Canadian Volcanoes
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Volcanoes of Canada 1 V4 C.J. Hickson and M. Ulmi, Jan. 3, 2006 Presentation Outline 2 V4 • Global Volcanism and Plate tectonics Where do volcanoes occur? Driving forces • Volcano chemistry and eruption types • Volcanic Hazards Pyroclastic flows and surges Lava flows Ash fall (tephra) Lahars/Debris Flows Debris Avalanches Volcanic Gases • Anatomy of an Eruption – Mt. St. Helens • Volcanoes of Canada Stikine volcanic belt Anahim volcanic belt Wells Gray – Clearwater volcanic field Garibaldi volcanic belt • USA volcanoes – Cascade Magmatic Arc Global Volcanism and Plate tectonics 3 V4 Volcanoes in Our Backyard In Canada, British Columbia and Yukon are the host to a vast wealth of volcanic landforms. Global Volcanism and Plate tectonics 4 V4 How many active volcanoes are there on Earth? • • • • • Erupting now Each year Each decade Historical eruptions Holocene eruptions (last 10,000 years) about 20 50-70 about 160 about 550 about 1500 Although none of Canada’s volcanoes are erupting now, they have been active as recently as a couple of hundred years ago. 5 V4 Global Volcanism and Plate tectonics The Earth’s Beginning Global Volcanism and Plate tectonics The Earth’s Beginning These global forces have created, mountain ranges, continents and oceans. ntal contine t cr us a nic oce us t cr 6 V4 mantle 7 V4 Global Volcanism and Plate tectonics Where do volcanoes occur? 8 V4 Global Volcanism and Plate tectonics Driving Forces: Moving Plates 9 V4 Global Volcanism and Plate tectonics Driving Forces: Subduction 10 V4 Global Volcanism and Plate tectonics Driving Forces: Hot Spots Global Volcanism and Plate tectonics Driving Forces: Rifting Ocean plates moving apart create new crust. The longest volcano in the world is the Mid 11 Atlantic ridge! V4 Volcano Chemistry and eruption types 12 V4 Volcano Schematic and Chemistry Some basic terminology used to describe volcanoes. Depending on the type of lava erupting, different types of volcanoes will form. The lava is classified by the amount of silica dioxide it contains. Basalt Andesite 45-52% 52-63% Dacite Rhyolite 63-68% >68% least explosive most explosive most fluid least fluid Volcano Chemistry and eruption types 13 V4 Volcano Types Volcanoes come in a variety of shapes and sizes. These names are used to define them. Volcano Chemistry and eruption types 14 V4 Relative Size of Volcano Types 190km/120 mi. Volcano Chemistry and eruption types 15 V4 Shield vs. Composite volcano Needs replacement/upgrade Stratovolcanoes are known for their powerful, explosive eruptions, but they are small in size relative to shield volcanoes, the largest volcanoes on earth. Volcano Chemistry and eruption types 16 V4 Eruption Types • • • • • • • • Hawaiian Strombolian Vulcanian Pelean Plinian Surtseyan Subglacial Caldera Forming Volcano Chemistry and eruption types 17 Lava Compositional Differences Basalt Andesite 45 - 52% 52 - 63% Dacite Rhyolite 63 - 68% >68% Due to compositional differences, lava erupts differently V4 - either explosively, or more passively as flows. Volcano Chemistry and eruption types 18 V4 Lava Flows Basaltic lavas are among the least viscous. Large areas of central British Columbia are covered with basaltic lava flows. Volcano Chemistry and eruption types 19 V4 Lava Rivers Low viscosity basaltic lava can flow for 10’s of kilometres Volcano Chemistry and eruption types 20 Smooth, Ropey Lava – Pahoehoe The surfaces of basaltic lava flows varies. Often it is smooth or ropey. V4 Volcano Chemistry and eruption types 21 V4 Rubbly Surface, Rough and Jagged – Aa Lava Another common form of basaltic lava. 22 V4 Volcano Chemistry and eruption types Lava flows with gas bubbles Volcano Chemistry and eruption types 23 V4 Shield Volcanoes Most shield volcanoes are