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169-561: Eruptions along the length of the chain have created at least three major volcanic zones. The first began in the Powder Mountain Icefield 4.0 million years ago. Mount Cayley began its formation during this period. Multiple eruptions from 2.2 million to 2,350 years ago created the Mount Meager massif , and eruptions 1.3 million to 9,300 years ago formed Mount Garibaldi and other volcanoes in

338-430: A hornblende andesite stratovolcano on the drift-covered floor of a circular basin. After this stratovolcano was constructed, volcanism moved to the west where a series of andesite-dacite lava flows and pyroclastic flows were extruded during a period of Peléan activity 300,000 years ago. This created the 2,050 m (6,730 ft) high cone of Mount Price, which was later buried under glacial ice. Before Mount Price

507-586: A large landslide from Devastation Glacier buried and killed a group of four geologists on July 22, 1975. The estimated volume of this landslide is 13,000,000 m (460,000,000 cu ft). A considerable landslide as large as Meager's largest throughout the Holocene would likely produce a lahar that would devastate most of the growth in the Lillooet River valley. If such an event would occur without it being identified by authorities who would send out

676-600: A 70 m (230 ft) high waterfall composed of at least four basaltic lava flows with columnar joints. Its name origin is unclear, but it may have originated from two surveyors named Jack Nelson and Bob Mollison. Like other volcanic zones in Canada, the Garibaldi Volcanic Belt is not monitored closely enough by the Geological Survey of Canada to ascertain how active its magma system is. This

845-603: A deep north trending U-shaped valley on the eastern flank of The Black Tusk . Subsequent volcanism produced another sequence of basaltic lava flows 4,000 years ago that flowed in the same glacial valley. The Black Tusk, a black pinnacle of volcanic rock on the northwestern shore of Garibaldi Lake, is the glacially eroded remnant of a much larger volcano that formed during two periods of volcanic activity. The first between 1.1 and 1.3 million years ago erupted hornblende andesite lava flows and tuffs. These volcanics compose mountain ridges southwest, southeast and northwest of

1014-571: A depth of less than 70 km (43 mi) are classified as "shallow-focus" earthquakes, while those with a focal depth between 70 and 300 km (43 and 186 mi) are commonly termed "mid-focus" or "intermediate-depth" earthquakes. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, deep-focus earthquakes may occur at much greater depths (ranging from 300 to 700 km (190 to 430 mi)). These seismically active areas of subduction are known as Wadati–Benioff zones . Deep-focus earthquakes occur at

1183-488: A depth where the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure. Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes . Such earthquakes can serve as an early warning of volcanic eruptions, as during

1352-475: A few exceptions to this: Supershear earthquake ruptures are known to have propagated at speeds greater than the S wave velocity. These have so far all been observed during large strike-slip events. The unusually wide zone of damage caused by the 2001 Kunlun earthquake has been attributed to the effects of the sonic boom developed in such earthquakes. Slow earthquake ruptures travel at unusually low velocities. A particularly dangerous form of slow earthquake

1521-428: A lava dome that comprises the current 2,316 m (7,598 ft) high pinnacle. Consequently, the regional Late Pleistocene ice sheet carved a deep north-trending U-shaped valley into the eastern flank of the second-stage cone. Here, subsequent lava flows from Cinder Cone filled the valley. Immediately southeast of Mount Cayley lies Mount Fee , an extensively eroded volcano containing a north–south trending ridge. It

1690-514: A major debris avalanche about 4,800 years ago that dumped an areal extent of 8 km (3.1 sq mi) of volcanic material into the adjacent valley bottom. This blocked the Squamish River for a long period of time. Although there are no known eruptions from the massif in the past 10,000 years, it is associated with a group of hot springs. Evans (1990) has indicated that a number of landslides and debris flows at Mount Cayley in

1859-584: A major long-distance threat to communities throughout southern British Columbia and Alberta because of its explosive history. It is estimated that over 200 eruptions have occurred throughout the entire Cascade Volcanic Arc in the past 12,000 years, many of them in the United States. Many eruptions in the western United States have sent large amounts of tephra in southern British Columbia. However, all major cities in southwestern British Columbia with populations more than 100,000 are located west of

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2028-537: A mass of andesite lava flows and small amounts of pyroclastic material. It lies on the eastern portion of the large glacial icefield that covers much of the Mount Cayley volcanic field. Much of the lava flows form gentle topography at high elevations but terminate in finely jointed vertical cliffs at low elevations. The first volcanic activity likely occurred about 25,000 years ago, but it could also be significantly older. The most recent volcanic activity produced

2197-458: A particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word earthquake is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining , fracking , and nuclear tests . The initial point of rupture is called the hypocenter or focus, while

2366-560: A particular location in the Earth is the average rate of seismic energy release per unit volume. One of the most devastating earthquakes in recorded history was the 1556 Shaanxi earthquake , which occurred on 23 January 1556 in Shaanxi , China. More than 830,000 people died. Most houses in the area were yaodongs —dwellings carved out of loess hillsides—and many victims were killed when these structures collapsed. The 1976 Tangshan earthquake , which killed between 240,000 and 655,000 people,

2535-415: A public warning, it would kill hundreds or even thousands of residents. Because of this, computer programs would be able to identify the approaching information and activate an automatic notice when a large lahar is identified. A similar system for identifying such lahars exists at Mount Rainier in the U.S. state of Washington. Large landslides from Mount Cayley have occurred on its western flank, including

2704-563: A quick check of the old hot-spots when I get off the Peak Chair ;..." Recent seismic imaging from Geological Survey of Canada employees supported lithoprobe studies in the region of Mount Cayley in which scientists found a large reflector interpreted to be a pool of molten rock roughly 15 km (9.3 mi) below the surface. The existence of hot springs at the Mount Meager massif and Mount Cayley indicates that magmatic heat

2873-564: A range from andesite to dacite . Glassy volcanic rocks are abundant, with glass contents as high as 70%. Volcanoes such as the Slag Hill tuya were formed when magma intruded into and melted a vertical pipe in the overlying Powder Mountain Icefield. The partially molten mass cooled as a large block, with gravity flattening its upper surface, forming its flat-topped, steep-sided subglacial volcanic edifice. The latest volcanic activity in

3042-536: A region like southwestern British Columbia where the Garibaldi volcanoes are located in a highly populated area. The volcanoes comprising the Garibaldi chain are adjacent to the highly populated southwest portion of British Columbia. Unlike the central Cascade Arc, renewed volcanic activity in the Garibaldi Belt at a single feeder to create stratovolcanoes is not typical. Instead, volcanic activity results in

3211-422: A result, subglacial volcanoes that erupt silicic content melt less qualities of ice and are not as likely to contain water close to the volcanic vent. This forms volcanoes with structures that display their relationship with the regional glaciation. The surrounding landscape also changes the flow of meltwater, favouring lava to pond within valleys dominated by glacial ice. And if the edifice is eroded, it could change

3380-564: A series of lava flows that were erupted when the vent area was not covered by glacial ice. However, the flows show evidence of interaction with glacial ice in their lower units. This indicates that the lavas were erupted about 10,000 years ago during the waning stages of the Fraser Glaciation. The ice-marginal lava flows reach thicknesses of up to 100 m (330 ft). Pali Dome West consists of at least three andesite lava flows and small amounts of pyroclastic material; its vent

3549-635: A series of well-preserved columnar joints. This is the last phase of the 2350 BP eruption, and subsequent stream erosion has cut through this lava flow to form a waterfall. A group of small volcanoes on the upper Bridge River , known as the Bridge River Cones , includes stratovolcanoes, volcanic plugs and lava flows. These volcanoes are unlike others throughout the Garibaldi Volcanic Belt in that they are mainly composed of volcanic rocks with mafic compositions, including alkaline basalt and hawaiite . The different magma compositions might be related to

