On a EEW system FREQL andits working situation at the time ofthe 2011 Tohoku Earthquake

Yutaka NAKAMURA, Dr. Eng.
System and Data Research, Tokyo, JAPAN1

System and Data ResearchVideos Recorded at the Moment of Earthquake Attack

2

System and Data ResearchWe can see for EEW based on experience asfollows;
EEW can get only short time margin.

It is extremely necessary and important forEEW to prepare and exercise in advance.
In any case, only the immediate warning canbe useful.

3

System and Data Research

Concept of Earthquake Early WarningOn-Site
Detection/AlarmFrontDetection/AlarmP
P-wave Alarm

SS-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-wave Alarm”.

4System and Data Research

Concept of the Front Alarm
by Dr.Cooper, 1868
In 1972, researchersfor earthquake disaster
San FranciscoAlartDaily Evening
prevention in JapanW
Bulletin, 3
advocated the "StrongaveNovember 1868
Prearthquake alarm
opag
system 10 seconds
ation
Alarm Seismometer before". Although thiswas an idea similar toDr. Cooper's front
Wave PF
ropagat au
detection system inion lt
1868, nobody had put
in practical use until
Epicenterthen.

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

System and Data Research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Functions of the UrEDAS
There are two types of UrEDAS; “UrEDAS” and “Compact
UrEDAS”.
Function of the UrEDAS (1985) is to estimate the magnitude
and the 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.
7

System and Data ResearchExamples of Monitoring
Earthquakes by UrEDAS
Pasadena The 1994 Northridge

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

M<6System and Data Research

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.

UrEDAS Alarm based on M-D Diagram
after Bitoh, Nakamura and Tomita (1985)
Possible Damage Area
for magnitude M

No DamageDDamages for Bridge

100

Epicenter

al
G
02

1
3

4567Magnitude M
9UrEDAS can issue an alarm
based on the distribution of
the past earthquake damage
on magnitude to epicentral
distance plane. This alarmis referred to as an M-ΔAlarm.

DllaG04120
Ga1080GalEpicentral Distance in km

Damages for Embankments

System and Data Research

8Moreover UrEDAS cansupport restarting operation
based on the detailed
earthquake parameters.

Captured Video at the time of the 1995 Kobe Earthquake

P wave arrival

Principal motion arrival

Motivation of Compact UrEDAS development is the Kobe Earthquake. On theVideo, they noticed the initial P wave motion as something happening, and thenthe severe motion attacked them after a few seconds. Although there was only afew seconds between something happening and recognition of earthquake, itwas anxiousness and fearful because they could not understand what happened
and felt relieved after recognition of the earthquake occurrence. As the counterof this kind of feeling, the earlier earthquake alarm is required and I developed
the Compact UrEDAS to make the alarm within one second after P wave arrival.
10

System and Data Research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/s
2m

RI ＝ 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. Based on the DI, a newseismic intensity, realtime intensity RI, or MMI are defined as this slide.
11System and Data Research

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. M7.0

12

System and Data Research

When P wave arrives, RI
increases drastically. Afterinitial P wave, RI keeps almost
same value until the S wave
arrival. After the arrival of Swave, it reaches to its maximum
value. This value can be relatedon damage and Instrumental
Seismic Intensity of JMA orother scales like MMI.
Instrumental JMA Intensity scaleis defined to calculate artificiallyonly after the earthquake
termination. On the other hand,
RI can be calculated in realtime
with physical background. Thiscan be concluded as, with thecontinuous observation of RI,
earthquake alarm can be issued
efficiently and damage can beestimated precisely.

The ONLY Succeeded Example of EEW
the 2004 Niigataken-Chuetsu earthquake (M6.8) with Compact UrEDAS
Kawaguchi observatory detected P
wave 2.6 seconds after theearthquake occurrence, and one
second after that, issued P wavealarm. When the derailed train, Toki
No. 325, encountered the earthquake
motion at the point running 75 m fromthe exit of Takiya tunnel, it was 3
seconds after the earthquake
occurrence. 3.6 seconds after theearthquake occurrence, the train
received the alarm from Compact
UrEDAS and was interrupted thepower supply. Shinkansen train issituated automatically to break
immediately by the interruption ofpower supply. S wave hit the train 2.5
seconds after the alarm and thenmore one seconds after, large motion
attacked the train. This large motion
continued about five seconds.
13System and Data Research

The P wave alarm of Compact UrEDAS demonstrates
the effectiveness as making the derailment not catastrophic
This shows the outlineof the situation of thederailment. It seems
that the derailed cars
were running the large
displacement section.
The later the alarm
2 号車（後からVehicle②:2 両目）3 号車寄り台車の状
況、車輪がレールに密着していること、胴体 reached, the more theSuccessive
A Success You
can see derailment situation
がレールに接触していることなどが分かる。
andcontactsituation
between body number of derailed car,
（NEWS23取材班提供VTR から）
Exampleof and railroad,
Example ofbecause of the risk of
図 12 脱線状況の例
Compactrunning the large
UrEDAS
displacement section.
Warning
From the view point ofthis, the P wave alarmof Compact UrEDAS
Front ⑩
Rear ①demonstrates the図 14
地震後の脱線状況
effectiveness for thederailment making not
All 154 passengers and stuffs have been survived without injury. catastrophic.
×100m

