（４）新しい総合的かつ基本的な施策に盛り込むべき事項①

次期総合基本施策の位置づけについて
国民の生命と財産を守るという直截的な活動を展開することの一端をになうべきこと．

（様式１）4/5

（様式１ 関係府省用）②

今後の地震調査研究の目指すべき目標について
政策委員会でも取り上げられていたが、防災に役立つという視点での研究を望む。
地震防災に係わる総合的な研究，即ちソース，パスの検討と共に，構造物，都市，ライフライン，人間等への影響，応急対応，復旧・復興，教育システム等々の，地震防災に向けての一体的な取り組みが必要であり,その推進および調整．

③

地震調査研究の推進方策について
研究体制の偏在をなくし，数多くの関連研究分野，機関，人材を活かす体制を構築し，地震防災に向けた一体的，総合的取り組みを行うため，予算分配等の調整を透明性を確保した中で実施することが望まれる．

（５）その他
消防庁が所管している震度情報ネットワークについては、①市区町村での初動対応の迅速化、②市町村、都道府県及び消防庁間でのネットワーク化による広域応援体制確立の迅速化を目的として整備されたものである。現在、地震波形データが活用できるよ
う次世代のネットワークシステムへの更新について推進している。

（様式１）5/5

Ninth Canadian Conference on
Earthquake Engineering
Ottawa, Ontario, Canada
26-29 June 2007

REVISION OF DESIGN SPECTRA FOR LIQUID SLOSHING OF OIL STORAGETANK IN JAPANS. Zama1

ABSTRACTThe 2003 Tokachi-oki earthquake (Mw=8.0) caused severe damage to oil storage tanks by liquid sloshing.
In particular, at the Idemitsu Refinery at Tomakomai in Hokkaido (northern part of Japan), two tank fires
broke out and seven floating roofs sank, where large liquid sloshing more than 3m was excited by thelong-period strong ground motions.
According to the Japan Fire Service Law regulating liquid level at that time, the distance (Hc) between
liquid surface and top angle is calculated assuming that the velocity response spectrum (Sv) is about 100
cm/s at a period of sloshing, which is roughly equivalent to about 2m of Hc. On the other hand, Sv
calculated from records at Tomakomai exceeded about two times as the regulation at periods from about
4 to 8 sec. Thus, it was necessary to revise Sv as a function of period and region.
Prediction of long-period ground motions, which are mainly composed of surface waves, is very difficult
because the S-wave velocity structures down to the basement (which strongly affect characteristics oflong-period ground motions) have not been clarified in the whole region of Japan. Attention was paid tothe seismic records of JMA displacement type strong motion seismographs, which can accurately record
long-period ground motions and have been working at 112 observatories from 1950 to1990.
It was suggested from records that the effects of source and path on the ground motion characteristics
are almost the same for every earthquake in a seismotectonic zone, and that the empirical prediction
seems to be available considering scaling law of fault parameters. The author proposed that the empiricalprediction equations be based on recent studies associated with the relations between earthquake
magnitude and fault parameters, and developed the database of more than 10,000 components ofdigitalized records.
Considering both predicted spectra at petroleum industrial complexes for earthquakes with maximum
expected magnitude in each seismotectonic zone and damage pattern of oil storage tanks at Tomakomai,
the author proposed design spectra for liquid sloshing of oil storage tank in Japan as a function of period
and region as shown in Fig. 14. The design spectra were adopted in the revised Japan Fire Service Law
enforced on April 2005.

