probabilistic seismic hazard analysis (psha).pptx

8/18/2019 Probabilistic Seismic Hazard Analysis (PSHA).pptx

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Probabilistic Seismic

Hazard Analysis(PSHA)

Site/Building Specifc Spectral Analyses,

Liqueaction Susceptibility and Deaggregation oRisk or Grenada

By: Kevin M. Blache - 8!""""


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Aim:

#he $ltimate %oal o& this 'roect as to cona Probabilistic Seismic Hazard Analysis (PS

&or *renada.

As a res$lt o& this a series o& obectives %eared toards achievi'rescribed %oal ere created.


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+bectives:#he obectives re,$ired ere as &ollos:

• #o cond$ct a revie o& Seismicity and the res$ltanSeismic Hazard both on a *lobal scale and mores'ecically &or the /aribbean 0e%ion.

• #o research and dene the methods o& assessin%Seismic Hazard and hence com'are methods.

• #o ded$ce the method &or cond$ctin% a ProbabilisSeismic Hazard Analysis and 1ea%%re%ation o& Se0is2.


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+bectives:#he obectives re,$ired ere as &ollos:

• #o 'er&orm a Probabilistic Seismic Hazard Analysis and 1ea%%re%ation Analysis &or *re

• #o com'are the res$lts o& the analyses cond$

to similar analyses thro$%ho$t the re%ion.


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Seismicity 3 Seismic Hazar

• An 4arth,$a2e is a s$dden violent sha2in% o& the %ro$&rom movements o& the 4arth5s cr$st. (6e 1ictionary/ivil 4n%ineerin%)

• Seismicity re&ers to the occ$rrence or &re,$ency o&

earth,$a2es in a re%ion.• #he %enesis o& seismic activity is the res$ltin% moveme

the s$r&ace o& the 4arth ca$sed by convection c$rrentlocated beneath 4arth5s cr$st in the mantle.

• A seismic hazard in a /ivil 4n%ineerin% conte7t arisethe seismicity o& a re%ion 'oses a threat to citizens5 sa

ell as '$blic and 'rivate 'ro'erty.


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Seismicity 3 Seismic Hazar

#y'es o& 4arth,$a2es


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Seismicity in the /aribbean


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Past St$dies on Seismicity in

/aribbean• Pereira and *ay ("8) 9 Seismic Hazard Analysis (amaica 3 #

• #aylor et al. ("8) 9 Seismic Hazard Analysis

• Ambeh (;) 9 4arth,$a2e Hazard in the /aribbean

• #anner 3 She'herd (") 9 Seismic Hazard in


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Seismic Hazard Analysis Metho1eterministic vs. Probabilistic

1eterministic Analysis:=ses 'ast events to determine seismic ris2 in an e?ort to ens$re thatan event is realistic. @t ass$mes that all events are %overned by 'astevents.

Probabilistic Anal@nvolves all deterministic events ith a nite 'robabilocc$rrence (all 'ossible events). @t also a''lies statistmethods to determine the seismic ris2.


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Probabilistic Seismic Hazar Analysis Method

irst 'ro'osed by /ornell (8).

/om'osed o& ive (C) Ste's as 'resented by Kramer (and Ba2er (;>C).


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Ste's &or Probabilistic Seismic Hazard Ana(PSHA)

• @denti&y So$rce Dones &or 4arth,$a2es in an area. #h$s deteso$rce to site distances.

• /ond$ct *$tenber%-0ichter


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Statistical 3 Probability #heory @nvolved inProbabilistic Seismic Hazard Analysis Met

• 1iscrete 3 /ontin$o$s0andom Eariables

• Probability Mass 3 1ensity$nctions (PM 3 P1 )

•

/$m$lative 1ensity $nctions(/1)

• Probability 1istrib$tions(Poisson and 6ormal)

• /onditional Probabilities

• Total roba

• B


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Probabilistic Seismic Hazard Analysi#otal Probability #heorem

#his can then be ada'ted to the analysis o& seismic haas &ollos:

•


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*$tenber%-0ichter 0ec$rrence

Ma%nit$de

Ghere: is the rate o& earth,$a2es ith a ma%nit$de %reater than m occ$r

and are constants estimated &rom re%ression analysis o& 'ast seismic data

0ate o& e7ceedin% a %iven ma%nit$de:

(/1)

Probability o& a %iven ma%nit$de occ$rrin%

•


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So$rce to Site 1istance

Probability o& an earth,$a2e occ$rrin% at a %iven dist

#he so$rce zone m$st be s$bdivided into smaller areaHence the 'robability is calc$lated as a ratio o& a smaarea to the total zonal area.

