Following the 2011 Tōhoku earthquake, there was speculation in the media that the shock may induce volcanic unrest at Mount Fuji. In September 2012, mathematical models created by the National Research Institute for Earth Science and Disaster Prevention (NRIESDP) suggested that the pressure in Mount Fuji's magma chamber could be 1.6 megapascals higher than it was before its last eruption in 1707. This was interpreted by some media outlets to mean that an eruption of Mount Fuji could be imminent. However, since there is no known method of directly measuring the pressure of a volcano's magma chamber, indirect calculations of the type used by NRIESDP are speculative and unverifiable.
Current eruptive danger
Mount Fuji
Mount Fuji | Current eruptive danger
Yes,  indicators suggestive of heightened eruptive danger, such as active fumaroles and recently discovered faults, are typical occurrences at this type of volcano. NRIESDP suggested that the pressure in Mount Fuji's magma chamber could be 1.6 megapascals higher than it was before its last eruption in 1707 Following the 2011 Tōhoku earthquake, there was speculation in the media that the shock may induce volcanic unrest at Mount Fuji. In September 2012, mathematical models created by the National Research Institute for Earth Science and Disaster Prevention (NRIESDP) suggested that the pressure in Mount Fuji's magma chamber could be 1.6 megapascals higher than it was before its last eruption in 1707. This was interpreted by some media outlets to mean that an eruption of Mount Fuji could be imminent. Sorry. I cannot find the answer based on the context.
where do jet streams occur in the atmosphere
user
On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds
assistant
how were they discovered?
user
In 1920s, Wasaburo Oishi, detected the jet stream from a site near Mount Fuji.
assistant
where is this mountain located?
user
It is  located on the island of Honshū, is the highest mountain in Japan
assistant
how do people climb this mountain?
user
Climbers usually start at the fifth stations, as these are reachable by car or by bus. The summit is the tenth station on each trail. The stations on different routes are at different elevations
assistant
is it a volcanic mountain?
user
Yes, Scientists have identified four distinct phases of volcanic activity in the formation of Mount Fuji. The first phase, called "Sen-komitake", is composed of an andesite core recently discovered deep within the mountain.
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is it a threat currently?
user
Experts have found that the internal pressure of the Mount Fuji magma chamber has increased to an estimated 1.6 megapascals, raising speculation over the possibility of an eruption. The financial damage to Japan from a Fuji eruption is estimated at ¥2.5 trillion (about $25 billion).
Historic eruptions of Mount Fuji | Current eruptive danger
Other indicators suggestive of heightened eruptive danger, such as active fumaroles and recently discovered faults, are typical occurrences at this type of volcano.
Mount Fuji | Current eruptive danger
Following the 2011 Tōhoku earthquake, there was speculation in the media that the shock may induce volcanic unrest at Mount Fuji. In September 2012, mathematical models created by the National Research Institute for Earth Science and Disaster Prevention (NRIESDP) suggested that the pressure in Mount Fuji's magma chamber could be 1.6 megapascals higher than it was before its last eruption in 1707. This was interpreted by some media outlets to mean that an eruption of Mount Fuji could be imminent. However, since there is no known method of directly measuring the pressure of a volcano's magma chamber, indirect calculations of the type used by NRIESDP are speculative and unverifiable.
Mount Fuji | Current eruptive danger
Scientists study the activity of the magma rising by measuring CO emissions in the deeper parts of the volcano. Studies from before the Tohoku earthquake show the CO emissions below 5 gCO/m/day, which is the detection limit. If the emissions rise above 5 gCO/m/day then seismic activity is occurring and an eruption could possibly take place. According to a five-stage evolutionary model for the release of volcanic gas, Mt. Fuji would be considered stage I. Magma is at a considerable depth and no emissions of gases can be observed regularly. Following the 2011 Tōhoku earthquake and tsunami, much attention was given to the volcanic reaction of Mount Fuji.
Historic eruptions of Mount Fuji | Current eruptive danger
Two fatal incidents have happened in modern history due to volcanic gas emitted from the northern group. On 12 July 1997, three soldiers of the Japan Self-Defense Forces died after gas accumulated in the valley they were training in. On 20 June 2010, a teenage girl died after being exposed to volcanic gas near Sukayu Onsen. After the 2011 Great East Japan earthquake, seismic activity around the volcanic group increased. After a series of earthquakes between February and October 2013, Mount Ōdake saw a degree of deformation. Future eruptions are forecast to come from the peak of Mount Ōdake and Jigokunuma, a volcanic crater lake.
Hakkōda Mountains | Modern activity and the current threat
Due to volcanic deformation, the summit of Mount Takada-Ōdake shifted to the west and increased in elevation by , shifting its summit from the border of Aomori and Towada to being entirely in the city of Towada. As of May 2020, intense fumarole activity is ongoing at Jigokunuma near Sukayu Onsen and National Routes 103 / 394.
Hakkōda Mountains | Modern activity and the current threat
The volcano continues to pose a serious threat to nearby towns and villages. The most likely hazard is small-volume eruptions, which might destabilize glaciers and trigger lahars. Despite the significant retrenchment of the volcano's glaciers, the volume of ice atop Nevado del Ruiz and other volcanoes in the Ruiz–Tolima massif remains large. Melting merely 10% of the ice would produce mudflows with a volume of up to —similar to the mudflow that destroyed Armero in 1985. Such lahars can travel up to along river valleys in a matter of few hours. Estimates show that up to 500,000 people living in the Combeima, Chinchiná, Coello-Toche, and Guali valleys are in danger, and 100,000 of these are considered to be at high risk.
Nevado del Ruiz | Current threats and preparedness
Erciyes Dagi volcano has manifested explosive eruptions preceding the formation of lava domes. Such eruptions may endanger the cities of Kayseri, Hacilar, and Talas. Melting of the remnant ice on the volcano may generate dangerous lahars; in 1985 an eruption of Nevado del Ruiz volcano in Colombia claimed 20,000 fatalities after such a mudflow. Even without an eruption, strong rainfall could form mudflows on the densely populated steep slopes of the volcano. About five hotels exist at the mountain, which is a major winter sports site. In 2010, 324,221 tourists visited the mountain and Kayseri, most of them domestic tourists.
Mount Erciyes | Threats and human interaction
With a warming climate, increased rain and increasing glacial meltwater may accelerate edifice collapse. This has potential implications for more landslide hazards in the area of the volcano, and tsunami risks in the lake area.
