8th Annual Meeting, Asia Oceania Geosciences Society, August 2011, Taiwan.
SE85 / Earthquake Early Warning, SE85-D3-PM1-201C-003, Invited.

On the Effective
Earthquake Early Warningand its Verifications

Yutaka NAKAMURA, Dr. Eng.
System and Data Research, Co., Ltd.
Visiting Professor, Tokyo Institute of Technology

1

System and Data Research Co., Ltd.
Tokyo Institute of TechnologyWe can see from this video as follows;¾EEW can get only short time margin.
¾It is extremely necessary and importantto prepare and exercise for EEW in advance.
¾In any case, only the immediate and proper
warning can be useful.
And one of the lessons from the 3.11 Earthquake is¾Avoid that Warning becomes crying Wolf.
3System and Data Research Co., Ltd.
Tokyo Institute of Technology

Concept of Earthquake Early Warning
On-SiteDetection/Alarm
Front
Detection/AlarmP
P-wave Alarm

S

S-wave Alarm

Fault Rupture

There are two kinds of theearthquake alarm. One is“On-site Alarm” which is thealarm based on theobservation at the side of
the objects to be warned.
The other is “Front Alarm”
which is the alarm based on
the observation near theepicentral area to warn forthe possible damaged area.
Both alarm types described
can make use of two
different triggers, also called“alarms”.

One is so-called “S-wave Alarm” or “Triggered Alarm”. And the other is “P-waveAlarm”.
4System and Data Research Co., Ltd.
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Concept of the Front Alarm
by Dr. Cooper, 1868
San Francisco
Daily Evening
Bulletin, 3
November 1868

AlartW
aveP
ropa
gationWave P
ropagat Fau
ion ltIn 1972, Dr. Hakuno et al.,researchers forearthquake disasterprevention in Japan,
advocated the "Strongearthquake alarm system
10 seconds before".
Alarm Seismometer Although this was an idea
similar to Dr. Cooper's
front detection system in1868, nobody had put inpractical use until then.

Epicenter
We have developed a prototype system for EEW as UrEDAS in early 1980’s.
5

System and Data Research Co., Ltd.
Tokyo Institute of Technology

Introduction of UrEDAS
UrEDAS, Urgent Earthquake Detection and Alarm System,
is the first real time P-wave alarm system over the world inpractical use in 1992 for Tokaido Shinkansen.
It is characterized to be able to process digitized waveformstep by step without storing waveform.
Amount of procedure is not differ from each other either
earthquake occurs or not, so it expected not to be occurred
the system down due to the over load.
UrEDAS is able to use not only for the On-site alarm but
also for the Front alarm.
6System and Data Research Co., Ltd.
Tokyo Institute of Technology

Functions of the UrEDAS
There are two types of UrEDAS; “UrEDAS” and “CompactUrEDAS”.
Function of UrEDAS (1985) is to estimate the magnitude andthe location of detected earthquake in three seconds after
initial P-wave detection and issuing the alarm for expected
damage area.
On the other hand, Compact UrEDAS (1998) can evaluate
whether the earthquake will be destructive or not using
Destructive Intensity DI and issues alarm one second afterP-wave detection if needed.
7System and Data Research Co., Ltd.
Tokyo Institute of Technology

Examples
Examples ofof Monitoring
Monitoring
Earthquakes
Earthquakes byby UrEDASUrEDAS
Pasadena The 1994 Northridge

Earthquake monitoredby Pasadena UrEDAS
M<3 M<4M<5M<6Kongo-San
M<3 M<48M<5M<6The 1995 Hyogo-KenNambu Earthquake
monitored by KongoSan UrEDAS

UrEDAS worked at the time ofthe 1994 Northridge Earthquake
and the 1995 Kobe Earthquake.
During the first 24 hours after theNorthridge earthquake, UrEDAS
in Pasadena detected about 700
aftershocks. The upper figure
shows the distribution of theaftershocks. Their magnitude
and locations of hypocenter wereautomatically estimated.
Lower figure shows the result ofmonitoring the Kobe Earthquake
sequence for two weeks after themain shock. Although thesefigures based on the data of only
one UrEDAS station, aftershock
activity was almost correctlytraced.

System and Data Research Co., Ltd.
Tokyo Institute of Technology

UrEDAS Alarm based on M-∆ Diagramafter Bitoh, Nakamura and Tomita (1985)
Possible Damage Area
for magnitude MNo Damage∆

Damages for Bridge

100EpicenterlaG
20

1345

UrEDAS can issue an alarm
based on the distribution ofthe past earthquake damage
on magnitude to epicentral
distance plane. This alarm isreferred to as an M-Δ Alarm.

