Seismic Hazard Assessment Study for the Eastern Caribbean...

Seismic Hazard Assessment Study for Seismic Hazard Assessment Study for the Eastern Caribbean Islands the Eastern Caribbean Islands

Carlo G. Lai

Francesca Bozzoni Mirko CoriglianoLaura Scandella Elisa Zuccolo

Walter Salazar

Richard RobertsonLloyd LynchJoan Latchman

Trinidad, 26 May 2010

Outline

Critical Review of the Past Seismic Hazard Assessment StudiesThe Studied Area

Probabilistic Seismic Hazard Analysis (PSHA)Methods of calculation

- Classical Cornell-McGuire approach- Zone-free approach by Woo (1996)

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Construction of the Earthquake CatalogueIdentification of Seismic Zones

Attenuation RelationshipsProcessing of the Catalogue

- Zone-free approach by Woo (1996)

PSHA analysis and resultsCompatibility with IBC 2009/ASCE 7-05

Influence of seismogenic zoneVertical component

Practical application

Probabilistic Seismic Hazard Analysis Probabilistic Seismic Hazard Analysis (PSHA)(PSHA)

33

Identification of Identification of seismogenicseismogenic zoneszones(Cornell(Cornell--McGuire approach)McGuire approach)

Definition of Seismogenic Sources

WE NEED TO SEPARATE THE WE NEED TO SEPARATE THE EVENTS LISTED IN THE

CATALOGUE IN SEISMOGENIC ZONES ACCORDING TO THE

TECTONIC-GEOLOGICAL INFORMATION

Used instruments

In-depth investigation of the scientific publications regarding the seismotectonic setting of the Eastern Caribbean region

55

Analysis of transversal sections

Compatibility analyses between the proposed seismic delimitation and the Catalogue events using ArcGIS

General seismo-tectonic setting

Subduction

VOLC

TransformFaults and

Subduction

Transitions

Jordan, 1975

SubductionCANOES

Subduction

Transitions

(60-61 W)

Trasversal section

0

7 9 11 13 15 17 19 21Lat (km)USGS/PDE (1973-2009)

Transversal section

Upper Crustal seismicity and

inter and intra-plate

subduction seismicity

77

-250

-200

-150

-100

-50

0

Dep (km)

Seismogenic sources

Proposed geometric delimitation

• Zone 1: Volcanic Island-arc.• Zone 2-5: Subduction in the Lesser-

Antilles.

88

Antilles.• Zones 6-8: Puerto Rico and Virgin

Islands.• Transition Zones 9 and 10A.• Zone 10B: East of Trinidad.• Zone 11: North of Paria Peninsula.• Zone 12: Trinidad Faults.• Zones 13 and 14: El Pilar fault. • Zone 15: South of Trinidad.

Zone 1: Volcanic Island-arc.

• The upper-crustal seismicity concentrates within theupper 35 km of the Caribbean continental plate in theLesser Antilles Arc (Boynton et al. 1987), with epicentersplotting from the island of Martinique to Anguilla within anearly continuous belt of 100 km width along both, theaxis of the principal active volcanoes and the inland and

99

axis of the principal active volcanoes and the inland andoffshore shallow faults which run parallel to theSubduction Trench.

• Within this zone the magnitudes are moderate, reachinga maximum value of about 6.6 through historic times

Bengoubou-Valerius (2008):

- Oceanic trench;

- Limit low/high seismicity along the arc (“We have been able to confirm a

Transversal sections

1010

arc (“We have been able to confirm a progressive increase of seismic activity from south to north between Martinique and Antigua”).

Transversal Sections

Upper Crustal seismicity inter and intra-plate subduction seismicity

1111

Bengoubou-Valerius (2008)

1212

(Byrne, Davis and Sykes, 1988)

(McCann, 1985)

Interface and Intraplate subduction

and

Volcanic island arc seismicity

Zone 1: Volcanic Island-arc.

• Bernard & Lambert (1988) suggested that the evaluation ofseismic hazard must also take into account these shallow-moderate earthquakes as the ones occurred on 1851 and1897 in Guadeloupe (~5.5-6.0 Mw), March 16th 1985 (6.4M ) at South of Nevis, and the event occurred on

1313

Mw) at South of Nevis, and the event occurred onNovember 21st 2004 with a magnitude of 6.3 (Mw) in theNorth-West of Dominique near the Les Saintes Islands.

• The fault plane solutions in this zone yield both, normaland strike-slip focal mechanisms.

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McCann (1985):

- position of Volcanic Arc

- dimension of Volcanic Arc;

The moderate shallow earthquakes do not necessarily occur in conjunction with

volcanic eruptions and frequently appears in clusters with no discernible mainshock

(swarms)

Zone 2-5: Subduction in the Lesser-Antilles.

• The volcanic island-arc lays about 300 km from the EasternCaribbean Trench, where the North American plate begins tosubmerge underneath the Caribbean plate reaching depths of 200km below the islands generating earthquakes as large of magnitude8.0 Mw. We include in Zones 2 and 3 all the shallow focusearthquakes (depth ≤ 50 km) along the inclined inter-face seismic

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earthquakes (depth ≤ 50 km) along the inclined inter-face seismiczone that yields underthrust focal mechanisms (Byrne et al. 1988).