Yate (volcano) | Future Dangers
The volcano continues to pose a serious threat to the surrounding area. In 1997, a group of university and industry scientists associated with the Geological Survey of Canada spent six weeks camping at the edge of Hoodoo's summit ice cap to determine the volume of water on the volcano's summit which could be mobilized in the event of an eruption using ice-penetrating radar. This group included Mark Stasiuk and Catherine Hickson of the Geological Survey of Canada, Alison Rust, Kelly Russell and Ben Edwards of the University of British Columbia, Trevor Page of Lancaster University, Guy Cross and Jeff Schmok of Golder Associates and Jim Nicholls of the University of Calgary.
Hoodoo Mountain | Current threats and preparedness
Hoodoo's summit ice cap remains thick and in diameter and throughout the volcano's history, it has been influenced by glacial ice. Most of the volcano's volcanic activity has produced lava flows from its flat-topped summit, indicating any potential volcanism will occur under the summit ice cap to trigger considerable melting, flooding and mudflows, which could have a disastrous effect on the adjacent Iskut and Stikine rivers. Although very few people live in the region, large mining and mineral exploration camps exist south of Hoodoo Mountain on the Iskut River. Should there be renewed activity in the form of lava flows, damming of the Iskut River would be a significant hazard to these mining and mineral operations.
Hoodoo Mountain | Current threats and preparedness
Localized carbon dioxide toxicity, known locally as 'mazuku', has killed children even more recently. In locations where the gas seeps from the ground at relatively high levels, without the dispersing effects of wind, its effects can be deadly. On March 8, 2016, Goma Volcano Observatory discovered a new vent that opened in the northeast edge of the crater, following local reports of rumblings coming from the volcano. Some fear that this could lead to a flank eruption.
Mount Nyiragongo | Ongoing threat
Past eruptions of Quizapu Crater ejected enormous amounts of ash that traveled as far as Brazil. After the 1932 eruption, the local vegetation was devastated, and the area remained barren until the 1990s, though human life was not impacted. Despite the extent of its eruptions, the threat to humans from Quizapu is relatively small because of the remote location of Cerro Azul. Nevertheless, the size of past eruptions is large enough for scientists to be worried. Evidence of a potentially deadly threat lies in a lahar at Descabezado Grande. Historically, lahars have killed thousands in the Andes. There is, however, a possibility that a large reservoir of rhyodacite magma may exist under the Azul–Descabezado complex.
Cerro Azul (Chile volcano) | Threats and preparedness
The mountain, being seen as sacred by the local inhabitants, and it's remoteness means that deforestation is not a current problem. The most serious threat to the species is the horticultural trade. There have been instances of foreign collectors entering the area and removing 100-200 seedlings at one time.
Encephalartos kanga | Threats
Minor hydrothermal explosions could still potentially be dangerous, as the ejection of ballistic blocks or tall waves could threaten people standing near the lake, traveling at speeds from . Landslides could threaten visitors to the national park or researchers by creating tsunami-sized waves, also potentially damaging infrastructure surrounding the lake.
Mount Mazama | Recent activity and potential hazards
Today, the volcano lies dormant within Nisga'a Memorial Lava Beds Provincial Park. Gases currently being emitted by the volcano are evidence that the volcano is still active and potentially dangerous. Signs of unrest such as seismic activity and increased gas output will almost certainly precede any future eruptive activity from the Tseax Cone. If the Tseax Cone were to erupt, its effects would be felt throughout the interior of British Columbia. There may be a repeat of the poisonous gas disaster that happened to the Nisga'a people during the last eruption. If the lava flows are voluminous enough, they could spark forest fires and dam local rivers, crippling the local ecosystem.
Tseax Cone | Potential for a future eruption
If eruptive activity were to resume, scientists would likely be able to detect increased seismicity as magma makes its way through the crust. The abundance of seismic activity and the sensitivity of the existing Canadian National Seismograph Network in this area would alert the GSC and possibly trigger an expanded monitoring effort. As the magma nears the surface, the volcano would likely swell and the surface fracture, causing greatly increased vigour in the hot springs and the creation of new springs or fumaroles. Minor and possibly large landslides could occur and might temporarily block the Squamish River, as has happened in the past without earthquake shaking and intrusion-related deformation.
Mount Cayley massif | Volcanic hazards
In 2018, the United States Geological Survey National Volcanic Threat Assessment gave Kīlauea an overall threat score of 263, and ranked it first among volcanoes in the United States most likely to threaten lives and infrastructure. In June 2019, readings from USGS instruments indicated that Kīlauea's shallow summit magma chamber was slowly refilling with magma. The presence of the new water lake in Halemaʻumaʻu means that Kīlauea's next summit eruption could be explosive, if magma rises rapidly to the surface. However, this is uncertain, as there is plenty of underground water present at Kīlauea's summit, and yet, the volcano did not experience any explosive eruptions over the past century.
Kīlauea | Future threats
Though the Mount Cayley massif is currently quiet, it still poses potential hazards to nearby towns as well as logging and recreational areas. GSC seismic data suggest that the volcano still contains magma, indicating possible future eruptive activity and associated volcanic hazards such as landslides. An eruption scenario for the volcano was organized by GSC scientists in 2000 to show how Western Canada is vulnerable to such an event. They based the scenario on past activity in the Garibaldi Volcanic Belt and involved both explosive and effusive activity. The scenario was published in 2003 as an article for "Natural Hazards", a Springer journal devoting on all aspects of natural hazards including risk management and the forecasting of catastrophic events.
Mount Cayley massif | Volcanic hazards
Large scale eruptions from Mount Ōdake have the potential to send lahars (volcanic mudflows) to heavily populated areas of the cities of Aomori and Towada, to the northwest and east, respectively, of the volcanic complex. Potential lahars would flow to Towada by the Oirase River and its tributaries and to Aomori by the Tsutsumi and Komagome rivers. The junction of the Tsutsumi and Komagome rivers just north of Tsutsui Station on the Aoimori Railway Line would be the most heavily impacted populated area during a large eruption, with many areas struck by over a meter of debris. An eruption from Mount Ōdake could also produce pyroclastic flows that could travel up to and expel lava up to from the volcano.
Hakkōda Mountains | Modern activity and the current threat
Mount Fuji is the tallest volcano in Japan, and also the highest peak. The mountain as it appears now is the "New Fuji volcano", which began to erupt about 10,000 years ago. Under the "New Fuji volcano" lies the "Old Fuji volcano", which was active between 100,000 years ago and 10,000 years ago, and the "Komitake volcano", which became active 700,000 years ago.
Historic eruptions of Mount Fuji | Introduction
Whether the ongoing unrest at Uturuncu is part of a benign process of pluton growth or the prelude of a new eruption or even a caldera-forming eruption is an open question; a large caldera-forming eruption could have catastrophic, globe-spanning consequences as demonstrated by the 1815 eruption of Mount Tambora in Indonesia and the 1600 eruption of Huaynaputina in Peru; this possibility has resulted in international media attention. Evidence does not clearly indicate that a future "super-eruption" such as past events in the region is possible and there is no indication for a near-future eruption, but there is certainly potential for a smaller eruption.