∆Galla
G
04120

1080G
alEpicentral Distance in km

Damages for Embankments

6M 7

8Magnitude M
9System and Data Research Co., Ltd.
Tokyo Institute of Technology

Moreover UrEDAS cansupport restarting operation
based on the detailed
earthquake parameters.Captured Video at the time of the 1995 Kobe Earthquake

P wave arrival

emiT

Principal motion arrival

Motivation of Compact UrEDAS development is the Kobe Earthquake. On the video,
they noticed the initial P wave motion as something happening, and then the severe
motion attacked them after a few seconds. Although there was only a few seconds
between notification of something happening and recognition of earthquake, it wasanxiousness and fearful because they could not understand what happened andfelt relieved after recognition of the earthquake occurrence. As the counter of thiskind of feeling, the earlier earthquake alarm is required and I developed theCompact UrEDAS to make the alarm within one second after P wave arrival.
10System and Data Research Co., Ltd.
Tokyo Institute of Technology

Definition of DI, Destructive Intensity,andSeismic Intensities RI (corresponding to JMA
Instrumental Intensity) and MMI
F = mav

Power = F･v = ma･v
DI = log10|a･v|

unit for a: Gal (cm/s2)
unit for v : kine (cm/s)

Power Density PD = Power/m = a･v
for a: m/s
LPD = log10|a･v| unit
unit for v : m/s2mRI ＝ DI + 2.4 = LPD + 6.4
MMI = (11/7)･RI + 0.5

Compact UrEDAS estimates the destructiveness of the earthquake immediately fromthe earthquake motion directly, not from the earthquake parameters as UrEDAS, andthen issues the alarm if needed. To estimate destructiveness of the earthquake motion,
I defined DI, Destructive Intensity, as shown in this slide (1998). Based on the DI, a
new seismic intensity, realtime intensity RI, or MMI are defined as this slide (2003).
11System and Data Research Co., Ltd.
Tokyo Institute of Technology

The Change of RI for Earthquake Motion
Acceleration in Gal_ EW

100500-50-100NSZ

The Change of RI and Acceleration observed at the 2003 Miyagiken-Oki Eq. M7.012When P wave arrives, RI increases
drastically. After initial P wave, RI
keeps almost same value until theS wave arrival. After the arrival ofS wave, it reaches to its maximum
value. This value can be relatedon damage and Instrumental
Seismic Intensity of JMA or otherscales like MMI.
Instrumental JMA Intensity scale isdefined to calculate artificially only
after the earthquake termination.
On the other hand, RI can becalculated in realtime with physicalbackground. This can beconcluded as, with the continuous
observation of RI, earthquake
alarm can be issued efficiently anddamage can be estimated precisely.

System and Data Research Co., Ltd.
Tokyo Institute of Technology

The P wave alarm of Compact UrEDAS demonstrates the effectivenessas making the derailment not catastrophic (the 2004 Niigataken-Chuetsu Earthquake M6.8)
×100m

This railway track is built
on many viaducts, andP-wave Arrival
P-wave Alarmviaducts with different
S-wave Arrival
characteristics are joined at
Principal Motion
300m. The train derailed
Main Derailments
passing at the 300m point.
The alarm was issued
Vehicle ②:
Successive You can see derailment situation
about 2.5 seconds before
AExample
Successand contact situation between body
Derailmentofthe arrival of the S-wave
and railroad,
Location
ExampleofCompact
at the location of the train.
Compact
UrEDAS
The large motion started
normal vehicle
UrEDAS
Warningderailment vehicle by
one more second after
Warningflange climbing
that. So the P-wave alarm
large relative displacement
preceded the large motion
railway deformation
Front ⑩
Rear ①by about 3.5 sec. If FREQL
was installed, the P-alarm
issued 0.8 sec earlier.
Without the emergency breaking triggered by the alarm the train would have arrived at the 300m point
earlier and more vehicles would have passed that point during the large motion. With the very highpossibility of the rail buckling, this would have caused more serious derailment and overturning.
0123456789 1 0 11 1 2 1 35 seconds

