thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

Application of Earthquake Early Warning System and Real-time Strong-motion Monitoring
System to Earthquake Disaster Mitigation of a High-Rise Building in Tokyo, Japan
Tomohiro Kubo1, Yoshiaki Hisada2, Shigeki Horiuchi3 and Shunroku Yamamoto4
1

ABSG Consulting, Tokyo, Japan Email: tkubo@absconsulting.co.jp
2
Professor, Kogakuin University, Tokyo, Japan
3
National Research Institute for Earth Science and Disaster Prevention, Ibaraki, Japan
4
Railway Technical Research Institute, Tokyo, Japan
ABSTRACT :We apply Earthquake Early Warning System (EEWS) and Real-time Strong-motion Monitoring System(RSMS) to reduce earthquake-related damage of the 29-story building of Kogakuin University in the
downtown Tokyo, Shinjuku, Japan. EEWS, which is operated by National Research Institute for Earth Scienceand Disaster Prevention, is the system to provide earthquake information, such as the location and magnitudeof an earthquake, the arrival time of the S-wave, and the estimated seismic intensities, before the actual
arrivals of S-waves. We estimate the ground motion using EEWS, not only the S-wave, Using EEWS, weestimate not only the arrival time and the amplitude of the S-wave and the surface waves, but also the building
response. We apply EEWS to the emergency control systems of the elevators by estimating ground motions at
the Shinjuku site and the corresponding building response. To do this, first, we construct a Green’s function
library to estimate roughly the strong ground motions including the surface waves using the wavenumber
integration method for various seismic regions, and a library of the corresponding maximum response valuesof the building using the modal analysis. To check the accuracy of the library, we compare between theobserved record for the 2004 Chuetsu Earthquake and the estimated waves. The results show good agreementswith the observations in the first half of the records in the arrival time, the amplitudes. Once an earthquake
occurs, the ground motion and the building response are quickly estimated using the proposed method. And,the emergency control systems stop automatically the elevators at the nearest floors to prevent people fromtrapping. On the other hand, we use RSMS to estimate the building damage during earthquakes, and to reduce
secondary damages, such as making an announcement for the building safety to prevent a panic.
KEYWORDS:

Earthquake Early Warning System, Real-time Strong-motion Monitoring System, High-rise
Building, Surface Wave, Green’s function library, Elevator Emergency Control Systems

1. INTRODUCTION
The Shinjuku campus of Kogakuin University is located in the downtown Tokyo, and is a high-rise buildingof the 29-stories with 149m of height and about 3 sec of the 1st natural period. The campus building needs toprepare for the two types of large earthquakes: one is M7 earthquakes under the Tokyo area, and the other is
M8 earthquakes from a rather far subduction zone. The Headquarters for Earthquake Research Promotion
estimated about 70% of the occurrence probability of an M7 class earthquake in the southern Kanto area forthe next 30 years (Headquarters for Earthquake Research Promotion, [1]). When this type of earthquake
occurs, it is estimated disastrous damage in the Tokyo metropolitan area, according to the Central Disaster
Prevention Council of Cabinet Office [2]. On the other hand, the occurrence probability of the Tokai
earthquake (M8.0) for the next 30 years is estimated at 86% [1]. When the earthquake occurs, the long-period
strong ground motions, which are the surface waves excited in the Kanto sedimentary basin, will vigorously
shake long-period structures in Tokyo, such as high-rise buildings and oil storage tanks.
In order to reduce earthquake related damage from those earthquakes, we apply EEWS (Early Earthquake
Warning System) and RSMS (Real-time Strong-motion Monitoring System) to the elevator control system of
the high rise building of Kogakuin University. The Japan Meteorological Agency (JMA) has been distributing
the EEWS information to public users since 1st October 2007, which are the estimated seismic intensities andthe expected arrival time (JMA, [3]). On the other hand, the National Research Institute for Earth Science andth

