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A PROPOSAL FOR A CARIBBEAN PLATE BOUNDARY OBSERVATORY

A PROPOSAL FOR A CARIBBEAN PLATE BOUNDARY OBSERVATORY. GLEN S. MATTIOLI 1 , SIMON R. YOUNG 2 , BARRY VOIGHT 2 1 - Department of Geosciences, University of Arkansas 2 - Department of Geosciences, Pennsylvania State University. Acknowledgments.

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A PROPOSAL FOR A CARIBBEAN PLATE BOUNDARY OBSERVATORY

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  1. A PROPOSAL FOR A CARIBBEAN PLATE BOUNDARY OBSERVATORY GLEN S. MATTIOLI1, SIMON R. YOUNG 2, BARRY VOIGHT 2 1 - Department of Geosciences, University of Arkansas 2 - Department of Geosciences, Pennsylvania State University

  2. Acknowledgments • NSF CANAPE Research Group:E. Calais, C. DeMets, T. Dixon, P. Jansma, and P. Mann • NSF-NERC CALIPSO Research Group:D. Elsworth, A. Linde, P. Malin, S. Sacks, E. Shalev, S. Sparks, and L. Nueberg • The Montserrat Volcano Observatory:P. Dunkley, R. Herd, and G. Norton • NSF REU Students:B. Blessing, J. Mischler, J. McBee, R. Davidson, J. Parra, L. Roberts • UARK/UPRM/RSMAS/PSU Graduate Students:P. LaFemina, D. Hydiat, A. Lopez, S. Matson, A. Stone, H. Turner, L. Van Boskirk, H. Rodriguez, L. Rodriguez • Others: A. Eby (UPRM), K. Fitzgibbon (UARK), A. Smith (CSUSB)

  3. Outline of Talk • Introduction • Motivation and Background • Scientific Goals • Survey of Existing Resources • Issues of Coordination and Data Sharing • Some Regional Science Snapshots • Recent Improvements in Infrastructure • MVO/CALIPSO Partnership • Estimated Needs for Caribbean PBO • New Instrumentation • Costs and Possible Funding Sources

  4. EarthScope Summary • What is EarthScope? • Funded by National Science Foundation Major Research Instrumentation Account. • ~$350 M over 10 year period starting in FY03. Additional funding possible with future NASA contribution for geophysical InSAR satellite. • EarthScope is a bold undertaking to apply modern observational, analytical and telecommunications technologies to investigate the structure and evolution of the North American continent and the physical processes controlling earthquakes and volcanic eruptions. • Major Instrumentation Components of EarthScope • Plate Boundary Observatory: High spatial resolution array of continuous GPS sites and borehole strainmeters • USArray: Transportable array of broadband seismometers • SAFOD: Deep drilling through seismogenic zone of the San Andreas Fault Zone with core recovery and sonde installation Source: http://www.earthscope.org

  5. US Plate Boundary Observatory • Geodetic quality GPS receivers (Trimble NetRS) • Dorne-Margolin Choke Ring antenna • SCIGN-type monuments • Real time data acquisition (some sites at 1 Hz; most at 30 s sync rate) • Incorporates existing CGPS networks • Borehole strainmeters Source: http://www.earthscope.org

  6. Instrumental Characteristics NB different instruments can access different zones within the overall strain field of the plate boundary. Source: http://www.earthscope.org

  7. Major Science Objectives of US PBO • What are the forces that drive plate-boundary deformation? • What determines the spatial distribution of plate-boundary deformation? • How has plate-boundary deformation evolved? • What controls the space-time pattern of earthquake occurrence? • How do earthquakes nucleate? • What are the dynamics of magma rise, intrusion, and eruption? • How can we reduce the hazards of earthquakes and volcanic eruptions? Source: http://www.earthscope.org

  8. Important Issues Specific to a Caribbean PBO • Caribbean-North American/-South American/-Cocos relative plate motions are generally slower than Pacific-North American motion. • Geodetic measurements are less precise over generally short funding cycles (3-5 years). • Long repose intervals of magmatic/volcanic systems limits targets of opportunity for coordinated study. • Lesser Antilles arc is an ocean-ocean convergent environment, while Cascades arc is ocean-continent. • Crustal structure, fabric and composition are different, which may affect deformation mechanisms and magmatic pathways. • Tectonic deformation zone spans over 25 international political entities including sovereign nations, dependent territories, Commonwealths, and Departments. • Field work, data access and coordination are often difficult.

  9. Specific Scientific Questions for a Caribbean Plate Boundary Observatory • What determines the spatial distribution of Caribbean plate-boundary deformation? • Needed: Higher spatial density and increased distribution of CGPS sites. • What controls the space-time pattern of plate margin and intraplate and interplate earthquake occurrence? • Needed: Higher spatial density and increased distribution of broadband seismometer sites. • What are the dynamics of magma rise, intrusion, and eruption? • Needed: Arrays of CGPS with borehole strainmeters and seismometers on all potentially active volcanoes. • How can we reduce the Caribbean regional hazards of earthquakes and volcanic eruptions? • Needed: Increased scientific data integration combined with improved community outreach and education.

