Covering western North America and Alaska, EarthScope's network of high precision Global Positioning Systems (GPS) and Strainmeter stations will measure deformation across the active boundary between the Pacific and North American plates.
PBO Project Pages
Instrument Data
Data Products
The Plate Boundary Observatory (PBO) component of EarthScope is a geodetic observatory designed to study the three-dimensional strain field resulting from deformation across the active boundary zone between the Pacific and North American plates in the western United States.
More Info
The PBO mission is to site, recon, permit, install, and maintain 852 GPS, 103 borehole strainmeters (BSM), and 5 laser strainmeters (LSM) on-schedule, on-budget, and to specification within 5 years. Taken together, these instrument types span the broad temporal and spatial spectrum of plate boundary deformation anticipated in the project area. The geodetic focus of the Plate Boundary Observatory will address the following scientific questions:
- › What are the forces that drive plate-boundary deformation?
- › What determines the spatial distribution of plate-boundary 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?
GPS measures millimeter-scale ground movement on time scales of days to decades and over large spatial scales.
Borehole strainmeters measure strain change by sensing changes in the shape of an instrument cemented into rock. They play a central role in observing the deformation that accompanies and precedes earthquakes and volcanic eruptions.
Long-baseline laser strainmeters measure the change in distance between two points several hundred meters apart on the Earth's surface. Laser strainmeters have the high resolution of the borehole strainmeters combined with the long-term stability of GPS measurements.
Status
To date, the PBO network includes 886 GPS instruments of which 165 are PBO Nucleus, 3 Long-Baseline Laser Strainmeters, 31 Borehole Strainmeters, 30 Borehole Seismic instruments, and 4 tiltmeters dispersed across the western United States and Alaska.
Observatory Facility
UNAVCO, a non-profit, membership-governed consortium, supports and promotes Earth science by advancing high-precision techniques for the measurement and understanding of deformation. UNAVCO also supports education to meet the needs of the community and the public.
