| Silverthrone Caldera | |
|---|---|
| Silverthrone Caldera Complex | |
 Approximate outline of the Silverthrone Caldera | |
| Highest point | |
| Peak | Silverthrone Mountain[1][2] |
| Elevation | 2,860 m (9,380 ft)[3] |
| Coordinates | 51°31′03″N126°06′47″W / 51.51750°N 126.11306°W /51.51750; -126.11306[4] |
| Dimensions | |
| Width | 20 km (12 mi)[5] |
| Geography | |
  Silverthrone Caldera Location in British Columbia | |
 | |
| Interactive map of the Silverthrone area | |
| Country | Canada[3] |
| Province | British Columbia[3] |
| District | Range 2 Coast Land District[6] |
| Parent range | Pacific Ranges[7] |
| Topo map(s) | NTS 92M9Machmell River[4] NTS92M8Catto Creek[6] |
| Geology | |
| Formed by | Subduction zonevolcanism[3] |
| Rock age(s) | 750,000 years and younger[5] |
| Rock type | Calc-alkaline rocks[5] |
| Volcanic arc | Cascade Volcanic Arc[8] |
| Volcanic belt | |
| Last eruption | Unknown[3] |
| Climbing | |
| Access | Helicopter or trekking on foot[1] |
TheSilverthrone Caldera, also referred to as theSilverthrone Caldera Complex, is a potentially activevolcano in Range 2 Coast Land District of southwesternBritish Columbia, Canada. It lies within thePacific Ranges of theCoast Mountains and reaches anelevation of 2,860 metres (9,380 feet), although some sources give the elevation as high as 3,160 m (10,370 ft). Thecaldera is about 20 kilometres (12 miles) wide and has been deeply eroded, resulting in the formation of ruggedtopography. Several glacial meltwater streams originating from the caldera flow through valleys in the Pacific Ranges; among these streams are thePashleth,Selman andCatto creeks and theKingcome andWakeman rivers. The volcano shares its name withSilverthrone Mountain which is a subfeature of the caldera.
Volcanic rocks deposited by eruptions of the Silverthrone Caldera and associated vents includerhyolites,dacites,andesites andbasaltic andesites. They are exposed in valleys, but at higher elevations, they are largely buried under glacial ice of the 3,600 km2 (1,400 sq mi)Ha-Iltzuk Icefield. These rocks comprise three units; a 750,000-year-old basalbreccia unit, a 400,000-year-old unit of overlyinglava flows anddomes, and a less than 13,000-year-old series of lava flows andpyroclastic cones. The caldera mainly poses a threat to air traffic from renewedexplosive eruptions since there are no communities nearby, butlahars ordebris flows could be produced from the melting of glacial ice.
The Silverthrone Caldera was a source ofobsidian for indigenous peoples during thepre-contact era and was studied in the 1970s as a potential source ofgeothermal energy. Geological studies have been conducted at the volcano since at least the 1960s, but its very remote location has impeded detailedfieldwork. As a result, the eruptive history of the caldera is poorly known and its affinity to theGaribaldi Volcanic Belt remains unclear. The volcano can only be reached by helicopter or, with great difficulty, by trekking on foot through valleys of the Pacific Ranges.