1

Senior researcher, National Research Institute of Fire and Disaster, Chofu City, Tokyo 182-8508, Japan（様式１－別添資料） 1 / 11

Introduction
The 2003 Tokachi-oki earthquake (Mw=8.0) occurred on 26 September, east off Hokkaido, north ofJapan, and caused two disappeared by tsunami and more than one hundred collapsed houses.
Considering its magnitude, the extent of damage is not so large. On the other hand, oil storage tanks inand around Tomakomai, a coastal city in southern Hokkaido, were severely damaged by liquid sloshing inspite of 225km of the epicentral distance. Especially in the Idemitsu Refinery, two tank fires broke out andseven floating roofs sank, and 30 tanks suffered some amount of damage such as overflow and splash ofoil, deformation of rolling ladder, weather shield, guide pole, gauge pole and air foam dam and so on.
Fire and Disaster Management Agency (FDMA) and the author have investigated the damage of oil
storage tanks and cause of tank fires, and also investigated characteristics of seismic ground motions
near the tank sites. In this paper, the investigation results are briefly described. Based on the relation
between damage and ground motion characteristics in the 2003 Tokachi-oki earthqauke, seismic design
spectra for liquid sloshing of storage tank oil in the Fire Service Law in Japan was revised in order toprevent the damage due to earthquakes in the near future.
Structure of Tank and Liquid Sloshing
Structure
In general, oil storage tanks are classified by
the type of roof, such as corn roof tank (CRT),
floating roof tank (FRT) and covered floating
roof tank (CFRT). Severe damage such as fireand roof sink was seen in single-deck floating
roof tanks in the 2003 Tokachi-oki earthquake.
Figure 1 shows a typical structure of singledeck FRT. Floating roofs are used in manylarge-size oil storage tanks to reduce
evaporation. A single deck floating roof
consists of a thin circular plate (deck) attachedat the edge to a buoyant ring (pontoon) of
boxed shaped cross section as illustrated inFig. 2. The pontoon consists of the inner rim,
the outer rim, the upper plate and the bottom
plate. Each plate is usually single-fillet welded
along all of their edges and is required to makeeach compartment liquid tight. The single deck
floating roofs are usually designed to havesufficient buoyancy to remain afloat for thecondition that single deck and any two
adjacent pontoon compartments are punctured.
The space between the outer rim and tankshell is sealed by a flexible device thatprovides a reasonably close fit to the shellsurfaces.

Rolling ladder

Gage poleWind girder

Deck

Seal
Pontoon
Shell

Roof drain
BottomFigure 1.

Typical structure of a single-deck floating roof
tank.
PontoonDetail of Pontoon
Deck
Pontoon roof plate
Bulkhead
Pontoon

Seal

Deck

BottomOuter rim
Deck

Shell
Inner rim

Pontoon bottom plate

Figure 2. Single-deck floating roof.

Liquid Sloshing
According to the velocity potential theory with rigid tank, the natural period Ts of sloshing is given by Eq.1:

TS = 2πDHcoth 2ε1 
2gε 1
D


(1)

（様式１－別添資料） 2 / 11

where g is the acceleration due to gravity and ε1 is 1.841. D is a tank diameter and H is liquid height.
Maximum sloshing height ηmax can be expressed by the following equation using the velocity response
spectrum Sv at a period of Ts:η max = 2.6295

D
SV
gTS

(2)

Eq. 2 means that Sv is decisively important to estimate liquid sloshing. According to the regulation in Fire
Service Law of Japan enforced in 1983, about 2m of maximum liquid height was determined by thevelocity response spectrum Sv which is assumed constant, that is, about 100 cm/s (damping factor =0.5%) in the long-period range and in the whole of Japan.
Characteristics of Seismic Ground Motions in the 2003 Tokachi-oki Earthquake
Japan has installed many seismometers, such as K-NET, after the 1995 Hyogo-ken Nanbu earthquake.
Fig. 3 shows the velocity waveforms along the coast from Erimo observatory closest to the epicenter to it
and around Tomakomai where many oil tanks were severely damaged. PGV at Erimo is 0.12m/s, but theone at Tomakomai is 0.35m/s, in spite of the large distance (about 230km) from the epicenter.
Furthermore, long-period ground motions predominate and duration time becomes larger. Such featuresof ground motions are considered as the influence of the thick sediment of Yufutsu Plain in and around
Tomakomai (Aoi et al. 2004). Sv calculated from the records in and around Tomakomai showed larger
than the regulation value at that time in the period range from 5 to 10 sec. as shown in Fig. 4.