• Convergence between the Caribbean and North American platesoccurs at a rate of about 37 mm/yr (Sykes et al., 1982; McCann1985). The focal mechanisms of deeper intra-plate events (>50 km)indicate that there is a normal faulting resulting from initial flexure ofthe down going Atlantic slab (Zone 4 and 5) with an average ofwestward dipping angle of 50º (Bengoubou-Valeruis et al, 2008).

Trasversal section

0

-67 -65 -63 -61 -59 -57Long (km)USGS/PDE (1973-2009)

Transversal section

Upper Crustal seismicity and

inter and intra-plate

subduction seismicity

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(12-14 N)

-250

-200

-150

-100

-50

0

Dep (km)

Zone 2 and 4 cover the latitudes from 14.8ºN to 20.0ºN and it is characterized witha higher seismic activity than Zone 3 and 5 (from 11.0ºN to 14.8ºN latitude).Bengoubou-Valeruis et al. (2008) and Russo et al. (1993) attributes thedifferences of the seismic activity to the following reasons:

• a) changes in the tectonic structures mapped by Feuillet et al. (2002);

• b) enough sediments to lubricate or decouple the two plates in the Subduction

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• b) enough sediments to lubricate or decouple the two plates in the SubductionZone;

• c) strengthening caused by thick accretionary prism overbudden which liesabove the shallow reach of the subduction zone; the quiescent area coincideswith the deepest part of the Barbados accretionary wedge. The upper-crustalseismic activity level observed along the volcanic-island arc reflects also thedifferences observed in the seismic activity in the Subduction Zone.

• The Puerto Rico and the Virgin Islands region isconsidered as a microplate that is surrounded by theobliquely subducting North America plate, the Caribbeanplate and several major faults as the Mona Canyon tothe East and Abnegada Passage to the West (McCann,

•

Zones 6-8: Puerto Rico and Virgin Islands.

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the East and Abnegada Passage to the West (McCann,1985, Jansma et al. 2000) and the Muertos Trough tothe South.

• Puerto Rico accommodates approximately 16.9 mm/yr ofdeformation relative to North America and 2.4 mm/yrrelative to the Carribbean Plate (Clinton et al., 2006).

2020

Clinton et al. (1996)

• Zone 6. This zones includes the Puerto Rico Trench areawithin depth less than 50 km including the megathurstfaulting along the plate interface of the subducting NorthAmerican Plate southward deepening.

• Also this zone comprises the left lateral strike slip faulting

2121

that is subparallel to the Puerto Rico trench North andNorth-West of Puerto Rico including the Septentrionalfault.

(17-18 N)Trasversal section

0

-67 -65 -63 -61 -59 -57Long (km)USGS/PDE (1973-2009)

Transversal section

Crustal seismicity, interface and intra-

plate seismicity

2222

-250

-200

-150

-100

-50

0

Dep (km)

(Z6)

(Z8)

2323

(McCann, 1985)

(Z7)(Z7)

• Zone 7. This zone comprises the shallow faults (less than 50 km depth) inland Puerto Rico and offshore namely, Mona Canyon, South Lajas Fault, Great Northern and Southern Puerto Rico fault zone, the Anegada Trough and Sombrero Seismic Zone (Clinton et al., 2006).

• This seismogenic source has produced yielding normal

2525

• This seismogenic source has produced yielding normal faulting in a broad zone of active crustal extension and accompanied by destructive tsunamis (Mueller et al., 2003). The absence of volcanism in Puerto Rico and the Virgin Islands suggests that this zone is not an extension of the island-arc Lesser Antilles structure (Molnar & Sykes, 1969).

• Zone 8. This zone includes the intra-plate subductionseismicity generated mainly the bending of North-American slab with depth greater than 50 km.

2626

2727

Right Lateral

Normal Faulting

Transition Zones 9 and 10A.• We define these seismogenic zones as the intersections amongst

the transform faults and subduction zones with the Lesser AntillesArc located at the North and the South of the Eastern Caribbean.Zone 10A includes the shallow seismic activity in the South part ofthe island of Tobago which we consider within the Caribbean-SouthAmerican plate boundary (Latchman 2009, Weber, 2009 and

2828

American plate boundary (Latchman 2009, Weber, 2009 andBurmester et al 1996). Moderate but shallow earthquakes occurredwith right-lateral strike slip and normal faulting mechanism,respectively (Morgan et al., 1988; Latchman 2009).

• The transition Zone 9 is characterized by a low-seismicity level inthe boundary zone between the Lesser Antilles arc and the PuertoRico Trench yielding mainly normal focal mechanisms.

Zone 10B: East of Trinidad.

• Russo & Speed (1992) suggested that the earthquakeslocated in this zone are consistent with the detachmentand bending-flexure of the South American slab movingtoward the collision zone.

3030

• The zone covers mainly normal faulting mechanism withENE-WSW striking planes and strike slip faults with anaverage depth of 45 km.

3131

(Russo et al., 1993)

Trasversal section

-67 -65 -63 -61 -59 -57Long (km)

USGS/PDE (1973-2009)

Transversal section

Crustal seismicity and intra-plate

seismicity

3232

(10-11 N)-250

-200

-150

-100

-50

0

-67 -65 -63 -61 -59 -57

Dep (km)

Zone 11: North of Paria Peninsula• This zone constitutes a subducting detached oceanic

lithosphere with depth ranging from 50 to 300 km andrepresents one of the most active seismogenicsources in the Eastern Caribbean (Russo et al. 1993;SRC, 2009b).