Uturuncu | Threats
Beginning in June, repeated collapse of this erupting dome generated ash flows that swept down the mountain's slopes at speeds as high as . Unzen is one of more than 75 active volcanoes in Japan; an eruption in 1792 killed more than 15,000 people—the worst volcanic disaster in the nation's history.
Stratovolcano | Hazards
However, according to the Volcano Hazards Program of the United States Geological Survey, the threat potential from the field is "Low/Very Low." Eruptive activity within the nearby Cascades Range is likely to resume. Deformation near the Three Sisters complex volcano suggests the presence of intrusive magma in the region, which could eventually lead to eruptions, though the intrusion appears to be currently stalled. Further magma intrusions could lead to eruptions that would create new cinder cones similar to those in the Sand Mountain Field. Moreover, hazardous volcanic gases could accumulate after an eruption, such as sulfur dioxide, hydrogen chloride, and hydrogen fluoride.
Sand Mountain Volcanic Field | Future threats
Moreover, the Lassen volcanic center poses threats to visitors from sudden avalanches that could be entirely unrelated to eruptive activity. Due to the threat of an avalanche from nearby Chaos Crag if volcanic activity renewed in the area or an earthquake occurred, the Visitor Center for Lassen Peak located at Manzanita Lake closed in 1974. In 1993, a rockfall with a volume of fell down Lassen Peak's northeastern flank, but no visitors were harmed. Despite the volcano's current quiet state, rockfalls still pose significant hazards due to the peak's inherent instability.
Lassen Peak | Recent activity and current threats
The most recent recorded volcanic eruption was between 1820 and 1854, but many eyewitnesses reported eruptive activity in 1858, 1870, 1879, 1882, and 1894 as well. Seismic monitors have been placed in Mount Rainier National Park and on the mountain itself to monitor activity. An eruption could be deadly for all living in areas within the immediate vicinity of the volcano and an eruption would also cause trouble from Vancouver, British Columbia, Canada to San Francisco, California because of the massive amounts of ash blasting out of the volcano into the atmosphere. Mount Rainier is located in an area that itself is part of the eastern rim of the Pacific Ring of Fire.
Mount Rainier | Modern activity and threat
In the 1980s, the Iskut River was studied as a possible site for a hydroelectric plan. However, the plain was left alone partly because of the uncertain volcanic potential in the surrounding environment. High columns of volcanic ash associated with explosive eruptions would have more widespread effects, including disruption of air traffic between Canada, Alaska, and Asia. However, this is a less possibility because most eruptions at Hoodoo Mountain are lava flows. The Interagency Volcanic Event Notification Plan, Canada's volcanic emergency notification program, was established to outline the notification procedure to some of the main agencies that would be involved in response to a volcanic eruption in Canada, an eruption close to Canada's borders, or an eruption significant enough to have an effect on Canada and its people.
Hoodoo Mountain | Current threats and preparedness
Many farmers live in the paths of such possible destructive events. Although volcanic eruptions are notoriously chaotic in their frequency, some scientists warn that a large eruption is "overdue". Research from Massey University indicates that significant seismic activity is likely again in the next 50 years. Prevailing winds would probably blow ash east, covering much of the North Island, and disrupting air routes, power transmission lines and local water supplies.
Mount Taranaki | Hazards
Future eruptions from Volcano Mountain would probably be lava flows, since there is a lack of pyroclastic material. The main hazards from Volcano Mountain are forest fires started by the lava flows and poisonous gases. Older volcanic deposits south of Volcano Mountain indicate that lava flows may have once partly blocked or at least altered the course of the Yukon and Pelly Rivers. Any future activity in this area could disrupt the course of both of these major rivers and could have a serious impact on people living or working downstream.
Volcano Mountain | Volcanic hazards
Route 97, disabling transportation in the area, in addition to likely ruining gas pipelines and power lines that extend electricity to California, both of which would be accompanied by serious economic consequences. Flank lava flows, which would likely be basaltic in origin, might form lava fountains that could scatter cinders and lava for several thousand meters, building cinder cones or initiating forest fires. While the flows themselves move at rates of per minute, and thus could be escaped by animals and humans, they would destroy stationary structures in their paths. Pyroclastic flows, on the other hand, travel at speeds of , and their violent force could incinerate or pulverize objects in their path, or asphyxiate living things.
Newberry Volcano | Recent activity and current threats
In light of the dangers it presents to nearby populations, Sakurajima was designated a Decade Volcano in 1991, identifying it as worthy of particular study as part of the United Nations' International Decade for Natural Disaster Reduction.
Sakurajima | Recent activity
The population is thought to be between 1,505 and 52,734. Accurate numbers are hard to estimate due to cloud coverage over its range. Some of its natural threats include birds, snakes, and the giant civet. Mount Awu can also be considered a natural threat as well, since it is an active and deadly volcano on the island. Anthropogenic causes include habitat loss or fragmentation, the introduction of cats and dogs to the island, population density increases in its territory, and pet trade.
Sangihe tarsier | Threats
Mazama is considered dormant, but it remains monitored by the United States Geological Survey Cascades Volcano Observatory. Future eruptions would likely take place near the western side of the complex and within the caldera rim; they could occur underwater. The ejection of lava rich in gas from shallow water could produce huge ash columns, but submarine eruptions at deeper depths may decrease the explosiveness of the event. Nonetheless, the rapid mixing of water and lava could produce dangerous pyroclastic surges, which are more gaseous and less solid than pyroclastic flows. Such flows could pass over topographic barriers, move rock fragments at , and travel several miles from their vent.
Mount Mazama | Recent activity and potential hazards
Seismic data suggest that these volcanoes still contain active magma chambers, indicating possible future eruptive activity. Although the available data do not allow a clear conclusion, these observations are indications that some of Canada's volcanoes may be active, with significant potential dangers. This seismic activity correlates both with some of Canada's most youthful volcanoes and with long-lived volcanoes with a history of significant explosive activity, such as Hoodoo Mountain and the Mount Edziza volcanic complex. If magma were to rise towards the surface of Nazko, new earthquake swarms would occur, with a significant increase in the size and number of earthquakes.