The Silverthrone Caldera has also been described as the Silverthrone Caldera Complex and the Silverthrone Depression.[11][12] Other terms, such as the Silverthrone volcanic complex and the Silverthrone volcanic field, refer to the caldera and associatedvolcanic rocks.[13][14] Such terms are derived fromSilverthrone Mountain, a volcanic feature associated with the caldera whose name has been identified inCanadian Alpine Journal articles as early as 1933.[4][14] In a 1968Geological Survey of Canada report, the eruptive products of the caldera were referred to as the Mount Silverthrone volcanic complex byJack Souther, Canada's firstvolcanologist.[15][16]
In addition to Silverthrone Mountain, the Silverthrone Caldera also shares its name withSilverthrone Glacier, anoutlet glacier of the localHa-Iltzuk Icefield which covers approximately 3,600 km2 (1,400 sq mi) of the southernCoast Mountains.[17]Silverthrone is descriptive of the icy landscape; it was probably coined byDon Munday who carried out thefirst ascent of Silverthrone Mountain along with his wifePhyllis Munday in 1936.[4][9][18]
The volcano is 55 km (34 mi) north ofKingcome Inlet and 60 km (37 mi) northwest ofKnight Inlet in southwesternBritish Columbia, Canada.[3] It lies in a rugged, ice-dominated portion of thePacific Ranges which are the southernmost subdivision of the Coast Mountains.[7] The surrounding mountains are the highest in British Columbia south of theSaint Elias Mountains;Mount Waddington northeast of the head of Knight Inlet has anelevation of 4,016 m (13,176 ft) and is the highest mountain entirely within British Columbia.[7][19] Characterizing the landscape at higher elevations areglaciers and massiveicefields, althoughbedrock composed ofgranitoids is greatly exposed. The area is part of the Central Pacific Ranges Ecosection which is one of the sevenecosections comprising the Pacific Ranges Ecoregion.[7]
Moist air originating from thePacific Ocean ascends overQueen Charlotte Sound,Queen Charlotte Strait or theVancouver Island Ranges before reaching the Pacific Ranges. While ascending the Pacific Ranges, this air comes in contact with cold air from theBritish Columbia Interior and drops significant precipitation in the form of heavy rains or snow. The heavy rains are absorbed by wetmountain hemlocksubalpine forests on mid-elevation slopes and wetwestern hemlock forests in valleys and lower elevation slopes.Alpine vegetation is restricted to a narrow band between the subalpine forests and the higher icefields. There are no settlements near the Silverthrone Caldera, although summersport fishing recreation camps andlogging operations have been in the area.[20]
FromKingcome Glacier in the southern part of the caldera, theKingcome River flows south into the head of Kingcome Inlet northeast ofBroughton Island.[21][22][23]Trudel Creek, atributary of the Kingcome River, originates from the head ofTrudel Glacier and flows southwest along the inferred southeastern boundary of the Silverthrone Caldera.[21][24][25]Charnaud Creek originates from a valley-fillinglava flow adjacent to the southeastern boundary of the caldera and flows southwest into the Kingcome River.[21][24][26] At the terminus ofPashleth Glacier in the northern part of the caldera isPashleth Creek; it flows northwest into theMachmell River which flows west intoOwikeno Lake at the head ofRivers Inlet.[21][27][28][29]
Selman Creek, a tributary of Pashleth Creek, flows to the northeast fromSelman Lake at the northwestern end of the Silverthrone Caldera.[21][27][30][31] From an unnamed glacier just south of Selman Lake at the western end of the central volcanicridge, theWakeman River flows south intoWakeman Sound of Kingcome Inlet.[21][24][32]Catto Creek originates from an unnamed glacier on the central volcanic ridge and flows southwest across the inferred southwestern boundary of the caldera before it empties into the Wakeman River.[21][24][33]
The relationship of the Silverthrone Caldera to other volcanoes in southwestern British Columbia remains unclear due to there having been very little geological studies conducted at thecaldera.[13][34] It has been considered to be part of theGaribaldi Volcanic Belt, but it lies 190 km (120 mi) west-northwest of the main portion of this volcanic zone, making its connection to the Garibaldi Volcanic Belt questionable.[13][35][36] The volcano has also been included as part of the much olderPemberton Volcanic Belt, which overlaps with the trend of the Garibaldi Volcanic Belt nearMeager Creek to the southeast.[10][37] Bothvolcanic belts were formed bysubduction zonevolcanism along thecontinental margin of western North America in the last 29 million years and are part of theCascade Volcanic Arc.[38][39][40] The types ofvolcanic rocks at the Silverthrone Caldera are comparable to those found incontinental arcs; they belong to thecalc-alkaline magma series.[38][41] Likewise, the lifespan of the caldera is comparable to most of the large evolved eruptive centres in the Cascade Volcanic Arc, which have lifespans ranging from 100,000 to 1,000,000 years.[42][43]
