Session I.4 Yamamoto

7/23/2019 Session I.4 Yamamoto

1/51

Failure Build-up of stress (strain energy)

Dicult to predict time and place Breaks at weakest point Hear precursors Sound of breaking same as seismic wav

Breaking of !opstick


2/51

Sources of "sunami

Sudden submarine topographic change

Crustal deformation by earthquake.

Submarine volcanic eruption.

Landslide near coastline or

submarine landslide.


3/51

"sunami by #olcanic $ruption

Ref. http://www.geology.sdsu.edu/howvolcanoeswork/!rakatau.htmlMore than 36,000 peoplewere killed.

"ruption of !rakatau in #ug.

$%%&.

!rakatau


4/51

"sunami by %andslide

'he landslide was triggered by

an earthquake on (ay )$* $+,).

(ore than $-* people were

killed mainly by tsunami.

Landslide

'sunami


5/51

"sunami by $art!&uake


6/51

$% 66

$. eneration of 'sunami $. eneration of 'sunami

). 'sunami rade 0 ). 'sunami rade

&. "1pected arrival time &. "1pected arrival time 2. Expected tsunami height

Empirical method a3 4istance to epicenter

b3 (agnitude of earthquake

Quantitative methodSimulation of tsunami

$% 55

5. 6ntroduction of Simulation 'echnique7since $,,,3

average issuance time

& to - min

Occurrence

of

Earthquake

Detectionof

Seismic

Wave

Determinationof

Source

Parameters

Evaluation

ofTsunami

Issuance

of

TsunamiWarning

Mp

Dedicated telephone netor!

"trong motion

seismograph

#utomatic $rocessing "%stem

"hort&period

seismograph

Quantitative Tsunami Forecast


7/51

'!at is t!e $art!&uake Source $lastic ebound

Fault Slip Double-couple Force

Seismic *oment "ensor

*odels of $art!&uake Faults

$art!&uake Si+e *agnitudes Seismic *oment $nergy

"!eoretical Seismology , Sources


8/51

'!at is t!e cause of $art!&uakes

.ssociated wit! faults (source or cause)

.ssociated wit! magma

(*ost) $art!&uakes arefault movements


9/51

"ypes of faults

"!rust (everse) fault

/ormalfault

Strike-slip fault


10/51

Strike-Slip Faults

%eft-lateral ig!t-lateral


11/51


12/51

,012 3mperial #alley4 alifornia (*s 56,)


13/51

San Francisco $art!&uake.pril ,74 ,028

*w 565-560152 km rupture ofSan .ndreas fault


14/51

Japan Meteorological Agency 2005/3/9

Seismogram

$ phase

19:23:04.7

8

" phase

19:23:07.5

3

'%pocenter (Distance)

Reading Maximum

#mplitude

Determination

of magnitude

Reading arrival time

of $ phase * " phase

Determination

of '%pocenter

Maximum amplitude

15.3mm


15/51

9-wave :rst motions

"!is type more likely to produce large tsunamis


16/51

Harvard;/$3 *oment "ensor Solutions


17/51

Haskell %ine SourceDislocation Source

8askell* $,52sumatra

Sumatra eart!&uake 3s!ii et al64


18/51

omplicated Slip Distributions

9

,000 !i-!i4 "aiwan $art!&uake


19/51

Single-force eart!&uakesvolcanic eruptions and landslides

*ount St6 Helens4 >S. ?anamori et al6 ,071


20/51

$art!&uake Si+e @ *agnitude

* A log . @ log .2 ic!ter4 ,0=7

!arles ic!ter,022-,07=

log of amplitudeDistance correction


21/51

*agnitude Determination

Magnitude+ "i,e of Earth-ua!e

(Defined .% Richter (/012) at first)

M3log/4(#mplitude)5(Correction for Distance)

#mplitude47/ M

#mplitude/4 M

#mplitude/44 M


22/51

*% %ocal magnitude (alifornia) regional S and 26,-,

surface waves

* C*. (Capan *eteorol6 .gency) regional S and =-,2 s

surface waves

mb Body wave magnitude teleseismic 9 waves

*s Surface wave magnitude teleseismic surface

waves*w *oment magnitude teleseismic surface


23/51

*agnitudes for t!e Sumatra $art!&uake

mb 562 , sec 9 wave ,E, station

mblg 865 , sec %g waves 8 station

*wp 762 @ 76= 82 sec 9 waves

*s 76= - 767


24/51

elations!ip between dierent types of magnitudes


25/51

Seismic *oment A (igidity)(.rea)(Slip)

$art!&uake si+e - Seismic *oment

.rea (.)