2007–2008 Nazko earthquakes | Preparedness and hazards
The latest eruption, in 1707 (the 4th year of the "Hōei" era), was known as the great "Hōei" eruption. It followed several weeks after the Great "Hōei" earthquake, an 8.7 on the Richter scale. The earthquake severely damaged the city of Osaka, but more than that, it created enough seismic activity to compress the magma chamber 20 km deep in the inactive Mt. Fuji. Due to the compression of the magma chamber, basaltic lava rose from the bottom to the higher dacitic magma chamber at 8 km deep. The mixing of the two different types of magma caused a Plinian eruption to occur.
Historic eruptions of Mount Fuji | Hōei eruption
The mountain is currently under an immense deforestation threat. Locals have cited that there is a man in the mountain, angry due to the deforestation that was happening. Others say that it was Aring Sinukuan.
Mount Arayat | Introduction
The threat of landslides started in October 2017. The monsoons in early June caused problems. Surveyors say that it is due to the fact that the volcano is composed of soft sandstone. With the heavy rain and the buildings on the mountain changing the flow of water there have been landslides. There have also been problems with deforestation making the soil erodible and more susceptible to landslides. The government is now putting into place projects to consolidate soil on the mountain. There is also planning to put in place better drainage systems. The government is also making efforts to move residents to safety off of the mountain, however, many are refusing to relocate.
Mount Popa | Landslides
To date, Edziza and Hoodoo pose the greatest threats in the Northern Cordilleran Volcanic Province. A large pumice deposit scattered throughout the Edziza complex highlights one of the significant volcanic hazards associated with the complex, including the possibility of a large explosive eruption. This large pumice deposit indicates that the Mount Edziza volcanic complex has a history of producing not only fluid and passive basaltic lava flows, but also more silica-rich trachytic and rhyolitic lava flows and explosive eruptions. The silica-rich compositions are similar to those associated with the most catastrophic eruptions on Earth. A large explosive eruption at the Edziza complex could produce an eruption column that would affect parts of the Pacific Northwest.
Volcanic history of the Northern Cordilleran Volcanic Province | Recent activity and hazards
Eruptive activity began about 4,000,000 years ago and has since undergone three stages of growth, the first two of which built most of the massif. The latest eruptive period occurred sometime in the last 400,000 years with lesser activity continuing into the present day. Future eruptions are likely to threaten neighbouring communities with pyroclastic flows, lahars (volcanically induced mudslides, landslides and debris flows) and floods. To monitor this threat, the volcano and its surroundings are monitored by the Geological Survey of Canada (GSC). Eruption impact would be largely a result of the concentration of vulnerable infrastructure in nearby valleys.
Mount Cayley massif | Introduction
Pre-Komitake started erupting in the Middle Pleistocene in an area north of Mount Fuji. After a relatively short pause, eruptions began again which formed Komitake Volcano in the same location. These eruptions ended 100,000 years ago. Ashitake Volcano was active from 400,000 to 100,000 years ago, and is located southeast of Mount Fuji. Mount Fuji started erupting 100,000 years ago, with Ko-Fuji (old-Fuji) forming 100,000 to 17,000 years ago, but which is now almost completely buried. A large landslide on the southwest flank occurred about 18,000 years ago. Shin-Fuji (new-Fuji) eruptions in the form of lava, lapilli and volcanic ash, have occurred between 17,000 and 8,000 years ago, between 7,000 and 3,500 years ago, and between 4,000 and 2,000 years ago.
Mount Fuji | Geology
An eruption from the volcano would threaten the immediate surrounding area, in addition to places downstream near river valleys or downwind that could be affected by ashfall. Lahars (volcanically induced mudslides, landslides, and debris flows) and tephra could extend far from the volcano, and Mount Jefferson may also produce pyroclastic flows, lava domes, and lava flows. Though the population within is only about 800 people, there are more than 550,000 people living with of the volcano. Lava flows from Mount Jefferson or another volcano nearby might form lava domes that could collapse, also yielding pyroclastic flows. Moreover, while basaltic lava flows from surrounding monogenetic vents tend to travel slowly and typically only reach from their source, and therefore would not pose serious hazards to much wildlife or humans, they would still burn and bury anything they encountered.
Mount Jefferson (Oregon) | Recent activity and potential hazards
Threats from future eruptions of Isluga consist primarily in the contamination of aquifers and destruction of agricultural areas by ash falls, both limiting factors in the desertic environment surrounding the volcano. Additionally, the cultural value of the region would be endangered, also given the relative lack of documentation thereof.
Isluga | Threats
In late 2012 the mountain became quite active, spewing volcanic ash. In November 2012, and continuing into 2013, a 3 km exclusion zone was set up and residents living around the mountain were evacuated or moved to Maumere city on the main island of Flores. In the first 8 months of 2013 there was regular activity from the lava dome including repeated ash plumes – generally reaching altitudes of 2–3 km – dome collapses, explosions, avalanches and pyroclastic flows.
Paluweh | 2012–2013
Though Newberry Volcano is currently quiet, the United States Geological Survey considers it an active volcano with a "very high" threat level. Hot springs within the caldera remain active, and small earthquakes have occurred within recent local history. Any future eruptions would likely show similar characteristics to eruptions from the past 15,000 years, ranging from effusive production of lava flows to explosive eruptions ejecting pumice and ash. If future lava flows from Newberry Volcano are of comparable size to its late Pleistocene eruptions, they would bury settlements throughout the Central Oregon region. They would also likely destroy segments of U.S.
Newberry Volcano | Recent activity and current threats
Based on the history of Tutupaca, a future eruption can be envisaged where renewed activity causes another collapse of the volcano. In this case, about 8,000–10,000 people, as well as neighboring geothermal power and mining infrastructure, would be in danger. Several small towns, diversion dams, irrigation canals, and the two roads IloDesaguadero and TacnaTarataCandarave would also be vulnerable. Other dangers are ballistic rocks, pyroclastic flows, scoria avalanches, ash and pumice rains, volcanic gas and lahars. The Peruvian Instituto Geológico, Minero y Metalúrgico (INGEMMET) has published a volcano hazard map for Tutupaca, but the volcano itself was not monitored since it is not active.
Tutupaca | Hazards
There has been volcanic activity in the vicinity of Mount Fuji for several million years. The earliest geologically known volcano was that became active 700,000 years ago. Another volcano to the south-east of Mount Fuji—known as —was also highly active throughout the period. The peak of Komitake is about above sea-level on the north face of Mount Fuji (at the fifth station). Komitake entered another period of activity around 100,000 years ago. This created a new volcano known as that reached a height of . It created many explosive eruptions that threw out large amounts of scoria, volcanic ash and lava.