formed of fluid basaltic lava flows, therefore, the edifices are not as visually dramatic as stratovolcanoes. Their volumes can exceed that of stratovolcanoes by several orders of magnitude and they often form during single long-term effusive eruptions. The Ilgatchuz range in west central British Columbia is an example of a shield volcano. Volcano Chemistry and eruption types Lava Fountains (fire fountains) Basaltic lava often erupts gas rich, the ejection of the gas can create spectacular fire fountains, often leading to the 24 formation of cinder cones. V4 Volcano Chemistry and eruption types Cinder Cones Also known as pyroclastic cones or scoria cones, can form rapidly, but remain active only for geologically short periods of time. Cinder cones typically range from a few tens of metres to a few hundred metres in height and are most often formed during single eruptions, when explosively ejected 25 material accumulates around the vent in a process called V4 fire fountaining. Calderas Volcano Chemistry and eruption types Calderas are large volcanic depressions formed after an eruption when the mountain collapses into its underlying magma chamber. The magma chamber is emptied by 26 the explosive eruption or the effusion of large volumes V4 of lava flows. Volcano Chemistry and eruption types Composite or Stratovolcanoes Stratovolcanoes are classic cone-shaped mountains formed from repeated eruptions of viscous lava and are 27 common in subduction zones. Explosive eruptions are often associated with these volcanoes. V4 Volcanic Hazards 28 V4 Eruptions are Natural Hazards Volcanic Hazards Volcanic Explosivity Index (VEI) 29 V4 The size of a volcanic eruption is quantified using a scale called the Volcanic Explosivity Index (VEI). This scale takes into account the volume of material erupted, the height of the eruption cloud, the duration of the main eruptive phase, and other parameters to assign a number from 0 to 8 on a linear scale. Hawaiian VEI 1 - 2 1992, Pinatubo VEI 6 Most Deadly Eruptions since 1500 AD Volcanic Hazards Volcano 30 Year Casualties (causes) VEI Nevado del Ruiz, Colombia 1985 25,000 (mudflow) 3 Mont Pelee, Martinique 1902 40,000 total, 29,000 (pyroclastic flow) 4 Santa Maria, Guatemala 1902 6,000 (pyroclastic flow) 5 Krakatau, Indonesia 1883 36,000 (tsunami) 6 Tambora, Indonesia 1815 12,000 (pyroclastic flow) 80,000 (starvation) 7 Unzen, Japan 1792 15,000 (tsunami) 3 9,000 (starvation) 4 10,000 (mudflow) 4 Lakagigar (Laki), Iceland 1783 V4 Kelut, Indonesia 1586 Volcanic Hazards 31 V4 Hazards Associated with Volcanic Eruptions Erupting volcanoes can generate many primary hazards including lava flows, pyroclastic flows, pyroclastic surges, volcanic bombs, ash clouds, landslides, debris flows, and clouds of poisonous gas. V4 Role 32 of the scientist Volcanic Hazards Volcanic Hazards Main types of Volcanic Hazards •Pyroclastic flows and surges •Lava flows •Ash falls (tephra) •Lahars/Debris flows •Debris avalanches 33 V4 •Volcanic gases Volcanic Hazards Hazard: Pyroclastic Flow 34 V4 Pyroclastic flows are dense avalanches of hot gas, hot ash, and blocks (tephra) that cascade down the slopes of the volcano during an eruption. Pyroclastic flow at Mt. St. Helens Volcanic Hazards Hazard: Pyroclastic Flows Pyroclastic flow deposits are often lobe-like and contain large blocks of pumice. The largest pumice 35 blocks are commonly found at the flow’s surface. V4 Volcanic Hazards Hazard: Pyroclastic Surge 36 V4 Pyroclastic surges are dense clouds of hot gas and rock debris, that are generated when water and hot magma interact. They are more violent and travel much faster than pyroclastic flows; surges have been clocked at over 360 km/h. Before: March 25, 1980 After: June 4, 1980 Pyroclastic surge at Mt. St. Helens, May 18, 1980 Volcanic Hazards Pyroclastic