•


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*ro$nd Motion Prediction 4,$at

(*MP4) &or Ma%nit$de and 1istaSam'le *ro$nd Motion Prediction 4,$ation:

Probability o& e7ceedin% a *ro$nd Motion %iven a 'artic$ma%nit$de and distance:

Ghere: is the normal c$m$lative distrib$tion &$nction

is the mean s'ectral acceleration (%) val$e

is the standard deviation o& s'ectral acceleration (%) val$es

•


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/ombination o& All 0ates an

Probabilities

Ann$al 0ate o& 47ceedance o& a *ro$nd Motion %iven both earth,$ma%nit$de and distance:

•


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1ea%%re%ation 3 Bayes5

#heoremBayes5 #heorem $ses conditional 'robability:•


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1ea%%re%ation 3 Bayes5

#heoremGhen ada'ted to Probabilistic Seismic Hazard Assessment yi•


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Probabilistic Seismic Hazard Analysis &or *renada

A''lyin% the a&orementioned ste's accordin% to the /orne(8) Method.


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*renada

$apital% St. *eor%e5sopulation% >>>>>

aris!es%

Sister &sles%/arriaco$ 3 Petite

Martini,$e


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Selection o&So$rce Dones


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ShalloSo$rce Dones

(>-"> 2m)


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@ntermediate

So$rceDones (">-

!>> 2m)


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Eerication o& So$rce Done


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*$tenber%-0ichter

0elationshi's&or So$rce Dones

-I


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1iscrete P1 o&Ma%nit$des &or

So$rce Dones -I


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S$bdivision o& So$rce Done


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*ro$nd Motion Prediction 4,$at(*MP4)

Pea2 *ro$nd AccelerationP*A(%)

• is described as the motionthat a 'article on the %ro$nd

ill e7'erience.

•Both are meas$red as $nits

o& acceleration d$e to %ravity(%) mJs;

• #y'ical accelerations: >.>C%to %

• >.>>C% barely &elt >.>C%

$n'leasant >.C% o$ld

S'ectral Acceleration

• is described as the motiob$ildin% a''ro7imately e7'

• @t is modelled by a 'armassless vertical rod havin%

nat$ral 'eriod o& vibrat

• Hence is more $se&$l &ren%ineerin% st

• Period o& vibration o& a str$>. times the n$mber


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4nd 0es$lt o& ProbabilisticSeismic Hazard Analysis

/ombination o& 0ates and Probabilities to com'leProbabilistic Seismic Hazard Analysis (PSHA)

1ea%%re%ation o& Seismic 0is2

A i S i t & /i il 4 i


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American Society o& /ivil 4n%ineers AS/4 "->C

Minim$m 1esi%n


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American Society o& /ivil 4n%ineers AS/4 "->C

Minim$m 1esi%n


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/alc$lation o& 0et$rn Perio

Ghere: is the 'robability o& a seismic event occ$rrin%in C> years)

is the rate o& rec$rrence o& a seismic event

is the ret$rn 'eriod &or a seismic event (;I"C years)

•


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Hazard/$rve at

>.; Seconds

Shos contrib$tiono& Dones


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Hazard /$rveat .>

Seconds

Shos contrib$tion o&Dones


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0es$lts &rom Hazard /$rve

Spectral

Acceleration

$orresponding

To Return

eriod o '()*

years

+' Seconds -+ Secon

>.> % >.> %


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1ea%%re%ation o& Seismic 0is2 &or Dones 3>.; Seconds


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1ea%%re%ation o& Seismic 0is2 &or Dones ! 3 I aSeconds


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1ea%%re%ation o& Seismic 0is2 &or Dones ! 3.> Seconds


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1ea%%re%ation o& Seismic 0is2 &or Dones ! 3.> Seconds


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S$mmary o& 1ea%%re%ation0es$lts

.one

+' Seconds -+ Se

Ma%nit$de 1istance(2m)

Ma%nit$de

(Shallo - 6orth o&

Eenez$ela) I.C-C.> ;> C.>-C.C; (#oba%o) I.C-C.> >> C.>-C.C

! (4ast o& #rinidad) .>-.C ;>> .>-.C

I (@ntermediate - 6orth o& Eenez$ela)

I.C-C.> > C.>-C.C


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0ecommendations

• /ollect s$?icient stron% motion records &or/aribbean re%ion and develo' a *ro$nd MotPrediction 4,$ation s'ecic to the re%ion.

• A''ly *ro$nd Motion Prediction 4,$ations &r

re%ions aro$nd the Gorld ith a similar &a$ltty'e to the /aribbean.

• /om'are res$lts o& the above recommendatio veri&y res$lts.


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/oncl$sion

• Probabilistic Seismic Hazard Analysis (PSHA) is an a''romethod &or assessin% seismic ris2.

• 1ea%%re%ation o& 0is2 is also a''ro'riate since it yields ms'ecic res$lts as it re%ards the ma%nit$de and so$rce todistance associated ith the e7ceedance o& a s'ectral

acceleration SA(%) as re,$ired by the AS/4 "->C.• Altho$%h the /aribbean re%ion has a hi%h level o& seismic

active the s'ectral acceleration e7'ected &or *renada isrelatively lo.


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N$estionsO

#han2 o$.

probabilistic seismic hazard analysis (psha).pptx

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