Silverthrone and its closest prominent neighbour, theFranklin Glacier Complex about 55 km (34 mi) to the east-southeast, are sometimes excluded from the Garibaldi Volcanic Belt due to their ambiguous affinity.[13][36] When included, Silverthrone is the northernmost major eruptive centre of both the Garibaldi Volcanic Belt and the Cascade Volcanic Arc.[44] However, the relationship of the minorMilbanke Sound Cones further to the northwest with volcanoes of the Garibaldi Volcanic Belt also remains unclear.[45][46] This is because little is known about thesevolcanic cones; they may reflect a northern extension of the Garibaldi Volcanic Belt or they may have formed as a result of a different geological process.[46] Further studies of themagmatic products of the Silverthrone and Franklin Glacier complexes are required to provide additional insights onmantle andslab processes.[36] TheSmithsonian Institution'sGlobal Volcanism Program lists thetectonic setting of the Silverthrone Caldera as a subduction zone and the underlyingcontinental crust more than 25 km (16 mi) thick.[3]
The tectonic settings of the Silverthrone and Franklin Glacier complexes appear to differ from other volcanoes in the Garibaldi Volcanic Belt.[37] The main portion of this volcanic belt, which extends from theSalal Glacier volcanic complex in the north to theWatts Point volcanic centre in the south, is the result of subduction of theJuan de Fuca Plate beneath theNorth American Plate.[37][38] Immediately north of the Juan de Fuca Plate is theExplorer Plate, both of which are separated by theNootka Fault.[37] The Silverthrone and Franklin Glacier complexes lie inboard of the Explorer Plate which is subducting under the North American Plate at a rate of about 2 centimetres (0.79 inches) per year.[37][47] However, bothtectonic plates are currently locked to some degree in theCascadia subduction zone.[47]
The Silverthrone Caldera is a roughly circular subsidence structure about 20 km (12 mi) wide in the central part of the Coast Crystalline Complex.[14][15] Such structures form whenmagma chambers are partially emptied during volcanic eruptions, resulting in the land surface subsiding and the area above the magma chamber collapsing.[48] Subsidence of the area above the magma chamber results in the formation of steep-sidedring faults which are cylindrical fractures around the edges of calderas.[49][50] Calderas as large as Silverthrone form as a result of massivePlinian eruptions, which sendash columns high into thestratosphere and create large-scalepyroclastic flows.[48][51] These caldera-forming eruptions are orders of magnitude larger than the1980 eruption of Mount St. Helens; they range from 6 to 8 on theVolcanic Explosivity Index. Their extreme explosivity is caused bysilica-rich magma which cools on the land surface in the form of volcanic rocks such asdacite andrhyolite.[48] Reconnaissance mapping of volcanic rocks associated with the Silverthrone Caldera prior to 1980 indicates it is one of the largest centres of Quaternaryfelsic[a] volcanism in British Columbia.[53]
The inferred boundaries of the Silverthrone Caldera are exposed to the south and west whereas the northern and eastern boundaries are buried under volcanic deposits and glacial ice, respectively.[21] Unlike the neighbouring Franklin Glacier Complex whose volcanic rocks have been mostly eroded away to expose underlyingsubvolcanicintrusions, the Silverthrone Caldera still possesses mainly volcanic rocks.[14][54] The main volcanic rocks at the caldera are rhyolites, dacites,andesites andbasaltic andesites which comprisebreccias,lava domes, lava flows and volcanic cones.[14] Deepdissection of these volcanic deposits by erosion has created the current ruggedtopography, although some of them remain hidden at higher elevations under glacial ice of the Ha-Iltzuk Icefield.[13] The volcanic deposits extend over a distance of more than 25 km (16 mi) and vary in elevation from near sea level to 2,860 m (9,380 ft) or 3,160 m (10,370 ft).[3][5][13] They have a volume of at least twice as much as that of theMount Meager complex, which consists of 20 km3 (4.8 cu mi) of volcanic rocks.[55][56]
Underlying the eruptive products of the Silverthrone Caldera are older rocks of theCoast Plutonic Complex.[14][57] This 1,700 km (1,100 mi) long and 50–175 km (31–109 mi) wide geological feature is the largestmagmatic arc of theNorth American Cordillera and one of the largest subduction-relatedplutonic rock assemblages on Earth.[58][59] Dominated bytonalite,diorite andquartz diorite, the Coast Plutonic Complex is also one of the least felsicbatholith-like belts encircling the Pacific Ocean. It isEarly Jurassic-to-Paleogene in age and formed during a time when large-scaleterrane and magmaticaccretion led to significant continental growth in the North American Cordillera.[59]