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3718-765: A single rupture) are approximately 1,000 km (620 mi). Examples are the earthquakes in Alaska (1957) , Chile (1960) , and Sumatra (2004) , all in subduction zones. The longest earthquake ruptures on strike-slip faults, like the San Andreas Fault ( 1857 , 1906 ), the North Anatolian Fault in Turkey ( 1939 ), and the Denali Fault in Alaska ( 2002 ), are about half to one third as long as

3887-568: A small basetown at Callaghan Lake. In 1987, Forests and Lands Minister Jack Kempf was instructed by then-Premier Bill Vander Zalm to "cease and desist" in favour of Callaghan Resorts Inc., which was backed by then-Attorney-General Les Peterson. Court action for breach of contract and abuse of office taken by Powder Mountain Resort promoters Nan and Dianne Hartwick was dismissed by the Supreme Court of British Columbia in 1999, though in 2000

4056-413: A smaller degree of partial melting in the Earth's mantle or a descending plate edge effect. The oldest volcano in the group, known as Sham Hill , is a 60 m (200 ft) high volcanic plug with a potassium-argon date of one million years. It is about 300 m (980 ft) wide and its uncovered glaciated surface is strewn with glacial erratics. Its massive level rock columns were constructed inside

4225-412: A story of the flood covering the land. During this time, only two mountains peaked over the water, and Garibaldi was one of them. It was here that the remaining survivors of the flood latched their canoes to the peak and waited for the waters to subside. The Black Tusk on the northwestern end of Garibaldi Lake and Mount Cayley northwest of Mount Garibaldi are called ta k 'ta k mu'yin tl'a in7in'axa7en in

4394-700: A subaerial vent and ponds against glacial ice. The Barrier , a lava dam impounding Garibaldi Lake in the southern segment, is the best represented ice-marginal lava flow in the Garibaldi Belt. Flow-dominated tuyas and the absence of subglacial fragmental deposits are two uncommon glaciovolcanic features in the Garibaldi chain. This is due to their different lava compositions and decline of direct lava-water contact during volcanic activity. The lava composition of these volcanic edifies changes their structure because eruption temperatures are lower than those associated with basaltic activity and lava containing silica increases thickness and glass differentiation temperatures. As

4563-436: A sudden release of energy in the lithosphere that creates seismic waves . Earthquakes can range in intensity , from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at

4732-504: A thickness no more than 40 m (130 ft). Ember Ridge Northwest, the most roughly circular subglacial dome, comprises at least one lava flow. Ember Ridge Southeast is the most complex of the Ember Ridge domes, consisting of a series of lava flows with a thickness of 60 m (200 ft). It is also the only Ember Ridge dome that contains large amounts of rubble. Ember Ridge Southwest comprises at least one lava flow that reaches

4901-411: A thickness of 80 m (260 ft). It is the only subglacial dome of Ember Ridge that contains hyaloclastite. Ember Ridge West comprises only one lava flow that reaches a thickness of 60 m (200 ft). To the northwest, Mount Cayley constitutes the largest and most persistent volcano in the central Garibaldi Belt. It is a highly eroded stratovolcano composed of dacite and rhyodacite lava that

5070-445: A vent adjacent to upper Cauldron Dome that is currently buried under glacial ice. Lying at the northern portion of the Mount Cayley volcanic field is a subglacial volcano named Slag Hill . At least two geologic units compose the edifice. Slag Hill proper consists of andesite lava flows and small amounts of pyroclastic rock. Lying on the western portion of Slag Hill is a lava flow that likely erupted less than 10,000 years ago due to

5239-410: A volcanic vent on the northeastern flank of Plinth Peak . It was Plinian in nature, sending an eruption column at least 20 km (12 mi) high into the stratosphere . As prevailing winds carried ash of the column eastwards, it deposited across British Columbia and Alberta . Subsequent pyroclastic flows were sent down the flanks of Plinth Peak for 7 km (4.3 mi) and were later succeeded by

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5408-408: Is a minor portion of pyroclastic rock . This is evidence of explosive volcanism from Fee's eruptive history, as well as its first volcanic event. The second volcanic event produced a sequence of lavas and breccias on the eastern flank of the main ridge. These volcanics were likely placed when a sequence of lava flows and broken lava fragments erupted from a volcanic vent and moved down the flanks during

5577-525: Is a theory that earthquakes can recur in a regular pattern. Earthquake clustering has been observed, for example, in Parkfield, California where a long-term research study is being conducted around the Parkfield earthquake cluster. An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. Rapid changes of stress between rocks, and the stress from the original earthquake are

5746-524: Is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior. There are three main types of fault, all of which may cause an interplate earthquake : normal, reverse (thrust), and strike-slip. Normal and reverse faulting are examples of dip-slip, where

5915-400: Is divided into 754 Flinn–Engdahl regions (F-E regions), which are based on political and geographical boundaries as well as seismic activity. More active zones are divided into smaller F-E regions whereas less active zones belong to larger F-E regions. Standard reporting of earthquakes includes its magnitude , date and time of occurrence, geographic coordinates of its epicenter , depth of

6084-520: Is heavily forested and the BC Rail mainline passes through the lower portion of the outcrop about 40 m (130 ft) above sea level. It represents a feature in the Squamish volcanic field. Mount Garibaldi, one of the larger volcanoes in the southern Garibaldi Belt with a volume of 6.5 km (1.6 cu mi), is composed of dacite lavas that were erupted in the past 300,000 years. It

6253-654: Is influenced by tectonic movements along faults, including normal, reverse (thrust), and strike-slip faults, with energy release and rupture dynamics governed by the elastic-rebound theory . Efforts to manage earthquake risks involve prediction, forecasting, and preparedness, including seismic retrofitting and earthquake engineering to design structures that withstand shaking. The cultural impact of earthquakes spans myths, religious beliefs, and modern media, reflecting their profound influence on human societies. Similar seismic phenomena, known as marsquakes and moonquakes , have been observed on other celestial bodies, indicating

6422-540: Is just to its south. Numerous subglacial eruptions beneath the Powder Mountain Icefield have formed many distinctive subglacial volcanoes in the Mount Cayley volcanic field and contain abundant glass and fine-scale jointing from rapid cooling of lava , such as Ember Ridge and Slag Hill . Mineralogically, the volcanics range from andesite to rhyodacite , and chemically, the rocks span

6591-445: Is largely destroyed by erosion. A series of dikes and subvolcanic intrusions compose the complex, a few of which seem to represent vents for the overlying sequence of volcanic deposits. Volcanics include dacite breccia and small remnants of hornblende andesite lava flows associated with tuffs that reach 450 m (1,480 ft) thick. The complex is poorly known due to minimal studies, but potassium-argon dates obtained from some of

6760-503: Is one of the older volcanic features in the central Garibaldi chain. Its volcanics are undated, but its large amount of dissection and evidence of glacial ice overriding the volcano indicates that it formed more than 75,000 years ago before the Wisconsinan Glaciation . Therefore, volcanism at Mount Fee does not display evidence of interaction with glacial ice. The remaining product from Fee's earliest volcanic activity

6929-408: Is only to re-establish their right to complete their resort proposal. 50°08′48.8″N 123°16′36.1″W  /  50.146889°N 123.276694°W  / 50.146889; -123.276694  ( Powder Mountain ) Earthquake An earthquake  – also called a quake , tremor , or temblor  – is the shaking of the Earth 's surface resulting from

