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

2 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?

3 Science PBO science goals PBO: What is it? PBO opportunities for investigators UNAVCO: What is it? What does it have to do with EarthScope/PBO?

4 Plate Boundary Observatory Study the four-dimensional strain field A suite of instruments to cover broad frequency range

5 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?

6 Finite Element Model Velocity Field Viscosity L. Flesch and B. Holt, unpublished, 2002 PBO Backbone

7 Alaska Basin and RangeCascadiaSan Andreas Fault Existing Planned Backbone PBO Clusters

8 Integrated Monitoring Systems GPS Permanent Stations Campaign Measurements Deep Borehole Strainmeters Shallow Tiltmeters Portable US Array (“hotfoot”)? Rapid Deployments Volcano Studies

9 N. Basin and Range/YellowstoneVolcano Deformation Kinematic Finite Element Model Smith and others, 2001 PBO Clusters: Detailed Models Mogi source and a closed pipe Dzurisin, 2001

10 Deformation across Basin and Range Velocity vectors observed with campaign surveys (big error ellipses) and continuous stations (small error ellipses) Bennett et al. 2001

11 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

12 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)

13 PBO Facility PBO science goals PBO: What is it? PBO opportunities for investigators UNAVCO: What is it? What does it have to do with EarthScope/PBO?

14 PBO Stations

15 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

16 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

17 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

18 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

19 USArray and PBO 180 Possible Collocated Sites GPS/Seismic Integration USArray PBO PBO + USArray

20 Joint USArray NSN/GSN/PBO sites

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

22 Tools for Data and Data Product Query and Retrieval GSAC Web-Based Query Form Data Retrieval Response GSAC Client Command-line Interface GPS Seamless Archive Centers

23 Opportunities PBO: What is it? PBO science goals PBO opportunities for investigators UNAVCO: What is it? What does it have to do with EarthScope/PBO?

24 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

25 Frequently Asked Questions Frequently Asked Questions FAQ Web Page answers questions about PBO

26 UNAVCO PBO science goals PBO: What is it? PBO opportunities for investigators UNAVCO: What is it? What does it have to do with EarthScope/PBO?

27 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

28 Investigator Support from UNAVCO Project Conception and Planning Network Architecture Infrastructure Requirements New Software and Hardware Development Budgets Pre-Installation Phase Design of permanent station systems Design of new antenna radome, power systems Purchasing, Fabrication, Testing, and Shipping Reconnaissance Development of data management systems Installation Monument drilling and installation Installation of GPS and repeater systems Verify data downloading and transfer, QC Network Operations Data Management Network Monitoring Network Maintenance Maintain operations database Archive and distribute data to community Archive velocity results and provide display tools Campaign Support Provide Equipment (15 receivers) In-field Training by field engineer Participate in making field survey Archive data

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