Blanco fracture zone

[4] The principal feature of the eastern portion of the zone is the Blanco Ridge,[5] a 150 km right lateral-moving fault that is responsible for the largest earthquakes in the region.

The western part of the zone is made up of a series of depressions separated by transform fault ridges.

[8] The West Blanco Depression is shallow in the south, reaching only a depth of 3400 m, but quickly reaches depth near the Juan de Fuca Ridge, dropping down to 4800 m. This basin is at a slightly different angle than the other western depressions, likely due to interference from the Juan de Fuca Ridge.

[7] Most large events in this zone occur on the Blanco Ridge, as the motion on this fault accounts for the majority of the plate movement.

[5] Tectonic activity in the central part of the zone is weaker and deeper than on the Blanco Ridge.

Further investigation revealed an active hydrothermal vent, the first of its kind to be discovered in a transform fault zone.

On April 23, activity moved to the Blanco fault zone itself, near its junction with the Gorda Ridge.

[12] In December 2021, a swarm of earthquakes occurred on the northwest portion of the Blanco fracture zone, with multiple being stronger than magnitude 5.