追分
早来
厚真

千歳
Tomakomai
Shiraoi

M ukawa
Monbetsu
Shizunai
Mitsuishi
Urakawa

Samani
Erimo

Epicenter

Erimomisaki

Figure 3. Velocity response spectra at K-net stations in and around Tomakomai.
Heavy Damage of Oil Tank and its Cause
Two tank fires occurred. One broke out during the earthquake as shown in Fig. 5, which shows three fires;（様式１－別添資料） 3 / 11

a ring fire between the floating roof and the shell plate, a fire on the ground of tank side, and a fire from apipe located at the north side of the tank. According to Nishi and Yokomizo (2006), the cause of ring fire isconsidered as the spark at the collision between the roof and the equipments for support of the guide andthe gauge pole above the top angle. Fire on the ground was brought from overflow of the burning oil in thering fire. The cause of the pipe fire is due to the oil that splashed out of the crack of the pipe due to theearthquake ground motions of at most 70 gals in PGA took fire from overflowed burning oil of the ring fire.

Fire from pipe

Ring fireFire on the ground#300066:00 on September 26（photographed by Tomakomai Fire Department）
Figure 4. Velocity response spectra at
K-net stations in and around
Tomakomai.

Figure 5. Tank fire just after the earthquake (photo by
Tomakomai Fire Service).

Figure 6. Tank fire occurred two days after the
event (photo by Fire and Disaster
Management Agency).

Figure 7. Sunken floating roof (D and E) andpool fire tank (C).

Another fire at the naphtha tank that became a full surface fire occurred two days after the earthquake(Fig. 6) and continued for 44 hours despite the best efforts of the fire brigades. Until fire broke out from theevent, fire foam was dropped on the oil surface in order to prevent fire breakout, because the floating roof
sank and the naphtha was exposed to the atmosphere. It has been inferred that covering by the foam was
not complete and isolated foam accumulated electricity while the fire foam went down into the vapor and（様式１－別添資料） 4 / 11then sparks came off between isolated foam and the shell plate (Nishi and Yokomizo, 2006).
There were seven tanks of which floating roofs sank as shown in Fig. 7. Furthermore, overflow of oil fromsome tanks were observed because of large sloshing excited by the unexpected long-period strong
ground motions. Large amounts of oil spilt on the floating roof and flew through the drainpipe out of thetank. Another damage due to liquid sloshing such as deformation or failure of gauge pole, guide pole,rolling ladder, roof or its rafter, weather hood, foam dam, and so on were also observed in and around
Tomakomai.
Relation between the Maximum Sloshing Wave Height and Damage in Tomakomai
Since there was not much data about maximum sloshing wave height ηmax, ηmax was calculated for alltanks in Tomakomai shown in Fig. 8, applying the two dimensional response analysis method (Zama,
1985) assuming appropriate damping for each roof-type tank to seismic records at tank sites after
confirming the accuracy through the comparison between estimations and observations. As is obvious,
2D-response analysis is required because of the complex orbit of horizontal ground motions. Estimatedηmax exceeds 2m at the periods of 3.5 to 9 sec, and especially exceeding 3m at the periods of 5 and 7.5
sec. Severely damaged tanks such as fire and sinking of the floating roof, are enclosed by large circles in
the figure, which are almost under the conditions that ηmax is over 2m and Ts is longer than 7 sec.

