Résumé
The Gofar transform fault of the East Pacific Rise, generates a M (sub W) approximately 6 earthquake every 5 to 6 years on short ( approximately 20 km) along-strike segments separated by a barrier zone. Therefore, the Gofar Transform fault presents the opportunity to investigate the relation between fault structure and material properties of this fault to earthquake processes. Here, we develop new three-dimensional seismic velocity models (V (sub P) , V (sub S) and V (sub P) /V (sub S) ) of the easternmost segment of the Gofar transform fault using two-year long OBS data collected in 2020. The fault zone is characterized by a 9-km wide low-velocity zone (delta V approximately -20%) extending through the entire crust. This low-velocity zone may reflect a high density of fractures and/or mineral alteration (seawater infiltration?). The V (sub P) /V (sub S) model shows along-strike variations within the crust and the 2020 M (sub W) 6.1 hypocenter is located in a high V (sub P) /V (sub S) zone (> 1.9). We also provide Moho depth estimates (derived from our velocity models) around the fault zone. Moho depth estimates range between 7 and 10 km depth below sea level. Interestingly, we note that most of the seismicity is located beneath the inferred Moho.