Download Mattioli et al. presentation at IGC, Firenze, Italy, August 25, 2004

A PROPOSAL FOR A
CARIBBEAN PLATE
BOUNDARY OBSERVATORY
GLEN S. MATTIOLI 1, SIMON R. YOUNG 2, BARRY VOIGHT
1 - Department of Geosciences, University of Arkansas
2 - Department of Geosciences, Pennsylvania State University
2
Acknowledgments
 NSF CANAPE Research Group:
DeMets, T. Dixon, P. Jansma, and P. Mann
E. Calais, C.
 NSF-NERC CALIPSO Research Group:
D.
Elsworth, A. Linde, P. Malin, S. Sacks, E. Shalev, S. Sparks, and
L. Nueberg
 The Montserrat Volcano Observatory:
Dunkley, R. Herd, and G. Norton
P.
 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),
(CSUSB)
A. Smith
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
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
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
Instrumental Characteristics
NB different instruments can access different zones
within the overall strain field of the plate boundary.
Source: http://www.earthscope.org
Major Science Objectives of US PBO
 What are the forces that drive plate-boundary
deformation?
 What determines the spatial distribution of plateboundary 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
Important Issues Specific to a Caribbean PBO
 Caribbean-North American/-South American/-Cocos
relative plate motions are generally slower than PacificNorth 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.
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.
circum-Caribbean seismicity (defines plate)
Caribbean
epicenters < 30 km depth from USGS
Population at Risk for Natural Hazards
Source: CIA Factbook
Total = 130 M
0.3 M
11.3 M
6.8 M
3.9 M
2.7 M
16.5 M
2.0 M
6.6 M
5.4 M
4.0 M
1.1 M
3.0 M
42 M
25 M
Survey of Existing Geophysical Resources
 Greater Antilles - Cuba, Jamaica, Hispaniola, Puerto
Rico, British and US Virgin Islands




14
45
13
16
continuous GPS sites (only 7 available in real time; 4 IGS)
short period seismometers (single and 3 component)
digital broadband instruments (PR only)
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
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
Caribbean Regional Seismic Networks - I
SRU-UWI
INETER
(Nicaragua)
OVSICORI
(Costa Rica)
Regional Networks - II
UPRM (PRVI)
INGEOMINAS
(Columbia)
FUNVISIS (Venezuela)
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
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
Regional GPS Field and CA Frame
Source: DeMets et al., 2000; Mann et al., 2002
best fit NOAM-CARIB rate
~19 mm/yr
ENE azimuth
• twice as fast as NUVEL-1A
• azimuth ~N70°E at PR
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!).
CA Residual Velocities NE Caribbean
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
No Surface Flux
Explosions ->
Renewed
Dome
Growth
<-Dome Growth
Subsidence
Again! ->
Inflation ->
<- Subsidence
Neotectonic/Volcanic Summary
 Caribbean Reference Frame still needs refinement for
detailed examination of plate boundary and intervolcanic 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.
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.
CALIPSO Borehole Sites
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.
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.
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.