450

CRT Damaged

400

CRT None

)350

m(c
th300
gie
He250
va
W200
mu
mix150aM

CFRT Damaged
CFRT None
FRT(S) Damaged
FRT(S) None
FRT(W) Damaged
FRT(W) None

100

50
0

0

1

2

3

4

5

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Natural Period of Liquid Sloshing (sec)Figure 8. Estimated maximum sloshing wave height at Tomakomai. Shaded symbols show tankswith some damage. Data enclosed by circles indicate tanks with severe damage such as
fires, sinking roofs and so on.
On the other hand, there were two floating roof tanks of 100,000kl crude oil storage in these severely
damaged tanks, although ηmax is at the highest about 1.3m. The tank diameter is 78.2m, the shell height is
24.5m, and the liquid height was 14.414m at the time of the earthquake, and the sloshing natural period
was T1=12.0 sec, 2nd mode was T2=5.5 sec. Fig. 9 shows the damage of the floating roof of this tank. The
direction of the main sloshing was roughly presumed to be a direction of EW, and damage with the main
buckling deformation was seen in the outer rim and the inner rim of the pontoon located in this direction.
Moreover, similar damage was also seen in the pontoon located in orthogonal direction to the main
sloshing, NS direction. This floating roof sank several days after the earthquake.

（様式１－別添資料） 5 / 11

The sloshing mode at a certain time in the 2-D sloshing analysis for the case of without floating roof,
namely free surface, indicates more than 1m in high at about one-third of radius from the center. It isconsidered that the large wave height at this portion was brought by the second mode of sloshing,because the Sv value at T2 is very large as shown in Fig. 5. Yamauchi et al (2006) concluded that thebuckling of pontoons or failure of the joint between deck and pontoon were caused by the large
deformation of deck due to the second mode of sloshing, on the basis of the detail FEM analysis by the
LS-DYNA which can treat the interaction between fluid and floating roof (Miura 2004).

Figure 9. Failure of pontoon.

Figure 10. Seismotectonic zoning map by JMA (1990), observatories
treated in this report, and Region -1 indicated by large circles.
Specified Seismic Design Spectra for Countermeasure against Liquid Sloshing
Basic Concept
As mentioned above, it is indispensable to properly control the liquid height. Thus, specifying velocity
response spectrum Sv is important at the natural period of sloshing as understood from Eq. 2. In addition,（様式１－別添資料） 6 / 11

Sv at a period of second mode is also important for countermeasures against sloshing of huge oil tanks.
Long -period ground motions are mainly composed of surface waves, and strongly affected by the deep
velocity sediment structure between a source region and a site. Since such structural model for the wholeof Japan is still uncertain except in limited areas such as the Tokyo area, Osaka area, where large cities
locate, we cannot use the theoretical or numerical method such as Finite Difference Method. Thus, anempirical method for prediction of long-period ground motions at more than eighty oil industrial complexes
is employed.
Regionality and Ground Motion Prediction
Characteristics of long-period ground motions strongly depend on a combination between source and tanksite region. Then we adopted a concept of seismotectonic zoning, where source characteristics seem tobe similar, in order to extract regionality in the long-period range at each site using displacement recordsof mechanical seismograph operated by Japan Meteorological Agency from 1950 to 1990. Someseismotectonic zoning maps have been proposed in Japan as shown in Fig. 10. Since the natural periodof seismometer is 6 sec, it is pertinent for long-period ground motion prediction. Records were analogue,
and were digitized by means of an image processing method. Regionality R(T) in the long-period range ata site is assumed as follows.
R(T) = ∑(Fo(T)i / Fc(T)i) / N

，N

(3)

i=1

Fo(T)i , Fc(T)i, and N are observed Fourier acceleration spectrum, standard spectrum defined by Eqs. 5 10 for i-th earthquake, and number of earthquakes in a seismotectonic zone, respectively. Thus, we caneasily predict acceleration spectrum at a site using Eq. 4, magnitude (M) of a target earthquake, epicentral
distance r, and R(T) given by Eq. 3.
Fp(T) = R(T)Fc(T)(4)

