Earthquake Hazard in the Caribbean

Eric CalaisUNDP and Purdue University

Whose Fault?

• Hispaniola is “squeezed” at a constant, inexorable, speed of 2 cm per year• This motion puts the whole islandunder pressure – earthquakes release it• As long as plates will move, there will be earthquakesLesson #1: since plate motion is inexorable, seismic hazard is inexorable

Population at Risk for Natural Hazards

11.3 M

2.7 M

0.3 M

16.5 M

3.9 M

2.0 M

1.1 M

25 M42 M3.0 M

4.0 M

5.4 M

6.8 M

6.6 M

Total = 130 MSource: CIA Factbook

Seismic Research UnitThe University of the West IndiesSt. AugustineTrinidad

Tel 868 662 4659 Fax 868 663 9293 e-mail sruuwi@tstt.net.tt

-8 5 W -8 0 W -7 5 W -7 0 W -6 5 W -6 0 W

-8 5 W -8 0 W -7 5 W -7 0 W -6 5 W -6 0 W

Longitude

1 0 N

1 5 N

2 0 N

2 5 NLatitude

10 N

15 N

20 N

25 N

Caribbean earthquakes The instrumental Period

This slide shows earthquakes since 1964. Note that although there is far greater detail, the general pattern is the same

Frankel, A.et al.,Documentation for Initial Seismic Hazard Maps for Haiti, USGS Open-File Report 2010.

Includes GPS and some fault information.

Range of above map

2010

OAS Caribbean Disaster Management Project, mapsimilar to GlobalSeismic Hazard Assessment Program(GSHAP) 1999.

Based on recent seismicity

= 33 % g

= 3 % g

2001

PAP = 0.13 g

PAP = 0.40 g

http://www.oas.org/CDMP/document/seismap/

Grou

nd sh

akin

g

SDQ = 0.5 g

SDQ = 0.3 g

Jamaica Spectral Hazard Maps

Compilation R. Bilham (U. Colorado), figure A. Freed (Purdue)