surge/flow 37 V4 Pyroclastic surge over the ocean at Montserrat. Volcanic Hazards Impact: Pyroclastic Flow/Surge • Extends km’s to 10’s of km’s • People → death 38 • Equipment → destruction V4 Risk Reduction Methods: hazard mapping, hazard zonation, monitoring, public education, evacuation Volcanic Hazards Hazard: Lava Flow Lava flows commonly accompany volcanic eruptions of basaltic and andesitic compositions. They are among the least hazardous processes associated with a volcanic eruption. Flows travel slowly, a few kilometres an hour to a fraction of a kilometre an hour, and people and animals can normally move easily out of the way, however immobile objects (houses, buildings etc.) are usually doomed. Basaltic lava flow on Mt. Etna 39 V4 Volcanic Hazards Impact: Lava Flow 40 V4 • Extend km’s to 10’s of km’s • People → discomfort, displacement • Equipment → destruction Risk Reduction Methods: hazard mapping, hazard zonation, engineering diversion structures, evacuation, monitoring, public education, evacuation Volcanic Hazards Impact: Lava Flow 41 V4 Lava flow diversion attempt at Mount Etna Volcanic Hazards Hazard: Lahar/Debris Flow Lahars or debris flows, are slurries of water and rock particles that behave like wet concrete. Because of the range of particle size - from flour-sized to blocks as large as houses - they are extremely destructive. Lahars are topographically controlled and usually follow river valleys where they are confined to valley bottoms. Debris flows have resulted in huge losses of life. 42 V4 Toutle River lahar, Mt. St. Helens, May 18, 1980 Volcanic Hazards Hazard: Debris Flow 43 V4 For months or even years following an eruption, vast areas around a volcano may be covered by loose, unconsolidated ash and blocks (tephra). This material is easily mobilized by heavy rainfall, forming mudflows and debris flows. Hazard: Lahar/Debris Flow 44 V4 Between August 1992 and July 1993, debris flows triggered by heavy rains around Mt. Unzen volcano, Japan, damaged about 1,300 houses Volcanic Hazards Impact: Lahar/Debris Flow • • • 45 V4 Risk reduction methods: hazard mapping, hazard zonation, engineering diversion and retention structures, monitoring/alerting systems, public education, evacuation Extend km’s to 10’s of km’s People → death, displacement Equipment → destruction Sediment retention structures built to control debris flows in Japan. Volcanic Hazards Hazard: Tephra (ash) 46 V4 Tephra (ash) is finely broken volcanic rock and is a product of explosive volcanic eruptions. In very energetic eruptions, tephra is carried upward into the upper atmosphere and the finest tephra can be carried by the jet stream for hundreds and thousands of kilometres. Significant quantities of tephra in the atmosphere can affect the climate. Volcanic Hazards Hazard: Tephra Volcanic tephra can be a significant health hazard and create economic problems over a wide area. It can pollute water supplies and disrupt transportation; thick accumulations of heavy ash can cause buildings or other structures to collapse. Inhaled ash can aggravate 47 respiratory conditions such as asthma and bronchitis. V4 Volcanic Hazards Tracking Tephra 48 V4 Volcanic Hazards Hazard: Debris Avalanches/ Sector collapse Collapse of part of a volcanic edifice can create a much larger than anticipated eruption. Almost instantaneous unroofing can create massive explosions. The debris 49 avalanche can be very far travelled, and if it hits a water body, can create a tsunami. V4 Volcanic Hazards Debris Avalanches 50 V4 Hummocks recognized for the first time at Mt. St. Helens. The avalanche was 2.8 km3 in size and traveled ~ 22 km Volcanic Hazards Debris Avalanches Sector collapse leading to a debris avalanche was first observed at Mt. St. Helens and opened up a 51 whole new aspect to hazard studies at