TimeFinal Derailment
Final Situation
Situation(a)先頭車
Tunnel Exit

13(b)最後尾車

System and Data Research Co., Ltd.
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FREQL(Fast Response Equipment against Quake Load)
FREQL is developed for the earthquake
warning system based on the experiencesof development and operation of the world
first P wave alarm system UrEDAS.
FREQL integrates the functions ofUrEDAS, Compact UrEDAS and AcCo.
P wave alarm is available 0.2 seconds inminimum after P wave detection ( thefastest time was shortened to 0.1 seconds
in 2009).
S wave alarm is also available. (Based onacceleration and realtime seismic intensityRI)14

System and Data Research Co., Ltd.
Tokyo Institute of Technology

FREQL is toward to the new field, asfor the Hyper Rescue Team under the risk ofaftershocks
Hyper rescue team acts undera risk of large aftershocks.
After the Niigataken Chuetsu
Earthquake, the hyper rescue
team approached us to adopt
FREQL as a supporting system
for the rescue activity.
Rescue Activity of Hyper Rescue Team-15

System and Data Research Co., Ltd.
Tokyo Institute of Technology

Tokyo fire department andother departments in nation
wide have adopted the portable
FREQL as equipment to keep
the safety against the risk of thesecond hazards caused byaftershocks during their rescue
activity, not only in Japan but
also in Pakistan, China andNew Zealand.

Processing 警報処理時間
Time for P-wavein sec.
）
（ 秒Alarm

Change of processing time for EEW
10cf. Equipment developed by JMA

SDR products

5

UrEDAS 3 sec.

3

UrEDAS
2 Test observation
1Average 5.4 sec.

JR Tokaido Shinkansen
Tsunami warning system Minimum 2.0 sec.
for Wakayama Prefecture

Compact UrEDAS 1 sec.
Tohoku Shinkansen
Tokyo Metro

0.5

Min.
0.1sec.

FREQL Minimum 0.2 sec.

0.2

Tokyo Metro, Odakyu
Fire Departments of Tokyo, Osaka and so on0.1
1980

1985

1990

1995

2000

2005

2010

Year

Development of Processing Time
16

System and Data Research Co., Ltd.
Tokyo Institute of Technology

This figure shows thechange of the processing
time for EEW.
While JMA system performs
every one second for thealarm processing
intermittently with stored
data, UrEDAS and FREQL
perform the procedurecontinuously in every
sampling time.

Actual Example with Simulated Results of FREQL or
AcCo for Recent Damaged Earthquake in JAPANThis figure
RI=1.5) by FREQL
P -waveAlarm ( RI=1.5)
2008.6.14, compares the EEW
45
Triggered Alarm (5HzPGA=10Gal) by AcConBeginning of Principal Motion
jma 7.2, by JMA and theMo40it
OccurrenceTime of Maximum
MotionaximumMotionosimulatedM
Depth8km on-site alarm of35mu
FREQL Quicker Zone xim
30
FREQL and AcCoMa
using strong motion
25
Damaged Arearecords.
20
Horizontal axis is
15
epicentral distance,
Alarm byJMA
10
Vertical axis is timeJMAAlarmmraAlfrom occurrence of5LQ
Earthquake. SolidFR E
0line shows P-wave
0 10 20 30 40 50 60 70 80 90 100 110 120
Epi-central Distance in kmarrival.
JMA alarm spread after the strong motion in damaged area. In contrast this, the time
margin by FREQL alarm is several seconds before the beginning of strong motion,even at the epicenter itself.
18

System and Data Research Co., Ltd.
Tokyo Institute of Technology

Early Warning Simulation For the 2010 JiansianEarthquake（M6.4, h22.6km）
Time in seconds from2010/3/4,00:18:52.1440

台湾・甲仙地震 M6.4, h22.64km

35

5.1

Maximum Motion
4.8

5.030

5.5 4.5

5.0

5.9 5.6

20
4.8 5.0
4.3 3.8
5.3155440Gal ↱10Gal ↗
5HzPGA105Derailed Train

4RI = 2

5.4

25
5.1

3.9

1.5

1
Derailment was Occurred
40Gal Alarmat ISCER10

10GalP-wave arrival
FREQL Alarmat ISCER10

3Derailment might be Not Occurred
Fastest FREQL Alarm

0050

100

Realtime Intensity RIThis figure shows a result of simulation using strong records with changing of the RI. The 40 Gal alarm
near the derailment point was issued 18 seconds after the occurrence. FREQL on-site alarm should beissued at 10 seconds after the occurrence, or 8 seconds earlier than the 40 Gal alarm. It is clear thatthe FREQL alarm proceeding to the strong motion with over three seconds at even the focal area.
20

