Attachment 1
Design Basis Earthquake Ground Motion Ss Established during Seismic Safety Evaluations at Respective Nuclear Power Stations Following the Revision of the Guidelines for Seismic Design Evaluation and the Approach Used
April 16, 2008
A. Earthquake ground motion decided by identifying a hypocenter for each site
Utilities

Hokkaido
Electric Power
Company

TomariHigashidori
TohokuElectric Power
Company
Onagawa

Tokyo ElectricPowerCompany

Chubu
Electric Power
Company

Hokuriku
Electric Power
Company

KansaiElectric PowerCompany

Fukushima
Daiichi
Fukushima
DainiHamaoka

Hypocenter

ScaleFault lengthShiribetsugawa Fault

M7.016km

FB -2 Fault
Hypothetical Northern Sanriku-okiearthquake(interplate earthquake)
Site eastern offshore fault(inland crustal earthquake)
Hypothetical multi-segment Miyagi-okiearthquake(interplate earthquake)
Site lower side earthquake(ocean intraplate earthquake)
F-6~F-9 fault

Shiozaki-oki earthquake(interplate earthquake)

Futaba fault(inland crustal earthquake)2003 Miyagi-oki earthquake(ocean intraplate earthquake)
Hypothetical Tokai
earthquake
HypotheticalInterplate
Tokai/Tonankai earthquake
earthquake
Hypothetical
Tokai/Tonankai/Nankaiearthquake
Suruga Tootoumi 1589 earthquake(ocean intraplate earthquake)
Senoumi ocean basin west margin fault
zone

KyushuElectric PowerCompany

101km

8.3-

6.8

14.5km

8.2-

7.1-

7.1

22km

7.5
7.3-

7.6

47.5km

7.1

-

8.0-

8.4-

8.7-

6.7-

7.4

34km

Sasanami-oki fault zone(total length)7.643km

MihamaC fault

6.918km

Main characteristics
Newly considered
Consider continuity of multiple faults

Changed fault length from the former 15km

ShimaneFo-A fault

6.923km

Shinji fault7.1

22km

Izumo 880A.D. earthquake

Ikata

GenkaiSendaiHypothetical Nankai earthquake(interplate earthquake)
Hypothetical site lower side intraplate
earthquake(ocean intraplate earthquake)
Takekoba fault

7.6

42km

8.6-

7.0-

6.9

5km

Evaluation results(*)

Both earthquake ground motion forresponse spectrum and fault model
analysis were below the design basis
earthquake ground motion Ss
Both earthquake ground motion forresponse spectrum and fault model
analysis were well below B indicated tothe left

450 gal450･Response spectrum Ss-D:580 gal

Consider continuity of multiple faults
In addition to the earthquake ground motion evaluation of thetwo earthquakes to the left (M7.5, M7.3) which occurred in
November 1938, included the M7.0 earthquake which occurred in
May of the same year, to estabish the hypotheical Shiozaki-oki
earthquake in which these 3 become a multi-segmented
Shiozaki-oki earthquake group as the earthquake for considerationand conduct evaluation.
Changed fault length from the former 18kmFor evaluation, presume the hypocenter of the main earthquake
to be within the ocean plate at the lower side of the site

Design basis earthquake groundmotion(*)
S2(reference)

550 gal370･To decide design basis earthquake ground motion Ss, consider
additional margin to the earthquake ground motion evaluatedin A and B

375･For intraplate earthquake, it is not established as an earthquake
for consideration since the impact to the site is minimal･Design basis earthquake ground motion Ss is represented by B
(A is well below B)

375･ Ss-D:Establish earthquakes for consideration so that itenvelopes the evaluation result of the earthquake groundmotion based on response spectrum.
･ Ss-F:Conduct earthquake ground evaluation based on fault
model analysis for the earthquake for consideration, andselect the one with the most impact.

370･ Ss-1:Establish so that it exceeds the evaluation results forinland crustal earthquake/interplate earthquake･Ss-2:Establish so that it exceeds the evaluation results for ocean
intraplate earthquake

600･ Ss-1H:Hypothetical Tokai earthquake (empirical Green’sfunction method)･ Ss-2H:Hypothetical Tokai earthquake (statistical Green’sfunction method)･Ss-3H:HypotheticalTokai,
Tonankai,Nankai
earthquake(statistical Green’s function method)490･Ss-2:Establish asperity based on survey results･Ss-3:Establish asperity close to site
･Use Ss-1 as representative because B is significantly below
Ss-1

450

Ss-D:580
Ss-F:445
Ss-B:450

Ss-3:450

Ss-1:450
Ss-2:600
Ss-3:450

Envelope Ss-DH -Ss-DH:800
Ss-1H:617
Ss-2H:588
Ss-3H:766

450

Ss-1:600
Ss-2:482
Ss-3:509

Ss-1:450

Approach to decision and other commentsSs(established thistime)

Ss-B:450･Fault model analysis Ss-F:445 gal

Ss-2:600･Response spectrum Ss-DH:800･Fault model analysis Ss-1H:617
Ss-2H:588
Ss-3H:766

Consider continuity of multiple faults
As a result of the active fault survey, considered the continuity ofthe Sasanami fault zone (eastern part) and the Sasanami fault zone(western part) just in case, even though they are considered to besingle faults.