Silverthrone was studied for producinggeothermal energy in the 1970s due to its potential similarity to the Mount Meager complex which is the most advanced, volcano-hosted, high temperature geothermal energy project in Canada.[60][61] Evidence for a geothermal system at Silverthrone includeshot springs, geologically recent volcanism and extensivehydrothermal alteration. There is limited heat flow data available for the volcano, but if a geothermal system is present, it would potentially be hosted in the localcrystalline basement rocks. No flow rates for the local springs have been reported and the heat exchange potential remains unknown.[62] At least one spring with a recorded temperature of 50 °C (122 °F) possibly occurs along a ring fault associated with the collapse of the Silverthrone Caldera.[63] As of 2016, the onlygeothermal exploration conducted at Silverthrone has beengeological mapping.[62]
The lack of detailed geothermal analysis for the Silverthrone Caldera is due to its very remote location and the lack of electrical development at the volcano.[64][65] As a result, geothermal exploration at the volcano is less favourable than elsewhere in British Columbia such as atMount Cayley,Mount Garibaldi and Mount Meager.[66] Based on the volume of the silicious volcanic rocks found at Silverthrone, itsgeothermal power potential is 2,000megawatts, which is comparable to that for theMount Edziza region but greater than those for Mount Cayley and Meager Creek combined. Unlike the Meager Creek–Mount Cayley complex and Mount Edziza region which have high and medium surface thermal manifestations, respectively, the surface thermal manifestation at Silverthrone is low.[67] Nevertheless, there is a good possibility of finding a geothermal resource that is less than 80 °C (176 °F).[62]
The eruptive history of the Silverthrone Caldera is poorly known due to limited geological studies but it is probably similar in age to those of other volcanoes in the Garibaldi Volcanic Belt.[13] Three stages of volcanic activity have been identified at the caldera, each of which have beenradiometrically dated. Most of the volcanic deposits inside the Silverthrone Caldera appear to have been erupted between 100,000 and 900,000 years ago during thePleistocene epoch.[68][69] According to the Smithsonian Institution's Global Volcanism Program, the last eruption of the Silverthrone Caldera is unknown, but there is credible evidence for the caldera having been active during the currentHolocene epoch, which began about 11,700 years ago.[3][70][71]Radiocarbon dating indicates the latest volcanic eruptions occurred in the last 13,000 years and the volcanic deposits from these eruptions postdate the current topography.[3][68] The Silverthrone Caldera has been much more recently active than the neighbouring Franklin Glacier Complex, which has yielded dates no younger than 2.2 ± 0.1 million years.[13][72]
Volcanism during the first stage of activity about 750,000 years ago deposited a 1,200 m (3,900 ft) thick breccia unit at the base of theintracaldera sequence.[73] The breccia is deeply eroded, exposed in valley bottoms and has been locally welded together by volcanic heat.[13][68] Angular to subangular granitic,metamorphic and volcanic fragments up to 3 m (9.8 ft) in diameter, derived from the underlying basement rocks, occur in the breccia which contains a white to light greymatrix.[15][68] Characterizing the welded breccia is aneutaxitic texture, a banded appearance which forms whenpumice-rich material is eruptedexplosively and is then quickly covered and compressed by overlying volcanic rocks while still in a hot, plastic state.[68][74][75]
Evidence for the basal breccia having been deposited during caldera collapse includes the existence of irregular subvolcanic intrusions and a profusion ofdikes within the breccia but not in the surroundingcountry rocks, as well as steep contacts of the breccia with the older country rocks which is indicative of afault-bounded structure.[1][68]Potassium–argon dating of rhyoliteglass about 100 m (330 ft) above the basal breccia has yielded a date of 0.75 ± 0.08 million years.[68]
The second stage of volcanic activity about 400,000 years ago issued a series of lava domes and flows over the basal breccia deposited during the first stage. These eruptive products are rhyolitic, dacitic and andesitic in composition; the lava flows reach a composite thickness of 900 m (3,000 ft). Like the basal breccia, erosion has greatly modified the lava domes and flows of this second stage of volcanic activity.[73] Near the summit of Silverthrone Mountain are overlapping andesite and rhyolite domes which most likely formed during this stage of volcanism.[1] Potassium–argon dating of an andesite flow overlying rhyolite in the south-central part of the caldera has yielded a date of 0.4 ± 0.1 million years.[73]
