Master event relocation of Gorda Block earthquakes: Implications for deformation

We have used the “master‐event” technique to relocate 73 earthquakes in the northern half of the Gorda block. The revised epicenters indicate a systematic eastward bias of ∼30 km in epicenters as published in the ISC Bulletin. The new seismicity pattern reflects a more symmetric distribution of earthquakes about the Gorda Rise, and a reduced degree of seismicity within the Gorda block. Although the level of intraplate activity has apparently been reduced, a significant number of events (10–20) still appears to be related to intraplate deformation. Further relocation studies, coupled with focal mechanism determinations, are necessary to better constrain deformation models for this region.