Map view of imaged slab structure and seismicity in the northern Vancouver Island region. Note the clear alignment between a drop in the top of subducting crust and Moho depths on PD02 and PD03 across earthquake lineations denoting the Exp and JdF slab tears, respectively (blue outlines). The Exp tear is inferred (dashed blue line) as extending to its northern slab edge near Brooks Peninsula. Earthquake epicenters from (40–43) are shown in dark green. Low-frequency earthquakes from (90) are shown in pink diamonds; note that they terminate abruptly at the projected NFZ trace, suggesting Exp slab decoupling. (A) Depth to top of crust horizon along CASIE21 profiles. (B) Depth to oceanic Moho along CASIE21 profiles.

[7/8] À l’échelle humaine, le risque reste inchangé : Cascadia peut encore produire de très puissants séismes et tsunamis. Mais savoir comment ces nouvelles failles influencent la propagation des ruptures affine les modèles de prévision des aléas sismiques. #geography #VancouverIsland #NootkaFZ

Slab tearing and segmented subduction termination driven by transform tectonics Transform faults act as tectonic segmentation boundaries, enabling diachronous slab detachment and subduction termination.

[1/8] Des chercheurs montrent, grâce à des images sismiques inédites, qu’au large de l’île de Vancouver la subduction de la plaque Juan de Fuca est en train de se déchirer. #geography #tectonics #subduction #earthquakes #VancouverIsland #NootkaFZ #PacificNorthwest