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COCONet : An Opportunity for Strengthening Disaster Risk Reduction in the Eastern C aribbean. LLOYD LYNCH Seismic Research Centre University of the West Indies St. Augustine Trinidad and Tobago. 2011 COCONet Network June 28-29, 2011. - PowerPoint PPT Presentation
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COCONet: An Opportunity for Strengthening Disaster Risk Reduction
in the Eastern Caribbean
LLOYD LYNCH
Seismic Research Centre
University of the West Indies
St. Augustine
Trinidad and Tobago
2011 COCONet NetworkJune 28-29, 2011
Selected Disastrous Geologic Events in the Caribbean in the Last 110 years
Event Date Country Fatalities No Affected Damage
Volcanic Eruption 08/05/1902 Martinique 30000Volcanic Eruption 08/05/1902 St. Vincent 1670Earthquake 14/01/1907 Jamaica 2000Earthquake 25/05/1972 Nicaragua 6000 300000 2968Earthquake 08/10/1974 Antigua/Barbuda 0 4200 61Earthquake 29/05/1976 Guatemala 23000 2550000 2147Earthquake/Tsu 4,8/08/1946 Dom Rep 1700?Volcanic Eruption 07/06/1985 Colombia 22000 200000 465Earthquake 07/06/1985 Mexico 8000 150000 6216Earthquake 08/06/1986 El Salvador 1200 520000 1352Pacific Tsunami 14/06/1992 Nicaragua 116 40500 30Volcanic Eruption 19/07/1995 Montserrat 19 12000Earthquake 21/06/1999 Colombia 1,185 559,401 1,580Earthquakes 23/06/2001 El Salvador 1159 1412938 1518Earthquake 12/01/2010 Haiti 270000 3000000 12000
Sources:EM-DAT/OFDA/CRED/ECLAC/IDB
“The number of attempts to synthesize the tectonic framework of the Caribbean are infinite as are the number of different frameworks that have been suggested….In terms of the plate tectonic revolution in earth science it would be very much preferable if the Caribbean area and the Bahamas did not exist.”
Quote from F. Nagle, Caribbean Geology, Bulletin Mar. , Sci, 1970
Caribbean Geodynamics Setting
[after, e.g., Jordan, 1975; Adamek et al., 1988; Holcombe et al., 1990; Mascle and Letouzey, 1990; Pindell and Barrett, 1990; Heubeck and Mann, 1991; Mann et al., 1995; Flinch et al., 1999; Weber et al., 2001]. Bathymetry from Smith and Sandwell [1997]. Subduction rates from DeMets et al. [2000] and Weber et al. [2001].
The Quill, St. Eustatius
The Bottom, Saba
Mt St. Catherine, GrenadaKick ‘em Jenny The Soufriere, St. Vincent
Sulphur Springs, St Lucia
Montagne Pelee, Martinique
Morne Aux Diables, Dominica
Volcanoes of the Eastern Caribbean La Soufriere,
Guadeloupe
Soufriere Hills, MontserratNevis Peak, Nevis
Mt. Liamuiga, St. Kitts
Existing seismic stations that are already contributing and regional stations that could potentially contribute to CTEWS – Global View, 207 Stations
Subset of Intermediate Period and Broadband Instruments in Caribbean and adjacent Regions (2008)
-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 N
Latit
ude
1 0 N
1 5 N
2 0 N
2 5 N
Caribbean earthquakes 1 Historical 1530-1964
Seismic Research UnitThe University of the West IndiesSt. AugustineTrinidad
Tel 868 662 4659 Fax 868 663 9293 e-mail [email protected]
-8 5 W -8 0 W -7 5 W -7 0 W -6 5 W -60 W
-8 5 W -8 0 W -7 5 W -7 0 W -6 5 W -60 W
Longitude
1 0 N
1 5 N
2 0 N
2 5 NLa
titud
e
1 0 N
1 5 N
2 0 N
2 5 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
Plate Dynamics in the Eastern Caribbean
Oblique Collision
Transpression
Eastern Caribbean seismicity
p.72
Eastern Caribbean Earthquake Statistics
Mag. (Mw)
Freq. (Year)
Since (# of Evts.)