System and Data Research Co., Ltd.
/ Tokyo Institute of Technology

14:46:46
FREQL Alarm
estimated

Seismic Wave Propagation
by Realtime Intensity

14:46:49
JMA EEW
14:46:54
JMA EEWon TV screen
14:47:03
JR Alarm
14:47:06
JR Emergency
Braking started

23

System and Data Research Co., Ltd.
Tokyo Institute of Technology

300
14:51:00

100

240

MisawaMorioka

Tsukidate
0200

Aomori

Yamabiko #144 Max

300

400

229s: Emergency Warning via NHK
226s: Tsunami Warning by JMA via NHK

14:50:00

180
14:49:00

120137s: End of EEW via NHK…

Time in seconds from 2011/03/11,14:46:26 JST

14:52:00-100

Hayate #27-200

Yamabiko #61-300

Fukushima
Sendai3.0
360-400

Tsukuba
Mito

4.0

Shinjuku

5.0

14:48:00④79s

60
14:47:00

0-400

2 8 s: EEW via NHK

20s: First EEW of FREQL-300

south side

24

37s:
EEW ofJR②36s
Shinkansen①2 3 s: EEW o f JMA

③44s

-200

-100

0

100

200

Epicentral Distancein km minus
Difference
between Epic.Dis.
and127km
127km

300

The 2011.3.11
East Japan Eq. M9.0

Warning Area
①Miyagi, Iwate,Fukushima butAizu, south inlandof Akita andYamagata but
Shounai andOkitama; JMA#4②Add. Aizu,Shonai,Okitama, Ibaraki,
coast of Akita,
Sampachi-Kamikita
of Aomori, Kaetsu ofNiigata, north-eastof Chiba and southof Saitama; JMA#7③Add. Tochigi andeast of Kanagawa;JMA#10④Add. the rest ofAomori, Chuuetsu,
south of Gumma,
north of Saitama,
the rest of Akita,
north-west of Chiba
and the 23 wards ofTokyo; JMA#12

6.0
Yokohama

Realtime Intensity
RImaxRimax©SDR: 2011.4.7., modified at 5.19 and 7.3

7.0

RI MMIPeakMax
6.5 10.7
6.0 9.9
5.5 9.1
5.0 8.4
4.5 7.6
4.0 6.8
3.5 6.0
2.5 4.4
2.0 3.6
1.5 2.9
0.5 1.3
0.0 0.5
P-arrival

This figure shows the Realtime
Intensity RI varied in time and space.
The first EEW of FREQL is threeseconds faster than that of JMA.
At any places, on-site FREQL alarm
leads more than 20 seconds.
For Kanto region including Tokyo
metropolitan area, more than one
minute are expected as lead time.

400north side

System and Data Research Co., Ltd.
Tokyo Institute of TechnologyK-NETKitakami

The 2011.3.11 East Japan Eq. M9.0

Comparison EEWs

(continue)

OnsiteNetworkOnsite

FREQLJMAJR

The timings of the warning by several systems as EEWs by FREQL,JMA and JR are summarized as follows.
14:46:46
The fastest FREQL warning is estimated to be issued at 14:46:46(20) simulated with the data of K-NET Kitakami station, MYG008.

* (estimated)

14:46:49*

14:46:54

NHK-TV, celler phone
Many people felt this earthquake themselves

14:46:59

JMA issued EEW at 14:46:49 (23) and it appeared on the NHK-TVscreen at 14:46:54 (28) or on cellular phones between 14:46:54
and 14:46:59.
14:48:00

60

RI>3

*

14:47:06

Emergency Breaking*) Time of issuing alarm

RI>4

RI>1p

④79s
37s:
EEW of②36s
JRShinkansen①2 3 s: EEW o f JMA③44s

14:47:00

0-400
25

14:47:03…

120

cellular phone

2 8 s: EEW via NHK

20s: First EEW of FREQL
-300

-200

-100

0100

System and Data Research Co., Ltd.
Tokyo Institute of Technology

200300400

The 2011.3.11 East Japan Eq. M9.0

Comparison EEWs

(continue)

OnsiteNetworkOnsite

FREQLJMAJRJR issued EEW at 14:47:03 (37) for all the Shinkansen operated by
JR-East, and then an emergency brake started at 14:47:06 (40).
14:46:46
First destructive wave arrived at the Shinkansen lines around
Sendai at 14:47:15 (49), and second wave attacked around at
14:48:00 (94).