3333

• The focal mechanisms indicate that there is a normalfaulting resulting from the initial flexure of the downgoing slab with a steeply NW-dipping of 60º. However,mixed-motion earthquakes with thrust and strike slipindicated bending of the subducting slab at deeperdepths.

TRINIDAD

3434

Weber et al

(2009)

Zone 12: Trinidad Faults.• Regional tectonic-geological studies conclude that el Pilar Fault

might right-step into Central Trinidad (i.e. Flinch et al., 2000),however, Weber (2001, 2009) affirms that the N68ºE oblique trendingin the Central Range Fault is not associated with el Pilar Fault 90ºtrending of pure wrenching.

3535

• The Northern Range and the Arima Fault comprises a complex faultsystem with lateral strike-slip, thrust and normal faulting. OnDecember 2nd and 3rd 2004 events with a magnitude of 5.8 and 5.4(Mw) occurred in the central north-east of Trinidad; fault planesolutions suggest mainly a normal motion with a component of right-lateral strike slip. The location of these earthquakes and thecorrespondent focal mechanisms coincides with the Northern Rangenormal fault dipping southward mapped by Algar & Pindell (1993)beneath the Caroni Swamp area.

Zones 13 and 14: El Pilar fault. • These zones comprise the boundary between the Caribbean and the

South American plate. The events that have their origin in the fault areshallow - less that 50 km depth - and they are characterized mainly byright lateral strike slip mechanism in the northern coast of SouthAmerica. The Caribbean Plate is moving about 20 mm/yr in an easterlydirection relative to South America (Perez et al. 2001).

3737

direction relative to South America (Perez et al. 2001).

• However, thrust focal mechanism also takes place in this regionreflecting the oblique collision at crustal levels between the Caribbeanand the South American Plate. We observed a high level seismicoutput in Zone 14 that extends from 63.5º W to 62.3ºW longitudecovering the Araya-Paria Isthmus, and a moderate seismicity level inZone 15 that extends from 67.0º to 63.5º W longitude covering thevicinity of Caracas to the Araya region.

Zone 15: South of Trinidad.

• Russo et al. (1993) defined this zone as a passivemargin edge in the Foreland basin in North ofSouth America continent, covering events withstrike slip, mixed thrust and strike slip, and thrust

3838

strike slip, mixed thrust and strike slip, and thrustmechanism around the Orinoco-Delta region inVenezuela, with an average depth of 50 km and amaximum magnitude of 6.6 (Mw).

Main characteristics of the seismic zones Depth (km) Type Main Focal Mechanism

ZONE 1 19.1 Upper-crustal Normal and Strike-Slip

ZONE 2 29.6 Interface Thrust (Inverse)

ZONE 3 29.4 Interface Thrust (Inverse)

ZONE 4 86.0 Intraplate Normal


ZONE 6 32.3 Interface Thrust and Strike-Slip

3939

ZONE 6 32.3 Interface Thrust and Strike-Slip

ZONE 7 28.4 Shallow Normal


ZONE 9 24.4 Transition Normal and Strike-Slip

ZONE 10 43.9 Transition/Intraplate Normal and Strike-Slip


ZONE 12 32.5 Crustal Normal and Strike-Slip

ZONE 13 23.3 Crustal Strike slip and Thrust



Seismogenic sources with events

4040

Ground Motion Prediction Equations (GMPEs)Ground Motion Prediction Equations (GMPEs)

4141

Ground Motion Prediction Equations (GMPEs)Ground Motion Prediction Equations (GMPEs)

• GROUND MOTION PREDICTION EQUATIONS (GMPEs)

• Log y = a + b M + c log R + d R + s + sigma

SOURCE PATH SITE

4242

SOURCE PATH SITE

y : ACCELERATION, M: MAGNITUDE, R: DISTANCE

a,b,c,d,s and sigma: regression analysis

Analyzed GMPEs

SUBDUCTION ZONES:

� Youngs et al. (1997)� Atkinson and Boore (2003-2008)� Zhao et al. (2006)� Kanno et al. (2006)� Lin and Lee (2008)

4444

� Lin and Lee (2008)

CRUSTAL ZONES:

� Kanno et al. (2006)� Zhao et al. (2006)� Abrahamson and Silva (2008)� Boore and Atkinson (2008)� Campbel and Bozogornia (2008)� Chiou and Youngs (2008)

VOLCANIC ZONE:

� Sadigh et al. (1997)� Salazar (2004)� Zhao et al. (2006)� Kanno et al. (2006)� McVerry et al. (2006)� Abrahamson and Silva (2008)� Chiou and Youngs (2008)

El Salvador

New Zealand

• We corrected the acceleration time histories using a base-line correction, a band pass filter and perform the integration in the frequency domain yielding the velocity and displacement yielding the velocity and displacement postscript plots. The correspondent Fourier and Response Spectra for 5% damping are also reproduced in this scheme.

4545

Comparison of GMPEs with available data• Seismic Research Centre (SRC)

• BRGM (Bureau de Recherches

Géologiques et Minières - France)Date Mw H

Earthquaketype

Lat. Long.

