00:00The ground is suddenly to tremble.
00:03While the waves of gas are in the sky,
00:06plunging the day in obscurity,
00:08some parts of the ground begin to deform.
00:12Or even to fall off,
00:14many signs of an imminent eruption.
00:17And this scenario could be repeated with the Mont Spur.
00:21Located at about 120 km of Anchorage,
00:23one of the most dynamic areas of Alaska,
00:26the Mont Spur represents a tangible threat.
00:29More than half of the United States,
00:31the most in the north of the United States,
00:33reside in Anchorage.
00:34Every day, a huge amount of freight aériens
00:37transit via its international airport.
00:40Ainsi, when a volcano located so close,
00:43such as crucial,
00:44manifest signs of agitation,
00:46this inevitably attracts the attention of all.
00:51In terms of information,
00:52about 350 millions of people in the world
00:55live in the zone at risk of a volcano.
00:59This means that a person on 20
01:01is exposed to a danger
01:03related to a volcanic eruption.
01:05The Alaskans would probably hope
01:07that the wake of the Mont Spur
01:08relates to fiction.
01:09But the reality is different.
01:11The Volcanology of Alaska
01:13has recorded several signs
01:15characteristic of an imminent activity
01:17volcano,
01:18so that the level of alert
01:20has been raised in the jaune,
01:21indicating an agitation
01:23surpassing the usual levels.
01:25The Mont Spur
01:28is entered in eruption
01:29at two reprises
01:30in the 90's
01:31and its events
01:32were quite powerful.
01:33On a scale of 1 to 10,
01:35they would probably get a note
01:37of 6 or 7.
01:38Without being catastrophes,
01:40they have caused
01:41any damage
01:42estimated
01:43between 10 and 17 millions of dollars.
01:45Cependant,
01:46these numbers
01:47are very terrifying
01:48face
01:49to the eruption
01:50of the Mont Redoute
01:51in Alaska
01:52in 1988,
01:53another volcano
01:54which has caused
01:55some astronomical damage
01:56totaling
01:57345 millions of dollars.
01:59The main reason
02:01is in the volcanic volcano
02:02which has disturbed
02:03the engines of planes
02:04as the image
02:05of KLM 747
02:06where all the engines
02:07were stopped
02:08under the effect
02:09of the sand
02:10before starting
02:11in extremis.
02:12If the geology
02:13unstable
02:14of Alaska
02:15had until now
02:16little attention,
02:17this event
02:18has changed
02:19the data.
02:21When we talk
02:22about the risks
02:23related to the volcanism,
02:24the first image
02:25that is often
02:26that of Pompéi
02:27in Italy.
02:28Of course,
02:29it is the most dramatic scenario
02:31in the city
02:32englouti
02:33by the lava.
02:34Compared to Vésuve,
02:35the Mont Spur
02:36could seem
02:37less dangerous,
02:38but it has still
02:39left the traces
02:40notable.
02:41During its last eruption
02:42in the 1990s,
02:44it has propelled
02:45the aerosols
02:46volcanics
02:47to more than 18000
02:48meters
02:49of altitude.
02:50Clarifying
02:51a scientific point
02:52essential.
02:53The aerosols
02:54volcanics
02:55are liquid
02:56which are
02:57in the atmosphere
02:58during an eruption.
02:59They are formed
03:00generally when
03:01the volcanic gases
03:02like the dioxide
03:03of sulfur
03:04interact with the
03:05water
03:06and other particles
03:07present in the air.
03:08These aerosols
03:09have the capacity
03:10to refroidir the surface
03:11terrestrial
03:12directly
03:13to the solar light
03:14towards the space.
03:15The worst,
03:16they can
03:17remain in the atmosphere
03:18for several years
03:19after an eruption
03:20causing
03:21serious problems
03:22of the sea.
03:23The eruption
03:24has liberated
03:25the avalanches
03:26fulgurantes
03:27of gas
03:28and of the sand
03:29called
03:30pyroclastics
03:31accompanied
03:32of the
03:33sea crues
03:34known as
03:35as
03:36as
03:37as
03:38as
03:39as
03:40as
03:42as
03:43as
03:45as
03:46as
03:47as
03:48as
03:49as
03:50as
03:51as
03:52the
03:53sea
03:54of
03:55the
03:56sea
03:57Despite everything, the first eruption of Mont Spur has had a positive aspect.
04:03The main lesson was the importance of the volcanic surveillance.
04:07With the local control systems, the economic losses could be limited,
04:12which is essential for a city where the air traffic is also dense.
04:16Being considered as currently dormant,
04:19the Mont Spur remains imprevisible and could enter in eruption at every moment.
04:24These volcanoes are generally classified in three categories,
04:27active, dormant or ate, according to their level of activity.
04:31A active volcano is still growing and is still in eruption with a certain regularity.
04:36A dormant volcano, he, shows signs of activity recent,
04:40but is currently asleep.