temperate, V4 snow clad volcanoes. Debris Avalanches Volcanic Hazards • Mount Shasta, USA, • 40 cubic km, run-out ~ 50 km Shortly after the May 18, 1980 eruption of Mt. St. Helens, the hummocks at Mt. Shasta were recognized 52 for what they were - evidence of a major, catastrophic V4 failure of the mountain. Volcanic Hazards Impact: Debris Advances • Extend km’s to 10’s of km’s • People → death, displacement • Equipment → destruction Risk reduction methods: hazard mapping, hazard zonation, monitoring, public education 53 V4 Secondary impact: ¾larger than anticipated explosion/eruption ¾Tsunami generated if impacts a water body Volcanic Hazards Hazard: Poisonous Gases 54 V4 Mostly H2O, but often contains: • Carbon dioxide (CO2) – concentrates in crater lakes and topographic lows, present during non eruptive periods. Causes asphyxiation. • Sulphur Dioxide (SO2) – combines with water to form sulphuric acid, present during non eruptive periods. Causes eye and lung irritation. • Fluorine (F) – rare, coats ash, when ingested by live stock results in death “VOG” volcanic smog, Hawaii Impact: Poisonous Gases Volcanic Hazards Risk reduction methods: hazard mapping, hazard zonation, public education Damaged broccoli plants, Hawaii Secondary impact Long term impact on water supplies, crops • Extends 100s of meters to km’s • People → death, displacement, bronchial complications 55 • Equipment → corrosion V4 • Pollution of water supplies Volcanic Hazards Secondary Hazards 56 V4 Secondary hazards are those that are not associated with an eruption, but rather result from the environment created by the volcano. They include landslides, mudflows, debris flows, landslides, ground and surface water contamination, and soil contamination. In addition, lava flows, debris flows, debris avalanches and pyroclastic flows can dam the natural drainage. Failure of these dams can lead to catastrophic flooding. The impact of a volcanic eruption can last decades. Volcanoes can also have positive impacts such as the enrichment of soil, expansion of arable land, creation of mineral deposits and building material. Mt. St. Helens 57 V4 Mt. St. Helens, May 18, 1980 and ongoing activity Anatomy of an eruption Mt. St. Helens 58 V4 ntal contine t crus a nic oce us t cr mantle Mt. St. Helens 59 V4 May 18, 1980 sector collapse and phreatomagmatic explo Mt. St. Helens May 18 1980 sector collapse (debris avalanche/ landslides) and phreato60 magmatic explosion V4 V4 Mt. St. Helens Mt. St. Helens: Devastated zone 61 Mt. St. Helens “Before:” Mount St. Helens, May 17, 1980; Summit elevation 2,950 m (9677 ft) Largest ever observed landslide, and first ever observed sector collapse and pyroclastic surge “After:” Same view, after debris avalanche and blast. Summit Elevation 2,549 m (8,363 ft.), 400 m and 2.8 cubic km (1,314 ft 62 and 0.67 cubic mi ) V4 removed by avalanching. Mt. St. Helens 63 V4 Over 632 km2 of alpine to sub alpine environment was destroyed. Virgin timber was blasted away from many areas and blown over in others. Mt. St. Helens 64 V4 The pyroclastic surge killed most of the 57 people who died in the eruption. Mt. St. Helens The debris avalanche (sector collapse that created the gaping amphitheatre), transformed Spirit Lake and the Toutle River 65 Valley. V4 Mt. St. Helens Graphical time-series of MSH eruptions, 1980-86 66 V4 Mt. St. Helens The crater formed from the landslides is outlined in red 67 (right). Snow began accumulating almost as soon as the V4 1980-1986 dome finished growing. Mt. St. Helens The volcano began growing a second dome, Sept. 29, 2005 1980 – 1986 dome 68 V4 May 13, 2005 Mt. St. Helens 69 V4 Although Mt. St. Helens had been outwardly quiet since 1986, inwardly significant seismic activity was present. Two seismic crises were cause for concern, but didn’t lead to an eruption until the seismic activity started again on Sept. 28, 2005. Mt. St. Helens From 1986 onward, a glacier grew behind the 1980-1986 dome. The mountain was 70 outwardly tranquil, but, V4 inwardly there was turmoil. Mt. St. Helens The seismic crises built rapidly and very soon the media was “tuned” to the mountain. 