Update on Plate Boundary Observatory (PBO) Activities in the PNW Region Abstract


  • As of January 2006 The Plate Boundary Observatory (PBO), part of the larger NSF-funded EarthScope project, is 4 months into year 3 of the installation phase of 875 continuous GPS instruments in the Western United States. The PBO plan for the Pacific Northwest (PNW) region calls for the installation of 126 continuous GPS stations by the year 2008. These sites are largely distributed along the Cascadia Subduction Zone and at Mt. St. Helens. As of January 31st, 2006, the PNW Region of PBO has installed 46 GPS monuments. These PBO stations are operating throughout the states of Washington and Oregon. The scientific emphasis during year 3 continues to be installation of GPS sites in southern and coastal Oregon, on the Olympic peninsula and on Mt. St. Helens. Other sites will be installed where permits were available. Monitoring of the Mt. St. Helens volcano, including data analyses from the five sites installed in October 2004, showed that one of the PBO sites located high on the SE flank of the volcano moved 4 cm SE between mid-November 2004 and January 2005. This was most likely due to growth of the new lava dome against the SE crater wall. As a result of this activity, the PBO obtained two additional permits from the USFS, and these sites were installed at the beginning of February, 2005. PBO has continued to work with the USFS to complete the permitting process for nine more GPS locations on the flanks of the volcano. Due to required cultural and botanical surveys, these permits are not expected to be approved until at least June of 2006. During Year 3 of the PBO project, the pace of installations continues to increase. In the PNW region, this translates into approximately 4 new GPS installations per month. In addition to continued construction, activities will focus on completing reconnaissance and permit submittal activities for all sites proposed to be located on Federal and State Lands. We plan to have all of these permits in the approval process by the end of September of 2006. The PNW is currently on target in reconnaissance and permitting activities.

publication date

  • 2006

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