≥5.3 4 1950 (250)
≥ 5.8 1 - 2 1950 (77)
≥6.3 1/2 1910 (58)
≥ 6.8 1/8 1810 (25)
≥7.3 1/15 1810 (13)
≥7.8 1/80 1690 (4)
≥8.0 1/270 ? 1530 (2)
Expected Frequency based on 2009 study of boxed area
(12-14 N)
Seismotectonic Source Zones along the eastern Boundary of the Caribbean Plate
EC Eqs. with M>5.9 (1502-2007) and PGA Hazard Map (RP=475 yrs)
2009 Revision of East. Caribbean Hazard Maps depicting Spectral Acceleration at 0.2 and 1.0sec for Return Period of 2475 years
Map of Stations Contributing Data to the Tsunami Warning Network
http://rmsismo.uprm.edu/Estaciones/estatus.php?maptype=1&stat_type=100
Eastern Caribbean Broadband Stations
Total = 32 Stns
V VSAT Comms
V
V
V
VV
V
V
VV
V
Planned VSAT Stns
Planned Internet Stns
Surface elevations for the Lesser Antilles Scenario (in source region which produced M7.5+ 1843 event)
Moment Tensor Solutions
• Used in the definition of sources
Generalised structure map of the Southern Caribbean (After Pindell et al 2007)
Tectonic setting of Trinidad showing results of previous GPS studies (with stable S. America as a reference frame). Green vectors from Perez et al. (2001); orange vectors from Trenkamp et al. (2002); blue vectors from Weber et al. (2001). [After Soto et al]
Tectonic setting of Trinidad
shortening and overthrusting,
Arc-parallelextension.
Transition zone
After FEUILLET ET AL.
Key Considerations
• In the Eastern Caribbean , several populated centres are (may be) threatened by near –surface, potentially active faults
• GPS has the potential to identify such faults and help is assessing the contribution to earthquake hazard.
• Population centres are also threatened by large subduction earthquakes• Study of the distribution of strain rate through GPS could help to resolve
uncertainty of the earthquake source parameters.• The Eastern Caribbean is at risk from “short fused” tsunamis an
subsidence surge• GPS could add another dimension to the Coastal Hazard and Tsunami Early
Warning System• More than 300,000 West Indians live and/or work along the flanks of live
volcanoes .• GPS is currently used to develop and maintain a database of flank
elevation
TYPICAL SRC ISLAND NETWORKSExample 1: DOMINICA
Installed 3 cGPS (red stars) at DOMI, ROSS & PNVL
Total of 15 benchmarks (red dots) periodically measured.
Measurement interval ~ 2 hrs
Recording rate ~ 1 sec
Morne Aux Diables - N. Dominica
Since June 2009 to present, there has been elevated seismic activity or ‘seismic unrest’ beneath Morne Aux Diables.
GPS surveys have been more frequent, in February 2010 & again in October 2010. Networks utilized ROSS &PNVL as base stations and benchmarks measured ~ 2 hrs.
So far, results highlight no clear changes in co-ordinate location or baseline length.
Qu ickTime™ and a decompr essor
are needed to see this p ictu re.
Typical GPS benchmarks are:
1/ 10 cm long pins
2/ 15 cm metal screw-threaded rods
Both types drilled & epoxied onto concrete roofs
Eg THBD pin at Thibaud village (on Health Centre roof)
Morne Aux Diables complex from Morne Diablotins
SRC GPS Network
SRC, OSVG and OSVM operate and share a growing Network of cGPS stations in the eastern Caribbean (currently 11 stations). Files are sampled at 1 hz and FTPed in hourly files to servers for redistribution to the wider community of stakeholders. SRC uses the network primarily for referencing for the campaigns of volcano deformation networks but as the network grows it is increasingly providing more insights on regional plate dynamics.
Eastern Caribbean cGPS Stations
2007 GPS Time Series - ALBI, Antigua SVGB, St. Vincent & ANTG, Antigua
ANTG
SV
GB
AL
BI
Priorities/Goals
• Reduce Downtime;• Expand the network;• Characterize and reduce noise;• Add redundancy;• Improve latency;
• Improve overall quality of next generation stations, particularly stability of site/monument;
• Improve data archiving/processing infrastructure;• Establish QQ regime and visualization tools;• Integrate into EW Systems;• Bootstrap research program.
Station Siting• St Barts vE• Anguilla N*• St Kitts vE• St. Marteen E*• Redonda NP• Montserrat vPF• Antigua vERF*• Barbuda vNS*• Guadeloupe vE*• Dominica (2) vE, NF*• Martinique (4) vE*,vNF**• St. Lucia vNF*• St. Vincent (2) vE*• Barbados vE*• Mustique NF• Carriacou vNF*• Grenada vE*• Tobago (2) vE, E*• Trinidad (5) E*, E**
Legend• V – VSAT Comms• E – Existing• N – Not in Existence• R – To be Refurbished• F – Funded