November 29, 2007 7.4 148.0 intraplate 14.97 -61.26

October 4, 2000 6.1 110.4 intraplate 11.16 -62.29

4646






January 25, 2001 4.6 85.5 intraplate 10.70 -62.57

June 8, 1999 5.8 52.4 interface 15.07 -60.40

December 2, 2004 5.8 48.2 crustal 10.49 -61.45

December 3, 2004 5.4 40.5 crustal 10.54 -61.46

June 21, 2003 5.3 10.0 crustal 10.79 -59.27

November 21, 2004 6.3 21.2Volcanic island arc

15.73 -61.68

• DISTANCE P G A (cm/s/s)

• st yy mm dd hh mi sec lat lon depth Mw Epic. Hy po. N-S E-W UD slat slon ele. stype filename

• km km km m

• INTERFACE EARTHQUAKE

• GADA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 177.06 184.65 9.8447 15.7043 6.3001 16.2356 -61.5309 15 B0.0 1999.06.08-12.04.13.GADA

• GBRA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 177.62 185.19 2.9142 3.0210 1.4393 16.2556 -61.5162 10 R 1999.06.08-12.02.99.GBRA

• GCCA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 180.49 187.94 3.8948 3.4213 1.6637 16.2768 -61.5319 5 S 1999.06.08-12.04.13.GCCA

• GFEA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 177.81 185.37 7.9028 6.7112 2.5837 16.2395 -61.5369 5 S 1999.06.08-12.04.14.GFEA

• GGSA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 180.33 187.79 11.5927 7.9312 3.9028 16.2662 -61.5417 5 S 1999.06.08-12.04.17.GGSA

• GLAA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 179.28 186.79 1.3991 1.1585 0.8851 16.2495 -61.5460 5 S 1999.06.08-12.03.99.GLAA

• GPAA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 176.63 184.24 2.8366 2.0558 1.3097 16.2330 -61.5279 70 R 1999.06.08-12.04.13.GPAA

• GSPA 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 177.35 184.93 6.1690 3.4603 1.7735 16.2368 -61.5336 5 S 1999.06.08-12.03.99.GSPA

• GT2A 1999 6 8 12 4 0.00 15.07 -60.40 37.0 5 .8 180.62 188.07 12.6054 6.5531 4.5061 16.2694 -61.5421 5 S 1999.06.08-12.04.12.GT2A

• MBRA 1999 6 8 12 4 0.00 15.07 - 60.40 37.0 5.8 89.21 103.47 37.7433 49.9062 34.7575 14.6038 - 61.0773 0 R 1999.06 .08 - 11.56.99.MBRA

ACCELEROMETRIC CATALOGUE

• MBRA 1999 6 8 12 4 0.00 15.07 - 60.40 37.0 5.8 89.21 103.47 37.7433 49.9062 34.7575 14.6038 - 61.0773 0 R 1999.06 .08 - 11.56.99.MBRA

• INTRA PLATE SUBDUCTION

• TPTC 2000 10 4 14 37 50.50 11.16 -62.29 110.4 6. 1 94.85 145.55 58.7540 52.1042 44.2556 10.6800 -61.5700 49 R DQ538

• TWMO 2000 10 4 14 37 50.50 11.16 -62.29 110.4 6. 1 96.38 146.55 59.3524 66.0256 38.4493 10.6700 -61.5600 0 S LZ132

• TBH 2000 10 4 14 37 50.50 11.16 -62.29 110.4 6. 1 153.00 188.67 13.0708 20.9575 7.5213 10.4840 -61.0670 199 R EV019

• INTRA PLATE SUBDUCTION

• ALNG 2001 1 25 4 33 43.00 10.70 -62.57 85.5 4. 6 112.15 141.02 0.4806 0.4959 0.2186 10.1814 -61.6883 0 R CU2150

• TWMO 2001 1 25 4 33 43.00 10.70 -62.57 85.5 4. 6 110.22 139.49 3.8811 3.5447 2.6283 10.6700 -61.5600 0 S ME1391

• TBH 2001 1 25 4 33 43.00 10.70 -62.57 85.5 4. 6 165.73 186.49 0.2265 0.2770 0.1899 10.4840 -61.0670 199 R FA125

• VOLCANIC ARC

• GBRA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 60.90 64.49 47.6633 64.8085 28.9273 16.2556 -61.5162 10 R 2004.11.21-11.40.59.GBRA

• GFEA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 58.58 62.30 84.1276 72.6331 38.1838 16.2395 -61.5369 5 S 2004.11.21-11.38.99.GFEA

• GGSA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 61.32 64.88 98.0630 127.9714 85.7834 16.2662 -61.5417 5 S 2004.11.21-11.41.00.GGSA

• GHMA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 27.95 35.08 217.3862 198.8346 65.6423 15.9808 -61.7035 430 O 2004.11.21-11.42.99.GHMA

• GJYA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 31.59 38.04 201.6058 189.5425 109.8338 16.0136 -61.7046 300 R 2004.11.21-11.41.00.GJYA

• GLAA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 59.41 63.08 119.6347 133.9601 98.2238 16.2495 -61.5460 5 S 2004.11.21-11.40.99.GLAA

• MDIA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 141.47 143.05 7.7459 9.4713 4.6378 14.6099 -61.0499 0 S 2004.11.21-11.41.99.MDIA

• MTHA 2004 11 21 11 41 7.00 15.73 -61.68 21.2 6. 3 140.78 142.37 13.4849 14.9873 8.0515 14.6067 -61.0699 0 S 2004.11.21-11.38.99.MTHA

Adopted GMPEs (subduction zones)Attenuation

EquationApplication

Magnitude definition and

limitations

Distance definition and limitations

Hypocentre depth and limitations Database

Youngs et al.. (1997)

PGA and PSA for 0.075 to 3

s. Horizontal component

Mw ≥ 5

Closest distance to the faulttrace for earthquakes withavailable fault models,otherwise hypocentral distance10 ≤ Rrup ≤ 500 km.

