La Terre abrite d'immenses volcans appelés "supervolcans" qui peuvent causer d'énormes éruptions, bien plus importantes que tout ce que nous avons jamais vu à l'époque moderne. Certains d'entre eux, comme le Yellowstone aux États-Unis et Campi Flegrei en Italie, montrent des signes d'activité que les scientifiques surveillent de près. Une éruption d'un supervolcan pourrait libérer tellement de cendres et de gaz dans l'atmosphère qu'elle bloquerait la lumière du soleil, entraînant une chute spectaculaire des températures mondiales et affectant l'approvisionnement alimentaire. L'idée que ces géants se "réveillent" semble effrayante, mais les scientifiques travaillent dur pour surveiller tout changement et comprendre ce qui se passe en profondeur. En ce moment, ils améliorent les moyens de détecter les signes d'alerte précoce, comme de petits tremblements de terre ou le soulèvement du sol, qui pourraient annoncer une éruption. Bien que nous ne soyons pas totalement préparés, en savoir plus sur ces supervolcans nous aide à nous préparer, au cas où. Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/ Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ---------------------------------------------------------------------------------------- Si tu en veux encore plus, fais un tour ici: http://sympa-sympa.com
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00:00The largest and most evil supervolcanoes of our planet are awakening.
00:05When they erupt, you will certainly notice it, even if you live thousands of kilometers from the epicenter.
00:11Scientists fear that we do not have enough time to prepare ourselves and face the consequences of a super-eruption.
00:18We observe a volcanic activity near the Italian city of Naples.
00:22And no, it has nothing to do with the famous Vesuvius, but with another volcano.
00:28This one is more difficult to see because its summit is not so high.
00:32But do not let yourself be abused by this bad boy.
00:34It could be much more dangerous than its gigantic neighbor.
00:37It has a huge crater about 13 km wide.
00:41This volcano is called Champs-Légrains.
00:44It is one of the largest in Europe and is located in the Gulf of Pouzole.
00:48The Champs-Légrains erupted 39,000 years ago with such a massive explosion
00:53that it spread ashes throughout the Mediterranean region.
00:57It also caused a temperature drop of more than 9 ° C throughout Eastern Europe.
01:02This was the largest volcanic eruption on the continent in 200,000 years.
01:07Since then, the Champs-Légrains have experienced more modest eruptions, the last dating from 1538.
01:13Today, the region is full of small craters, hot springs and boiling pools
01:19that prove that this supervolcano is still alive and that it has not forgotten us.
01:24Since the beginning of the 2000s, the ground of the giant crater and the neighboring city
01:29slowly rises from 3 to 4 cm per year.
01:32At least 150 earthquakes have shaken this area in recent times.
01:36In May 2024, an earthquake of a magnitude of 4.4 occurred in the region,
01:41the most important in the last 40 years.
01:44Residents had to leave their homes and camp outside because they feared other earthquakes.
01:49No one knows how the Champs-Légrains will behave in the months and years to come,
01:54so the authorities are organizing evacuation exercises to prepare the population for the worst.
02:02But this Italian volcano looks like an innocent kitten compared to the Caldeira of Yellowstone.
02:07For a volcano to deserve the title of supervolcano,
02:10it must be capable of producing catastrophic eruptions
02:13and ejecting huge amounts of magma, ash and volcanic gas.
02:17The Yellowstone Giant meets these criteria.
02:21Even if it moves from time to time, this American supervolcano has not erupted for 640,000 years.
02:27But when it wakes up, it will probably do so with incredible power,
02:32equivalent to that of 10 huge nuclear power plants.
02:36Under the ground of Yellowstone, there is a very hot area filled with melting rocks, the magma.
02:42As this burning matter moves into what is called the magmatic chamber,
02:47the ground above begins to inflate and rise.
02:50When the magma cools down, the ground cools down.