Standard spectrum was extended by adopting recent studies on the relation between M and source
parameters such as seismic moment, fault length, and so on, based on the representation by Kudo (1989),
which gave the attenuation curve of acceleration spectrum as a function of both M and r, in the long-period
range using the source model of Savage (1989) and normal mode theory.
Standard spectrum for earthquakes in a subduction zone:･
Fc(T) = 4.8･10
Fc(T) = 4.8･10

Fc(T) = 4.8 10

0.5M - 1.5・r) / rexp(-α・r) / r
exp(-α・r) / r

0.5(M>=6.9)(5)

1.25M - 6.7

0.5(6.2=<M<6.9)(6)

0.5M - 2.1

0.5(M<6.2)(7)(M>=6.8)(8)

0.5(6.4=<M<6.8)

(9)

0.5

(M<6.4)(10)

exp(-αStandard spectrum for inland earthquakes:･
Fc(T) = 4.8･10
Fc(T) = 4.8･10
Fc(T) = 4.8 10

0.5M - 2・r) / rexp(-α・r) / r
exp(-α・r) / r

exp(-α0.6M - 2.76
0.9M -4.68

0.5

where, α=0.001km－１.
Regionality and Ground Motion Prediction（様式１－別添資料） 7 / 11

Figure 11 shows an example of regionality in Tokyo, Niigata, and Osaka for each source zone (3, 9, and
11 in Fig. 10). For earthquakes in zone 3, ground motions in Niigata at a period of 10 sec will be about
three times as strong as in a standard region. As to Tokyo, ground motions from 8 to 9 sec forearthquakes in zone 9 will be shakable more than three times as standard. Thus, we can narrow down
source regions and period range to be careful at each observatory from these regionalities.

Figure 11. Regionalities at Tokyo, Niigata, and Osaka for zone-3 (left), zone-9 (mid), and zone-11 (right)
in Fig. 10, respectively.
Fig. 12 shows the comparison between observed acceleration spectrum and estimated spectrum by Eq. 4
in Niigata for the 1993 Hokkaido-nansei Oki earthquake (Mw7.8) as an example of large earthquake insubduction zone, and Fig. 13 shows the comparison for the 1930 Kita-Izu earthquake (Mw7.0) as an
example of an inland earthquake. They are in good agreement with each other. Thus, it is concluded thatthe empirical method is available for the prediction of spectra of long-period strong ground motions.

1000

1930 Kita-Izu EQ.

)c
se･
la
g( 100
ED
U
TI
PLM
A
LA 10
R
TC
EP
S
1

+σ
MEAN
-σ
OBS
1

10
PERI OD( sec)

100

Figure 13. Comparison between observed andcalculated spectra at Tokyo for the 1930
Kita-izu earthquake.
Figure 12. Comparison between observed andcalculated spectra at Niigata for the 1993
Hokkaido Nansei-oki earthquake. Shaded
area shows predicted spectrum withstandard deviation.