Depth ≤ 50 km for interface eventsDepth > 50 km for inslab events

Developed from a database includingworldwide earthquakes in subductionzones: Alaska, Chile, Cascadia, Japan,Mexico, Peru, Solomon Islands

Atkinson and Boore (2003-

2008)

PGA and PSA for 0.33 to 25

s. Horizontal component

Mw ≥ 5Mw =8.5 for interface events with Mw > 8.5Mw =8 for interface events with Mw > 8

Closest distance to the faulttraceRrup ≤ 400 km.

Depth < 50 km for interface eventsDepth ≥ 50 km for inslab eventsDepth=100 km for events with Depth>100 km

Developed from a database includingthousands of strong motion recordingsfrom events occurring in subductionzones around the world, based on bothCruise (1991) and Youngs et al. (1997)catalogues and added events:Cascadia, Japan, Mexico, CentralAmerica.America.

Zhao et al. (2006)

PGA and PSA for 0.05 to 5 s.

Horizontal component

5.0 ≤ Mw ≤ 8.3

Shorter distance to the rupture zone for earthquakes with

available fault models, otherwise hypocentral distanceRrup ≤ 300 km for slab events

Depth < 25 km for crustal eventsDepth < 50 km for interface eventsDepth ≥ 50 km for inslab eventsDepth =125 km for events with Depth > 125

Developed from the Japanese strongmotion dataset and additional overseasdata from the Western part of US andthe 1978 Tabs, Iran evens to constrainthe near-source behaviour (20 overseasevents of a total of 269 events).This GMPE was used also for thevolcanic zone.

Kanno et al. (2006)

PGA, PGV, PSA for 0.05 to

5 s. Horizontal component

Mw ≥ 5.5

Closest distance to the fault plane for earthquakes with

available fault models, otherwise hypocentral distane

1 ≤ Rrup ≤ 30 km for shallow events

30 ≤ Rrup ≤ 300 km for deep events

Depth ≤ 30 km for shallow eventsDepth > 30 km for deep events

Developed from Japanese seismicwaveform data: earthquake recordsfrom K-NET and KiKnet databases.This GMPE was used also for shallowand volcanic zones.

Lin and Lee (2008)



4.1 ≤ Mw ≤ 6.7 for intraslab events

5.3 ≤ Mw ≤ 8.1 for interface events

Hypocentral distance40 ≤ R ≤ 600 km

for intraslab events20 ≤ R ≤ 300 km

for interface events

Depth ≤ 50 km for interface eventsDepth > 50 km for inslab events

Regional relation based on Chileandata.

Adopted GMPEs (crustal zones)Attenuation Equation Application

Magnitude definition and limitations

Distance definition and limitations

Fault depth definition and contributions to seismic responce

Database

Abrahamson & Silva (2008)

PGA and PSA

for 0.01 to 10 s

Rotation-independent

average horizontal

component

5 ≤ Mw ≤ 8.5Rupture distance0 ≤ Rrup ≤ 200 km

Z_TOR: Depth to the top of the coseismic rupture plane(used in “depth-to-top rupture model” contribution).Z_1.0: Depth to the 1 km/s shear wave velocity horizon(used in “soil-depth” contribution, which is null ifZ_1.0<200 and VS30 ≥ 1000 m/s).In our analysis the hanging wall contribution is notconsidered.If V S30 ≥ 1100 m/s the soil response is assumedlinear for all the periods.

NGA database plus Kocaeliand Chi-Chi mainshocks, ChiChi and Duzce aftershocks.This GMPE was used also forthe volcanic zone.

Campbell &

PGA and PSA

for 0.01 to 10 s.

Mw > 4Mw < 7.5 for normal eventsMw < 8

Closest distance to the surface projection of the coseismic rupture

Z_2.5: Depth to the 2.5 km/s shear wave velocityhorizon (used in “sediments” contribution 0 < Z_2.5 <10 km).If 2 ≤Z_2.5≤ 3, f_sed=0.Z_TOR: Depth to the top of the coseismic rupture plane

Developed from the updatedPEER strong motionCampbell &

Bozorgnia (2008)s.

Horizontal component (geometric

mean)

Mw < 8 for reverse eventsMw < 8.5 for strike-slip events

the coseismic rupture plane0 ≤ Rrup ≤ 200 km

Z_TOR: Depth to the top of the coseismic rupture plane(used in “style-of-foulting” and “hanging wall”contributions, 0<Z_TOR<15 km.In our work hanging wall contribution is not considered.If VS30 ≥ 1100 m/s the soil response is assumed linearfor all the periods.

PEER strong motiondatabase, referred to simplyas the NGA database.