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7098-802: Is over 25 km (16 mi) in length. Its small amount of erosion indicates that it could be 1,000 years old or younger. At least four volcanoes have had seismic activity since 1985, including Mount Garibaldi (three events), Mount Cayley (four events), Mount Meager massif (seventeen events) and the Silverthrone Caldera (two events). Seismic data suggest that these volcanoes still contain active magma chambers, indicating that some Garibaldi Belt volcanoes are likely active, with significant potential hazards. The seismic activity corresponds with some of Canada's recently formed volcanoes and with persistent volcanoes that have had major explosive activity throughout their history, such as Mount Garibaldi and

7267-435: Is partly because several volcanoes in the chain are located in remote regions and no major eruptions have occurred in Canada in the past few hundred years. As a result, volcano monitoring is less important than dealing with other natural processes, including tsunamis , earthquakes and landslides. However, with the existence of earthquakes, further volcanism is expected and would probably have considerable effects, particularly in

7436-643: Is poorly known due to minimal studies. The region surrounding the Silverthrone complex is significantly jagged due to the mountainous terrain of the Coast Mountains. Near vertical flanks extend from near sea level to more than 3,000 m (9,800 ft) in elevation. Silverthrone is significantly younger than the Franklin Glacier Complex to the east-southeast and its volcanics likely have ages comparable to other volcanics throughout

7605-425: Is presently buried under glacial ice. At least three eruptions have occurred at Pali Dome East. The age of the first volcanic eruption is unknown, but it could have occurred in the past 10,000 years. The second eruption produced a lava flow that was erupted when the vent area was not buried under glacial ice. However, the flow does show evidence of interaction with glacial ice at its lower unit. This indicates that

7774-545: Is probably a statistical fluctuation rather than a systematic trend. More detailed statistics on the size and frequency of earthquakes is available from the United States Geological Survey. A recent increase in the number of major earthquakes has been noted, which could be explained by a cyclical pattern of periods of intense tectonic activity, interspersed with longer periods of low intensity. However, accurate recordings of earthquakes only began in

7943-423: Is proportional to the area of the fault that ruptures and the stress drop. Therefore, the longer the length and the wider the width of the faulted area, the larger the resulting magnitude. The most important parameter controlling the maximum earthquake magnitude on a fault, however, is not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins,

8112-412: Is specific data, including the temporal grouping of eruptions synglacially or just postglacial within the Garibaldi Belt, that suggests this could be probable. Dominating the Garibaldi chain are volcanoes and other volcanic formations that formed during periods of intense glaciation. This includes flow-dominated tuyas , subglacial lava domes and ice-marginal lava flows . Flow-dominated tuyas differ from

8281-400: Is still present beneath or near these volcanoes. This long history of volcanic activity along a still active plate boundary indicates that volcanic eruptions in the Garibaldi Belt have not ended and risks for future eruptions remain. The largest threat from volcanoes in the Garibaldi chain would likely be due to tephra released during explosive eruptions. Mount Meager massif in particular poses

8450-488: Is that these developments violate the agreement-in-principle they had with the province, which the provincial government had claimed was without sufficient backing. In 2007, RCMP Commercial Crimes Unit head Kevin deBruyckere confirmed that a review is underway, and which the Hartwicks say is based on new evidence of conflict of interest. The Hartwicks emphasize that they are not anti-Olympics, but that their ultimate goal

8619-410: Is the tsunami earthquake , observed where the relatively low felt intensities, caused by the slow propagation speed of some great earthquakes, fail to alert the population of the neighboring coast, as in the 1896 Sanriku earthquake . During an earthquake, high temperatures can develop at the fault plane, increasing pore pressure and consequently vaporization of the groundwater already contained within

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8788-534: Is the valley of the Squamish River , while on its east is the Callaghan Valley , which is the setting for the Nordic facilities for the 2010 Winter Olympics . The icefield is studded by several volcanic formations, including active Mount Cayley . Other summits are Powder Mountain , Brandywine Mountain and Mount Fee . Mount Callaghan , a dormant volcano, is just northeast of the icefield. Mount Brew

8957-454: Is unusually long for a dacite flow, which commonly travel only short distances from a volcanic vent due to their high viscosity. The Opal Cone lava flow represents the most recent volcanic feature at Mount Garibaldi. On the western shore of Garibaldi Lake, Mount Price represents a stratovolcano with an elevation of 2,050 m (6,730 ft). It was constructed during three periods of activity. The first phase 1.2 million years ago formed

9126-458: The 1960 Valdivia earthquake in Chile, the largest ever recorded at 9.5 magnitude. Earthquakes result in various effects, such as ground shaking and soil liquefaction , leading to significant damage and loss of life. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami . Earthquakes can trigger landslides . Earthquakes' occurrence

9295-400: The 1980 eruption of Mount St. Helens . Earthquake swarms can serve as markers for the location of the flowing magma throughout the volcanoes. These swarms can be recorded by seismometers and tiltmeters (a device that measures ground slope) and used as sensors to predict imminent or upcoming eruptions. A tectonic earthquake begins as an area of initial slip on the fault surface that forms

9464-587: The 2004 Indian Ocean earthquake is simultaneously one of the deadliest earthquakes in history. Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of kilometers away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes. Tectonic earthquakes occur anywhere on

9633-569: The British Columbia Court of Appeal refused to overturn the lower court's ruling. An appeal at the Supreme Court of Canada is still pending. A special prosecutor was appointed but the investigation was halted for lack of evidence in 2003, three weeks before Vancouver and Whistler won the bid to host the 2010 Winter Olympics . In the meantime, a Nordic lodge was founded in the Callaghan Valley in 1998, just prior to

9802-609: The California border and east-southeast of the massive Newberry shield volcano adjacent to the Cascade Range in central Oregon because the Brothers Fault Zone lies in this region. This rift zone might explain the massive amounts of basaltic lava in this part of the central Cascade Arc. A low convergence rate in a compressional setting with massive stationary bodies of magma under the surface could explain

9971-632: The Fraser Glaciation . Their current structures are comparable to their original forms due to the minimal degree of erosion. As a result, the domes display the shaps and columnar joints typical of subglacial volcanoes. The random shaps of the Ember Ridge domes are the result of erupted lava taking advantage of former ice pockets, eruptions taking place on uneven surfaces, subsidence of the domes during volcanic activity to create rubble and separation of older columnar units during more recent eruptions. The northern dome, known as Ember Ridge North, covers

10140-624: The Garibaldi Lake area. These major volcanic zones lie in three echelon segments, referred to as the northern, central, and southern segments. Each segment contains one of the three major volcanic zones. Apart from these large volcanic zones, two large poorly studied volcanic complexes lie at the northern end of the Pacific Ranges, namely Silverthrone Caldera and Franklin Glacier Complex . They are considered to be part of

10309-499: The Himalayan Mountains . With the rapid growth of mega-cities such as Mexico City, Tokyo, and Tehran in areas of high seismic risk , some seismologists are warning that a single earthquake may claim the lives of up to three million people. While most earthquakes are caused by the movement of the Earth's tectonic plates , human activity can also produce earthquakes. Activities both above ground and below may change

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10478-588: The Late Pleistocene also deposited massive amounts of sediment into the trench. However, in common with other subduction zones, the outer margin is slowly being compressed, similar to a giant spring. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large earthquakes, such as the magnitude 9.0  Cascadia earthquake on January 26, 1700 . However, earthquakes along

10647-757: The Miocene period, the northern remnant of the Farallon Plate fractured into two tectonic plates, known as the Gorda and Juan de Fuca plates. After this breakup, subduction of the Juan de Fuca Plate might have been coincident with the northern end of Vancouver Island eight million years ago during the late Miocene period. This is when the Alert Bay Belt became active. A brief interval of plate motion adjustment about 3.5 million years ago may have triggered

10816-599: The Squamish language , which means "Landing Place of the Thunderbird". The Thunderbird is a legendary creature in North American indigenous peoples' history and culture. The rocks that make up The Black Tusk and Mount Cayley were said to have been burnt black by the Thunderbird's lightning. A number of volcanic features in the Garibaldi Belt are protected by provincial parks . Garibaldi Provincial Park at