（様式１－別添資料） 8 / 11

Zoning and Revised Velocity Response Spectra
We estimated Fourier acceleration spectrum Fp(T) for earthquakes with expected maximum magnitude ineach seismotectonic zone (Hagiwara, 1991). Here, we regarded Fp(T) as velocity response spectrum Sv
in Eq. 2, because it was confirmed through many calculations that smoothed Fp(T) is equivalent to Sv with
damping factor of 0.5% for liquid sloshing of a single-deck floating roof tank, and also regarded anenvelope of superposed predictions as a predicted spectrum at the site.
Based on the observation of damage situation and current regulation, more than 80 oil industrial
complexes throughout the whole of Japan were divided into the following three categories,
Region-1: predicted spectral amplitudes are over 100 cm/s at periods of more than 7 sec.
Region-2: predicted spectral amplitudes are over 100 cm/s at periods of less than 7 sec.
Region-3: predicted spectral amplitudes are below 100 cm/s at the whole period range.
When JMA observatories are not located near tank sites, records should be newly collected and analyzed,
because it was found that characteristics of long-period ground motion at the tank site differ considerablyfrom the observatory, even if the distance is no more several km, as observed at Tomakomai in the 2003
Tokachi-oki earthquake. Then, we collected and analyzed data from strong motion observation networks(K-NET, KiK-net) operated by the National Research Institute for Earth Science and Disaster Prevention
and data by Port and Harbor Research Institute near the tank sites. Furthermore, some prediction resultsby the empirical Green function method and numerical method such as FDM (Aichi Pref. 2003; Furumura
2004; Hayakawa and Furumura 2004; Hijikata et al. 2004; Kamae 2004; Nozu 2004, Tsurugi et al. 2005)
were also collected and re-examined. Overall, 9 areas including 20 oil industrial complexes are
categorized into Region-1 shown as great circles in Fig. 10 and are considered having high potential risk
for large liquid sloshing of oil storage tanks.
For practical use, envelopes of predicted spectra in Region-1 were simplified and broken down into threepatterns based on their dependency on the period as shown in Fig. 14, while existing horizontal design
spectrum for liquid sloshing is constant in both period and region. Proposed spectra have a maximum of
210cm/s, which is equivalent to about 4m of the distance between liquid surface and top angle.
REGION- 1- ( 1)250
es )200
no s/
ps m
150
e c(
R
yit umrt
co ce100
le p
V S

0

es )200
no s/
ps m
e c(150R
yit umr
co tce100
le p
V S

RevisedExsisting

50

0

5

10
Period( sec)

REGION- 1- ( 2)

250

15

20

0

es )200
no s/
ps m
e c(150R
yit umr
co tce100
le p
V S

RevisedExsisting

50

0

5

10
Period( sec)

REGION- 1- ( 3)

250

15

RevisedExsisting

50

20

0

0

5

10
Period( sec)

15

20

Figure 14. Proposed velocity response spectra for Tomakomai, Sakata, Niigata (right), for Tokyo bay area
(middle), and for Hakodate, Akita, Shimizu, Nagoya area, Yokkaichi, Osaka area (left).
Concluding Remarks
Considering the heavy damage to oil storage tanks in the 2003 Tokachi-Oki earthquake, the intensity oflong-period ground motions supposed at more than 80 petroleum industrial complexes throughout Japanby large earthquakes in the future has been investigated. Using the proposed empirical prediction
equations and data, more than 10,000 components of digitalized records of JMA displacement typeseismometers, long–period strong ground motion at tank sites were predicted, and twenty petroleum
industrial complexes with higher risk of large sloshing were extracted. Velocity response spectra predicted
at these extracted sites were classified into three patterns shown in Fig. 14, and have 210cm/s in（様式１－別添資料） 9 / 11

maximum which is equivalent to about 4m of the distance between liquid surface and top angle. FDMA
amended Fire Service Law associated with the horizontal seismic intensity for liquid sloshing based on the
spectra presented in Fig. 14, which were enforced on April 2005. After that, FDMA has implemented thestrong motion observations at 9 areas categorized into Region-1 by the velocity type seismometers inorder to enhance the accuracy of predicted spectra, experiments on liquid sloshing of large-scale tanks inorder to understand sloshing behavior correctly, and investigation of suitable enforcement to pontoons inorder to prevent damage of oil storage tanks due to liquid sloshing excited by the long-period strong
ground motions, which will be strongly generated from very large earthquakes along the Nankai Trough inthe near future.
Acknowledgements
We thank Prof. Kamae of Kyoto Univ., Prof. Furumura of Tokyo Univ., Dr. Nozu of Port and Airport
Research Institute, Drs. Zhao, Tsurugi, Kagawa, and Miyakoshi of Geo-Research Institute, and Aichi Pref.
for providing data of long-period ground motion predictions. We also thank Japan Meteorological Agency,
National Research Institute for Earth Science and Disaster Prevention, and Port and Airport ResearchInstitute for the use of their strong motion records, and Mr. Endo and Miss. Ide of Fire Research Institutefor their cooperation associated with digitalization of displacement records of JMA.
References
Aichi Pref., 2003. Report on the Damage Prediction due to the Tokai and Tonankai Earthquakes, 2-8.
Aoi, S., R. Honda, N. Morikawa, H. Sekiguchi, Y. Hayakawa, and H. Fujiwara, 2004. 3-D Finite Difference
Simulation for the 2003 Tokachi-oki Earthquake, Special Project for Earthquake Disaster
Mitigation in Urban Areas Symposium, 121-124.
Fire Defense Agency, 1965. Research on Fires in the 1964 Niigata Earthquake, 153-180.
Furumura T., 2003. Simulation of Strong Ground Motions for Tokai and Tonankai Earthquakes,
http://www.eri.u-tokyo.ac.jp/furumura/tokai.htm.
Hagiwara T. ed., 1991. Earthquakes in and around Japan，Kajima Shuppan，192-197.