Chiou & Youngs (2008)

PGV, PGA,PSA for 0.01 to 10 s.Orientation-independent

average horizontal

component

Mw ≥ 4Mw ≤ 8.5 for strike-slip eventsMw ≤ 8 for reverse and normal faulting events

Closest distance to the rupture plane0 ≤ Rrup ≤ 200 km

Z_TOR: Depth to the top of rupture (used in “sourceeffects and hanging wall” contributions )Z_1.0: Depth to the 1 km/s shear wave velocity horizon(used in “sediments” contribution), which is minimumfor Z_1.0=0. Z_1.0= 40 m is suggested.In our work hanging wall contribution is not considered.Site effects are null for VS30≥1130 m/s (linearresponse).150≤VS30≤1500 m/s

PEER-NGA database (3551recordings from 173earthquakes).This GMPE was used also forthe volcanic zone.

Boore & Atkinson (2008)

PGV, PGA, PSA for 0.01

to 10 s.Average

horizontal component

5.0 ≤ Mw ≤ 8.0

Closest horizontal distance to the surface projection of the fault planeRJB ≤ 200 km

It does not account for basin response and depth-to topof rupture model as Abrahamson & Silva (2008) andCampbell & Bozorgnia (2008).If VS30(Rock)>760 m/s site response is linear and siteamplification is null.

Developed from NGA database, calibrated for Western US and other similar tectonically active region of shallow crustal faults. Representative of the NGA models and confidently applicable within Europe (Stafford et al., 2008)

Attenuation Equation

ApplicationMagnitude definition

and limitationsDistance definition and

limitationsFault depth definition and contributions to

seismic responceDatabase

Equation and limitations limitations seismic responce

Sadigh et al. (1997)



45.0 ≤ Mw ≤ 8.0+

Shorter distance to the rupture surface for

earthquakes with available fault models, otherwise hypocentral distance

Rrup ≤ 100 km

Strike-slip and normal events are distinguished from reverse/thrust faulting events (amplification

coefficient of 1.2).VS30 (Rock) > 750 m/s

California earthquake (<1994) plus Gazli (USSR, 1976) and Tabas (Iran, 1978) earthquakes

Comparison of GMPEs with available data

10-2

10-1

100

Mw =6.1 T =0 sec

Acc

ele

ratio

n (

g)

10-2

10-1

100

Mw =6.1 T =0.2 sec

Acc

ele

ratio

n (

g)

5252

102

10-3

10-2

10-1

100

Mw =6.1 T =1 sec

Acc

ele

ratio

n (

g)

Hypocentral distance (km)

102

10-3

Hypocentral distance (km)10

210

-3


Youngs et al. 97 - average " - average +σ " - average - σKanno et al., 06 - average " - average +σ " - average - σLin & Lee 08 - average " - average +σ " - average - σZhao et al. 06 - average " - average +σ " - average - σAtkinson & Boore 08 - average " - average +σ " - average - σ2000-10-4 component=1 station=TPTC2000-10-4 component=2 station=TPTC2000-10-4 component=1 station=TBH2000-10-4 component=2 station=TBH

INTRAPLATE EVENT

October 4, 2000


-4

10-3

10-2

10-1

100

Mw =5.8 T =0 sec

Acc

ele

ratio

n (

g)

-4

10-3

10-2

10-1

100

Mw =5.8 T =0.2 sec

Acc

ele

ratio

n (

g)

5353

INTERFACE EVENT

June 8, 1999

102

10-4

10-3

10-2

10-1

100

Mw =5.8 T =1 sec

Acc

ele

ratio

n (

g)


102

10-4

Hypocentral distance (km)10

210

-4

Hypocentral distance (km)Youngs et al. 97 - average " - average +σ " - average - σKanno et al., 06 - average " - average +σ " - average - σLin & Lee 08 - average " - average +σ " - average - σZhao et al. 06 - average " - average +σ " - average - σAtkinson & Boore 08 - average " - average +σ " - average - σ1999-6-8 component=1 station=mbra1999-6-8 component=2 station=mbra1999-6-8 component=1 station=gbra1999-6-8 component=2 station=gbra1999-6-8 component=1 station=GPAA1999-6-8 component=2 station=GPAA


10-3

10-2

10-1

100

Mw

=5.4 T =0 sec

Acc

ele

ratio

n (g

)

10-3

10-2

10-1

100

Mw

=5.4 T =0.2 sec

Acc

ele

ratio

n (g

)

5454

CRUSTAL EVENT

December 3, 2004

102

10-4

Hypocentral distance(km)10

210

-4

Hypocentral distance(km)

102

10-4

10-3

10-2

10-1

Mw

=5.4 T =1 sec

Acc

ele

ratio

n (g

)

Hypocentral distance(km)

Zhao et al. 08 - average " - average +σ " - average - σKanno et al. 06 - average " - average +σ " - average - σAbrahamson & Silva 08 - average " - average +σ " - average - σCampbell & Bozorgnia 08 - average " - average +σ " - average - σBoore & Atkinson 08 - average " - average +σ " - average - σ2004-12-3 component=1 station=ALNG2004-12-3 component=2 station=ALNG2004-12-3 component=1 station=TCHG2004-12-3 component=2 station=TCHG2004-12-3 component=1 station=TBH2004-12-3 component=2 station=TBH