Volcanism during the third stage was characterized by the eruption of basaltic andesite lava flows andpyroclastic cones.[73] Most of the lava flows issued from vents around the parameter of the caldera, the largest of which is continuously exposed for more than 25 km (16 mi) in the Pashleth Creek and Machmell River valleys.[1][13] It has a blocky surface and originated from the northern margin of the caldera; theMachmell River Cone lies at the head of this lava flow at51°31′N126°13′W / 51.51°N 126.21°W /51.51; -126.21 (Machmell River Cone).[1][76] A relatively small basaltic andesite flow at the head of the Kingcome River originated inside the southern part of the caldera and travelled to the southeast just outside the inferred boundary of this collapse structure.[1] The lava flow is considered to be Holocene in age and is in the form of an eroded volcanicoutcrop at themouth of Trudel Creek.[1][24][77] A smaller north–south trending basaltic andesite flow on the southeastern side of the caldera at the head of Charnaud Creek was erupted during the Holocene and is also in the form of an eroded volcanic outcrop.[1][24][78] Several pyroclastic cones were formed at higher elevations on the eastern side of the caldera; the eroded remains of these cones project through glacial ice of the Ha-Iltzuk Icefield.[73]
Potassium–argon dating of the basaltic andesite flow occupying the Machmell River and Pashleth Creek valleys has yielded ages of 1.0 ± 0.2 million years and 1.1 ± 0.1 million years.[68] These ages are considered to be too old since high-energy streams originating from glaciers have only begun to erode achannel along the edge of the lava flow.[3][68] An explanation for the erroneous ages lies in the presence ofxenoliths[b] and other inclusions from the underlyingMesozoic basement, which can negatively influence the ages of rocks in radiometric dating.[68][80] Radiocarbon dating has yielded a date of 12,200 ± 140 years forbarnacles buried by the lava flow. This radiocarbon date was obtained 8.5 km (5.3 mi) upstream from the mouth of the Machmell River and provides a maximum age for the lava flow, which may have been extruded much more recently.[3] The low degree of erosion of this lava flow by the Machmell River, coupled with the presence of unconsolidated glaciofluvial[c] sediments under the flow, suggest it was erupted less than 1,000 years ago.[1]
A review of Canadian volcanoes published in 2024 assessed Silverthrone as the only "moderate" threat volcano in Canada.[82] The review noted that although the volcano scores highly for primaryvolcanic hazard factors, it has a relatively low exposure score due to its very remote location.[65][83] Therefore, the review gave Silverthrone a lower hazard rating than for Mount Edziza,Mount Price, Mount Cayley, Mount Meager and Mount Garibaldi, which were rated as "high" and "very high" threat volcanoes.[84] Small magnitude, shallowearthquakes have been recorded near Silverthrone since 1980, but because thisseismicity is not demonstrablymagmatic in origin, the volcano was given a score of 0.5 on a scale of 0 to 1 for observed seismic unrest.[85] Nevertheless, the presence of seismicity suggests the Silverthrone Caldera is potentially active and its volcanic hazards may be significant.[86]
Silverthrone mainly poses a threat to air traffic since there are no communities near the volcano.[83]Volcanic ash reduces visibility and can cause jet engine failure, as well as damage to other aircraft systems.[87] Silverthrone was rated "high" in the 2024 review for volcano knowledge uncertainty and was scored "positive" forsector collapse potential.[88] Sector collapses are one of the most hazardous volcanic events on Earth, involving the structural failure and subsequent collapse of at least 1 km3 (0.24 cu mi) of a volcano.[89][90] Such collapses can result from destabilization by magma intrusion or associatedphreatomagmatic eruptions.[90] More than 3 km3 (0.72 cu mi) of snow and ice permanently covers Silverthrone, making it a potential source oflahars ordebris flows which typically enter river valleys.[91][92] Eruptions may trigger lahars by melting snow and ice but lahars can also begin aslandslides of wet, hydrothermally altered rock on steep slopes.[92]
Like other volcanoes in Canada, the Silverthrone Caldera is notmonitored closely enough by the Geological Survey of Canada to ascertain its activity level. TheCanadian National Seismograph Network has been established tomonitor earthquakes throughout Canada, but it is too far away to provide an accurate indication of activity under the mountain. It may sense an increase in seismic activity if the Silverthrone Caldera becomes highly restless, but this may only provide a warning for a large eruption; the system might detect activity only once the volcano has started erupting.[93] If the Silverthrone Caldera were to erupt, mechanisms exist to orchestrate relief efforts. TheInteragency 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 theCanada–United States border or any eruption that would affect Canada.[94]