10985-527: The Turbid and Shovelnose Creek valleys near the Squamish River. This subsequently created two minor parasitic lava domes 200,000 years ago. These three volcanic events are in contrast to several others around Cayley in that they do not show signs of interaction with glacial ice. Pali Dome , an eroded volcano north of Mount Cayley, consists of two geological units . Pail Dome East is composed of

11154-788: The United States Geological Survey . Powder Mountain Icefield The Powder Mountain Icefield , also called the Powder Mountain Icecap and the Cayley Icefield , is a glacial field in the Pacific Ranges of southwestern British Columbia, Canada , about 20 kilometres (12 mi) west of Whistler and about 90 kilometres (56 mi) north of Vancouver . On the west side of the icefield

11323-597: The Vancouver Organizing Committee for the 2010 Olympic and Paralympic Winter Games , and those in the provincial administration who helped quash their project. The province has also issued permits for other operations in the valley, such as cat-skiing and snowmobile tour operations, as well as pushed through permits for construction of the Whistler Olympic Park , which is the site of the games' Nordic events. The Hartwicks' position

11492-426: The brittle-ductile transition zone and upwards by the ground surface. The mechanics of this process are poorly understood because it is difficult either to recreate such rapid movements in a laboratory or to record seismic waves close to a nucleation zone due to strong ground motion. In most cases, the rupture speed approaches, but does not exceed, the shear wave (S wave) velocity of the surrounding rock. There are

11661-413: The least principal stress. Strike-slip faulting is intermediate between the other two types described above. This difference in stress regime in the three faulting environments can contribute to differences in stress drop during faulting, which contributes to differences in the radiated energy, regardless of fault dimensions. For every unit increase in magnitude, there is a roughly thirty-fold increase in

11830-553: The 20th century and has been inferred for older anomalous clusters of large earthquakes in the Middle East. It is estimated that around 500,000 earthquakes occur each year, detectable with current instrumentation. About 100,000 of these can be felt. Minor earthquakes occur very frequently around the world in places like California and Alaska in the U.S., as well as in El Salvador, Mexico, Guatemala, Chile, Peru, Indonesia,

11999-433: The 21st century. Seismic waves travel through the Earth's interior and can be recorded by seismometers at great distances. The surface-wave magnitude was developed in the 1950s as a means to measure remote earthquakes and to improve the accuracy for larger events. The moment magnitude scale not only measures the amplitude of the shock but also takes into account the seismic moment (total rupture area, average slip of

12168-603: The Bridge River volcanic field produced a series of basaltic lava flows in the regional valleys that overlie till of the last glacial period. The age of these valley-filling lava flows is unknown but the presence of unconsolidated glacial till under the flows suggests that they are less than 1,500 years old. To the northwest, the Franklin Glacier Complex is a set of volcanic bedrock that encompasses an area 20 km (12 mi) long and 6 km (3.7 mi) wide. It has an elevation of over 2,000 m (6,600 ft) and

12337-545: The Canadian Cordillera has stated, "at present the volcanoes of the Garibaldi Belt are quiet, presumed dead but still not completely cold. But the flare-up of Meager Mountain 2,500 years ago raises the question, 'Could it happen again?' Was the explosive eruption of Meager Mountain the last gasp of the Garibaldi Volcanic Belt or only the most recent event in its on-going life? The short answer is nobody really knows for sure ... So just in case I sometimes do

12506-555: The Canadian Olympic Committee's selection of Vancouver over Calgary and Quebec City as the site of the 2010 Olympics bid. The owner of the Nordic lodge was a promoter of using the Callaghan Valley for Olympic ski-jumping, cross-country, biathlon and other Nordic events. Powder Mountain promoters Nan and Dianne Hartwick continue to press for investigation of backroom dealing that led to the shunting-aside of their project and claim connections between members of VANOC,

12675-473: The Cascade Arc is minor. Individual volcanoes and volcanic fields remain quiet for a long period of time and certain vents may never erupt again. However, considerable volcanic activity has taken place in the geologically recent past, most notably the explosive eruption that occurred at the Mount Meager massif 2,350 years ago. Jack Souther , a leading authority on geothermal resources and volcanism in

12844-636: The Cascade Volcanic Arc during the Miocene period and their intrusive roots extend from the Fraser Valley in the south to Salal Creek in the north. The relationship of these hot springs to the Garibaldi Belt is not clear. However, a few hot springs are known to exist in areas that have experienced relatively recent volcanic activity. About five hot springs exist in valleys near Mount Cayley and two small groups of hot springs are present at

13013-528: The Cascadia subduction zone are fewer than expected and there is evidence of a decline in volcanic activity over the past few million years. The probable explanation lies in the rate of convergence between the Juan de Fuca and North American plates. These two tectonic plates currently converge 3 cm (1.2 in) to 4 cm (1.6 in) per year. This is only about half the rate of convergence of seven million years ago. Scientists have estimated that there have been at least 13 significant earthquakes along

13182-684: The Cascadia subduction zone in the past 6,000 years. The most recent, the 1700 Cascadia earthquake , was recorded in the oral traditions of the First Nations people on Vancouver Island. It caused considerable tremors and a massive tsunami that traveled across the Pacific Ocean. The significant shaking associated with this earthquake demolished houses of the Cowichan Tribes on Vancouver Island and caused several landslides. Shaking due to this earthquake made it too difficult for

13351-726: The Coast Mountains. This is a large batholith complex that was formed when the Farallon and Kula plates were subducting along the western margin of the North American Plate during the Jurassic and Tertiary periods. It lies on island arc remnants, oceanic plateaus and clustered continental margins that were added along the western margin of North America between the Triassic and Cretaceous periods. The Garibaldi Belt has formed in response to ongoing subduction of

13520-531: The Cowichan people to stand, and the tremors were so lengthy that they were sickened. The tsunami created by the earthquake ultimately devastated a winter village at Pachena Bay , killing all the people that lived there. The 1700 Cascadia earthquake caused near-shore subsidence, submerging marshes and forests on the coast that were later buried under more recent debris. Many thousand years of dormancy are expected between large explosive eruptions of volcanoes in

13689-399: The Earth's core was located in 1913 by Beno Gutenberg . S waves and later arriving surface waves do most of the damage compared to P waves. P waves squeeze and expand the material in the same direction they are traveling, whereas S waves shake the ground up and down and back and forth. Earthquakes are not only categorized by their magnitude but also by the place where they occur. The world

13858-484: The Earth. Also, the depth of the hypocenter can be computed roughly. P wave speed S waves speed As a consequence, the first waves of a distant earthquake arrive at an observatory via the Earth's mantle. On average, the kilometer distance to the earthquake is the number of seconds between the P- and S wave times 8. Slight deviations are caused by inhomogeneities of subsurface structure. By such analysis of seismograms,

14027-554: The Garibaldi Belt and other portions of the northern Cascade Arc took place mainly at the Franklin Glacier Complex and in the Intermontane Belt further east. When the Garibaldi Belt moved to its current location five million years ago, another volcanic event occurred at the Franklin complex. This final and most recent volcanic event occurred between two and three million years ago, about a million years after Mount Cayley to

14196-415: The Garibaldi Belt. A possible explanation for the lower rates of volcanism in the Garibaldi chain is that the associated terrain is being compressed in contrast to the more southern portions of the Cascade Arc. In continental rift zones, magma is able to push its way up through the Earth's crust rapidly along faults, providing less chance for differentiation. This is likely the case south of Mount Hood to