  10. circum-Caribbean seismicity (defines plate) Caribbean epicenters < 30 km depth from USGS

  11. Population at Risk for Natural Hazards Source: CIA Factbook Total = 130 M 0.3 M 11.3 M 3.9 M 2.7 M 16.5 M 6.8 M 2.0 M 6.6 M 1.1 M 5.4 M 3.0 M 42 M 25 M 4.0 M

  12. Survey of Existing Geophysical Resources • Greater Antilles - Cuba, Jamaica, Hispaniola, Puerto Rico, British and US Virgin Islands • 14 continuous GPS sites (only 7 available in real time; 4 IGS) • 45 short period seismometers (single and 3 component) • 13 digital broadband instruments (PR only) • 16 strong motion instruments (PR and DR) • Institutions: DRSN, UPRM, UWI, UARK, NOAA, and IGS • Eastern Caribbean - Lesser Antilles and Trinidad • 12 continuous GPS sites (10 in Montserrat; 1 IGS) • 74 short period seismometers (single and 3 component) • 6 digital broadband instruments (Montserrat only) • 0 strong motion instruments • 4 single component borehole strainmeters (Montserrat only) • Institutions: SRU, IPGP, MVO, UARK, IGS, and CALIPSO

  13. Existing Geophysical Resources, con’t. • South America - Venezuela and Columbia • 1 continuous GPS sites (IGS) • 52 short period seismometers (single and 3 component) • 3 digital broadband instruments • 42 strong motion instruments • Institutions: FUNVISIS,INGEOMINAS, and IGS • Central America - Panama, Costa Rica, Nicaragua, El Salvador, and Honduras • 4 continuous GPS sites (IGS) • 73 short period seismometers (single and 3 component) • 2 digital broadband instruments • 19 strong motion instruments (Nicaragua only) • Institutions: INETER, OVSICORI-UNA, ChiriNet, and IGS

  14. Caribbean Regional Seismic Networks - I SRU-UWI INETER (Nicaragua) OVSICORI (Costa Rica)

  15. Regional Networks - II UPRM (PRVI) INGEOMINAS (Columbia) FUNVISIS (Venezuela)

  16. Summary of Regional Resources • 31 continuous GPS sites (10 Montserrat) • 244 short period seismometers • 24 digital broadband instruments • 38 strong motion instruments • 4 single component borehole strainmeters (all in Montserrat) • NO CENTRAL DATA ARCHIVE

  17. Caribbean Neotectonics: Science Snapshots • Definition of Caribbean plate motion from GPS • Interseismic and intervolcanic deformation in the NE Caribbean • Forearc sliver definition and migration in Nicaragua • Long Term cyclic edifice deformation at Soufriere Hills volcano, Montserrat

  18. Regional GPS Field and CA Frame Source: DeMets et al., 2000; Mann et al., 2002

  19. best fit NOAM-CARIB rate ~19 mm/yr ENE azimuth • twice as fast as NUVEL-1A • azimuth ~N70°E at PR

  20. GPS-defined CA Reference Frame • Problems: • Too few sites and geographic distribution is poor. • Time series is still too short (noise remains significant) for key sites (AVES). • Solutions: • Additional CA reference frame sites in Honduras, Nicaragua, and Lesser Antilles. Many of these sites remain immature and do not yet contribute significantly to the latest realization of the CA frame (DeMets et al., unpublished). • CA-PBO would help here. • Additional occupations for key sites (e.g. AVES - last occupied in 1998!).

  21. CA Residual Velocities NE Caribbean

  22. Nicaragua Forearc Sliver Motion & Models Forearc translation does not require high kinematic coupling along plate interface in Nicaragua. 3 fault models are not sufficient to fit GPS data. Source: Turner, 2002; Turner et al., 2003

  23. No Surface Flux Renewed Dome Growth Explosions -> <-Dome Growth Subsidence Again! -> <- Subsidence Inflation ->

  24. Neotectonic/Volcanic Summary • Caribbean Reference Frame still needs refinement for detailed examination of plate boundary and inter-volcanic processes. • Residual velocities in the NE Caribbean are too large to be simply the result of elastic strain accumulation along the trench interface. Other processes must also be considered (e.g. volcanic edifice failure). • Rapid forearc translation is observed in Nicaragua. High kinematic coupling is not required. • SHV shows strongly non-linear deformation correlated with surface magma flux.

  25. CALIPSO Borehole Instrumentation • Sacks-Evertson single component dilatometer (10-9 strain) • Nearly broadband 3 component seismometer (~2 Hz to 1 kHz) • Pinnacle Systems short-baseline electronic tiltmeter • Ashtech µ-Z code-phase CGPS w/ choke ring antenna • See EOS Feature on August 24th, 2004 for details.

  26. CALIPSO Borehole Sites

  27. July 13, 2003 SHV Dome Collapse >120 M m3 (historical record) collapsed over 6 hrs Borehole strainmeter recorded signals from deep (magma chamber) and near surface processes (pyroclastic flow-generated tsunamis). Detailed modeling is progress as data set is unprecedented.

  28. Proposed Caribbean PBO Wish List • Improve GPS infrastructure throughout the region. Need approximate spacing of 25 km and 2 sites per volcano (min). Estimated number of sites is 100 @ $25K/site for a total of $2.5 M. Possible. • Improve broadband seismic backbone. Estimated number of sites is 40 @ $25K/site for a total of $1.0 M. Possible. • Install 3-site arrays of borehole strain, seismometer, and tilt on all potentially active volcanoes. Estimated number of sites is 90 @ $100K/site for a total of $9.0 M. Unlikely due to cost. • Development of a regional data and education and outreach center. Estimated cost of $1.0 M. Could be coordinated through IRIS, UNAVCO, MIDAS or other prominent regional institutions. Possible.

  29. Summary • A modest investment of $4.5 M (w/o borehole instruments) and $13.5 M (with BH) would greatly enhance geophysical infrastructure in the Caribbean. • This would be a starting point for increased scientific collaboration among the wide number of existing institutions active in the Caribbean. • Funding would have to be cost-shared by US, EU, and regional institutions. • IGC or some other international organization (e.g. IAVCEI or IASPEI) may want to consider a workshop to generate community input and gauge the level of support for such a venture.

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