- Copyright © 2003 Society of Exploration Geophysicists
EarthScope is a proposed new earth science initiative that will dramatically advance our physical understanding of the North American continent by exploring its three-dimensional structure and changes in that structure through time. By integrating scientific information derived from geology, seismology, geodesy, and remote sensing, EarthScope will yield a comprehensive, time-dependent picture of the continent beyond that which any single discipline can achieve. Cutting-edge land- and space-based technologies will, for the first time, resolve earth's structure and measure deformation in real-time at continental scales. These measurements will permit us to relate processes in the earth's interior to their surface expressions, including faults and volcanoes.
The Plate Boundary Observatory
The Plate Boundary Observatory (PBO), one of the core components of EarthScope, is a geodetic observatory designed to study the three-dimensional strain field resulting from plate boundary deformation. Such studies require that plate boundary deformation be adequately characterized over the maximum range of spatial and temporal scales common to active continental tectonic processes. PBO will do this by installing two types of geodetic instruments that overlap in sensitivity yet have broad temporal resolution, and by increasing the spatial scale and density of stations. The core of PBO is a permanent geodetic observatory consisting of a carefully designed and integrated network of strainmeters and GPS (Global Positioning System) receivers (Figure 1). The strainmeters are ideal for recovering short-term transient deformation, from minutes to a month, and will consequently play a central role in observing phenomena that accompany and precede earthquakes and volcanic eruptions. GPS is ideal for time scales greater than a month, thus covering long-period transients, such as those associated with viscoelastic relaxation following an earthquake, as well as decadal estimates of strain accumulation and plate motion and their spatial variations. Only an integrated deployment of these two instrument types is capable of providing temporal resolution over …