Hayakawa, T. and T. Furumura, 2004. 3D FDM Simulation of Strong Ground Motions for SE Off the Kii
Peninsula Earthquake of Sep. 5, Abst. of SSJ, PK17.
Hazardous Materials Safety Techniques Association, 2004. Report of Seismic Design of Floating Roof of
Oil Storage Tanks under Liquid Sloshing, 80-81.
Hijikata, K., T. Uetake, J. Kanatani, M. Mashita, T. Hayakawa, M. Watanabe, and T. Sato, Prediction oflong period strong ground motions in the KANTO sedimentary basin for the M8 Tokai earthquake,
Abst. of SSJ, B020.
th

Irikura, K., 1986. Prediction of Strong Acceleration Motion using Empirical Green’s Function, Proc. 7
Japan Earthquake Symp., 151-156.
Japan Meteorological Agency, 1990. Strong Motion Records Observed at Tokyo (1927~1989).

Kamae, K., H. Kawabe, and K. Irikura, 2004. Strong Ground Motion Prediction for Huge Subduction
Earthquakes using a Characterized Source Model and Several Simulation Techniques, 13 World
Conference of Earthquake Engineering, DVD No.655, 1-11.

（様式１－別添資料） 10 / 11

Kudo, K., 1989. Significance of Long-period Strong Motion in Seismic Risk Evaluation, Proc. 4th Int.
Symp. on the Analysis of Seismicity and Seismic Risk., 433-439.
Ministry of Home Affairs ,1983. Notification No.119.
Miura, M. 2004. Damage of Oil Storage Tanks due to the 2003 Tokachi-oki Earthquake andCountermeasures against Liquid Sloshing, Symp. on Reliability of Facility and Optimum Cost,
Japan Petroleum Institute, 10-19.
Nishi, H. and T. Yokomizo, 2006. Report on the Investigation of the Tank Fires at the Idemitsu Kosan
Hokkaido Refinery, Rept. of National Res. Inst. of Fire and Disaster, 100, 59-63.
Sakai, F., Some Proposals on Seismic Design Method of Cylindrical Tank, J. of High Pressure Inst. ofJapan，18，16-23.

Savage, J. C, 1972. Relation of Corner Frequency to Fault Dimensions, J. Geophys. Res., 77, 3788-3795.
Senda K. and K. Nakagawa,1954. On the Vibration of an Elevated Water Tank -I. Technical Report of the
Osaka University 4, 170, 247-264.
Tsurugi, M. O, B. Zhao, P. Anaoly, and T. Kagawa, 2005. Prediction of Strong Ground Motion at Osaka for
the Nankai and Tonankai Earthquake, Proc. of JSCE Structural Engineering, 51A, 501-512.
Yamauchi, Y., A. Kamei, S. Zama, and Y. Uchida, 2006. Seismic Design of Floating Roof of Oil Storage
Tanks, Proceedings of PVP2006-ICPVT-11 ASME, 1-9.
Zama, S., 1985. Sloshing of Liquid in Oil Storage Tanks at Tomakomai in Hokkaido, due to the 1983
Japan Sea Earthquake, Rept. of National Res. Inst. of Fire and Disaster，60，1-10.