10-2

10-1

100

Mw

=6.3 T =0 sec

Acc

ele

ratio

n (g

)

Sadigh et al., 97 - average " - average +σ " - average - σZhao et al. 08 - average " - average +σ " - average - σKanno et al., 06 - average " - average +σ " - average - σAbrahamson & Silva 08 - average " - average +σ " - average - σ


5555

101

102

10-4

10-3

Acc

ele

ratio

n (g

)


" - average - σChiou & Youngs 08 - average " - average +σ " - average - σSalazar, 04 - average " - average +σ " - average - σMcVerry et al., 06 - average " - average +σ " - average - σ2004-11-21 - PGA from Bengoubou-Valerius et al. 08

VOLCANIC ARC EVENT

November 21, 2004

Adopted GMPEs

SUBDUCTION ZONES:

� Youngs et al. (1997)� Atkinson and Boore (2003-2008)� Zhao et al. (2006)� Kanno et al. (2006)

Cornell-Mc-Guire method:

5656

CRUSTAL ZONES:

� Kanno et al. (2006)� Zhao et al. (2006)� Abrahamson and Silva (2008)� Boore and Atkinson (2008)� Campbel and Bozogornia (2008)

VOLCANIC ZONE:

� Sadigh et al. (1997)� Zhao et al. (2006)� Kanno et al. (2006)� Abrahamson and Silva (2008)� Chiou and Youngs (2008)

� Kanno et al. (2006)� Lin and Lee (2008)

Zone-free approach: Zhao et al. (2006), Kanno et al. (2006)

PSHA analysis and resultsPSHA analysis and results

5757

PSHA analysis and resultsPSHA analysis and results

RESULTSRESULTS

5858

Influence of Influence of seismogenicseismogenic zones zones

-92,16

-85.5,13

-92,10

-89.21,13.71

LOG N = 4.84 – 0.84 M

LOG Y = 1.8479+0.298M-LOGR-0.0013R

SIGMA = 0.2408

M MIN = 4.0 AND M MAX = 8.2

Comparison of hazard programs

-85.5,10FZ RISK OUR PROGRAM - SRC

Peak Ground Acceleration

(cm/s/s)

Number of earthquakes / year Number of earthquakes / year

50.00 0.133 0.134

100.00 0.0169 0.0170

150.00 0.0466 0.00468

200.00 0.00169 0.00173

250.00 0.000738 0.00075

300.00 0.000357 0.000361

350.00 0.000180 0.000180

400.00 0.0000998 0.000102

Island of TrinidadCornell-McGuire approach

Hazard dominated by Zone 11 –

Port of Spain (Trinidad)T=0s

1.00E+00

1.00E+01

1.00E+02

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

1/475 = 2.1E-031/2475 = 4.0E-04

6060

Zone 11 –North of Paria Peninsula

Zone 12 (Trinidad Faults) and Zone 10 (transitions) also contribute

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.1 1 10

Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ07

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

RP=2475 y

RP=475 y

Island of Trinidad Cornell-McGuire approachHazard dominated by Zone 11

Port of Spain (Trinidad)RP=2475 years

1.20

1.40

1.60

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

6161

0.00

0.20

0.40

0.60

0.80

1.00

1.20

0.00 0.50 1.00 1.50 2.00 2.50 3.00

T(s)

SA

(g)

SZ07

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

Zone-free approach - GMPE Zhao etal. (2006)Hazard dominated by deep seismicity; depth > 50 km


1.00E-01

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

RP=2475 y

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Trinidad

6262

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

RP=2475 y

RP=475 y

Zone-free approach - GMPE Kanno etal. (2006)Hazard dominated by deep seismicity seismicity depth > 30 km


1.00E-01

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

RP=2475 y

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Trinidad

6363

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

RP=2475 y

RP=475 y

Island of Barbados

Cornell-McGuire approach

Hazard

BarbadosT=0s

1.00E-01

1.00E+00

1.00E+01

1.00E+02

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

SZ08

1/475 = 2.1E-031/2475 = 4.0E-04

6464

Hazard dominated by Zones 3 –Interface subduction and Zone 5 – Intra plate subduction

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.1 1 10

Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

RP=2475 y

RP=475 y

Cornell-McGuire approachHazard dominated by Zones 3 and 5

BarbadosRP=2475 years

1.00

1.20

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

Island of Barbados

6565

0.00

0.20

0.40

0.60

0.80

0.00 0.50 1.00 1.50 2.00 2.50 3.00

T(s)

SA

(g)

SZ07

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

Zone-free approach - GMPE Zhao etal. (2006)Hazard dominated by deep seismicity; depth > 50 km

BarbadosT=0s

1.00E-01

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Barbados

6666

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

RP=2475 y

RP=475 y

Zone-free approach - GMPE Kanno etal. (2006)Hazard dominated by deep seismicity depth > 30 km

BarbadosT=0s

1.00E-01

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Barbados

6767

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

RP=2475 y

RP=475 y

Island of Dominica

Cornell-McGuire approachHazard dominated by Zone 4 – Intra plate and Zone 1 –

DominicaT=0s

1.00E-01

1.00E+00

1.00E+01

1.00E+02

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

1/475 = 2.1E-031/2475 = 4.0E-04

6868

plate and Zone 1 –Volcanic island-arc

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.1 1 10

Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

RP=2475 y

RP=475 y

Cornell-McGuire approachHazard dominated by Zone 4 and Zone 1

DominicaRP=2475 years

1.40

1.60

1.80

SZ01

SZ02

SZ03

SZ04

SZ05

SZ06

SZ07

Island of Dominica

6969

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

0.00 0.50 1.00 1.50 2.00 2.50 3.00

T(s)