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
Disaster Prevention (NIED) also provides the EEWS information for academic users with more detail
information than those of JMA, such as the magnitude, depth, location of an earthquake, which we use for
estimating the arrival time and amplitudes of the body and surface waves. On the other hand, the building has
RSMS for monitoring its response during earthquakes, which is also used to estimate the building damage bycomputing the story drift angles and the seismic intensities on each floor in real-time.
2. EEWS, RSMS AND ELEVATOR EMERGENCY OPERATION CONTROL SYSTEMS OF
KOGAKUIN UNIVERSITY
2.2. EEWS and RSMS of Kogakuin University
Figure 1 shows the EEWS between Kogakuin University and NIED; EEW information includes the locationof the epicenter of an earthquake, its magnitude, Seismic Intensity Magnitude (Yamamoto et al., [4]) and theobservation waves of Hi-Net. Figure 2 shows the elevation plans of the Kogakuin University buildings andthe location of the accelemeters of RSMS. The RSMS has been recorded a lot of observation data, such as
2004 Kii Peninsula Offshore Earthquake and 2004 Chuetsu Earthquake. Figure 3 shows the RSMS web pages,
the top page outlines the RSMS, the wave page shows the observation record or the real-time data on eachchannel, and the building response page shows the building response, the seismic intensity and the story drift
angle at each floor. When earthquake happens, security officers of the building are possible to check thebuilding damage on real-time by RSMS. Figure 4 shows the location of Kogakuin, a K-Net station [5] and theepicenter of 2004 Chuetsu Earthquake and Figure 5 shows the observed records of RSMS and the K-Net for2004 Chuetsu Earthquake. The P- and S-waves arrived at Shinjuku at about 37 sec and 59 sec, respectively,
after the occurrence of the earthquake. On the other hand, the surface waves arrived at about 93 sec, andshaken the building with the maximum response around at 125 sec. Therefore, we will have enough time forcontrolling the elevators before the arrival of the surface waves.
STEC BLDG

UDP

28F

FW

22F

Kogakuin Univ

FW

15F

NIED

8F

Kogakuin Univ

29F
22F
16F
8F
1F

Figure 1 EEWS between Kogakuin University
and NIED

B6 F
GL-100m

Figure 2 The elevation plan of Kogakuin University andthe locations of the accelerometers,

Top Page

Wave Page
Building Response Page
Figure3 Real-time Strong motion Monitoring Systemth

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
Acceleration (EW)

(cm/s/s)
20
P
15
2004 Chuetsu EQ

K-net
GL-100Surface wave(93sec)

10

2.41km

TKY00750-5 0

190.4km

50

100

150

200

250

300

-10

S wave(59sec)

-15
-20

Displacement (EW)

(cm)
6

29F

4

Kogakuin

2
0
-2

0

50

100

150

200

250

300

-4

Maximum Response（125sec）
Figure 4 The location of Kogakuin Building, K-net and -6
Figure 5 The observed wave in 2004 Chuetsu EQ
the seismic source in 2004 Chuetsu EQ

2.2. Elevator Emergency Control System during a Earthquake
Kogakuin University building has 3 types of elevators. Table 1 shows the locations of the P- and S-wave
sensors and their trigger levels for the emergency control during an earthquake. When the P-wave sensors are
triggered, the elevators stop by the nearest floors for about 60 sec to 90 sec, and automatically restart theirservice, if nothing happens afterward. On the other hand, when the S-wave sensors are triggered at the lower
levels, the elevators also stop by the nearest floors, but do not restart without confirming the safety by the
maintenance company staffs. When the S-wave sensors are triggered at the higher levels, the elevators stop
immediately, and thus, the people in the elevators are probably trapped.
Table 1 The P and S sensors, their locations and trigger levels for the emergency
operation control systems of elevators of the Kogakuin University
EV typeEVs for the higher andmiddle floors
EV for the lower floors
EV for Emergency