Historic eruptions of Mount Fuji | Komitake and Old Fuji
Climbers reported steam eruptions in the summit craters for decades after activity apparently ceased in 1921, and the naturalist Paul Schulz documented 30 steam vents at the summit in the 1950s. A report from the United States Geological Survey declared that "No one can say when, but it is almost certain that the Lassen area will experience volcanic eruptions again." Similarly, the California Volcano Observatory lists its threat level as "Very High." At the time of the early 20th century eruptions, the area surrounding the volcano was only sparsely populated, but a similar eruption today would threaten many lives and the northern Californian economy.
Lassen Peak | Recent activity and current threats
Renewed volcanism is likely to result in the creation of mafic cinder cones, with the latest such event having occurred with the eruption of Nazko Cone 7,200 years ago. However, eruptions of less mafic magma, typical of earlier activity of the Anahim hotspot, cannot be ruled out.
Anahim hotspot | Volcanic hazards
Volcanic eruptions occur with similar frequency to major earthquakes from the San Andreas Fault, and at least 10 eruptions have taken place within the state during the past 1,000 years, the most recent at Lassen Peak. Under 1 percent of the state's population lives within hazard zones that could be affected by an eruption, but collectively hazard zones are visited by more than 20 million people each year. Moreover, a number of the potentially active Californian volcanoes reside less than from highly populated areas, and explosive eruptions could produce ash that travels for several hundred miles. In the case of signs that suggest impending volcanic activity, the United States Geological Survey has a plan in place to utilize portable monitoring instruments, deploy scientists to the area, and implement an emergency response plan developed by the National Park Service if an eruption were imminent.
Lassen Peak | Recent activity and current threats
More than 9,000 people live in the danger zone. Ash fall from an eruption could extend southeastward to the border with Chile]and affect the towns of Candarave, Ilabaya, Pachia, Palca and Tarata. Volcanic earthquakes like the 1999 Ticsani earthquakes at a volcano farther north and volcanic gases constitute additional dangers.
Yucamane | Hazards
The volcano has potential to produce huge debris avalanches that could inundate large areas of the Pacific coastal plain. In areas around the volcanoes and downslope toward the coastal plain, more than 100,000 people are potentially at risk from these and other flowage phenomena.
Acatenango | Volcanic hazards
About 5,000 people live within to Ticsani and would be threatened in the case of a future eruption, with particular hazards including ash fall, lahars, pyroclastic flows and the collapse of lava domes. In addition to the local population, ashfall would hit major regional roads and reservoirs. Towns in the area include Calacoa, Cambrune, Carumas, Quebaya, San Cristobal and Soquezane. The volcano is classified as being a "High Risk Volcano". In 2015, facilities to monitor the chemical composition of hot springs around the volcano were installed, and devices to recognize deformations of the volcanic edifices are installed. The Peruvian Southern Volcanological Observatory (Observatorio Vulcanológico del Sur) publishes monthly reports on Ticsani since 2014, which include reports on seismic activity and on sulfur dioxide emissions.
Ticsani | Hazards
The flanks of the volcano do not pose a lower threat to the population than the area near the rift zones because the distance is short and the slopes are steep; lava poses as much of a threat as it does near its source. Since 1991, the Hawaiian Volcano Observatory (HVO) has maintained a seismic recording station east of Hualālai's summit to monitor the volcano. During this time, not a single earthquake swarm or harmonic tremor, indicative of activity at the volcano, has occurred. Although Hualālai does experience several magnitude-4 earthquakes per year, these are attributed to a deep source off the coast of the north-western rift zone and are not related to the movement of magma.
Hualālai | Future monitoring
About 30,000 people live in the immediate area of Huaynaputina today, although over 69,000 and 1,008,000 live in the nearby cities of Moquegua and Arequipa, respectively. The towns of Calacoa, Omate, Puquina and Quinistaquillas and others would be threatened in case of renewed eruptions. A repeat of the 1600 eruption would likely cause a considerably greater death toll owing to population growth since 1600, in addition to causing substantial socioeconomic disruption in the Andes. The 1600 eruption is often used as a worst case scenario model for eruptions at Peruvian volcanoes. In 2017, the Peruvian Geophysical Institute announced that Huaynaputina would be monitored by the future Southern Volcanological Observatory.
Huaynaputina | Hazards and volcanological research
It focuses primarily on aviation safety because air traffic can quickly enter areas of volcanic ash. The program notifies all impacted agencies that have to deal with volcanic events. Aircraft are rerouted away from hazardous ash and people on the ground are notified of potential ash fall.
Hoodoo Mountain | Current threats and preparedness
Presently, Parinacota is dormant, but future volcanic activity is possible. Explicit fumarolic activity has not been observed, but satellite imaging has shown the evidence of thermal anomalies on the scale of , and reports of sulfurous smells at the summit imply that a fumarole may exist in the summit area. The volcano is seismically active including one potential seismic swarm, but earthquake activity is less than at Guallatiri farther south. Based on Landsat Thematic Mapper images, it was considered a potentially active volcano in 1991. The volcano is one among ten volcanoes in northern Chile monitored by SERNAGEOMIN and has a volcano hazard level published.
Parinacota (volcano) | Present-day activity and hazards
Listed at a "moderate" threat level by the United States Geological Survey, Mount Bachelor poses little threat of becoming an active volcano in the near future. It may be part of a monogenetic volcanic field, meaning that the volcano only underwent one long series of eruptions before stopping activity altogether, but it may just be inactive, and it could erupt in the future. It remains unclear whether Mount Bachelor is merely dormant or whether it is completely extinct. The Bachelor volcanic chain lies within a lava flow hazard zone that exists in central Oregon, and eruptions from this field of mafic volcanoes may produce eruptions of tephra and lava flows extending for from their source vents.
Mount Bachelor | Potential hazards
Hualālai is expected to erupt again in the near future, as a 200- to 300-year estimated pause in activity is coming to an end. This presents a distinct hazard to the communities around it as well; for example, in the event of an eruption similar to the 1801 event, Kailua-Kona, which is from the volcano's summit, could be covered completely in a matter of hours. According to the USGS lava-flow hazard zones, on a scale of 1 to 9, all of Hualālai is listed as threat level 4. For comparison, almost all of Kīlauea and Mauna Loa is listed as threat levels 1 through 3.
Hualālai | Future monitoring
There is evidence that changes in stress caused by large earthquakes may be sufficient to trigger volcanic eruptions, assuming that the magma system involved is close to a critical state. The great earthquake in 1707 may have caused changes in pressure in the magma chamber beneath Mount Fuji through a static stress change. Mount Fuji erupted on 16 December 1707, 49 days later.