SA

(g)

SZ07

SZ08

SZ09

SZ10

SZ11

SZ12

SZ13

SZ14

SZ15

ALL

Zone-free approach - GMPE Zhao etal. (2006)Hazard dominated by deep and shallow seismicity

DominicaT=0s

1.00E-01

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

RP=2475 y

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Dominica

7070

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

RP=2475 y

RP=475 y

Zone-free approach - GMPE Kanno etal. (2006)Hazard dominated by deep and shallow seismicity

DominicaT=0s

1.00E+00

1.00E+01

Ann

ual F

requ

ency

of E

xcee

danc

e

Deep

Shallow

Total

1/475 = 2.1E-031/2475 = 4.0E-04

Island of Dominica

7171

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

0.01 0.10 1.00 10.00Acceleration (g)

Ann

ual F

requ

ency

of E

xcee

danc

e

Total

RP=2475 y

RP=475 y

• Conclusion- The complex tectonics of the Eastern

Caribbean suggests a detail seismogenicsources delimitation to be incorporated in thehazard assessment, which is dominated byintra-plate seismicity in most of the islandsintra-plate seismicity in most of the islandswith an important contribution of the upper-crustal earthquakes located in the volcanicarc as well.

- The installation of a new strong motionnetwork is a must to develop GMPEs for theEastern Caribbean.

7272

HAZARD MAPS 2475 YEARS RETURN PERIODAPPLICATION

7373

Design spectral acceleration parameters IBC – ASCE 7_05

• SDS = 2/3*Fa * Ss

• SD1 = 2/3*Fv * S1 Spectral acceleration for 1.0 s

Seismic Hazard maps

Spectral acceleration for 0.2 s

7474

Fa and Fv: depends on soil conditionsFor rock site conditions – CLASS B It Corresponds to a shear wave velocity Vs = 760 m/s:

Fa = 1.0 and Fv = 1.0

SDS

1Da

SS

T=

ELASTIC DESIGN RESPONSE SPECTRUM

7575

To

Ts

SD1

T

Practical Examples

• Get the design response spectra and the seismic coefficients Cs for the following sites:

7676

a) Scarborough -Tobago (Hotel – 20 stories)

b) Indian River – Dominica (Bridge – 30 m multi-span intermediate columns with height H = 15 m)

7777

Tobago Hotel

7878

1.85 g

7979

0.375 g

• Reading from the maps

1 0.250.2 0.2* 0.04D

o

ST s= = =

1

1.85

0.375SS g

S g

== 1

(2 / 3)*1.85 1.23

(2 / 3)*0.375 0.25DS

D

S g g

S g g

= == =

8080

0.4 0.6 1.23* 0.4 0.6 0.492 18.450.04a DS

o

T TS S T

T

= + = + = +

0.2 0.2* 0.041.23o

DS

T sS

= = =

T : the fundamental period of the structure in “s”

1 0.250.20

1.23D

SDS

ST s

S= = =

1.23a DSS S g= = Flat spectral response

Period to which begin the exponential decay

8181

1 0.25Da

S gS

T T= =

Spectral exponential decay

The Seismic Coefficient Cs

Fundamental Period:

T = 0.1 n = 0.1 (20 ) = 2.0 s

n: number of stories

1 0.25Da

S gS = =

1.23a DSS S g= =

0.492 18.45aS T= +

8282

T = 2.0 s

Cs = 0.13g

Reduction factor R= 8.0

Cs = 0.13g/8=0.016g

aST T

= =

0.20s

0.04s

0.13 g

8383

ETABS MODEL

MULTI SPAN BRIDGEINDIAN RIVER - DOMINICA

8484

Indian River Indian River1.55g 0.47g

8585

• Reading from the maps

1 0.310.2 0.2* 0.06D

o

ST s= = =

1

1.55

0.47SS g

S g

== 1

(2 / 3)*1.55 1.03

(2 / 3)*0.47 0.31DS

D

S g g

S g g

= == =

8686

0.4 0.6 1.03* 0.4 0.6 0.41 10.30.06a DS

o

T TS S T

T

= + = + = +

0.2 0.2* 0.061.03o

DS

T sS

= = =

T : the fundamental period of the structure in “s”

1 0.310.30

1.03D

SDS

ST s

S= = =

1.03a DSS S g= = Flat spectral response

Period to which begin the exponential decay

8787

DS

1 0.31Da

S gS

T T= = Spectral exponential

decay

The Seismic Coefficient Cs

Design of a column:

Fundamental Period:

T = 0.75 s (H=15 m and 30 m span)

1 0.31Da

S gS

T T= =

1.03a DSS S g= =

0.41 10.3aS T= +

8888

Cs = 0.42g/8=0.053g

Reduction factor R= 8.0

Cs = 0.42g

aST T

= =

0.30s

0.06s

0.42 g

Thank you

8989

Questions ?

Seismic Hazard Assessment Study for the Eastern Caribbean...

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