14365-441: The Garibaldi Belt. At the Mount Meager massif, considerable landslides have occurred from Pylon Peak and Devastator Peak in the past 10,000 years that have reached more than 10 km (6.2 mi) downstream in the Lillooet River valley. At least two significant landslides from the southern flank of Pylon Peak 8,700 and 4,400 years ago dumped volcanic debris into the adjacent valley of Meager Creek . More recently,

14534-531: The Garibaldi Volcanic Belt and prevailing winds travel eastwards. Therefore, these communities are less likely to have large amounts of tephra. In the Lower Mainland , a 10 cm (3.9 in) thick layer of volcanic ash can deposit once every 10,000 years and 1 cm (0.39 in) once every 1,000 years. More minor amounts of volcanic ash can be expected more commonly. During Mount St. Helens' eruption in 1980, 1 mm (0.039 in) of tephra

14703-566: The Garibaldi Volcanic Belt, but their tectonic relationships to other volcanoes in the Garibaldi chain are unclear because of minimal studies. Prior to Garibaldi Belt formation, a number of older, but related volcanic belts were constructed along the Southern Coast of British Columbia. This includes the east–west trending Alert Bay Volcanic Belt on northern Vancouver Island and the Pemberton Volcanic Belt along

14872-457: The Garibaldi chain. The oldest volcanics at the Silverthrone Caldera complex are composed of volcanic breccias, some of which became fused together by intense volcanic heat from when the deposits were first erupted. After these volcanics were deposited, a series of dacite, andesite and rhyolite lava flows were erupted upon volcanic breccia from the first volcanic phase. These eroded lava flows in total are 900 m (3,000 ft) thick. Volcanics in

15041-620: The Juan de Fuca Plate under the North American Plate at the Cascadia subduction zone along the British Columbia Coast. This is a 1,094 km (680 mi) long fault zone running 80 km (50 mi) off the Pacific Northwest from Northern California to southwestern British Columbia. The plates move at a relative rate of over 10 mm (0.39 in) per year at a somewhat oblique angle to

15210-471: The Mount Cayley and Mount Meager massifs. A series of hot springs adjacent to the Lillooet River valley, such as the Harrison , Sloquet, Clear Creek and Skookumchuck springs, are not known to occur near areas with recent volcanic activity. Instead, many are located close to 16–26 million year old intrusions that are interpreted to be the roots of heavily eroded volcanoes. These volcanoes formed part of

15379-410: The Mount Meager massif has been undertaken by BC Hydro since the late 1970s. Bottom hole temperatures have been calculated at an average of 220 °C (428 °F) to 240 °C (464 °F), with 275 °C (527 °F) being the highest recorded temperature. This indicates that the area around Meager is a major geothermal site. The geothermal power is expected to run throughout Western Canada and

15548-417: The Mount Meager massif. The springs at Meager massif might be evidence of a shallow magma chamber beneath the surface. No hot springs are known to exist at Mount Garibaldi like those found at Mount Meager and Mount Cayley, although there is evidence of abnormal high heat flow at the adjacent Table Meadows and other locations. Abnormal warm water adjacent to Britannia Beach could be geothermal activity linked to

15717-573: The Philippines, Iran, Pakistan, the Azores in Portugal, Turkey, New Zealand, Greece, Italy, India, Nepal, and Japan. Larger earthquakes occur less frequently, the relationship being exponential ; for example, roughly ten times as many earthquakes larger than magnitude 4 occur than earthquakes larger than magnitude 5. In the (low seismicity) United Kingdom, for example, it has been calculated that

15886-499: The Powder Mountain Icefield has occurred in the past 10,000 years. The icefield was one of several locations in the southern Coast Mountains that attracted ski resort development interest as a result of the success of the nearby ski resort town at Whistler, British Columbia . A proposal call in 1985 was won by Powder Mountain Resorts, who won approval in principle from the provincial government for its project design, which included

16055-508: The Ring Creek flow was normally heated to cook food because its pumice -like texture is able to maintain heat. It also did not break after it was used for a long period of time. A large pumice outcrop adjacent to the Mount Meager massif has been mined several times in the past, and extends more than 2,000 m (6,600 ft) in length and 1,000 m (3,300 ft) in width with a thickness of about 300 m (980 ft). The deposit

16224-598: The Watts Point volcanic zone. People have used resources in and around the Garibaldi Volcanic Belt for centuries. Obsidian was collected by the Squamish Nation for making knives, chisels, adzes and other sharp tools in pre-contact times. This material appears in sites dated 10,000 years old up to protohistoric time periods. The source for this material is found in upper parts of the mountainous terrain that surround Mount Garibaldi. At Opal Cone, lava of

16393-569: The associated lavas. If water were to enter a volcanic vent that is erupting basaltic lava, it may create a massive explosive eruption. These explosions are generally more extreme than those during normal basaltic eruptions. Therefore, the existence of water, snow, or glacial ice at a volcanic vent would increase the risk of an eruption having a large impact on the surrounding region. Subglacial eruptions have also caused catastrophic glacial outburst floods. [REDACTED]  This article incorporates public domain material from websites or documents of

16562-463: The average recurrences are: an earthquake of 3.7–4.6 every year, an earthquake of 4.7–5.5 every 10 years, and an earthquake of 5.6 or larger every 100 years. This is an example of the Gutenberg–Richter law . The number of seismic stations has increased from about 350 in 1931 to many thousands today. As a result, many more earthquakes are reported than in the past, but this is because of

16731-404: The brittle crust. Thus, earthquakes with magnitudes much larger than 8 are not possible. In addition, there exists a hierarchy of stress levels in the three fault types. Thrust faults are generated by the highest, strike-slip by intermediate, and normal faults by the lowest stress levels. This can easily be understood by considering the direction of the greatest principal stress, the direction of

16900-566: The cause of other earthquakes in the past century. A Columbia University paper suggested that the 8.0 magnitude 2008 Sichuan earthquake was induced by loading from the Zipingpu Dam , though the link has not been conclusively proved. The instrumental scales used to describe the size of an earthquake began with the Richter scale in the 1930s. It is a relatively simple measurement of an event's amplitude, and its use has become minimal in

17069-560: The coastal mainland. The Pemberton Belt began its formation when the former Farallon Plate was subducting under the British Columbia Coast 29 million years ago during the Oligocene epoch . At this time, the north-central portion of the Farallon Plate was just starting to subduct under the U.S. state of California, splitting it into northern and southern sections. Between 18 and five million years ago during

17238-419: The construction of a large volcano. Following extensive dissection, renewed volcanism produced a viscous series of lava flows forming its narrow, flat-topped, steep-sided northern limit and the northern end of the main ridge. The conduit for which these lava flows originated from was likely vertical in structure and intruded through older volcanics deposited during Fee's earlier volcanic events. This volcanic event

17407-529: The dip angle of the rupture plane is very shallow, typically about 10 degrees. Thus, the width of the plane within the top brittle crust of the Earth can reach 50–100 km (31–62 mi) (such as in Japan, 2011 , or in Alaska, 1964 ), making the most powerful earthquakes possible. The majority of tectonic earthquakes originate in the Ring of Fire at depths not exceeding tens of kilometers. Earthquakes occurring at

17576-678: The displacement along the fault is in the direction of dip and where movement on them involves a vertical component. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip. The topmost, brittle part of the Earth's crust, and the cool slabs of the tectonic plates that are descending into the hot mantle, are the only parts of our planet that can store elastic energy and release it in fault ruptures. Rocks hotter than about 300 °C (572 °F) flow in response to stress; they do not rupture in earthquakes. The maximum observed lengths of ruptures and mapped faults (which may break in

17745-439: The distance from the earthquake and the underlying rock or soil makeup. The first scale for measuring earthquake magnitudes was developed by Charles Francis Richter in 1935. Subsequent scales ( seismic magnitude scales ) have retained a key feature, where each unit represents a ten-fold difference in the amplitude of the ground shaking and a 32-fold difference in energy. Subsequent scales are also adjusted to have approximately

