Ash from the eruption spread west-northwest of Kurile Lake, covering a total surface of over ; it can be found at large distances from the caldera; layers have been found in the upper reaches of the Indigirka River, away from Kurile Lake. Thicknesses still reach several centimetres in Magadan. In the northern Kuriles, the thickness reaches several tens of centimetres. This ash is found in drilling cores in the Sea of Okhotsk. Coignimbrite ash formed when the ignimbrites reached the sea. In terms of composition, it ranges from rhyolite to dacite and is poor in potassium. The ash is an important tephrochronological marker and has been found as far away as Greenland.