BUBBLING NEAR THE DOCK AT PORT ORFORD, SOUTHERN COASTAL OREGON-FLUCTUATIONS IN GAS PRESSURES FROM INCREASING AND DECREASING FOREARC COMPRESSION

A record of observed bubbling was kept by Hallmark Fisheries on the dock at Port Orford Oregon and compared to earthquakes. Sometimes bubbling was unobservable from wind or stormy weather, but many times observation was good. I compared observable bubbling in 1993, 1994, 1998-1999, 2003, 2004, 2005, 2006, 2007, and 2008 to the ANSS List. Bubbling days most often matched sequences of earthquakes in which bubbling (and some offshore and coastal earthquakes) occurred within several days before, during, and after earthquakes in especially the Gorda Plate-Gorda Ridge and Juan de Fuca Plate-Blanco Fracture. I used the model of increasing forearc compression between the Juan de Fuca Slab and the North American Plate through the Cascadia Subduction Zone Transition and Locked Zones to increase gas pressure with bubbling. Many times it seemed as if a tensional acceleration went up the slab dip, pulled the locked NAP tight with bubbling and continued in the unsubducted slab to pull the earthquakes off the coast. Sometimes, it bubbled when other increased directional forces moved through the slab. Some earthquakes were not related to forces for bubbling. Bubbling and no earthquakes maybe was increases in compressional forces in the North American Plate itself. The Port Orford dock is over the Transition Zone, about 13 km to the slab . On the surface, the Battle Rock Fault is about 63 km to the Deformation Front and about 22.5 km to the Locked Zone about 10 km depth. The gas vents in the NW striking Battle Rock fault near the dock at Port Orford respond by bubbling from an increase in force, and/or rapidity, that afterwards decreases to no bubbling. Although a slow deformational adjustment could decrease forces or affect the gas source if lasting pressures were exerted, forces most likely decrease during lulls in tectonic activity with no bubbling and no earthquakes.