･Response spectrum Ss-1:600･Fault model analysis Ss-2:482
Ss-3:509- Response spectrum Ss-1H:600･Fault model analysis Ss-2H:430- Response spectrum Ss-1H:550

Takahama

Site frontal ocean fault group(inland crustal earthquake)
ShikokuElectric PowerCompany

8.2

ShigaOhi
ChugokuElectric PowerCompany

Earthquake for consideration

Powerstation

Evaluation result for
B Earthquake
ground motion
decided without
identifying ahypocenter(*)

Newly considered- Response spectrum Ss-1H:600
Changed fault length from the former 10km
Evaluation based on earthquake scale and epicenter location etc.
according to documentation
Earthquake that has the most significant impact on the powerplant
To take uncertainty into consideration, evalute making the fault
plane a slope (fault slope angle 30°)
Model of the Central Disaster Prevention Council

Envelope bothnuclear power plants
Ss-1H

Ss-1H:600
Ss-2H:430
550

405
370

･ Ss-1H:Establish earthquakes for consideration so that it
envelopes the evaluation result of the earthquake
ground motion based on response spectrum.
･Ss-2H:Establish separately because part of the calculation resultfor Mihama Power Station exceeds Ss-1H as a result ofconducting earthquake ground motion evalations byfault model analysis of the earthquake for consideration.

600405450600456･Use A because B is enveloped by A

･Response spectrum Ss-1 :570
･Fault model analysis Ss-2NS:318
Ss-2EW:298

Envelope Ss-1

Ss-1:570
Ss-2NS:318
Ss-2EW:298

473･Establish design basis earthquake ground motion Ss-1 so that it
envelopes B and S2 based on the former guideline.
･Ss-1 enevelopes both Ss-2NS and Ss-2EW･Response spectrum Ss-1:500･Fault model analysis Ss-2:277
Ss-3:329

Envelope Ss-1

Ss-1:500
Ss-2:277
Ss-3:329

370･Ss-2:Partially exceeds Ss-1 for horizontal motion (ShiroyamaMinami fault)･Ss-3:Partially exceeds Ss-1for vertical motion (Takekoba fault)･Response spectrum Ss-1:540

Envelope Ss-1

540

372

･The earthquake ground motion evaluation results by fault model
analysis for A does not exceed Ss-1

600

Presume the maximum scale earthquake in the relevant region at
the lower site of the site
Evaluated previously as not impacting the site

Shiroyama minami fault

7.0

19km

Evaluated previously as not impacting the site

Gotanda fault
F-A fault
F-C fault

6.9
6.9
6.8

19km
18km
16km

Evaluated previously as not impacting the site
Changed fault length from the former 15 km
Changed fault length from the former 10 km

A. Earthquake ground motion decided by identifying a hypocenter for each site
Electric PowerCompany

Earthquake for consideration

Powerstation
Hypocenter

Tokai DainiJapan AtomicPowerCompany
TsurugaKagoshimanaga 1896 earthquake(interplate earthquake)Southern area of Ibaraki pref. intraplate
earthquake(ocean intraplate earthquake)
Kanto plains northwest margin fault zone
(Inland crustal earthquake)
Kaburaki fault
Urasoko-Uchiikemi
Urasoko-Ikenokochi
Northern side of Utsurogi Pass-Ikenokochi
C fault series

Scale

Fault length

Main characteristics

7.3-

7.3-

8.0

82km

Consider continuity of multiple faults

6.8
6.9
6.9
6.9
6.9

19km
18km
25km
23km
18km

Evaluated previously as having minimal impact on the site
Evaluated previously as having minimal impact on the site
Changed fault length from the former 16 km
Evaluated previously as having minimal impact on the site

Evaluation results(*)

Evaluation result for
B Earthquake
ground motion
decided without
identifying ahypocenter(*)

Design basis earthquake groundmotion(*)
Ss(established thistime)

S2(reference)･Response spectrum Ss-DH :600
･Fault model analysis Ss-1H①:516
Ss-1H(2):475

Envelope Ss-DH

Ss-DH :600
Ss-1H①:516
Ss-1H(2):475

380･Response spectrum Ss-DH :650
･Fault model analysis Ss-1H①:498
Ss-1H(2):478

Envelope Ss-DH

Ss-DH :650
Ss-1H①:498Ss-1H(2):478

532

Approach to decision and other comments(*)Ss has both “horizontal motion” elements and “vertical motion” elements. The values indicated are representative values for “horizontal motion” for 0.02 sec. period.

Attachment 2