Lowest trigger level
P wave sensor

Low trigger level
S Wave sensor

High trigger level
S Wave sensor

OthersNo

80gal on penthouse

120gal on penthouse

Seismic Wave
Energy sensor

5gal on pit
5gal on pit

150gal on 8th floor
40gal on penthouseNo
80gal on penthouse

3. ELEVATOR EMERGENCY CONTROL USING EEWS FOR LONG-PERIOD GROUND MOTION
In this study, we propose the elevator emergency control flow using EEW for long-period strong groundmotions. As shown in a flow in Figure 6, when the system receives an EEW data (the magnitude, location anddepth of an earthquake), it immediately estimates the arrival time of the surface waves and the maximum
building response. We estimate the arrival time using an empirical relation, as shown below. To obtain the
maximum response, we first prepare database library of long-period ground motions and the corresponding
building response, which will be also represented bellow.
3.1. Development of the Empirical Equation for the Arrival Time of the Surface Wave
We collect the observation data from 1994 to 2006 and develop the empirical equation for the arrival timeof the surface wave. The number of the collected waves is 173, including the 15 waves of the surface wave
data. Figure 7 shows the distribution of the epicenters of observation data, and Figure 8 shows plots of thearrival times versus the distances between hypocenters and the Kogakuin site. The P, S, and surface waves
correspond to blue lozenges, red boxes, green triangles, respectively. The lines show the average velocities;
the P, S-wave and the surface wave are 5.9km/s, 3.5km/s and 2.5km/s, respectively. On the other hand, we
also calculate the theoretical velocities of the P, S-wave and the surface wave using the wavenumber
integration method (Hisada and Bielak [6]). Tables 2 and 3 show the crustal structure model by NIED andth

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
the sedimentary structure model, which consists of the crustal model and the sedimentary layers of the Kanto
basin (Yamada and Yamanaka, [7], J-SHIS, [8]). In figure 8, the dotted lines show the theoretical velocities,
which are in good approximation in those of the observations.
Receiving EEW data(magnitude、location of epicenter)

Library of building response by long period
ground motion
Estimation long period groundmotion by Green’s function

Estimation the arrival time of thelong-period ground motion(by empirical equation)

Estimation building response using
the lumped mass model response

Threshold level
Stop the elevator at nearest floor
Figure 6 The elevator emergency control flow

Epicentral distance (km)900
Depth (km)Obs P
5.9 km/s

800

Obs S
3.5km/s

Theory S
3.6km/sRock model
2.9km/s

700
Magnitude

600Theory P
500

6.3km/sObs Surface wave
2.5 km/s

400

Pwave
Swave
Surface wave

300
200
100

Sedimentary model
0.3 km/s

00Figure 7 The distribution of the epicenter in theobservation data

100

200

300

400

Arrival time (sec)Figure 8 The plot of the arrival time versus the
distance between hypocenter andKogakuin sitethThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

Layer Number
1
2
3
4
5
6
7
8
9

Table 2 The structure of Rock model
densityThichness
Vp(m/s) Vs(m/s)
Q(t/m3)
(m)
2.3
5450
3179
300
1000
2.3
5501
3209
300
1000
2.3
5527
3224
300
2500
2.3
5816
3392
400
3000
2.3
6035
3521
500
4000
2.3
6206
3620
600
3000
2.3
6381
3722
600
3000
2.3
6684
3899
1000
5000
2.3
7201
4200
1000
8000

Data

NIED Traveltime
Database

Table 3 The structure of Sedimentary model
Layer Number
1
2
3
4
5
6
7
8
9
10
11
12
13

density(t/m3)
1.85
1.9
2
2
2.3
2.3
2.3
2.3
2.3
2.3
2.3
2.3
2.3

Vp(m/s)Vs(m/s)