71 V4 Mt. St. Helens October 1, 2004 The first explosion was Oct. 1, but the glacier behind the 72 1980-1986 dome was heavily fractured and moving upwards V4 prior to the first explosions. Soon a large crater had formed. Mt. St. Helens Bezymianny, Russia 73 V4 Mt. St. Helens, March 15, 2005 Global Volcanism and Plate tectonics 74 V4 Volcanoes in Our Backyard In Canada, British Columbia and Yukon are the host to a vast wealth of volcanic landforms. This section provides a brief overview of these volcanoes, starting in the north. Volcanoes of Canada 75 V4 British Columbia’s place in the Pacific Ring of Fire Volcanoes of Canada Driving Forces - subduction, crustal rifting and a hotspot 76 V4 Western Canada has all tectonic elements found globally subduction zones, hotspots and crustal rifting. Volcanoes of Canada 77 V4 Canadian Volcanic Regions Over 200 volcanic centres exist in British Columbia and Yukon that have been active in the last two million years. Volcanoes of Canada Canadian Volcanic Regions The volcanoes younger than about 5 million years in western Canada can be grouped into 6 volcanic regions with specific tectonic origins: Wrangell Volcanic Belt - subduction Stikine Volcanic Belt - continental rifting Anahim Volcanic Belt - hotspot Wells Gray-Clearwater Volcanic Field crustal weakness? Chilcotin Plateau Basalts - back arc Garibaldi Volcanic Belt - subduction 78 V4 Volcanoes of Canada Top 10 Canadian Volcanoes, based on Recent Seismic Activity; There are over 200 geological young volcanic centres. • • • • • • 79 V4 • • • • Castle Rock Mt. Edziza Mt. Hoodoo Lava Fork Crow Lagoon (basaltic field) Wells Gray – Clearwater (basaltic field) Silverthrone Mt. Meager Mt. Cayley Mt. Garibaldi Castle Rock Mount Edziza Mount Hoodoo Lava Fork Crow Lagoon Silverthrone Wells Gray Mount Meager Mount Cayley Mount Garibaldi Volcanoes of Canada Fire and Ice – Canada’s peculiar subglacial volcanoes “SUGM” TUYA In addition to shield volcanoes, stratovolcanoes, cinder cones, etc., many volcanoes in Canada formed when they 80 were covered, or surrounded by glacial ice. This V4 interaction has lead to specific “subglacial” landforms. Volcanoes of Canada Fire and Ice – Canada’s peculiar subglacial volcanoes As the volcano grows in its subglacial prison, lava pours out and forms “pillows”. As the mound of pillows grows, the pillows start to role down the sides. The rolling pillows break apart and form “hyaloclastite” – a rock made up of broken pillows and the glassy rinds of the pillows. 81 V4 82 V4 Stikine Volcanic Belt crustal rifting Volcanoes of Canada Volcanoes of Canada Volcano Mountain, Yukon Volcano Mountain is a small, asymmetrical cinder cone approximately 300 m high in the Stikine Volcanic Belt. The surface of the lava from the vent broke into 83 chunks as it flowed, creating the clinkery surface. V4 Volcanoes of Canada Tuya Butte, Stikine Belt 84 Tuya Butte is the type locality for “tuyas” – flat topped, steep sided subglacial volcanoes. V4 Volcanoes of Canada Caribou SUGM, Stikine Belt 85 V4 Volcanoes of Canada Pillows and breccia, Stikine Belt 86 V4 As most of the volcanoes in the Tuya Butte area have formed sub glacially, extensive deposits of pillows and hyaloclastite can be found in the area. Volcanoes of Canada 87 V4 Mt. Edziza, Stikine Belt Volcanoes of Canada Pyramid Mountain, Stikine Belt 88 V4 Volcanoes of Canada 89 V4 Eve Cone near Mount Edziza Volcanoes of Canada Hoodoo Volcano, Stikine Belt 90 V4 Volcanoes of Canada Lava Fork, Stikine Belt 91 