Transcript COCONet: An Opportunity for Strengthening Disaster

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 Network
June 28-29, 2011
Selected Disastrous Geologic Events in the Caribbean in
the Last 110 years
Event
Date
Country
Volcanic Eruption
Volcanic Eruption
Earthquake
Earthquake
Earthquake
Earthquake
Earthquake/Tsu
Volcanic Eruption
Earthquake
Earthquake
Pacific Tsunami
Volcanic Eruption
Earthquake
Earthquakes
Earthquake
08/05/1902
08/05/1902
14/01/1907
25/05/1972
08/10/1974
29/05/1976
4,8/08/1946
07/06/1985
07/06/1985
08/06/1986
14/06/1992
19/07/1995
21/06/1999
23/06/2001
12/01/2010
Martinique
St. Vincent
Jamaica
Nicaragua
Antigua/Barbuda
Guatemala
Dom Rep
Colombia
Mexico
El Salvador
Nicaragua
Montserrat
Colombia
El Salvador
Haiti
Fatalities No AffectedDamage
30000
1670
2000
6000
0
23000
1700?
22000
8000
1200
116
19
1,185
1159
270000
300000
4200
2550000
2968
61
2147
200000
150000
520000
40500
12000
559,401
1412938
3000000
465
6216
1352
30
Sources:EM-DAT/OFDA/CRED/ECLAC/IDB
1,580
1518
12000
“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 Bottom, Saba
Mt. Liamuiga,
St. Kitts
Nevis Peak, Nevis
Soufriere Hills,
Montserrat
The Quill, St. Eustatius
Volcanoes of
the Eastern
Caribbean
Morne Aux
Diables, Dominica
The Soufriere,
St. Vincent
Sulphur Springs,
St Lucia
Kick ‘em Jenny
La Soufriere,
Guadeloupe
Montagne Pelee,
Martinique
Mt St. Catherine, Grenada
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
Caribbean earthquakes 1 Historical 1530-1964
Longitude
-85 W
25 N
-80 W
-75 W
-70 W
-65 W
-60 W
25 N
20 N
15 N
15 N
10 N
10 N
Latitude
20 N
-85 W
-80 W
-75 W
-70 W
-65 W
-60 W
Caribbean earthquakes The instrumental Period
Longitude
-85 W
25 N
-80 W
-75 W
-70 W
-65 W
-60 W
25 N
20 N
15 N
15 N
10 N
10 N
Latitude
20 N
-85 W
-80 W
-75 W
-70 W
-65 W
-60 W
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 [email protected]
Oblique Collision
Plate Dynamics in the
Eastern Caribbean
Transpression
Eastern Caribbean seismicity
p.72
Eastern Caribbean Earthquake Statistics
Expected Frequency based on 2009 study of boxed area
Mag.
(Mw)
(12-14 N)
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)
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/estat
us.php?maptype=1&stat_type=100
Eastern Caribbean Broadband Stations
V
V
V
V
V
V VSAT Comms
V
V
Planned VSAT Stns
Planned Internet Stns
Total = 32 Stns
V
V
V
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
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]
Arc-parallel
extension.
Transition
zone
shortening and
overthrusting,
After
FEUILLET ET AL.
Key Considerations
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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 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
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.
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)
Qui ckTi me™ and a
decompressor
are needed to see this picture.
Morne Aux Diables complex from Morne Diablotins
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
Eastern Caribbean cGPS Stations
ANTG
SVGB
ALBI
2007 GPS Time Series - ALBI, Antigua SVGB, St. Vincent & ANTG, Antigua
Priorities/Goals
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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
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St Barts
Anguilla
St Kitts
St. Marteen
Redonda
Montserrat
Antigua
Barbuda
Guadeloupe
Dominica (2)
Martinique (4)
St. Lucia
St. Vincent (2)
Barbados
Mustique
Carriacou
Grenada
Tobago (2)
Trinidad (5)
vE
N*
vE
E*
NP
vPF
vERF*
vNS*
vE*
vE, NF*
vE*,vNF**
vNF*
vE*
vE*
NF
vNF*
vE*
vE, E*
E*, E**
Legend
• V – VSAT Comms
• E – Existing
• N – Not in Existence
• R – To be Refurbished
• F – Funded