1707 Hōei earthquake | Eruption of Mount Fuji
Geologically, the mountain is a cinder cone of andesite, formed by volcanic activity. It is thought that the mountain is a dormant vent to a still active volcano (designated Iō-tō, the name of the island as a whole). From 1889 to 1957, the Japanese government recorded sixteen eruptions on the peak. One eruption lasted for sixty-five minutes, and created a crater with a diameter of 35 meters and a depth of fifteen meters on the runway near the former airfield from World War II. The Japanese Meteorological Agency reported that on May 2, 2012, a small eruption caused water discoloration to the northeast, and confirmed the appearance of a new fumarole.
Mount Suribachi | Geology
Sakurajima's activity became more prominent in 1955, and the volcano has been erupting almost constantly ever since. Thousands of small explosions happen each year, throwing ash to heights of up to a few kilometers above the mountain. The Sakurajima Volcano Observatory was set up in 1960 to monitor these eruptions. Monitoring of the volcano and predictions of large eruptions are particularly important because it is in a densely populated area, with the city of Kagoshima's 680,000 residents just a few kilometers from the volcano. The city conducts regular evacuation drills, and a number of shelters have been built where people can take refuge from falling volcanic debris.
Sakurajima | Recent activity
This would have disastrous short-term consequences for the important salmon fisheries found along the Nass River system. Further study and monitoring of the volcano is necessary in order to predict when the Tseax Cone might erupt, perhaps giving those living downslope and downwind the opportunity to evacuate, much like that which preceded the 1980 eruption of Mount St. Helens.
Tseax Cone | Potential for a future eruption
It is the worst volcanic disaster in the country's recorded history. Mount Fuji is a dormant stratovolcano that last erupted on 16 December 1707 till about 1 January 1708. The Hōei eruption of Mount Fuji did not have a lava flow, but it did release some of volcanic ash. It spread over vast areas around the volcano and reached Edo almost away. Cinders and ash fell like rain in Izu, Kai, Sagami, and Musashi provinces. In Edo, the volcanic ash was several centimeters thick. The eruption is rated a 5 on the Volcanic Explosivity Index. There are three VEI-7 volcanoes in Japan.
Geography of Japan | Volcanic eruptions
This includes mountains and calderas like Mount Shasta and Lassen Peak in California, Crater Lake, Three Sisters, and Mount Hood in Oregon, Mount Saint Helens, Mount Adams, Glacier Peak, and Mount Baker in Washington, and Mount Cayley, Mount Garibaldi, Silverthrone Caldera, and Mount Meager in British Columbia. All of the above are dormant, but could return to activity, and scientists on both sides of the border gather research of the past eruptions of each in order to predict how mountains in this arc will behave and what they are capable of in the future, including Mount Rainier. Of these, only two have erupted since the beginning of the twentieth century: Lassen in 1915 and St.
Mount Rainier | Modern activity and threat
In April 2005, the Directorate of Volcanology and Geological Hazard Mitigation raised an alert, forbidding visitors from going up the volcano. "Sensors on the slopes of the two mountains - Anak Krakatoa on the southern tip of Sumatra Island and Tangkuban Perahu in Java - picked up an increase in volcanic activity and a build-up of gases, said government volcanologist Syamsul Rizal." On the mountain's northern flank is Death Valley, which derives its name from a frequent accumulation of poisonous gases.
Tangkuban Perahu | Introduction
All Colombian cities were directed to promote prevention planning in order to mitigate the consequences of natural disasters, and evacuations due to volcanic hazards have been carried out. About 2,300 people living along five nearby rivers were evacuated when Nevado del Ruiz erupted again in 1989. When another Colombian volcano, the Nevado del Huila, erupted in April 2008, thousands of people were evacuated because volcanologists worried that the eruption could be another "Nevado del Ruiz". In 2006, heavy rains on Ruiz sent a mudslide down the Chinchiná River, killing nine youths aged 12–19 on a scouting expedition near the volcano.
Nevado del Ruiz | Current threats and preparedness
In a 1974 report by the United States Geological Survey, scientists wrote that "some of the most catastrophic geologic events of the recent past resulted directly or indirectly from volcanism at the site of the Chaos Crags." Pyroclastic flows and avalanches from the formation reached the areas where parts of the Manzanita Lake visitor center facilities now reside. If the Chaos Crags resumed activity, they could erupt pumice, pyroclastic flows, or swift rockfalls, in addition to creating lava domes, though these would not pose major threats to human life should the surrounding area be evacuated promptly. These pyroclastic flows could reach regions directly surrounding the eruptive volcanic vent, and would extend at least into the nearby valley floors.
Chaos Crags | Potential hazards and monitoring
The volcano has an approximate rock generation rate of , lower than other arc associated volcanoes. Nevertheless, with eruptive episodes being separated by gaps of about 40,000 years between the last episodes, dangerous eruptive activity in the future is possible. However, the region surrounding the volcano is thinly populated, so major damage to infrastructure or danger to human life is unlikely.
Nevado Tres Cruces | Hazards
Though the population within of Mount Mazama is only about 50 people, more than 270,000 live within of the volcano. Even so, highly consequential eruptions at Mazama seem unlikely in the near future. Large, pyroclastic eruptions like the climactic eruption are unlikely for thousands of years. Similarly, the release of lethal gases like carbon dioxide from Crater Lake, similar to the eruption from Lake Nyos in Cameroon in 1986, is unlikely as a result of the natural mixing of deep and surface water within the lake. There is no known mechanism by which Crater Lake's water could be catastrophically drained or by which the caldera walls would fail suddenly.
Mount Mazama | Recent activity and potential hazards
Future eruptions from Nazko Cone are unlikely to cause many fatalities, due to the region's remoteness. There is active logging and ranching in the region, and people engaged in these activities are at some risk. Lava flows are likely to flow only a few kilometres from the volcano which could possibly start forest fires in the dry region. Any future eruption is likely to affect low flying air traffic only, since eruptions would likely be in the form of Hawaiian eruption- lava fountains that create small cinder cones and lava flows rather than voluminous ash clouds.
Nazko Cone | Hazards
During the last stages of eruption, different and more resistant forms of lava that were cooler than those flows that created the shield volcano remained to form the current peak. The whole central Mount Warning massif was also pushed up by forces that remained active after lava eruptions had stopped.
Mount Warning | Shield volcano
The volcanoes are stratovolcanos that are 1 million to 200,000 years old. The rock is mainly basalt, dacite, and andesite. Mount Yoko has shown the most recent activity and is now considered an active volcano. It last erupted about 800 years ago. In 888 a debris avalanche on the East side of the volcanic massif caused Lake Matsubara to form. The Tateshina-kogen plateau was formed by a large lava flow.