5 seconds

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

14

System and Data Research(b)最後尾車

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 function is combined the functionsof UrEDAS, Compact UrEDAS and AcCo.
P wave alarm is available 0.1 seconds inminimum after P wave detection ( after2009).
Earthquake parameters are estimated with
one second after the P wave detection.
S wave alarm is also available based onacceleration and real-time seismic
intensity, RI, same as AcCo.

15System and Data ResearchFREQL is toward to the new field, asfor the Hyper Rescue Team in the risk of aftershocks
the 2008 Sichuan Earthquake Mw 7.9
the 2004 Niigataken Chuetsu Earthquake Mw 6.6

Rescue Activity of Hyper Rescue Team

16

System and Data Research

Hyper rescue team acts in arisk of large aftershocks.
After the Niigataken Chuetsu
Earthquake, the hyper rescue
team approached us to adopt
FREQL as a support system
for the rescue activity.
Tokyo fire department andother departments in nation
wide have adopted theportable FREQL as
equipment to keep the safety
against the risk of the second
hazards caused byaftershocks during theirrescue activity, not only inJapan but also in Pakistan,
China and New Zealand.

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

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

SDR products

5

UrEDAS 3 sec.

3UrEDAS
2 Test observation
1

Average 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.
0.1
sec.

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 Time17

System and Data ResearchThis figure shows thechange of the processing
time for EEW.

While JMA system
performs every one
second for the alarm
processing intermittently
with stored data,
UrEDAS and FREQL
perform the procedurecontinuously in every
sampling time.

Actual Example with Simulated Results of FREQL orAcCo for Recent Damaged Earthquake in JAPANThis figure shows
P -wave Alarm ( RI=1.5) by FREQL
2008.6.14, comparison between
45
Triggered Alarm (5HzPGA=10Gal) by AcCo
Beginning of Principal Motion
Mjma 7.2, the EEW by JMA40
OccurrenceTime of Maximum
MotionaximumMotion
and the simulated
Depth8km on-site alarm of
35
FREQL Quicker Zone
30
FREQL and AcCousing strong motion
25
Damaged Arearecords.
20
Horizontal axis is15
epicentral distance,
Alarm byJMA
10
Vertical axis is time
JMAAlarmfrom occurrence of5
Earthquake. Solid0line shows P-wave
010 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

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

120

137s: 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

Warning Area
①Miyagi, Iwate,
Fukushima but
Aizu, south inlandof Akita andYamagata but
Shounai andOkitama; JMA#4②Add. Aizu,Shonai,Okitama, Ibaraki,
coast of Akita,
Sampachi-Kamikitaof 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

14:48:00

④79s

60

③44s

14:47:00

0-400

2 8 s: EEW via NHK

20s: First EEW of FREQL-300

south side

2037s:
EEW of②36s
JRShinkansen①2 3 s: EEW o f JMA-200-100

0100200

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

300

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

400

north side

System and Data Research

The 2011 Tohoku Earthquake
This figure shows theRealtime Intensity RI
varied in time andspace.
The first EEW of FREQL
is three seconds fasterthan that of JMA.
Even closest place, onsite FREQL alarm leads
more than 20 seconds.
K-NETKitakami

On the other hand, forvarious area, people
felt it before severmotion withoutequipment.

14:46:46
FREQL Alarm
estimated

14:46:49
JMA EEW
14:46:54
JMA EEWon TV screen

FREQL Alarm

actual on rock site
14:47:03
JR Alarm

14:50:10
JMA Tsunami
Warning

21

System and Data Research14:46:39
First Detection

14:46:46
FREQL Alarm
estimated

14:46:49
JMA EEW

14:46:54
JMA EEWon TV screen

actual FREQL Alarmon rock site

14:47:03
JR Alarm using
JMA type devices

P-wave alarm was failed,
120Gal triggered alarm
only.

22

14:47:15
JR Damage?

14:50:10
JMA Tsunami
Warning

It is very sever situationfor Shinkansen withextremely short time
margin. It is lucky there
was no vehicles aroundhere.
System and Data Research

EEW andEarthquake Disaster Mitigation
Very Severe Situation
for Running Vehicles

The Basic Countermeasure isStrengthening the Facilities

EEW is only a Trigger for
Quick Response against Quake
It is important for EEW
to avoid Overestimation andCrying Wolf
Accurate earthquake Information
is Extremely Important for
Quick Response after the Event

Damage Examples of the 3.11 Earthquake (Mw 9.0)
23

System and Data Research

END
Thank you for your kindattention!
For More Information
Please Access Our Website

www.sdr.co.jp
24

System and Data Research