Subduction zones: The sites on Earth where convergent tectonic plates meet and one plate is forced to slide under the other, thereby sinking into the Earth’s mantle.

Subduction Zone Hat is a reversible design worked in two-colour brioche stitch with stripes of double knitting. The wavy brim and spiralling movement of the stripes over the brioche background are achieved with decreases and increases placed at the boundaries of the different stitch patterns.

Skills required
Two-colour brioche knitting in the round (including increases and decreases), double knitting basics. The pattern includes a photo tutorial explaining the necessary brioche decreases and the finishing stitches of the crown.

Measurements
Circumference, unstretched: 47 cm/18½’’ (52 cm/20½’’)
Length (fitted hat): 20 cm/8’’
Length (beanie): 24 cm/9½’’
(The first pictures show the fitted hat of the larger size worn on a head with 57 cm circumference.)

Yarn requirements
Approximately 85 m/93 yards (95 m/104 yards) of each colour
for the fitted hat and 110 m/120 yards (120 m/131 yards) of each colour for the beanie.

Subduction Zone Hat is the first in my upcoming series of brioche patterns themed around Danish geoscientist Inge Lehmann (1888–1993), who discovered the solid inner core of the Earth.

Thank you to Jo Torr for technical editing and to my test knitters for their excellent work and helpful feedback.