17914-554: The early 1900s, so it is too early to categorically state that this is the case. Most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000-kilometre-long (25,000 mi), horseshoe-shaped zone called the circum-Pacific seismic belt, known as the Pacific Ring of Fire , which for the most part bounds the Pacific plate . Massive earthquakes tend to occur along other plate boundaries too, such as along

18083-403: The earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane . The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increases the frictional resistance. Most fault surfaces do have such asperities, which leads to a form of stick-slip behavior . Once

18252-426: The earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, with some of the later earthquakes as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen earthquakes that struck the North Anatolian Fault in Turkey in

18421-542: The edifice. With a summit elevation of 2,192 m (7,192 ft), Ring Mountain had its last volcanic activity between 25,000 and 10,000 years ago when the Fraser Glaciation was close to its maximum. Northwest of Ring Mountain lies a minor andesite lava flow. Its chemistry is somewhat unlike other andesite flows comprising Ring Mountain, but it probably erupted from a volcanic vent adjacent to or at Ring Mountain. The part of it that lies higher in elevation contains some features that indicate lava-ice interactions, while

18590-504: The energy released. For instance, an earthquake of magnitude 6.0 releases approximately 32 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 1,000 times more energy than a 5.0 magnitude earthquake. An 8.6-magnitude earthquake releases the same amount of energy as 10,000 atomic bombs of the size used in World War II . This is so because the energy released in an earthquake, and thus its magnitude,

18759-414: The eruption of a lava flow that demolished many times. This created thick agglutinated rubble that successfully blocked the adjacent Lillooet River to form a lake. Subsequently, the breccia dam collapsed to produce a catastrophic flood that deposited house-sized boulders more than 1 km (0.62 mi) downstream. After the flood took place, a small dacite lava flow was erupted that later solidified to form

18928-458: The fact that no single earthquake in the sequence is the main shock, so none has a notably higher magnitude than another. An example of an earthquake swarm is the 2004 activity at Yellowstone National Park . In August 2012, a swarm of earthquakes shook Southern California 's Imperial Valley , showing the most recorded activity in the area since the 1970s. Sometimes a series of earthquakes occur in what has been called an earthquake storm , where

19097-462: The fault has locked, continued relative motion between the plates leads to increasing stress and, therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy . This energy is released as a combination of radiated elastic strain seismic waves , frictional heating of

19266-411: The fault plane that holds it in place, and fluids can exert a lubricating effect. As thermal overpressurization may provide positive feedback between slip and strength fall at the fault plane, a common opinion is that it may enhance the faulting process instability. After the mainshock, the pressure gradient between the fault plane and the neighboring rock causes a fluid flow that increases pore pressure in

19435-418: The fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory . It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or

19604-541: The fault, and rigidity of the rock). The Japan Meteorological Agency seismic intensity scale , the Medvedev–Sponheuer–Karnik scale , and the Mercalli intensity scale are based on the observed effects and are related to the intensity of shaking. The shaking of the earth is a common phenomenon that has been experienced by humans from the earliest of times. Before the development of strong-motion accelerometers,

19773-417: The focus. Once the rupture has been initiated, it begins to propagate away from the focus, spreading out along the fault surface. Lateral propagation will continue until either the rupture reaches a barrier, such as the end of a fault segment, or a region on the fault where there is insufficient stress to allow continued rupture. For larger earthquakes, the depth extent of rupture will be constrained downwards by

19942-406: The force that "pushes" the rock mass during the faulting. In the case of normal faults, the rock mass is pushed down in a vertical direction, thus the pushing force ( greatest principal stress) equals the weight of the rock mass itself. In the case of thrusting, the rock mass "escapes" in the direction of the least principal stress, namely upward, lifting the rock mass, and thus, the overburden equals

20111-401: The formation of volcanic fields. Of the entire Cascade Arc, the Garibaldi chain has the lowest rate of volcanic activity. In the past two million years, the volume of erupted material in the Garibaldi Belt has been less than 10% of that in the U.S. states of California and Oregon and about 20% of that within the U.S. state of Washington. As a result, the risk of eruptions throughout this part of

20280-498: The generation of basaltic magma along the descending plate edge. This eruptive period postdates the formation of the Garibaldi Belt and evidence for more recent volcanism in the Alert Bay Belt has not been found, indicating that volcanism in the Alert Bay Belt is likely extinct. Bedrock under the Garibaldi chain consists of granitic and dioritic rocks of the Coast Plutonic Complex , which makes up much of

20449-493: The ground level directly above it is the epicenter . Earthquakes are primarily caused by geological faults , but also by volcanic activity , landslides, and other seismic events. The frequency, type, and size of earthquakes in an area define its seismic activity, reflecting the average rate of seismic energy release. Significant historical earthquakes include the 1556 Shaanxi earthquake in China, with over 830,000 fatalities, and

20618-410: The intensity of a seismic event was estimated based on the observed effects. Magnitude and intensity are not directly related and calculated using different methods. The magnitude of an earthquake is a single value that describes the size of the earthquake at its source. Intensity is the measure of shaking at different locations around the earthquake. Intensity values vary from place to place, depending on

20787-473: The lack of features indicating volcano-ice interactions. The Slag Hill flow-dominated tuya 900 m (3,000 ft) northeast of Slag Hill proper consists of a flat-topped, steep-sided pile of andesite. It protrudes through remnants of volcanic material erupted from the Slag Hill proper, but it represents a separate volcanic vent due to its geographical appearance. This small subglacial volcano possibly formed between 25,000 and 10,000 years ago throughout

20956-601: The large sheets of glacial ice east of Garibaldi and cause floods. This could later endanger water supplies from Pitt Lake and fisheries on the Pitt River . An explosive eruption and the associated tephra may also create temporary or longer-term water supply difficulties for Vancouver and most of southern British Columbia. The water reservoir for the Greater Vancouver drainage area is south of Mount Garibaldi. Several landslides and lahars have occurred throughout

21125-451: The lavas were erupted during the waning stages of the Fraser Glaciation. The third and most recent eruption produced another lava flow that was largely erupted above glacial ice, but was probably constrained on its northern margin by a small glacier. Unlike the lava flow that was erupted during the second eruption, this lava flow was not impounded by glacial ice at its lower unit. This suggests that it erupted less than 10,000 years ago when

21294-476: The lengths along subducting plate margins, and those along normal faults are even shorter. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary . Earthquakes associated with normal faults are generally less than magnitude 7. Maximum magnitudes along many normal faults are even more limited because many of them are located along spreading centers, as in Iceland, where

21463-558: The likelihood of it extending into the western United States is probable. The belt of volcanoes has been the subject of myths and legends by First Nations . To the Squamish Nation, Mount Garibaldi is called Nch'kay . In their language it means "Dirty Place". This name of the mountain refers to the volcanic rubble in the area. This mountain, like others located in the area, is considered sacred as it plays an important part of their history . In their oral history , they passed down

21632-499: The low volume and differentiated magmas throughout the Garibaldi Volcanic Belt. In 1958, Canadian volcanologist Bill Mathews proposed there could be a connection between regional glaciation of the North American continent during glacial periods and higher rates of volcanic activity during regional glacial unload of the continent. However, this is hard to predict due to the infrequent geological record in this region. But there

21801-538: The lower portion of this series of lava flows give a potassium-argon date of 750,000 years while volcanics slightly above the lava flows are 400,000 years old. The most recent volcanic activity produced a series of andesite and basaltic andesite lava flows down Pashleth Creek and the Machmell and Kingcome river valleys. The lava flow extending from near Pashleth Creek to down the Machmell River valley

