49 pages. A thesis presented to the Department of Physics and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017Zones of reduced ‘Episodic Tremor and Slip’ along the Cascadia Subduction Zone (CSZ) are known to correspond to fluids anomalies at the Juan de Fuca-North American plate interface. We process Magnetotelluric models of the conductivity of the CSZ to isolate conductivity values adjacent to plate interface, as well as to compute a vertical conductivity ‘gradient’ away from the interface. We compare the average conductivity and non-volcanic tremor density in windows of various sizes along the Mantle Wedge Corner (MWC) and compute their correlation. Tremor and conductivity correlate moderately along a window extending 100km up-dip from the MWC. The correlation is weaker for windows of different sizes or those centered down-dip, which suggests a coupling mechanism along the interface up-dip of the MWC, linking conductivity and tremor occurrence. The conductivity gradient is anomalously low surrounding regions where serpentinization reactions are known to take place. Finally, we investigate the regions near crustal faults, around which tremor occurrence is suppressed. We find that conductivity anomalies do not consistently occur around these faults, and thus that the effect of these faults on tremor is likely mechanical
