Kyle Bohnenstiehl

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Plate Boundary Observatory Component Of the
EarthScope Project

• Kyle Bohnenstiehl
• PBO Reconnaissance and Permit Coordinator

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Talk Summary

• EarthScope Overview
• PBO Science Objectives
• PBO Operations Overview
• PBO Data Management Overview

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EarthScope Science Goals

• National Science Foundation Funded Observatory to
  Explore the Structure and Dynamics of the North
  American Continent
• Structure and evolution of the continent and deep
  Earth
• Earthquake processes and seismic hazards
• Magmatic processes and volcanic hazards
• Active deformation and tectonics
• Continental geodynamics
• Fluids in the crust
• Exploration and discovery

Requires an Interdisciplinary Approach
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Multi-use Facility

• Facility designed to address a multitude of
  scientific questions from a wide spectrum of
  Geoscience disciplines

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Components

• SAFOD San Andreas Fault Observatory at Depth
• 1) Vertical seismic array in Pilot Hole
• 2) Instrument drill hole near fault (within
  700m)
• 3) Instrument drill hole within active fault
  zone
• PBO Plate Boundary Observatory of geodetic
  sensors
• 4) Network of 100 Backbone GPS stations
• 5) Network of 775 Permanent GPS stations
• 6) Network of 175 Borehole strainmeters
• 7) Pool of 100 campaign GPS instruments
• 8) Geo-EarthScope Geochronology Images
• USArray Seismic arrays across the continent
• 9) Network of 39 ANSS Backbone Network stations
• 10) Network of 400 Transportable Array stations
• 11) Pool of 2400 campaign seismic instruments

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SAFOD
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SAFOD
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SAFOD
Luke Blair, USGS
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USArray
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USArray
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PBO
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PBO Science Objectives

• Determine through geodetic observations of the
  plate boundary
• the forces that drive plate-boundary deformation
• the spatial distribution of plate-boundary
  deformation
• how plate-boundary deformation has evolved
• the space-time pattern of earthquake occurrence
• how do earthquakes nucleate
• the dynamics of magma rise, intrusion, and
  eruption
• how to reduce the hazards of earthquakes and
  volcanic eruptions

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PBO Facility Objectives

• Provide high quality geodetic data and data
  products to meet the aforementioned scientific
  objectives by
• Installing a network of high-precision,
  continuously operating permanent GPS stations.
• Installing networks of deep drilled borehole and
  long baseline strainmeters, seismometers, and
  tiltmeters.
• Installing and operating the PBO Component of
  EarthScope on budget, schedule, and specification
• Listening to the PBO geodetic and broader
  EarthScope geoscience community and modifying our
  operation and data management plans to meet
  changing scientific needs
• Keeping a focus on the integrated EarthScope
  approach by working closely with USArray and
  SAFOD partners.

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Measurements

• What does GPS measure?
• High precision GPS measures the distance and
  change in distance (displacement) between
  permanent GPS stations to within a fraction of a
  millimeter over baselines 100s of kilometers
  long.
• Strain is the change in the length of the line.
• Changes in the length of the line over time gives
  strain rate.
• Station displacement, strain, and strain rate
  provide information about earth processes at the
  surface and at depth.

• What do strainmeters measure?
• Strainmeters measure changes in length (strain)
  across a six-inch borehole using a very sensitive
  instrument buried at 200m depth.

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Science Example - Transients

• Science example Slow and Silent(?) Earthquakes
  in the Pacific Northwest imaged using GPS .
• GPS networks on the Pacific northwest routinely
  measure 37 mm/year convergence rate on the
  presumed locked fault zone between the Juan de
  Fuca plate and the North American plate.
• Since 1992, continuously operating GPS stations
  in Canada and the Pacific Northwest have been
  recording a fairly steady state northeast
  migration of the stations landward.

North
East
Dragert et al., 2001.
1999
2000
2001
2002
Time series courtesy of SOPAC
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Science Example

• In the summer of 1999, Herb Dragert and his
  colleagues noticed that a cluster of seven GPS
  sites briefly reversed their direction of motion.
  