V4 Although the vent area at Lava Fork Volcano is relatively nondescript, significant quantities of lava poured down the steep slopes into the valley below, traveling over 15 km. At about 150 years old, it may be Canada’s youngest volcano. Volcanoes of Canada Nisga’a Memorial Lava Bed Provincial Park 92 V4 Tseax Cone and lava flows in the Stikine Belt, is the site of one of Canada’s worst geological disaster - an estimated 2000 people died of “poison smoke” (most likely CO2). V4 Volcanoes of Canada Map of Memorial Park 93 Cone Lava flows Volcanoes of Canada 94 V4 Crater Creek and Tseax River valley Volcanoes of Canada 95 V4 The Nass River valley was inundated by the lava flows from Tseax Cone Volcanoes of Canada 96 V4 Tseax lava flows contain abundant tree moulds and caves, formed from draining of the lava flows. Volcanoes of Canada 97 V4 Tseax volcano first nation’s story of destruction, Canada's worst known geophysical disaster. Over 2000 people killed from poison smoke (most likely CO2). 98 V4 Anahim Volcanic Belt Hot spot Volcanoes of Canada Ilgatchuz Range – Anahim volcanic Belt Ilgatchuz Range – a major shield volcano in the belt. Canada’s hot spot track – the Anahim volcanic belt, extends from the pacific Ocean to Nazko cone, west of Quesnel. The volcanoes range in age from 99 12 million (western end) to a V4 few thousand (western end). 100 V4 Wells Gray - Clearwater Volcanic Field Crustal rifting? Volcanoes of Canada Volcanoes of Canada 101 V4 Wells Gray - Clearwater volcanic field The Wells Gray region of eastcentral British Columbia is a volcanic field made up of numerous, small, basaltic volcanoes, many modified by glacial interaction. Volcanoes of Canada Dragon Cone, Wells Gray - Clearwater Dragon Cone is the source of the 15 km long Dragon's tongue lava flow that dams Clearwater Lake. The cone, 102 made up of cinders, blocks, and bombs, is perched on the side of a ridge of metamorphic rock. V4 Volcanoes of Canada Hyalo Ridge, Wells Gray - Clearwater 103 V4 Hyalo Ridge is an example of a tuya: a sub-glacial volcano with a characteristic flat-top. Tuya’s have subaqueous deposits such as pillows. Volcanoes of Canada Whitehorse Bluff, Wells Gray - Clearwater Whitehorse Bluff is a sub-aqueous volcano composed of 104 fragmented volcanic glass. The glass is the result of explosive interaction of the lava with water. V4 Volcanoes of Canada Pyramid Mountain, Wells Gray - Clearwater Pyramid Mountain was formed below several thousand metres of glacial ice. The eruptions ceased before it 105 became the characteristic “tuya” shape of subglacial volcanoes. V4 106 V4 Garibaldi Volcanic Belt Subduction Volcanoes of Canada Volcanoes of Canada 107 V4 Mt. Meager, Garibaldi Volcanic Belt 150 km north of Vancouver is the youngest of four overlapping stratovolcanoes. Recent volcanic activity started 2350 years ago from a vent on the northeast side of the mountain and consisted of a massive, dacitic, Plinian eruption, similar in size to the May 19, 1980 eruption of Mt. St. Helens. Volcanoes of Canada Mt. Meager, Garibaldi Volcanic Belt Vent area Mt. Meager’s most recent eruption was from the amphitheatre shaped area on the volcano’s flank. Falls Creek, a nearby waterfall cuts through the dacite 108 columns formed by the lava flows that followed the V4 explosive phase of the eruption. 