シーアスク山

The basaltic Tseax River cinder cones (Aiyansh volcano) at the southern end of the Stikine volcanic belt have been the site of some of the youngest volcanic eruptions in Canada. Nested cinder cones lying along a tributary of the Nass River were the source of a lava flow that traveled into the Tseax River, damming it and forming Lava Lake. The flow subsequently traveled 11 km N to the Nass River, where it filled the flat valley floor for an additional 10 km. Native legends of the Nisga'a People tell of a prolonged period of disruption by the volcano, including the destruction of their village on the Nass River and the death of some people from "poison smoke." The vent was active at least twice (625 and 220 radiocarbon years ago) and other remnants of lava flows exist in the area, which was designated the Nisga'a Memorial Lava Beds Provincial Park in 1993 (Hickson and Edwards, 2001).