1 EarthScope: Plate Boundary Observatory William Prescott UNAVCO, Inc AAPG Meeting Salt Lake City, Utah 12 May 2003

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EarthScope:Plate Boundary Observatory

William PrescottUNAVCO, Inc

AAPG MeetingSalt Lake City, Utah

12 May 2003

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Outline

• PBO science goals

• PBO: What is it?

• PBO opportunities for investigators

• UNAVCO: What is it? What does it have to do with EarthScope/PBO?

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Science





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Plate Boundary Observatory

• Study the four-dimensional strain field

• A suite of instruments to cover broad frequency range

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PBO Science/Directions

• Plate Boundary Deformation

– What are the forces that drive plate-boundary deformation?

– What determines the spatial distribution plate-boundary deformation?

– How has plate-boundary deformation evolved?

• Earthquakes

– What controls the space-time pattern of earthquake occurrence?

– How do earthquakes nucleate?

• Volcanoes

– What are the dynamics of magma rise, intrusion, and eruption?

– How can we reduce the hazards of earthquakes and volcanic eruptions?

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Finite Element Model

Velocity Field

Viscosity

L. Flesch and B. Holt, unpublished, 2002

PBO Backbone

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Alaska

Basin and Range CascadiaSan Andreas Fault

ExistingPlannedBackbone

PBO Clusters

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Integrated Monitoring SystemsGPS Permanent StationsCampaign MeasurementsDeep Borehole Strainmeters

Shallow TiltmetersPortable US Array (“hotfoot”)?Rapid Deployments

Volcano Studies

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N. Basin and Range/YellowstoneVolcano Deformation

Kinematic Finite Element ModelSmith and others, 2001

PBO Clusters: Detailed Models

Mogi source and a closed pipeDzurisin, 2001

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Deformation across Basin and Range

Velocity vectors observed with • campaign surveys (big error ellipses)• and continuous stations (small error ellipses)

Bennett et al. 2001

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Velocity Profiles

Thatcher et al, Science 1999

Inversion of velocity

Estimate slip on major active elements in B&R - Sierra Nevada Transition Zone and Central Nevada Seismic Zone

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Composite Models

Left

Inverting for lithospheric viscosity through a force-balance model of surface deformation

Right

Inverting for mantle flow

velocity by adding mantle

deformation from seismic

anisotropy.

(Flesch et al., 2000) (Silver and Holt, 2001)

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PBO Facility





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PBO Stations

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Instrument Suite

• Focused, dense deployments of GPS and strain• 775 continuous Global Positioning

Systems • 175 borehole strainmeters• 5 long baseline strain components

• Backbone network of GPS stations• 100 sites to provide a long-wavelength,

long-period synoptic view of the entire plate boundary zone

• Receiver spacing will be approximately 200 km

• Portable GPS receivers • Pool of 100 portable GPS receivers for

temporary deployments to areas not sufficiently covered by continuous GPS

• Earthscope/Geology • To Be Determined

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• GPS

– Low power GPS receivers and Choke Ring antennas

– Deep-drilled and short-drilled braced monuments. Others as needed

– Power – DC solar, option for wind

– Telemetry – combination of direct and satellite internet, microwave, and radio modem. VSAT and radio proposed for Aleutians

– GPS collocated at all strainmeter sites

– Some sites broadband seismometer ready

GPS Instrumentation

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• Borehole Strainmeters

– Borehole systems a combination of Sacks-Evertsen dilatometers and Gladwin Tensor Strain instruments installed in cluster of 4 or 5.

– Borehole systems have 3-component, 2-Hz, borehole seismometer, possible upgrade to 3-component broadband sensor.

– Borehole systems have tiltmeter, GPS, pore pressure & heat flow monitors

– GPS collocated at all strainmeter sites.

– Drilling managed by DOSECC, probably

– Nanostrain resolution

Strain Instrumentation

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Strain Instrumentation

• Long Base Laser Strainmeter– Laser interferometric distance measurement– ~500 m long– Above ground– Evacuated tube– Optically anchored to about 20 m– Nanostrain resolution with long term stability

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture.

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USArray and PBO

180 Possible Collocated Sites

GPS/Seismic Integration

USArray

PBOPBO + USArray

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Joint USArray NSN/GSN/PBO sites

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PBO will add 100 stations to the current US Ground-based GPS/Met Stations (SuomiNet)

GPS/Meterological Integration

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Tools for Data and Data Product Queryand Retrieval

GSAC Web-Based Query Form

Data Retrieval ResponseGSAC Client Command-lineInterface

GPS Seamless Archive Centers

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Opportunities





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Opportunities

Data from the permanent GPS and strainmeter stations

are freely available

There will be a pool of 100 high precision GPS receivers available for science studies

There will be a wealth of opportunities for education and

outreach

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Frequently Asked Questions

http://powell.unavco.org/EarthScope-PBO-FAQ.html

Frequently Asked

Questions

FAQ Web Page answers questions about PBO

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UNAVCO





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UNAVCO

UNAVCO, Inc. • A consortium of universities that cooperate in applying

geodetic techniques to Earth Science problems

UNAVCO has proposed to NSF to construct PBO in cooperation with IRIS, Stanford

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Investigator Support from UNAVCO

Project Conception and PlanningNetwork ArchitectureInfrastructure RequirementsNew Software and Hardware Development Budgets

Pre-Installation PhaseDesign of permanent station systemsDesign of new antenna radome, power systemsPurchasing, Fabrication, Testing, and ShippingReconnaissanceDevelopment of data management systems

InstallationMonument drilling and installationInstallation of GPS and repeater systemsVerify data downloading and transfer, QC

Network OperationsData ManagementNetwork MonitoringNetwork MaintenanceMaintain operations databaseArchive and distribute data to communityArchive velocity results and provide display tools

Campaign SupportProvide Equipment (15 receivers)In-field Training by field engineerParticipate in making field surveyArchive data

29http://www.earthscope.org

Documents

1 EarthScope: Plate Boundary Observatory William Prescott UNAVCO, Inc AAPG Meeting Salt Lake City, Utah 12 May 2003