Slip (S)

3737 tuStM =


26/51

*wp 9-wave moment magnitude

Guick magnitude from 9 wave >ses relatively long-period body waves (,2-82 Some problems for *762

*oA *a Iu+(t)dtI 1Er;Fp

*wA (log,2*o@ 06,);,6=


27/51

*wp 9-wave moment magnitude

u+(t)dt J *o


28/51

Seismic moments and fault areasof some famous eart!&uakes


29/51

$art!&uake *agnitude and"sunami

Ground

Length

Displa

cement

*agnitude

Displacement(m)

%engt!(km)

E 262E 2611 2627 ,61

= 26


30/51

*agnitude and "sunami

8ater volume lifted .% the fault motion(#rea)(Displacement)

Magnitude 5/

;


31/51

upture 9ropagationRupture :elocit% < "&ave "peed

Duration of Rupture3 Fault ;engthRupture :elocit%

Magnitude =

Duration 3 (24!m)(1!ms)

3/4and several (sec)

Magnitude

?

Duration 3 (/44

/24

)

1!ms 314 (sec)

/(min)

Earth-ua!e on Dec7 96 944@

Rupture :elocit% 9!ms

Duration > /4 min


32/51

*agnitudes for "sunami 'arnings

'ant to know t!e moment (fault area and si+e) but takes a long time (!ours) to collect surface wav or free oscillation data

*agnitude from 9 waves (mb) is fast butunderestimates moment

3f !ave time (!ours)4determine *mfrom mantle waves

K For &uick magnitude (seconds to minutes)4

determine *wpfrom 9 waves


33/51

"!ings to emember

,6 $art!&uake sources are a double couple force syst w!ic! is e&uivalent to Fault Slip


34/51

"sunami *agnitude

Distant tsunami (A> /444 !m)Mt3log/4'5C507/

C+ Correction constant7

;ocal tsunamiMt3log/4'5log/4A527?4

'+ Tsunami height (m)7

A+ Epicentral distance (!m)+

/44 !m A 1+244 !m7 (#.e+ /0=0+ /0?/)

7>sed to e1press si?e of tsunami effect.3


35/51

"!ank you for yourattention

Chang 8eng ASeismometerB #4$&)


36/51

iuseppe (ercalli

7$%-9$,$23@ohn (ilne

7$%-9$,$&3

g g

Sassa Seismometer 7$,&-3* #buyama* !yoto >niv.


37/51

"!e SourceFault mec!anisms

"!e S!aking'ave propagationStructures

'!at is an $art!&uake


38/51

$lastic ebound "!eory eid (,0,2)

74ata in $%-$95-* $%+29,)* $,53

%.- feet offset in San #ndreas fault

from $,5 earthquake. (irin County


39/51

Singleouple Double ouple

Single ouple versus Double ouple

9 polarity pattern same

S polarity pattern diferent

Single ouple LresemblesM fault slip

ontroversy settledby *aruyama (,08E)

S!owed t!at Doubleouple was e&uivalento fault slip


40/51

$&uivalent Body Forces

Single Force

Dipole

ouple(Single ouple)

Double ouple


41/51

*oment tensor dipoles and couples

7 3 7 * 3 7 3pq q pV

M t f t dV= B B

7L= p.&2&D #R p.-3

0 componentsSymmetric matri so 8 independent


42/51

&))&&$$&)$$) ====== MMMMMM

&&))$$ MMM ==

*oment "ensor for an $plosion


43/51

)$$) MM =

&$$&)&)&&&))$$ ======= MMMMMMM

Double ouple Fault - Slip

*oment "ensor for Fault Slip

/ort!

i l k S t d Hi ,05E


44/51

ircular rack @ Sato and Hirasawa4 ,05E


45/51

*m *antle *agnitude

*mA log,2(N()) O d O s @ E60

Distanceorrection

Source orrection

Spectral .mplitude

amplitude measured in fre&uency domain surface waves wit! periods


46/51

1944 TonankaiMw 81

,018 /ankai

*w 76,

,00=?obe

*w 860

Fault .reas ofDamaging $art!&uakes

Deat!s

,011 ,


47/51

Seismicity in /$3 catalog ,002 -


48/51

Fault areas of somefamous eart!&uakes


49/51

adiated $nergy A ,6=*wO ,,67

Seismic adiated $nergy

?anamori4 ,055

" f * it d S l


50/51

*% %ocal magnitude (alifornia) regional S and 26,-,surface waves

* C*. (Capan *eteorol6 .gency) regional S and =-,2 s

surface waves

mb Body wave magnitude teleseismic 9 waves

*s Surface wave magnitude teleseismic surface

waves

*w *oment magnitude teleseismic surface < waves*wp 9-wave moment magnitude teleseismic 9 waves ,2

*m *antle magnitude teleseismic surface

Documents

Session I.4 Yamamoto