• They first believed the reversal was a
  consequence of aseismic, episodic slip on the
  deeper portion of the fault beneath North
  America. Slip event initiated near Seattle and
  propagated to the northwest along the plate
  boundary affecting a 50 km by 300 km fault area
  over a period of 35 days.

Dragert et al., 2001
Dragert et al., 2001.
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Science Example

• Meghan Miller and her colleagues at Central
  Washington University looked farther back into
  the Pacific Northwest GPS record and noted gt 8
  slow and silent events occurred since 1992.
• Each event started over a 3-week period and
  lasted 2 to 4 weeks at any one station.
  Propagation of the slow earthquakes across the
  affected region may last for up to 8 weeks. The
  slow earthquakes occur on average every 14.5 ? 1
  months over the past 10 years.

Miller et al., 2002.
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Science Example
Dragert et al., 2003.
Examination of the past 6 years of digital
seismic records revealed a remarkable
correlation of tremor activity with slip events
observed in the Victoria region. The apparent
regularity of tremor and slip led us to expect
the most recent event, which occurred in March
2003.
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Science Example

• New data processing by Meghan Miller and her
  colleagues indicates the slow earthquakes are
  possibly recorded along the entire subduction
  zone.

Courtesy of Miller and Melbourne, unpublished
data .
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Science Example - Conclusion
Dragert et al., 2001.
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Network Overview
Network Overview

• 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
• 16 backbone sites in eastern US at 400 km
  spacing
• Portable GPS receivers
• Pool of 100 portable GPS receivers for temporary
  deployments to areas not sufficiently covered by
  continuous GPS
• Earthscope/Geology
• Lidar Imagery and Archive, Geochronology

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Operations Summary

• Project broken down into 6 regional offices.
• Regional offices take advantage of regional
  expertise.
• Provides flexible resources (i.e. crews migrate
  between regions as needed)
• Regional Engineers issue subcontracts as needed.
• Regional Engineers interface with Survey
  Community

winter
summer
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Station Installation Goals
Equipment (10) 10 Procurement and
assembly Siting (40) 5 Siting 10 Reconnaissanc
e 10 Permit submitted 15 Permit
accepted Installation (40) 20 Monument
installation 15 Equipment installation 5 Site
commissioning Data flow (10) 5 Data
flow 5 Product generation
Year 1
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Science and Construction Blueprint

• Science Specification
• Peer-reviewed PBO mini proposals condensed into
  the PBO White Paper
• Provides the science blueprint that must be met
  by the observatory
• Operational (construction) Specification
• Peer-reviewed MREFC PBO proposal
• Provides the construction blueprint designed to
  meet the scientific needs
• EarthScope Project Execution Plan (PEP)
• Provided cost, schedule, specification and change
  control mechanisms

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Site Selection Working Groups

• PBO Site Selection Working Groups recommend how
  the Observatory responds to changing science
  needs
• PBO Siting Committees provide broad guidance to
  PBO Director on station installation priorities.
• Committees provide recommendations to PBO
  Director on specific siting issues.
• Committees will choose Geo-EarthScope image
  targets
• Committees provide recommendation on which
  existing network sites will become part of and
  funded by PBO

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PBO Program Management
ES
NSF MREFC PAC
ESEC
NSF EarthScope Program Officer TBH
EarthScope Project Director Greg Van derVink
EFEC IRIS,UNAVCO,SAFOD
UNAVCO Inc President Will Prescott
PBO Standing Committee
UNAVCO Inc Board
UNAVCO Executive Director Wayne Shiver
PBO Committees Transform, Extension, Subduction,
Magmatic, Data/Products, Equipment
PBO
PBO Director Mike Jackson
PBO Data/Products Manager Greg Anderson
PBO Operations Manager Karl Feaux
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Staff Introductions
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Instrumentation

• GPS
• Low power GPS receivers and Choke Ring antennas
• Deep and Short-drill braced monuments. Others on
  case-by-case basis.
• Power DC solar option for wind. AC backup.
• Telemetry combination of direct and satellite
  internet, microwave, and radio modem. VSAT and
  radio proposed for Aleutians.
• Nominal 24-hour, 15-sec data file downloaded
  daily.
• 1-5 Hz buffered binex.