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Around 2013, Silverthrone was identified as the source of the Kingcomeobsidian bycultural resource management archaeologists and theTsawataineuk First Nation.[95] This makes the caldera one of several volcanoes in British Columbia with known obsidian source material often found atarchaeological sites throughout theprovince; others include Mount Garibaldi,Anahim Peak, theIlgachuz Range and theMount Edziza volcanic complex.[96] Artifacts made of Kingcome obsidian have been found at archaeological sites in theSunshine Coast region, which was the location of trading betweenindigenous peoples about 5,000–2,000 years ago.[95][97] Obsidian from Mount Garibaldi occurs with the Kingcome obsidian in this part of British Columbia, as does obsidian from Whitewater Ridge and Gregory Creek in the U.S. state ofOregon.[97]
The Kingcome and Mount Garibaldi obsidians are of only moderately good quality because they contain relatively largephenocrysts; these crystals would have made both obsidians more difficult to work with during thecrafting of artifacts.[97][98] As a result, artifacts made of Kingcome and Mount Garibaldi obsidian were not traded as widely as artifacts made of other types of volcanic glass. Kingcome obsidian mainly occurs north ofPowell River and inDesolation Sound where ancient settlements were established.[98] The Silverthrone Caldera lies inKwakwakaʼwakw territory which covers the northern end ofVancouver Island and surrounding lands.[98][99]
In 1967, Silverthrone was one of five eruptive centres visited by Jack Souther as part of a study to investigate geologically young volcanic rocks in theCanadian Cordillera. Specimens of the volcano were collected for chemical andpetrographic analyses. Souther also noted the basal breccia, the overlying lava flows, the deep dissection of the volcanic deposits and a possible fault-bounded structure associated with the collapse of the caldera. The youngest lava flows occupying the local valleys were said to be probably no older thanEarly Pleistocene age.[15] The other eruptive centres visited by Jack Souther in 1967 were the Mount Edziza volcanic complex in theNorthern Cordilleran Volcanic Province and theRainbow, Ilgachuz andItcha ranges in theAnahim Volcanic Belt.[100][101][102]
Further studies were carried out by Greenet al. (1988) who inferred the boundaries of the caldera and obtained the four aforementioned potassium–argon dates from three locations in and adjacent to the caldera.[73] Mejiaet al. (2002) sampled basaltic andesite flows from Silverthrone and obtained 16 potassium–argon dates. Most of these dates indicated the lava flows were extruded sometime in the last 120,000 years, but two of the potassium–argon dates gave ages as old as 400,000 years.[103] As of 2023, the remoteness of the Silverthrone Caldera has impeded detailedfieldwork.[11]
A mineralized daciticbreccia pipe was discovered at the Silverthrone Caldera in the 1990s following retreat of theheadwall of Kingcome Glacier. It was noted to contain multicoloured clay and silica minerals such asopal,malachite,pyrolusite andceladonite, which were characterized by intense hues of blue and green. The breccia pipe, partially enclaved by dacitepitchstone, was considered to behydrothermal in origin and was obscured by Kingcome Glacier in 1979 as evidenced by the photos andtopographic maps of that time. A report of the British Columbia Prospectors Assistance Program listedcopper andgemstones as commodities in the breccia pipe.[104]
Part of Silverthrone lies in the Catto Creek Conservancy, a 7,249-hectare (17,910-acre)conservation area in Range 2 Coast Land District established on August 23, 1973, under the Protected Areas of British Columbia Act.[6][65] This protected area was mainly established to preserve a group ofgeomorphological features known as “the paint pots”, but it also allows a number of recreational activities, such as camping, hiking, fishing and hunting. Both wilderness and winter camping are permitted in the Catto Creek Conservancy, but no facilities are provided, such that visitors must be fully prepared and self-sufficient to camp in this conservancy.[65]
Access to the Silverthrone Caldera is difficult due to its very remote location in the Pacific Ranges of the Coast Mountains.[5][7][65] It can be reached by charter helicopter fromTatlayvoko Lake orCampbell River, the latter of which is the nearest town to the volcano.[5][65] The flying times from Tatlayoko Lake and Campbell River are about one and two hours, respectively.[65] A much more difficult way to access Silverthrone is to traverse one of the severalintermontane valleys on foot, which can be reached from theBritish Columbia Coast or theInterior Plateau. The icefields of the Silverthrone area can be trekked on foot from the adjoining valleys.[1]
This article incorporates text from this source, which is in thepublic domain:"Explosive Calderas".National Park Service. 2023. Archived fromthe original on July 14, 2025.
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