60

14:46:54

NHK-TV, celler phone

14:46:59*

14:47:06

Emergency Breaking*) Time of issuing alarm

RI>4

④79s
37s:
EEW of②36s
JRShinkansen①2 3 s: EEW o f JMA

③44s

0-400

cellular phone

14:47:03

RI>1p

14:47:00

26*…

14:48:00

RI>314:46:49

Many people felt this earthquake themselves

Fortunately, there is no death and no injured for Shinkansen, only
one bogie of the vehicle for test running was derailed.

120* (estimated)

2 8 s: EEW via NHK

20s: First EEW of FREQL-300-200-1000100

System and Data Research Co., Ltd.
Tokyo Institute of Technology

200300400

The 2011.3.11 East Japan Eq. M9.0

Comparison EEWs

(continue)

OnsiteNetworkOnsite

FREQL

JMAJR

On the system of JR-East, their instruments for early warning has
been replaced some other system based on JMA system instead ofour Compact UrEDAS.

14:46:46* (estimated)

14:46:49*

14:46:54

NHK-TV, celler phone

The early warning system of JR could not issue alarm and they werefailed. Only ordinal 40Gal alarm systems along Shinkansen or
14:46:59
120Gal alarm system for front detection sites were issued alarm.
14:47:03

Many people felt this earthquake themselves
cellular phone*

14:47:06

This is a reason of too late alarm of JR.
14:48:00

60

RI>3

RI>4

RI>1
p

④79s
37s:
EEW of②36s
JRShinkansen①2 3 s: EEW o f JMA③44s

14:47:00

0-40027*) Time of issuing alarm…

120Emergency Breaking

2 8 s: EEW via NHK

20s: First EEW of FREQL-300-200-1000100

System and Data Research Co., Ltd.
Tokyo Institute of Technology

200300400

What is necessary for earthquake disaster prevention?
Before and During Quake
Quick Response
Using On-Site Alarm
against Sudden Quake
2.5
AcCoEscape toSafety Zone

# Escape to Safety Zone based on
Each Feeling or On-Site Alarm

It is clear that the primarypreventative action by
the people at the time ofthe earthquake is to keepaway from places where
they could be hit byfalling or loose objects.
Obviously to makepossible this requires atimely and immediate
warning to be issued.

# Check the Safety Zone Constantly# Imagine and Train to Escape actually28

System and Data Research Co., Ltd.
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What is necessary for earthquake disaster prevention?
After Quake
M6.9

ret National organizationssasi
Dshould specify the area
rofndof expected catastrophic
oeir
tiau
damage accurately andnqiegr
ainitiate rescue operations
si
Imwithout delay based on# Quick Rescue at the PossibleDamage Area is based on theExact Earthquake Information
by Authorized Organizations
29

the information from
responsible and capableorganizations in realtime.

System and Data Research Co., Ltd.
Tokyo Institute of Technology

EEW andEarthquake Disaster Mitigation
Very Severe Situation
for Running Vehicles¾The Basic Countermeasure isStrengthening the Facilities¾EEW is only a Trigger for
Quick Response against Quake¾It is important for EEW
to avoid Overestimation andCrying Wolf
¾Accurate Information is
Extremely Important for
Quick Response after the Event

Damage Examples of the 3.11 Earthquake (Mw 9.0)30

System and Data Research Co., Ltd.
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Problems of JMA warning
Tsunami warning by JMA is quite early for the 3.11 Earthquake, three minutes
and a half after detecting the P-wave, but is including many problems such as
low accuracy for height estimation:>Crying Wolf caused by frequent unnecessary warnings,>Loss tension and knowledge from both residences and local governors,
because JMA has prohibited Tsunami warning by local governors after theKobe earthquake.
The earthquake motion of the 3.11 Earthquake seems very strange and very
long by all people themselves in unusually. This is the best signal for quick
response against the tsunami. But almost all the people thought that thetsunami warning must be issued by JMA, just as JMA intend. But in practice,many people who could not receive warning took no action, then theirevacuation delayed fatally. This is very important lesson from this event.
These problems are appeared not only for Tsunami warning but also for EEW .
31

System and Data Research Co., Ltd.
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Urgent Craving for JMA
at 2011 AOGS in Taipei

JMA must quit all restriction for warnings onearthquake, EEW and Tsunami warnings.
JMA must issue
exact and detailed information
for main shock and aftershocks immediately,
to support quick response.

32

END
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