Northern Yatsugatake Volcanic Group | Geology and volcanic activity
On 2 May 2008, a level-1 warning was issued after GNS scientists who were monitoring the lake found irregular signs of volcanic activity. This included increased chemical changes, gases and temperature. The warning was used to let visitors know the potential of an explosion was higher than usual and could happen at any time. This could also be a follow-up to the previous year's 2007 eruption. A GeoNet New Zealand Bulletin was released on 21 July 2008 stating that "the current phase of volcano unrest appears to be over, however Ruapehu remains an active volcano. Future eruptions may occur without warning." However the level has remained at 1, where it has been since 1997.
Mount Ruapehu | Warnings post-2007
Moreover, if pyroclastic flows mix with snow or water overflowing from the crater lakes, they could spawn lahars, volcanically induced mudslides, landslides, and debris flows that could devastate the Paulina Creek valley and reach the La Pine valley within 30 minutes. Threats from the volcano pose hazards to about 16,400 people who live within and more than 180,000 people living within .
Newberry Volcano | Recent activity and current threats
The United States Geological Survey monitors Mount Shasta and rates it as a very high-threat volcano.
Mount Shasta | Volcanic status
The volcano is considered to be potentially active because of the fumarolic activity, and SERNAGEOMIN publishes a volcano hazard index for Ollagüe. A seismometer array was deployed in 2010-2011. Future eruptions of Ollagüe may threaten the town of Ollague away and the highway .
Ollagüe | Recent activity and hazards
Volcanic gases are another major hazard to Taveuni, as they can easily cause respiration problems, poison water, and corrode metal. Most of the gases include: and a few others.
Mount Taveuni | Volcanic Gases
The mountain has been selected by the Volcanic Eruption Prediction Council as a volcano that requires a complete monitoring and observation system for volcanic disaster prevention. It is a volcano that has a depression due to erosion between Mt. Shirane and Mt. Goshiki, which are composed of old Neogene volcanic rocks around the highest peak, Mt. Okushirane. This is a newly formed lava dome where there are mountains of the Shirane volcano group such as Maeshirane, Goshikiyama, Sotoyama, and Shiranekakuzan, which are stratovolcanoes. About 5300 years ago, there have been several large-scale eruptions, and it is believed that there are more than four eruptions that left sediments in the vicinity.
Mount Nikkō-Shirane | Volcanic History and Activity
National Science Foundation. Later, while a research professor and translator at Tokyo Metropolitan University, Glicken became involved with research at Mount Unzen. The volcano had recently resumed eruptive activity in November 1990, after being dormant for 198 years. In the months after its first activity, it erupted sporadically, and the government evacuated its vicinity near the end of May 1991. On June 2, 1991, Glicken visited the mountain with Katia and Maurice Krafft. The three entered a danger zone near the base of the volcano the following day, assuming that any potentially hazardous pyroclastic flows would follow a turn in the landscape and safely bypass them.
Harry Glicken | Research after St. Helens and death
The summit of the volcano has a number of small active fumaroles emitting sulfur dioxide and other gases, including low levels of hydrogen sulfide. A scientific assessment in 2006, published in the journal Eos, observed that "in the past 30,000 years, eruptions have occurred at a rate of only four to six per millennium, with a predominance (70%) of very low hazard, basaltic eruptions". The authors further commented that "the recent eruptive record, combined with the available petrological and radiometric data, provides a rather optimistic outlook on major volcanic hazards related to Teide and its rift zones, posing only very localized threats to the one million inhabitants of Tenerife and the 4.5 million annual visitors to Teide National Park." However, another study in 2009 concluded that Teide will probably erupt violently in the future, and that its structure is similar to that of Vesuvius and Etna.
Teide | Potential eruptions
On January 25, 2017, bereaved families of five victims filed a lawsuit against the country and Nagano prefecture, seeking damages of 150 million yen. They argued that the warning level should have been raised prior to the eruption. The government said that the Japan Meteorological Agency had not raised the warning level even though earthquake levels were slightly elevated, because the warning level was based on additional data and historical activity.
2014 Mount Ontake eruption | Trial
Beyond this distance, slope angles are about 27°, which is caused by an increase in scoria. Mid-flank slope angles decrease from 23° to less than 10° in the piedmont. Scientists have identified four distinct phases of volcanic activity in the formation of Mount Fuji. The first phase, called "Sen-komitake", is composed of an andesite core recently discovered deep within the mountain. "Sen-komitake" was followed by the ""Komitake" Fuji", a basalt layer believed to be formed several hundred thousand years ago. Approximately 100,000 years ago, "Old Fuji" was formed over the top of "Komitake" Fuji. The modern, "New Fuji" is believed to have formed over the top of Old Fuji around 10,000 years ago.
Mount Fuji | Geology
If another caldera-forming eruption of similar magnitude to previous ones at the volcano occurred, pyroclastic flows could devastate the area surrounding the volcano for up to . However, pyroclastic flows have been rare at Newberry. Tephra from explosive eruptions would short-circuit electric transformers and power lines, clog engine filters, produce clouds that might yield lightning, and pose a hazard to aircraft overhead. It would also pose health hazards because ash particles can irritate eyes, and when ingested, lungs, among other health issues. Because of water from the two crater lakes, eruptions at Newberry Volcano may become more explosive and more likely to produce pyroclastic flows.
Newberry Volcano | Recent activity and current threats
During an eruption, tephra could accumulate to in the city of Bend, and mudflows and pyroclastic flows could run down the sides of the mountain, threatening any life in their paths.
Broken Top | Recent history and potential hazards
Flank eruptions, mostly in the form of parasitic cinder cones, ceased in 1707. The largest cone, Omuro-Yama, is one of more than 100 cones aligned NW-SE and NE-SW through the summit. Mt. Fuji also has more than 70 lava tunnels and extensive lava tree molds. Two large landslides are at the head of the Yoshida-Osawa and Osawa-Kuzure valleys.
Mount Fuji | Geology
The volcano continues to pose a serious threat to nearby towns and villages. Of the threats, the one with the most potential for danger is that of small-volume eruptions, which can destabilize glaciers and trigger lahars. Although much of the volcano's glacier mass has retreated, a significant volume of ice still sits atop Nevado del Ruiz and other volcanoes in the Ruiz–Tolima massif. Melting just 10 percent of the ice would produce lahars with a volume of up to similar to the lahar that destroyed Armero in 1985. In just hours, these lahars can travel up to along river valleys.
Armero tragedy | Legacy
Although basaltic lava flows are the most common eruptive activity in the Lassen volcanic center, they could also produce more violent and thus more hazardous silicic lava flows, in addition to building additional, unstable lava domes that could collapse and spawn pyroclastic flows that could extend for several miles. Because Lassen Peak has a significant amount of snow and ice, these pyroclastic flows (or hot volcanic ash) might mix with water to form lahars (volcanically induced mudslides, landslides, and debris flows) that could destroy nearby communities. Dacitic eruptions could produce volcanic columns of gas and ash that could threaten aircraft in the area.