109 V4 Volcanoes of Canada Volcanoes of Canada Little Ring Mt., Garibaldi volcanic belt 110 V4 Little Ring Mountain, a subglacial volcano. Volcanoes of Canada 111 V4 Geology of Mt. Cayley Area, Garibaldi volcanic belt Volcanoes of Canada Mt. Cayley, Garibaldi Volcanic Belt 112 V4 Mt. Cayley is still the site of several hot springs and anomalous geophysical properties. Volcanoes of Canada Mt. Fee, Garibaldi Volcanic Belt 113 V4 V4 Mount Garibaldi and Garibaldi Lake volcanic field Volcanoes of Canada 114 To the east of the Cheakamus valley are many volcanoes – shown here in shades of green. These volcanoes are all part of the Garibaldi Volcanic Belt. Volcanoes of Canada 115 V4 Garibaldi satellite imagery This LandSAT image shows several different volcanic features including lava flows (Ring Creek), a volcanic neck (Black Tusk), a subglacial volcano (the Table) and a partly eroded stratovolcano (Garibaldi). Volcanoes of Canada Garibaldi Area Panorama 116 V4 Volcanoes of Canada Black Tusk, Garibaldi Volcanic Belt 117 V4 Black tusk is an erosional remnant of a much larger volcano. Volcanoes of Canada The Table, Garibaldi Area The Table is composed of lavas that cooled in contact with glacial ice, probably in a chimney like 118 void in the ice. V4 Volcanoes of Canada 119 V4 Mount Garibaldi: BC’s Best Known Volcano Volcanoes of Canada Mount Garibaldi, Atwell Peak and Dalton Dome - the three peaks that make up Garibaldi Volcano Formed from multiple eruptions, the volcano was built out onto glacial ice that filled the valley. The failure after the ice melted 120 left this steep, precipitous cliff on the volcanoes SE flank. V4 Volcanoes of Canada Garibaldi Area Volcanoes Garibaldi volcano consists of 3 peaks – Mt. Garibaldi, Atwell Peak, and Dalton Dome, seen here in the background. From left to right, Table Mountain is a flat-topped, steep-sided volcano that erupted under glacial ice. Clinker Peak and Mt. Price are the 121volcanoes in the foreground. V4 Volcanoes of Canada The Barrier, Garibaldi Area 122 V4 Clinker Peak lava flow was stopped by glacial ice filling the Cheakamus valley during eruption. The steep flow front has failed in a series of large landslides. Volcanoes of Canada Clinker Peak and Mt. Price, Garibaldi volcanic belt Clinker Peak Mt. Price and Clinker peak are the 123 source of the barrier lava flow. This V4 flow dams and forms Garibaldi Lake. Volcanoes of Canada Columnar basalt near Brandywine Falls Garibaldi Volcanic Belt Lava “esker” 124 V4 USA volcanoes 125 V4 Our neighbours to the south The Garibaldi Volcanic belt is the northern extension of the “Cascade Magmatic Arc” – the name used in the United States for the chain of volcanoes that extends northward from California. Closest to us are Mt. Baker and Glacier Peak USA volcanoes Mount Baker, Cascade Magmatic Arc 126 V4 Mount Baker is a towering stratovolcano that last erupted in the 1800’s. Mount Baker Hazard Map Sumas USA volcanoes Lynden M aple Falls N oo k s a c k o rth Fo rk N 542 Everson R ive r Glacier d Mi de rk N o Fo oksa Bellingham Bay Roman Wall Sherman Crater Mount Baker Dorr Fumaroles . Bellingham ck R 9 Kulshan Caldera l Deming Black Buttes Lake Whatcom Baker Lake Schriebers M eadow Cinder Cone 5 Concrete S k ag it R ive r Ba k Lake Shannon e r R iv er WHATCOM COUNTY SKAGIT COUNTY 20 Sedro Woolley Burlington EXPLANATION 127 V4 M ount Vernon 0 5 10 M iles Inundation Zone I - Pathways for eruption-related lahars due to large flank collapses or pyroclastic flows, or floods in the Skagit River valley caused by displacement of water in reservoirs by lahars. Inundation Zone II - Pathways of lahars resulting from more frequent, small-to-moderate flank collapses from the area of Sherman Crater. Proximal pyroclastic flow age hazard zone - Area that could be affected by pyroclastic flows and lava flows. USA volcanoes Mount Baker, Sherman Crater 128 V4 Sherman Crater, near Baker’s summit, is the hottest geothermal field in the Cascade Magmatic arc. USA volcanoes Glacier Peak, Washington, USA 129 V4 USA volcanoes Glacier Peak Hazard Map 130 V4 Web Resources Volcano sites: Volcanoes of Canada: www.nrcan.gc.ca/gsc/pacific/vancouver/volcanoes USGS Volcanic Hazards Program: http://volcanoes.usgs.gov Smithsonian Institution Global Volcanism Program: www.volcano.si.edu/index.cfm 131 V4
