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COCONet : An Opportunity for Strengthening Disaster Risk Reduction in the Eastern C aribbean

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.

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COCONet : An Opportunity for Strengthening Disaster Risk Reduction in the Eastern C aribbean

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  1. 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 COCONetNetwork • June 28-29, 2011

  2. Selected Disastrous Geologic Events in the Caribbean in the Last 110 years

  3. “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

  4. 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].

  5. Mt. Liamuiga, St. Kitts Soufriere Hills, Montserrat The Bottom, Saba Nevis Peak, Nevis The Quill, St. Eustatius Volcanoes of the Eastern Caribbean La Soufriere, Guadeloupe Montagne Pelee, Martinique Morne Aux Diables, Dominica Sulphur Springs, St Lucia The Soufriere, St. Vincent Kick ‘em Jenny Mt St. Catherine, Grenada

  6. Known Major Eastern Caribbean Earthquakes 1502 - 2007

  7. Subset of Intermediate Period and Broadband Instruments in Caribbean and adjacent Regions (2008) Existing seismic stations that are already contributing and regional stations that could potentially contribute to CTEWS – Global View, 207 Stations

  8. Caribbean earthquakes 1 Historical 1530-1964

  9. 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 Seismic Research Unit The University of the West Indies St. Augustine Trinidad Tel 868 662 4659 Fax 868 663 9293 e-mail sruuwi@tstt.net.tt

  10. Oblique Collision Plate Dynamics in the Eastern Caribbean Transpression

  11. Eastern Caribbean seismicity p.72

  12. Eastern Caribbean Earthquake Statistics Expected Frequency based on 2009 study of boxed area (12-14 N)

  13. Seismotectonic Source Zones along the eastern Boundary of the Caribbean Plate

  14. EC Eqs. with M>5.9 (1502-2007) and PGA Hazard Map (RP=475 yrs)

  15. 2009 Revision of East. Caribbean Hazard Maps depicting Spectral Acceleration at 0.2 and 1.0sec for Return Period of 2475 years

  16. Map of Stations Contributing Data to the Tsunami Warning Network http://rmsismo.uprm.edu/Estaciones/estatus.php?maptype=1&stat_type=100

  17. Eastern Caribbean Broadband Stations V V V V V V VSAT Comms V V Planned VSAT Stns V Planned Internet Stns V Total = 32 Stns V

  18. Surface elevations for the Lesser Antilles Scenario (in source region which produced M7.5+ 1843 event)

  19. Moment Tensor Solutions • Used in the definition of sources

  20. Generalised structure map of the Southern Caribbean (After Pindell et al 2007)

  21. Tectonic setting of Trinidad 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]

  22. Arc-parallel extension. Transition zone shortening and overthrusting, After FEUILLET ET AL.

  23. 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

  24. TYPICAL SRC ISLAND NETWORKS Example 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

  25. 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.

  26. 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)

  27. Morne Aux Diables complex from Morne Diablotins

  28. 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. SRC GPS Network

  29. Eastern Caribbean cGPS Stations

  30. 2007 GPS Time Series - ALBI, Antigua SVGB, St. Vincent & ANTG, Antigua ANTG SVGB ALBI

  31. 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.

  32. Station Siting • Legend • V – VSAT Comms • E – Existing • N – Not in Existence • R – To be Refurbished • F – Funded • St BartsvE • 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 • CarriacouvNF* • Grenada vE* • Tobago (2) vE, E* • Trinidad (5) E*, E**

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