21970-407: The lower-elevation portion of it does not. Therefore, this minor lava flow was likely extruded after Ring Mountain formed but when glacial ice covered a broader area than it does currently, and that the lava flow extends beyond the region in which glacial ice existed at that time. The Mount Meager massif is the most voluminous composite volcano in the Garibaldi chain and British Columbia, as well as

22139-402: The main causes of these aftershocks, along with the crust around the ruptured fault plane as it adjusts to the effects of the mainshock. An aftershock is in the same region as the main shock but always of a smaller magnitude, however, they can still be powerful enough to cause even more damage to buildings that were already previously damaged from the mainshock. If an aftershock is larger than

22308-483: The main volcanic vent of a stratovolcano that has since been reduced by erosion. To the southeast, the Salal Glacier volcanic complex was constructed between 970,000 and 590,000 years ago. It consists of subaerial tephra and thin lava flow deposits that are surrounded by 100 m (330 ft) thick ice-ponded lava flows. These ice-marginal lava flows were created when lava ponded against glacial ice in

22477-414: The mainshock, the aftershock is redesignated as the mainshock and the original main shock is redesignated as a foreshock . Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the mainshock. Earthquake swarms are sequences of earthquakes striking in a specific area within a short period. They are different from earthquakes followed by a series of aftershocks by

22646-401: The most recent to erupt. It has a volume of 20 km (4.8 cu mi) and consists of an eroded stratovolcano, ranging in composition from andesite to rhyodacite. Several dissected lava domes and volcanic plugs are present on its glaciated summit, as well as a clearly defined volcanic crater with a lava dome placed within it. At least eight volcanic vents compose the complex and have been

22815-751: The nearby valleys before the Wisconsin Glaciation . North of the Salal Glacier complex lies a small basaltic stratovolcano named Tuber Hill . It began to form about 600,000 years ago when adjacent valleys were filled by glacial ice. When lava flows were erupted from Tuber Hill, they interacted with the valley-filling glaciers on its southern flank and produced a glacial meltwater lake. Here, more than 150 m (490 ft) of stacked hyaloclastite, lahars and lacustrine tuff were deposited. A series of pillow lavas were also deposited during this eruptive period. The most recent volcanic activity in

22984-512: The north shore of Garibaldi Lake is a cinder cone partly engulfed by the Helmet Glacier. It consists of volcanic ash, lapilli and dispersed ropy and lava bomb segments that bring the cone's prominence to 500 m (1,600 ft). Its minimal degree of erosion indicates that it might have erupted in the past 1,000 years. A series of basaltic andesite flows were erupted from Cinder Cone about 11,000 years ago that traveled into

23153-708: The owners B. Chore and M. Beaupre. In a program from 1991 to 1992, workers evaluated the deposit for its properties as a construction material, absorber of oil and stonewash . About 7,500 m (260,000 cu ft) of pumice was mined in 1998 by the Great Pacific Pumice Incorporation. The hot springs associated with Meager and Cayley have made these two volcanoes targets for geothermal explorations. At Mount Cayley, temperatures of 50 °C (122 °F) to more than 100 °C (212 °F) have been measured in shallow boreholes on its southwestern flank. Further north, geothermal exploration at

23322-605: The past 10,000 years might have been caused by volcanic activity. Since the 4,800 BP landslide, a number of more minor landslides have occurred at it. In 1968 and 1983, a series of landslides took place that caused considerable damage to logging roads and forest stands, but did not result in any casualties. The threat from lava flows in the Garibaldi Belt is minor unless an eruption takes place in winter or under or adjacent to areas of glacial ice, such as ice fields . When lava flows over large areas of snow, it creates meltwater. This can produce lahars that could flow further than

23491-601: The plate finally slips, the 500 years of stored energy are released in a mega-earthquake. Unlike most subduction zones worldwide, there is no deep oceanic trench present in the bathymetry of the continental margin in Cascadia. This is because the mouth of the Columbia River empties directly into the subduction zone and deposits silt at the bottom of the Pacific Ocean to bury the oceanic trench. Massive floods from prehistoric Glacial Lake Missoula during

23660-449: The prime volcanic structure. Subsequent erosion demolished the newly formed volcano. This ultimately exposed the roots of the cone, which currently form the rugged edifice of The Black Tusk. After the cone was eroded, a series of hypersthene andesite lava flows were erupted between 0.17 and 0.21 million years ago. These end at adjacent ice-marginal lava flows that form 100 m (330 ft) cliffs. This eruptive phase also produced

23829-527: The prominence of fragmental glaciovolcanic deposits as well. On the eastern side of Howe Sound lies the southernmost zone of volcanic activity in the Garibaldi chain. This zone, known as the Watts Point volcanic centre , is a small outcrop of volcanic rock that is a portion of a subglacial volcano. The outcrop covers an area of about 0.2 km (0.077 sq mi) and an eruptive volume of roughly 0.02 km (0.0048 cu mi). The location

23998-537: The regional Fraser Glaciation retreated. Cauldron Dome , a subglacial volcano north of Mount Cayley, lies west of the massive glacier covering much the region. Like Pali Dome, it is composed of two geological units. Upper Cauldron Dome is a flat-topped, oval-shaped pile of at least five andesite lava flows that resembles a tuya. The five andesite flows are columnar jointed and were likely extruded through glacial ice. The latest volcanic activity might have occurred between 10,000 and 25,000 years ago when this area

24167-530: The rock. In the coseismic phase, such an increase can significantly affect slip evolution and speed, in the post-seismic phase it can control the Aftershock sequence because, after the main event, pore pressure increase slowly propagates into the surrounding fracture network. From the point of view of the Mohr-Coulomb strength theory , an increase in fluid pressure reduces the normal stress acting on

24336-437: The rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, fracking and nuclear tests . An earthquake's point of initial rupture is called its hypocenter or focus. The epicenter is the point at ground level directly above the hypocenter. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at

24505-522: The same numeric value within the limits of the scale. Although the mass media commonly reports earthquake magnitudes as "Richter magnitude" or "Richter scale", standard practice by most seismological authorities is to express an earthquake's strength on the moment magnitude scale, which is based on the actual energy released by an earthquake, the static seismic moment. Every earthquake produces different types of seismic waves, which travel through rock with different velocities: Propagation velocity of

24674-464: The seismic waves through solid rock ranges from approx. 3 km/s (1.9 mi/s) up to 13 km/s (8.1 mi/s), depending on the density and elasticity of the medium. In the Earth's interior, the shock- or P waves travel much faster than the S waves (approx. relation 1.7:1). The differences in travel time from the epicenter to the observatory are a measure of the distance and can be used to image both sources of earthquakes and structures within

24843-458: The sources for volcanic activity throughout massif's 2.2 million year history. A well-documented history of volcanism is present at the Mount Meager massif, with its most recent eruption about 2,350 years ago that was similar in character to the 1980 eruption of Mount St. Helens and the continuous eruption of Soufrière Hills on the island of Montserrat . This is the largest recorded Holocene explosive eruption in Canada, originating from

25012-409: The south began its formation. Silverthrone Caldera is the largest and best-preserved of the two caldera complexes in the northern Garibaldi chain, the other being the Franklin Glacier Complex 55 km (34 mi) to the east-southeast. The caldera has a diameter of 20 km (12 mi) and contains breccia, lava flows and lava domes. Like Franklin to the east-southeast, the geology of Silverthrone

25181-480: The southern end of the chain was established in 1927 to protect the abundant geological history, glaciated mountains and other natural resources in the region. It was named after the 2,678 m (8,786 ft) stratovolcano Mount Garibaldi, which in turn was named after the Italian military and political leader Giuseppe Garibaldi in 1860. To the northwest, Brandywine Falls Provincial Park protects Brandywine Falls,

