potentially active complex southwestern british_columbia canada located kilometres northwest city vancouver kilometres west largest western canada measuring kilometres long north south kilometres wide east west mount eroded lava dome northern flank metres high highest volcano canada main glaciers area glaciers lies largest southern half southwestern british_columbia mid-1980s global warming nearly half drained feeds remote rarely visited studied reached helicopter major difficulty hiking river valleys extending geology group deeply eroded complex called franklin volcano merges northwest belt volcanic fields extending near canada united_states border east vancouver thought bodies associated volcanic active early stages juan plate notable exception rocks mainly bodies broader scale rocks single largest granite north_america rocks extend approximately kilometres coast british_columbia southwestern remnant vast volcanic arc called coast range arc formed result periods contrast mount areas recent volcanic origin structure like formed result chamber beneath volcano erupted emptied chamber able support weight volcanic roughly circular fracture ring fault develops edge chamber ring serve fault known ring secondary volcanic form ring fracture chamber center volcano ring fracture begins collapse collapse occur result single eruption occur stages result series total area collapses hundreds thousands square kilometers steep contacts thick basal older rocks adjacent peaks suggest fill succession presence irregular adjacent country rock provide evidence potassium dates years lava basal consistent high rates erosion recorded origins largely unexplained causes produced matter ongoing research hawaii product zone found volcano zone issue current plate configuration rate chemistry indicates related zone long plate boundary separates juan explorer north american plates oceanic crust pacific_ocean beneath north_america rate millimetres year hot descending oceanic plate creates million years estimated zone existed million years time created line called stretches kilometres zone arc potentially active known historic arc united_states recent major eruption site canada recent major eruption years ago mount volcanic complex history little known history explosive nature involving glowing hot volcanic ash flows source rock classified acidic having high intermediate levels commonly associated forms explosive called considerably younger nearest prominent neighbour east southeast products heavily eroded alpine glaciers exposed slopes extending near sea level elevations metres bulk complex appears erupted years ago lava flows present old potassium dates years obtained large lava flow kilometres long creek valleys lava flow clearly younger potassium date high energy glacial streams begun channel margin lava flow younger rocks issued cluster ice covered ranged periphery high elevations eroded rest coarse derived older parts volcanic complex presence glacial deposits flow suggest years old particular index unknown chemistry structure volcano compared history producing world violent kilometres long kilometres wide oregon united_states kilometres long kilometres wide usually formed large reaching volcanic index described super current activity canadian associated recent seismic activity volcano seismic data suggests contain live systems indicating possible future activity available data allow clear conclusion observations indications canada potentially active associated hazards significant seismic activity canada youthful long lived volcanic centers history significant explosive behavior volcanic hazards volcanic canada rarely cause fatalities low level activity known fatality volcanic activity canada occurred cone kilometres long lava flow traveled destroying village killing approximately people volcanic gases towns cities south home half british_columbia human population likelihood future cause damage populated areas making belt south major potential hazard reason additional projects study belt south planned significant hazards canadian require hazard maps emergency plans exhibit significant seismic activity appear likely significant eruption belt significantly impact highway communities like possibly vancouver explosive explosive nature past suggests volcano poses significant long distance threat communities canada large explosive eruption produce large amounts ash significantly affect communities canada ash columns rise meters volcano hazard air traffic coastal vancouver alaska volcanic ash reduces visibility cause jet engine failure damage aircraft systems addition fall effect surrounding volcano melting glacial ice cause debris flows turn water supplies local water sources lava flows region remote exceptionally rugged danger lava flows low moderate high intermediate levels commonly slowly typically cover small areas form steep sided called lava lava grow individual flows metres thick period months years flows overlap typically meters hour lava intense cascade lava flows high intermediate levels rarely extend kilometres source produced kilometres long lava flow creek valleys evidence lava flows partly blocked altered course renewed activity area disrupt course river impact people living working downstream volcanic gas volcanic gas includes variety substances include gases trapped volcanic rocks dissolved gases lava gases directly lava indirectly ground water heated volcanic action volcanic gases pose greatest potential hazard people animals agriculture property dioxide carbon dioxide hydrogen locally dioxide gas lead acid rain air pollution volcano globally large explosive tremendous volume lead lower surface temperatures promote weakening earth layer carbon dioxide gas heavier air gas flow low lying areas collect soil concentration carbon dioxide gas areas lethal people animals vegetation monitoring currently monitored closely active volcano system existing network established monitor earthquakes far away provide good indication happening beneath sense increase activity volcano restless provide warning large eruption detect activity volcano started possible way detect eruption studying geological history volcano pattern behavior terms eruption style magnitude frequency future eruption expected similar previous likely abandoned volcano likelihood canada critically affected local close volcanic argues kind improvement program required benefit cost thoughts critical dealing natural hazards benefit cost examination needs correct data hazard types occurrences exist british_columbia canada detail required volcanic techniques hazard mapping displays volcano history detail speculates understanding hazardous activity possibly expected future present hazard maps created level knowledge insufficient large volcanic hazard program existed majority information collected lengthy separate way support employees scientists current knowledge best established likely rise considerably temporary mapping monitoring project knowledge established certain contributions intensive program exposure near young canadian quick hazard assessments individual volcanic associated recent seismic activity advance produce quick productive determination priority areas efforts existing network monitor earthquakes existed remained small population apart short term seismic monitoring experiments volcano monitoring accomplished canada level approaching established countries historically active active restless usually monitored approximately kilometres frequently kilometres better sensitivity detection reduced location errors particularly earthquake depth monitoring risk eruption offering capability important volcanic risk currently closer kilometres increasing distance declining numbers indicate seismic activity prediction capability reduced earthquake location depth measurement accuracy decreases inaccurate earthquake locations kilometers isolated northern regions kilometres location magnitude level magnitude magnitude carefully monitored located noticed events recorded surveyed immediately improve understanding future eruption events recorded surveyed british_columbia immediately easy access process countries like canada possible small precursor earthquake particularly events observed significant events larger detected minor subdivision events complex clarify confidence volcanic nature associate individual volcanic
Silverthrone Caldera