PBO will install 103 Gladwin tensor strainmeters along the Pacific-North American plate boundary over the next four years. Drilling for the first borehole strainmeter, located in the Cascadia region of Washington, started in November 2004. Installing the first borehole station in Cascadia should allow capture of the next anticipated silent earthquake on the Cascadia subduction zone. In the second year of PBO, four new borehole strainmeters will be installed at Parkfield, eleven more in the Cascadia region, including four on Vancouver Island. The remaining strainmeters will be distributed so as to improve our understanding of tectonic and volcanic processes along the entire plate boundary. The focus areas will be the Pacific Northwest, the Mendocino Triple Junction, the San Francisco Bay Area, central and southern California, and Long Valley.

» PBO Borehole Strainmeters
» PBO Long-baseline Laser Strainmeters