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GPS Monuments
Monument drilling
Moderate impact Deep Drill Braced
GPS Monument
Monument installation
Final site
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GPS Monuments
Low impact Short Drill Braced GPS
Monument
Monument drilling
Monument installation
Final site
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Talk Summary

• Overall Objectives
• PBO Management and Staff
• PBO Operations Overview Siting
• Reconnaissance
• Permitting
• Installation
• PBO Data/data Products Overview

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Benefits to Federal Agencies

• RTK data supplied through the serial port
• Agency provides power and equipment (radio)
• Survey control/Geodetic Control
• Useful for land surveys
• PBO monument is very stable and has known
  velocity vectors
• PBO GPS data is freely available as a 24hr, 15
  second GPS data file for post-processing of GPS
  data
• Similar model to NGS/CORS data
• Information about seismic activity and plate
  movement
• EarthScope Education and Outreach activities
• Availability of climate data from meteorological
  instruments on some stations
• Strainmeter installations provide water level
  information

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RTK Configuration
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PBO Siting and Permitting Strategy with Federal
Agencies

• PBO has flexibility in siting
• Wish to avoid sensitive areas and locate on
  disturbed ground
• Site security is important
• Good satellite visibility
• Siting tolerance buffer
• Varies by site- radius of 5km to 70km
• PBO would like to have the GPS sites operational
  for 10 years

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PBO Siting Workflow

• Siting plan based on PBO mini-proposals
• Potential station locations can be input on-line
  by general public, science community, or PBO
  personnel via web interface.
• Station location tolerance provide site selection
  flexibility.
• Sites out of station location tolerance need
  siting committee review.
• Simple 1-5 system for tracking siting status

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Siting Tolerance Buffers
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How to find out where PBO sites can go

• PBO can provide GIS files of GPS sites and
  buffers
• PBO on-line internet map server
• http//arcims.unavco.org
• Allows for the public to view site locations
  and buffers in the context of roads, towns, and
  other GIS data
• Users can lasso sites and copy and paste site
  coords into Excel or other application
• PBO can provide other GIS analysis if required by
  land owners

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How to submit a site for consideration

• Online web interface accessible from
• http//www.unavco.net/public/recon/submitinfo.aspx
  
• Can be found easily from www.unavco.org under the
  PBO section
• Call the PBO permitting hotline [phone]
• Email kyleb_at_unavco.org
• Ideally we want sites that are in the siting
  buffer area
• After the site is submitted a regional engineer
  will schedule a site visit
• If the site is suitable, permitting will begin

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Data and Data Products Overview

• Data Archives
• Two GPS data archives one at SOPAC one at UNAVCO
  Facility.
• One strainmeter archive at UC Berkeley
• Data Products
• Two funded GPS processing facilities awarded on
  competitive basis.
• One Analysis Center Coordinator awarded on
  competitive basis
• One strainmeter QC and data processing facility

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Data Flow
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PBO Data Products

• Level 0 Raw data Metadata
• Level 1 Processed data
• GPS station position time series
• Automatically corrected scaled gauge data
• Level 2 Derived quantities
• GPS station velocities
• Human corrected scaled linear/tensor strain
• Time series noise properties
• Properties of periodic time series components

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PBO Data Policy

• PBO data products freely available to community
  as rapidly as possible
• Survey-mode data products have 2-year hold
• PBO Software License governs all software
  developed by or with funding from PBO
• Source code freely available to US
  academic/non-profit community
• No PBO software may be used commercially
• Users must acknowledge PBO and NSF as sources for
  PBO data/products
• Other networks getting PBO support must follow
  this policy

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PBO Web Page
www.unavco.org/PBO/PBO.html