Lassen Peak | Recent activity and current threats
If this is the case, all previous eruptions in 1846–1967 were only preliminary, preclimactic leaks from the large magma chamber beneath, and a large caldera-forming eruption may be expected in the future.
Cerro Azul (Chile volcano) | Threats and preparedness
The risk of an eruption in any given year is currently estimated as 1 in 1,000. When lahars reach populated areas, they can bury structures and people. An example was the Armero tragedy at Nevado del Ruiz where 23,000 died from an enormous mudflow. Lahars from Glacier Peak pose a similar threat to the small communities of Darrington and Concrete and a lesser threat to the larger and rapidly growing towns of Mount Vernon and Burlington, as well as other communities along the lower Skagit and Stillaguamish Rivers. A 2005 study conducted by the United States Geological Survey identified nine Cascade volcanoes, including Glacier Peak, as "very-high-threat volcanoes with inadequate monitoring".
Glacier Peak | Hazards
Presently, Ampato is considered to be a dormant volcano. Potential hazards from future eruptions at Ampato are lahars induced by melting of the icecap and sub-Plinian eruptions, considering the history of explosive eruptions at this volcano. The Peruvian geological service has published a hazard map that describes danger areas of both Ampato and Sabancaya. Hazards mapped include both the fall of ash and the formation of lahars which can advance to distances of in the southerly valleys of Ampato. Pyroclastic fallout primarily threatens the vicinity of the volcano but large eruptions can result in fallout over large areas around the volcanic complex.
Ampato | Hazards
Sangay can and has been climbed. It was first ascended in 1929 by Robert T. Moore, prior to its current eruption beginning in 1934. However, the volcano's current active state presents dangers to mountaineers in the form of falling ejecta; in 1976, two members of an expedition on the volcano were struck and killed by falling debris. In addition, the volcano is located in a remote region with poor roads and is difficult to access, and periods of heavy rainfall can flood rivers and cause landslides, rendering the mountain routes impassable. Nonetheless, the Instituto Ecuatoriano Forestal y de Areas Naturales, which maintains an office near the mountain, facilitate such activities by providing local guides and rooms for rent to visitors.
Sangay | Recreation
In 1792, the collapse of one of its several lava domes triggered a megatsunami that killed 14,524 people in Japan's worst volcanic-related disaster. The volcano was most recently active from 1990 to 1995, and a large eruption in 1991 generated a pyroclastic flow that killed 43 people, including three volcanologists. Its highest peaks are at and at . The latter emerged during the eruptions of the early, eponymous Heisei era (1989–2019).
Mount Unzen | Introduction
After mid-2008, the number of volcanic earthquakes close to Ngauruhoe declined to the background level. Regular measurements of volcanic gas levels and the temperature of a summit gas vent failed to record any significant changes over the subsequent two and a half years. GNS Science accordingly reduced the alert level for Ngauruhoe to Level 0 on 2 December 2008. “The reduction in earthquake activity means that an eruption in the near future is unlikely without further earthquakes or other changes and the appropriate alert level is therefore zero”, said GNS Science Volcano Section Manager Gill Jolly. An increase in seismic activity in March 2015 resulted in the alert level being raised to Level 1.
Mount Ngauruhoe | Recent activity
The presence of an ice cap, and therefore the risk of incandescent volcanic rocks melting that ice, creates a hazard of lahars, or mudflows, such as those that in 1985 killed over 23,000 people at Nevado del Ruiz volcano in Colombia. The risk to life is further increased by Coropuna's steep slopes and by the concentration of people in nearby valleys. The terrain around the volcano has one of the greatest topographic reliefs in the world and a number of towns lie on the floor of the Majes valley, right down to the Pacific Ocean where the district capital Camaná with 20,000 inhabitants is situated.
Coropuna | Hazards and monitoring
So just in case I sometimes do 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 below the surface. The existence of hot springs at the Mount Meager massif and Mount Cayley indicates that magmatic heat 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.
Garibaldi Volcanic Belt | Volcanic hazards
Williams' 1944 paper defined the basic outline of the Three Sisters vicinity, though he lacked access to chemical techniques and radiometric dating. Over the past 70 years, scientists have published several reconnaissance maps and petrographic studies of the Three Sisters, including a detailed geological map published in 2012. Neither North nor Middle Sister is likely to resume volcanic activity. An eruption from South Sister would pose a threat to nearby life, as the proximal danger zone extends from the volcano's summits. During an eruption, tephra could accumulate to in the city of Bend, and mudflows and pyroclastic flows could run down the sides of the mountain, threatening any life in their paths.
Three Sisters (Oregon) | Recent history and potential hazards
Because of the small size of the earthquake swarms, Natural Resources Canada has added more seismographs in the region for better location and depth accuracy. However, the size and number of the 2007 earthquake swarms indicate there is currently no threat of an eruption. Before magma could erupt in the area adjacent to Nazko Cone, it is expected the size and number of the earthquakes would rise considerably, presaging an eruption.
Volcanism of Canada | Recent activity
If an eruption does occur, Taveuni's economy could easily be destroyed. Nearly all farms will catch on Fire and nearly every port in Taveuni is in a hydrovolcanic hazard zone or a lahar hazard zone, and all imports/exports would be completely stopped until the ports are repaired.
Mount Taveuni | Hazards
The volcano is currently active. A few volcano tectonic earthquakes occur on Martinique every year, and Mount Pelée is under continuous watch by geophysicists and volcanologists (IPGP). Before the 1902 eruption—as early as the summer of 1900—signs of increased fumarole activity were present in the Étang Sec crater (Scarth, p. 30). Relatively minor phreatic (steam) eruptions that occurred in 1792 and 1851 were evidence that the volcano was active. Signs of unrest are likely to precede any future eruptive activity from Mount Pelée, and its past activity (including the violent eruptions uncovered by carbon dating) is an extremely important factor for hazard assessment.
Mount Pelée | Current status
Rock fall would affect the area close to the summit domes, as would pyroclastic flows; these would be a further hazard to the valleys draining the volcano. The presence of an ice cap is an additional source of danger, as its melting during a volcanic eruption could form hazardous lahars, although the small volume of the ice cap limits their damage potential. The Majes River and Sihuasi River drainages would be threatened by such mudflows in case of an eruption; the former is the site of a major irrigation project. Other dangers from eruptions at Sabancaya are tephra fallout, which can impact the health of people; and lava flows, which however are not much of a threat to humans owing to their slow speed.
Sabancaya | Hazards