Q

1840
1900
2200
3863
5527
5816
6035
6206
6381
6684
7201
7775
7804

500
750
1350
2287
3224
3392
3521
3620
3722
3899
4200
4364
4380

100
100
150
300
300
500
500
600
600
1000
1000
1000
1000

Thichness
(m)
400
800
650
650
2500
3000
4000
3000
3000
5000
8000
9000
10000

Data
Yamada･Yamanaka(2003)
Japan Seismic Hazard
Information Station

NIED Traveltime
Database

3.2. Estimation of the Surface Wave and Building Response using EEWS
Next, we estimate the long-period strong ground motions including the surface waves, and thecorresponding building response. We compute the ground motions using the wavenumber integration method[4], and the building response using a lumped mass model. As an example of ground motion simulations,
Table 4 shows the source parameters of the 2005 Chuetsu, Niigata, earthquake, from EEWS. The JMA
magnitude is estimated from the moment magnitude using the empirical relation by Takemura [9], and thestress drop is the average value of crustal earthquakes in Japan (Turugi et al., [10]). We estimate the groundmotion at the Shinjuku site using the Sedimentary structure model shown in Table 3.
Figure 9 shows the radial and transverse components of the observed records by RSMS and the simulated
waves, using a band pass filtered from 0.1 Hz to 1 Hz. Figure 10 shows the corresponding Fourier spectrums.
The estimations show good agreements with the observations before 70sec in the waves and less than 4 sec ofperiod. After 70 sec いｎ duration and 4 sec in period, the simulations underestimate the observations,probably because of the 3D effects of the Kanto sedimentary basin.
Figure 11 shows the observed building response at the top floor and the simulated results using one-massmodel, which is equivalent to 1st mode of the building (3 sec of period and 2% of damping). Even though themethodology is very simple, the estimations show in good approximation in the observations, not only in thearrival time, but also in the amplitudes. Since our purpose is to estimate the maximum building response as
quickly as possible, the methodology is effectively enough to apply to the emergency control systems of theelevators

thThe 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China

Table 4 The point source parameter in 2004 Chuetsu Earthquake
Mjma Depth(km) Mo （dyne-cm）
Stress Drop (bar) fmax (Hz)
6.8
13.2
4.74E+25
30
6
(cm)

(cm)

5

5

Kogakuin
Radial4
3

Kogakuin
Transv erse

4
3

2

2
1

1
0

0

-1 0
-2

50

100

150

200

(sec)

-3
-4

-1 0

50

100

150

200

(sec)

-2
-3
-4

-5

-5

Figure 9 The comparison between the observed wave with the simulation wave in 2004 Chuetsu EQ
50

50

Fourier Spectrums (cm/s2/s)

Kogakuin
Radial45

Kogaku inTran sve rse

45

40

40

35

35

30

30

25

25

20

20

15

15

10

10

5

5
0

0
0

1

2

3

4

5

6

7

8

9

0

10

1

Period (sec)

2

3

4

5

6

7

Period (sec)

8

9

10

Figure 10 The comparison between the observed Fourier spectrums (red line) with thesimulation Fourier spectrums (black line) in 2004 Chuetsu EQ
Response displacement (cm)8

1 MassEW
Obs EW

6

8

4

4

2

2

0
-2 0

50

100

150

200

25 0

0
-2 0

-4

-4

-6

-6

-8

1 MassNS
Obs NS

6

50

100

150

200

25 0

-8

Figure 11 The comparison between the observed displacement with thesimulated response displacement in 2004 Chuetsu EQ
3.3. Estimation method of the building response for long-period Ground Motions
For the elevator emergency control during major earthquakes, we develop a database library of the building
response, and check the cases for stopping the elevators. Table 5 shows those cases at Kogakuin University.

th

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
We estimate the strong ground motion and the building response on these earthquakes using the above method.
Figure 12 shows the plot of the observed maximum displacements at the top of building versus the estimatedmaximum building responses,. The cases for stopping and not stopping the elevators are shown in the redboxes and the blue triangles, respextively. For most of the cases, the elevators stopped when the maximum
displacements exceed 2.1 cm. Therefore, the building response is estimated over 2.1 cm, we stop the elevator
sbefore arriving the surface wave.
Table 5 The case of the elevator stopped by the long-period ground motion
EQ
1998/4/9 Fukushima Offshore
1999/5/22 West Kanagawa
2000/7/15 Near Niijima & Kozushima
2003/7/26 East Miyagi
2003/9/26 Tokachi Offshore
2003/10/31 Miyagi Offshore
2004/9/5 Kii Peninsula (19o'clock)2004/9/5 Kii Peninsula (23o'clock)2004/10/23 Chuetsu (17o'clock)2004/10/23 Chuetsu (18o'clock)2004/10/27 Chuetsu
2004/11/8 Chuetsu
2005/8/16 Miyagi Offshore
2005/11/15 Miyagi Offshore
2006/4/21 East Shizuoka
2008/5/8 Ibaraki Offshore

Hypocenter
Distance (km)
184
53
146
330
695
359
411
425
194
193
189
200
358
540
95
181

Observed displacement at the
top of building (cm)Logitude Latitude
141.0
36.9
139.2
35.5
139.3
34.4
141.2
38.4
144.1
41.8
142.7
37.8
136.8
33.0
137.1
33.1
138.9
37.3
138.9
37.3
139.0
37.3
139.0
37.4
142.3
38.2
144.9
38.0
139.2
34.9
141.6
36.2

