The Volcano (British Columbia)

At least two phases of volcanic activity have been identified at The Volcano. Each event was followed by the eruption of lengthy basaltic lava flows that flowed down steep granitic flanks of the mountain ridge on which The Volcano lies.[3][6] After this took place, they travelled through the Lava Fork valley for 5 km (3 mi).[3] Here, the flows crossed the British Columbia border into the U.S. state of Alaska and blocked the Blue River, a tributary of the Unuk River, forming several lakes.[3][9] The lava flows in total are about 22 km (14 mi) long and still contain their original features from when they cooled, including pressure ridges and lava channels. A series of large trees were engulfed by the lava flows during eruption. The bases of the trees burned and the upper trunks and branches collapsed into the solidifying lava, leaving the trees embedded on the surface of the lava flows. After the flows solidified, tree molds and lava tubes collapsed to form volcanic pits.[5] At the southern end of one of the lava flows, it spreads into a broad terminal lobe on the flat alluvial plain of the Unuk River.[6] Volcanic ash and lava from The Volcano still linger on small glaciers near Mount Lewis Cass, a 2,094-metre-high (6,870 ft) mountain near the Alaska–British Columbia border.[10]

A recently erupted pāhoehoe lava flow extending down the vegetated flanks of a mountain ridge. The alpine lake in the upper left corner is the southern lake of the two Lava Lakes.

At least one lava flow from The Volcano was notified by a surveyor named Fremont Morse in 1905 during a survey for the International Boundary Commission. In 1906, Morse wrote that the most recently erupted lava flow had "probably occurred within less than fifty years".[10] Since Morse's report, tree ring and radiocarbon dating techniques have been used to establish the dates of The Volcano's two volcanic phases. The first is estimated to have occurred about 360 years ago and the latest possibly took place only 150 years ago.[5][6] This indicates that The Volcano is the youngest known volcanic mountain in Canada and that its volcanic activity is recent compared to many other volcanoes in British Columbia.[5] In several documents, the last eruption of The Volcano is written to have occurred in 1904.[11][12] However, according to the Smithsonian Institution's Global Volcanism Program, this eruption is considered uncertain.[2]

Although The Volcano is estimated to have last erupted 150 years ago, it is one of the five volcanoes in the Northern Cordilleran Volcanic Province that have recorded seismicity since 1985. Others include Castle Rock (two events), Hoodoo Mountain (eight events), Crow Lagoon (four events) and the Mount Edziza volcanic complex (eight events).[13] Seismic data suggest that these volcanoes still contain active magma chambers, indicating that some Northern Cordilleran volcanoes are probably active, with significant potential hazards.[13][14] The seismic activity corresponds both with some of Canada's recently formed volcanoes and with persistent volcanoes that have had major explosive activity throughout their history, such as Hoodoo Mountain and the Mount Edziza volcanic complex.[13]

The name of the peak was suggested by an explorer named Chris Dickinson during the Cambridge Coast Mountains Expedition in 1979. It was adopted on November 24, 1980, and has been its official name since then.[1] However, this name for the peak does not normally show up in any volcanological resources. Instead, it is informally referred to as Lava Fork or Lava Fork volcano due to its close association with the creek of the same name.[1][3][5] The reason for this controversy is because The Volcano is generic. In speech it may not be obvious whether The Volcano or the volcano is intended, leading to confusion. Similar named volcanoes in Canada include Volcano Vent in the Tuya volcanic field of northwestern British Columbia and Volcano Mountain in the Fort Selkirk volcanic field of central Yukon.[6][15] As of 2009, the unofficial terms for The Volcano continue to be used by Natural Resources Canada.[5]

The Volcano, its eruptive products and a large mineral spring are protected in Lava Forks Provincial Park. Founded in 2001 as a Class A provincial park, this highly remote park covers an area of 7,000 ha (17,000 acres). Lying within its boundaries are the Lava Lakes, two lakes dammed by lava flows erupted from The Volcano. Located in asserted traditional territory of the Tahltan First Nation, Lava Forks Provincial Park provides a location to study ecological processes associated with primary succession or the establishment of vegetation after a major disturbance. After 150 years of non-eruptive activity, vegetation has grown on the surface of the lava flows, including mosses and lichens. Western Hemlock, Mountain Hemlock and Alpine tundra biogeoclimatic subzones also occur in the area, which form part of the Boundary Ranges Ecosection.[11]

Like other Iskut-Unuk River Cones, The Volcano is not monitored closely enough by the Geological Survey of Canada to ascertain its activity level. The Canadian National Seismograph Network has been established to monitor earthquakes throughout Canada, but it is too far away to provide an accurate indication of activity under the mountain. The seismograph network may sense an increase in seismic activity if The Volcano becomes highly restless, but this may only provide a warning for a large eruption; the system might detect activity only once the mountain has started erupting.[16] If The Volcano were to erupt, mechanisms exist to orchestrate relief efforts. The Interagency Volcanic Event Notification Plan was created to outline the notification procedure of some of the main agencies that would respond to an erupting volcano in Canada, an eruption close to the Canada–United States border or any eruption that would affect Canada.[17]

A small range of effects are expected from future eruptions at The Volcano. Its remote uninhabited location makes volcanic hazards less extreme and is therefore not very hazardous. Ash and rock fragments (tephra) ejected during lava fountain activity are unlikely to be high enough to disrupt regional air traffic. However, they could possibly endanger lower flying aircraft along the northern coastal corridor between Vancouver and Alaska.[5] The closest major air route is about 170 km (110 mi) to the east.[19] Volcanic ash reduces visibility and can cause jet engine failure, as well as damage to other aircraft systems.[20]

Lava flows emitted during future volcanic eruptions would likely be basaltic in nature based on the composition of its lavas produced during past volcanic activity.[5] Basaltic lava flows are low in silica content and can spread rapidly and move quickly downslope.[21] The last eruption at The Volcano 150 years ago had a large impact on fish, plant and animal inhabitants in the valley the lava flows travelled through to cross the Canada–United States border.[22] Because of these circumstances, future eruptions may again block the flow of local water courses if the volume of the erupted lavas are significant enough. This would again have disastrous consequences for fish habitats and spawning grounds.[5] However, there are neither records of any impacts on people during this eruption, nor evidence that it was even witnessed by people.[22] A repeat of wildfires in the Lava Fork valley is also a possibility due to the existence of vegetation on and around the erupted lavas.[11]