25350-422: The stresses and strains on the crust, including building reservoirs, extracting resources such as coal or oil, and injecting fluids underground for waste disposal or fracking . Most of these earthquakes have small magnitudes. The 5.7 magnitude 2011 Oklahoma earthquake is thought to have been caused by disposing wastewater from oil production into injection wells , and studies point to the state's oil industry as

25519-402: The subduction zone. Because of the very large fault area, the Cascadia subduction zone can produce large earthquakes of magnitude 7.0 or greater. The interface between the Juan de Fuca and North American plates remains locked for periods of roughly 500 years. During these periods, stress builds up on the interface between the plates and causes uplift of the North American margin. When

25688-414: The subvolcanic intrusions indicate that Franklin formed during two volcanic events, each separated by about five million years of dormancy. The first event occurred between six and eight million years ago when volcanic activity in the Garibaldi Belt had not moved to its current location, but was becoming more aerially restricted within a large band to the east and west. During this period, volcanic activity in

25857-453: The summit and eastern flank of a mountain ridge. It comprises at least one lava flow that reaches a thickness of 100 m (330 ft), as well as the thinnest columnar units in the Mount Cayley volcanic field. The small size of the columnar joints indicates that the erupted lava was cooled immediately and are mainly located on the dome's summit. Ember Ridge Northeast, the smallest subglacial dome of Ember Ridge, comprises one lava flow that has

26026-490: The surrounding fracture networks; such an increase may trigger new faulting processes by reactivating adjacent faults, giving rise to aftershocks. Analogously, artificial pore pressure increase, by fluid injection in Earth's crust, may induce seismicity . Tides may trigger some seismicity . Most earthquakes form part of a sequence, related to each other in terms of location and time. Most earthquake clusters consist of small tremors that cause little to no damage, but there

26195-443: The thickness of the brittle layer is only about six kilometres (3.7 mi). Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary . Reverse faults, particularly those along convergent boundaries, are associated with the most powerful earthquakes (called megathrust earthquakes ) including almost all of those of magnitude 8 or more. Megathrust earthquakes are responsible for about 90% of

26364-461: The total seismic moment released worldwide. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other; transform boundaries are a particular type of strike-slip fault. Strike-slip faults, particularly continental transforms , can produce major earthquakes up to about magnitude 8. Strike-slip faults tend to be oriented near vertically, resulting in an approximate width of 10 km (6.2 mi) within

26533-597: The typical basaltic tuyas throughout British Columbia in that they are composed of piles of flat-lying lava flows and lack hyaloclastite and pillow lava . They are interpreted to have formed as a result of magma intruding into and melting a vertical hole through adjacent glacial ice that eventually breached the surface of the glacier. As this magma ascends, it ponds and spreads into horizontal layers. Lava domes that were formed mainly during subglacial activity comprise steep flanks made of intense columnar joints and volcanic glass . Ice-marginal lava flows form when lava erupts from

26702-505: The universality of such events beyond Earth. An earthquake is the shaking of the surface of Earth resulting from a sudden release of energy in the lithosphere that creates seismic waves . Earthquakes may also be referred to as quakes , tremors , or temblors . The word tremor is also used for non-earthquake seismic rumbling . In its most general sense, an earthquake is any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused mostly by

26871-436: The vast improvement in instrumentation, rather than an increase in the number of earthquakes. The United States Geological Survey (USGS) estimates that, since 1900, there have been an average of 18 major earthquakes (magnitude 7.0–7.9) and one great earthquake (magnitude 8.0 or greater) per year, and that this average has been relatively stable. In recent years, the number of major earthquakes per year has decreased, though this

27040-432: The waning stages of the Fraser Glaciation. Ring Mountain , a flow-dominated tuya lying at the northern portion of the Mount Cayley volcanic field, consists of a pile of at least five andesite lava flows lying on a mountain ridge. Its steep-sided flanks reach heights of 500 m (1,600 ft) and are composed of volcanic rubble. This makes it impossible to measure its exact base elevation or how many lava flows constitute

27209-491: Was also followed by a period of erosion, and likely one or more glacial periods. Extensive erosion following the last volcanic event at Mount Fee has created the rugged north–south trending ridge that currently forms a prominent landmark. Ember Ridge, a volcanic mountain ridge between Tricouni Peak and Mount Fee, consists of at least eight lava domes composed of andesite. They were likely formed between 25,000 and 10,000 years ago when lava erupted beneath glacial ice of

27378-662: Was constructed when volcanic material erupted onto a portion of the Cordilleran Ice Sheet during the Pleistocene period. This created the unique asymmetrical shape of the mountain. Successive landslides on Garibaldi's flanks occurred after glacial ice of the Cordilleran Ice Sheet retreated. Subsequent volcanism about 9,300 years ago produced a 15 km (9.3 mi) long dacite lava flow from Opal Cone on Garibaldi's southeastern flank. This

27547-557: Was constructed, lava flows, tephra and welded dacite rubble were erupted. This second phase of activity 2.7 ± 0.7 million years ago resulted in the creation of the Vulcan's Thumb , a craggy volcanic ridge on the southern flank of Mount Cayley. Lengthy dissection from an extended period of erosion demolished much of the original stratovolcano. Volcanic activity after this prolonged period of erosion produced thick dacite lava flows from parasitic vents 300,000 years ago that extended into

27716-455: Was deposited during three phases of volcanic activity. The first eruptive phase started about four million years ago with the eruption of dacite lava flows and pyroclastic rock. This resulted in the creation of Mount Cayley itself. Subsequent volcanism during this volcanic phase constructed a significant lava dome. This acts like a volcanic plug and composes the lava spines that currently form pinnacles on Cayley's rugged summit. After Mount Cayley

27885-445: Was deposited from southeastern British Columbia to Manitoba . Even though all major cities in southwestern British Columbia are located west of the Garibaldi chain, future eruptions from Mount Garibaldi are expected to have significant impacts on the adjacent townships of Squamish and Whistler . An eruption column released during Peléan activity would discharge large amounts of tephra that would endanger aircraft. Tephra may also melt

28054-431: Was first hired by J. MacIsaac, who died in the late 1970s. In the mid-1970s the second hirer, W.H. Willes, investigated and mined the pumice. It was crushed, removed then stored close to the village of Pemberton . Later, the bridge that was used to access the pumice deposit was washed out. Mining operations resumed in 1988 when the deposit was staked by L.B. Bustin. In 1990, the pumice outcrop was bought by D.R. Carefoot from

28223-625: Was overridden by glacial ice, volcanic activity took place on its northern flank where a satellite vent is present. Renewed activity took place at Clinker Peak on the western flank of Mount Price 9,000 years ago. This produced the Rubble Creek and Clinker Ridge andesite lava flows that extend 6 km (3.7 mi) to the northwest and southwest. After these flows traveled 6 km (3.7 mi), they were dammed against glacial ice to form an ice-marginal lava flow more than 250 m (820 ft) thick known as The Barrier. Cinder Cone on

28392-423: Was still influenced by glacial ice of the Fraser Glaciation. Lower Cauldron Dome, the youngest unit comprising the entire Cauldron Dome subglacial volcano, consists of a flat-topped, steep-sided pile of andesite lava flows 1,800 m (5,900 ft) long and a maximum thickness of 220 m (720 ft). These volcanics were extruded about 10,000 years ago during the waning stages of the Fraser Glaciation from

28561-641: Was the deadliest of the 20th century. The 1960 Chilean earthquake is the largest earthquake that has been measured on a seismograph, reaching 9.5 magnitude on 22 May 1960. Its epicenter was near Cañete, Chile. The energy released was approximately twice that of the next most powerful earthquake, the Good Friday earthquake (27 March 1964), which was centered in Prince William Sound , Alaska. The ten largest recorded earthquakes have all been megathrust earthquakes ; however, of these ten, only

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