Depth
90km
23km
10km
10km
42km
30km
38km
44km
13km
14km
12km
Shallow
42km
45km
7km
35km

MJMA
5.4
4.4
5.9
6.2
8.0
6.8
6.9
7.4
6.8
6.5
6.1
5.9
7.2
7.2
5.8
7.0

Elavator
StatusLowest trigger
Lowest trigger

Lowest trigger
Low trigger

2004Chuetsu EQ (17o’clock)8
7

correlation coefficient:0.64

2005 Miyagi Offshore

y = 1 .2 5 4 3 x 1.17 8

62008 Ibaraki Offshore
2004 Kii Peninsula EQ (23o’clock)5
42004 Chuetsu EQ (18 o’clock)3
2

2003Tokachi EQ

1
0
0

1

2

2.1cm

3

4

5

6

7

8

Estimated building response (cm)Figure 12 The plot of the observed displacement at the top of building versus
the estimated building response
4. CONCLUSIONS
We applied EEWS and RSMS to the emergency operation control systems of the elevators of the high-rise
campus building in downtown Tokyo, considering long-period strong motions. Once an earthquake occurs, themaximum building response can be quickly computed using the source data of EEWS and the databaseth

The 14 World Conference on Earthquake Engineering
October 12-17, 2008, Beijing, China
libraries, which are estimated by computing the surface waves in the Kanto basin, and by using a lumped massmodel of the building. If the response is estimated over a certain threshold value, the EEWS server sends asignal to the emergency control systems of elevators as the lowest trigger level for stopping them at the nearest
floors. In addition, we are planning to apply EEWS and RSMS to the announcement system to prevent a panicby providing the accurate information about the building's safety; this is important because the high-risebuilding will continue to shake vigorously for several minutes by the surface waves, especially for M8-class
earthquakes.
ACKNOWLEDGEMENTS
This research was supported by the Earthquake and Environmental Research Center of Kogakuin University
funded by the Frontier Research Promotion Program of Ministry of Education, Culture, Sports, Science andTechnology of Japan (MEXT), the Real-time Strong Motion Monitoring System of High-Rise building forLong-period ground motion funded by the MEXT, .a research project of Ministry of Land, Infrastructure andTransport Japan. The authors acknowledge the National Research Institute for Earth Science and Disaster
Prevention for use of K-NET and F-NET data.
REFERENCES[1] The long-term evaluation in Kanto Area, Headquarters for Earthquake Research Promotion[2] “Conference for Shuto Chokka Earthquake Disaster Mitigation”, (2004), Central Disaster Prevention
Council[3] The Japan Meteorological Agency[4] Yamamoto, S., Rydelek, P., Horiuchi, S., Changjiang, Wu., and Nakamura, H. (2008), “On the estimationof seismic intensity in earthquake early warning systems”, Geophysical Researvh Letter, Vol.35, L07302[5] Kyoshin Network, National Research Institute for Earth Science and Disaster Prevention,
http://www.k-net.bosai.go.jp/k-net/[6] Hisada, Y and J, Bielak. (2003), ”A Theoretical Method for Computing Near-Fault Strong Motions in
Layered Half-Space Considering Static Offset due to Surface Faulting, with a Physical Interpretation of
Fling Step and Rupture Directivity”, Bull. of the Seism. Soc.of America, Vol.93, No.3, pp.1154-1168[7] Yamada, N., and Yamanaka, H. (2003), “Ground Motion Simulation of Moderate Earthquakes for
Comparison of Performance of 3D Subsurfaxe Structural Models in Kanto Plain for Strong Motion
Prediction”(in Japanese), Zisin, Vol.56, No.2, pp 111-124[8] Japan Seismic Hazard Information Station, National Research Institute for Earth Science and Disaster
Prevention, http://www.j-shis.bosai.go.jp/[9] Takemura, M. (1990), “Magnitude-Seismic Moment Relations for the Shallow Earthquakes in and around
Japan”, Zisin, Vol.43, pp 257-265[10] Tsurugi, M., Kagawa, T., Okazaki, A., Hada, K. and Irikura, K. (2006), “Study on a high-cut filter forstrong ground motion prediction –Based on the observed records during the 1995 Hyogo-ken Nambu
Earthquake”, Journal of JAEE, Vol.6, No.4