Zama, S., 1990. Liquid Sloshing of Oil Storage Tank and Long Period Ground Motion, 18th Symp.on
Ground Vibrations，15-20．

Zama, S., 1995. Liquid Sloshing of Oil Storage Tank and Characteristics of Long-period Strong Ground
Motion, J. Japan Soc. for Safety Engineering, 34, 148-155.
Zama, S., 2000. Semi-empirical Expression for Acceleration Spectrum of Long-period Strong Ground
Motion, Rept. of National Res. Inst. of Fire and Disaster, 89, 1-10.
Zama, S., H. Nishi, Y. Hirokawa, M. Yamada, and K. Hatayama, 2004. Attenuation Factors of Liquid
Sloshing of Oil Storage Tanks, Rept. of National Res. Inst. of Fire and Disaster, 98, 66-73.
Zama, S 2005. Re-examination of Seismic Zoning based on Spectral Characteristics of Long-period
Strong Ground Motions, Safety & Tomorrow, 101, 14-26.

（様式１－別添資料） 11 / 11

［様式２］

1.所有する観測機器の整備状況及び今後の整備計画（予算額（見込み）を含む）（単位：箇所）
設置状況
陸域
海域
TYPE1
TYPE2
地上
強震計
地下
GPS
地殻
SLR
変動
VLBI
歪計等
海底地殻変動
地下水
地球地磁気
重力
験潮・津波

H7年度
（H8.3.31現在）

H8年度
H9年度
H10年度
H11年度
H12年度
H13年度
H14年度
H15年度
H16年度
H17年度
H18年度(小計①)（H9.3.31現在） （H10.3.31現在） （H11.3.31現在） （H12.3.31現在） （H13.3.31現在） （H14.3.31現在） （H15.3.31現在） （H16.3.31現在） （H17.3.31現在） （H18.3.31現在） （H19.3.31現在）

高感度
地震計
広帯域
地震計

9

10

3

3

3

3

（様式２-1.） 1/2

3

3

2

4

2

6

設置数が減っているのは廃棄したため

［様式２］

今後の設置予定（上段：数 下段：予算）
高感度
地震計

広帯域
地震計

H19年度

H20年度

H21年度

H22年度

H23年度

H24年度

H25年度

H27年度

H28年度

H29年度以降

陸域
海域
TYPE1
TYPE2
地上

強震計

0
0

0
0

0
0

0
0

0
0

0
0

地下
GPS
SLR

地殻
変動

H26年度

VLBI
歪計等

海底地殻変動
地下水
地球地磁気
重力
験潮・津波

（様式２-1.） 2/2

0
0

0
0

0
0

0
0

0
0

（単位：箇所）（単位：千円）
合計（①＋②）

小計②
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0
0
0
0
6
0
0
0
0
0
0
0
0
0
0
-

［様式２］

2.地震関係の研究者数
性別・年齢

年度
平成7年度

平成8年度

平成9年度

平成10年度

平成11年度

平成12年度

平成13年度

平成14年度

平成15年度

平成16年度

平成17年度

平成18年度

平成19年度

性別
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計
男
女
計

年齢
60-65 50-59 40-49 30-39 20-29
1
0

0

1
1

0

0

0

0

1
1

0

0
1

0

0

1
1

0

1
1

0

0

1
1

0
1

1

0

0

1
1

1
1

0

0

0

1
1

1
1

0

0

0

1
1

1
1

0

0

0
1

1

1
1

0

0

1
1

0

1
1

0

0

1
1

0

1
1

0

0

1
1

0

1
1

0

0

1
1

0

1

0

0

1

0

0

0

（様式２-２.） 1/1

計
1
0
1
1
0
1
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
2
0
2
1
0
1