04:42The volcanoes are still silent for so long,
04:46that they will never wake up again.
04:49Among the most dreadful volcanoes in the United States,
04:54the Mont Saint-Hélène,
04:56responsible for the most violent eruption in the history of the country.
04:59During its last explosion,
05:01the intensity of the breath took about 400 meters from its summit,
05:04making literally disappear the top of the mountain.
05:07If the sea of sand of the Mont Spur seemed spectacular,
05:10that of Saint-Hélène was surpassed by reaching 24 kilometers of altitude,
05:15plunging to the state of Washington in a total obscurity.
05:20But that's not all.
05:22In only three minutes,
05:24the eruption has projected about 3,7 milliards of meters cube
05:27of incandescent and sandals,
05:30of what to fill a million of Olympic piscines on a surface
05:33of 600 square kilometers of luxury forests.
05:36The eruption erupted several weeks before the 18th of 1980.
05:44Finally, a tsunami of a magnitude of 5,0
05:48has caused a gigantic collapse of terrain on one of the slopes of the volcano.
05:53At the end of this historical eruption, 57 lives were lost.
05:58Près de 7000 grand animals,
06:01comme les cerfs et les wapiti,
06:03avaient péri,
06:04tandis que des millions d'oiseaux jonchèrent la terre calcinée.
06:07Bien que les experts ne s'attendent pas à ce que le Mont Saint-Hélène
06:11rejoue un épisode de cette ampleur dans un avenir proche,
06:14ils continuent de le surveiller de près,
06:17car le volcan est loin d'être éteint.
06:19Pour la petite anecdote,
06:21le mot volcan tire son origine de Vulcain,
06:23la divinité romaine du feu.
06:25Les éruptions surviennent souvent au point de rencontre des plaques tectoniques,
06:29ces fragments de la croûte terrestre qui s'assemblent comme un puzzle.
06:33La fameuse ceinture de feu, située dans l'océan Pacifique,
06:37constitue la zone volcanique la plus active du globe.
06:40Elle abrite entre 750 et 915 volcans en activité.
06:45Le plus grand volcan de la ceinture de feu,
06:48et également le plus grand volcan actif au monde, est le Mauna Loa.
06:52Culminant à plus de 4000 mètres, il est situé à Hawaï.
06:56Les chercheurs estiment que ce volcan est en éruption depuis au moins 700 000 ans.
07:00La plus récente a débuté le 27 novembre 2022 pour s'achever le 13 décembre suivant.
07:06Resté silencieux depuis les années 80, le Mauna Loa a fini par s'éveiller.
07:11Heureusement, grâce à la surveillance continue assurée par l'observatoire volcanologique d'Hawaï,
07:16sa dernière éruption n'a fait aucune victime.
07:20Les scientifiques ont massivement investi dans le suivi des volcans.
07:24Non seulement pour limiter les impacts économiques, mais aussi pour sauver des vies.
07:28Leur dernier projet ambitieux consiste à forer directement dans les volcans.
07:34Récemment, des scientifiques ont entrepris un voyage jusqu'en Islande.
07:38Un véritable point chaud volcanique.
07:40Ce pays compte à lui seul près de 33 volcans actifs.
07:44Cependant, celui qui retient particulièrement leur attention est le système volcanique de Krafla,
07:50qui a connu environ 30 éruptions au cours du dernier millénaire.
07:54La plus récente, datant du milieu des années 80.
07:57Le projet Krafla Magma Testbed, ou KMT,
08:00vise à mieux comprendre le comportement du magma sous la surface terrestre.
08:04L'un des principaux atouts de ces recherches par forage est la prévision des risques d'éruption.
08:10Mais elles offrent aussi une opportunité de faire progresser l'énergie géothermique.
08:14Imaginez un monde où l'électricité serait alimentée par une source d'énergie aussi inépuisable que la puissance des volcans.
08:22L'équipe du projet KMT prévoit de débuter le forage en profondeur en 2027,
08:28avec pour objectif d'atteindre plus d'un kilomètre sous terre.
08:32Surveiller l'activité de la lave lorsqu'elle est en surface est une chose,
08:36mais l'étudier lorsqu'elle reste confinée sous terre en est une autre.
08:39Selon les chercheurs, cette approche permettra de véritablement écouter le pouls de la Terre.
08:45D'après eux, ces recherches pourraient être aussi révolutionnaires que la conquête de la Lune.
08:52Et en parlant de cela, saviez-vous que des volcans existaient ailleurs dans le système solaire ?
08:57Oui, d'autres planètes et lunes en abrident également.
09:00Le plus grand volcan connu est Olympus Mons, situé sur Mars.
09:04Il s'agit d'un volcan bouclier similaire à ceux des îles hawaïennes, mais il mesure près de 600 km de large.
09:10Si on l'amenait sur terre, il couvrirait presque toute la Pologne. Impressionnant.
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