02:54Between 2004 and 2009, the ground of Yellowstone rose by nearly 25 cm,
02:59but it began to descend slowly in 2010.
03:02Scientists do not know if this volcano will soon erupt.
03:06But there is another great volcano, the Caldeira of Long Valley, in California.
03:11It has been active since 1980 and could represent a very important threat to the inhabitants of this state.
03:17Scientists who study it have discovered that it only took a small year to prepare its largest eruption,
03:24which occurred 760,000 years ago.
03:28This is bad news, because the eruption of a supervolcano can have a considerable impact on the planet,
03:33like the eruption of the Toba volcano in Sumatra about 74,000 years ago.
03:38It was the largest volcanic eruption that the Earth has known in 28 million years.
03:43It covered part of Indonesia, India and the Indian Ocean with a thick layer of volcanic debris,
03:49like a 15 cm cover.
03:51The amount of rocks thrown corresponded to nearly 3 million Empire State Buildings stacked on top of each other.
03:57The giant crater created on this occasion is still visible from space.
04:02All the ash and gases rose in the air and blocked part of the sunlight.
04:08Result, a volcanic winter that lasted between 6 and 10 years.
04:12Some scientists think that this eruption could have affected the first humans.
04:16At the time of the eruption of the Toba, the human population suffered a brutal fall.
04:20Some even say that, for this reason, modern men are all from a small group of survivors.
04:26According to the theory of the Toba disaster, most of the first men in Europe and Asia did not survive the cold and harsh climate that followed the eruption.
04:34Only a few lucky people in Africa would have survived this ordeal.
04:38All scientists do not agree on this hypothesis.
04:41Some archaeological and climatic data testify to a completely different story.
04:47Another volcano that profoundly changed the world is the Tambora, in 1815.
04:53The following year entered history as the year without summer.
04:57It was cold and rainy, and there was snow and frost until mid-August, especially in Europe and North America.
05:04This is explained by the fact that the volcano rejected huge amounts of sulfur dioxide into the sky.
05:09The gas then spread throughout the world, which had the effect of cooling the planet.
05:15The eruption of the Tambora also caused devastating tsunamis, which killed nearly 10,000 people.
05:21As a result, about 80,000 other people died as a result of the eruption.
05:27The cold destroyed crops, so that food became very expensive.
05:31And since horses were then our main means of transport, the price of oats also increased considerably.
05:38Some even think that this led to the invention of a brand new means of transport in 1817.
05:44The bicycle.
05:46The eruption made the earth colder for about three years.
05:49But even if it was an event of rare power, it was the disaster of the Krakatoa.
05:54Another Indonesian volcano, which won the palm in 1883.
05:59At that time, it was simply easier to spread information through telegrams and photos.
06:04Its final explosion was the loudest noise ever recorded in history.
06:09People could hear it on 10% of the total surface of the earth.
06:13The eruption triggered a tsunami whose waves reached half the height of the Statue of Liberty.
06:19If we only had 12 months to prepare for the eruption of a supervolcano,
06:23it would be really difficult for us to store enough food for everyone.
06:28But don't panic right away.
06:30Supervolcano eruptions are very rare.
06:32The last one occurred 26,500 years ago in New Zealand.
06:36Scientists think that a super-eruption occurs on average once every 100,000 years.
06:41But what is sad is that the earth does not follow a perfect chronology.
06:45There could be super-eruptions with shorter intervals and longer periods of calm.
06:51Since there have already been two super-eruptions over the last 100,000 years,
06:55there is always a risk that one of them will occur earlier than expected.
07:00In addition to the supervolcanoes of Yellowstone and Long Valley,
07:03scientists state a few less well-known but equally worrying hot spots.
07:08In Chile, the Laguna del Maul has erupted in the past, leaving behind a huge crater.
07:14Over the last 20 years, the ground has risen by nearly 0.3 meters per year,
07:19that is, very quickly.
07:21Some people are worried that this could be the sign of a major eruption to come.
07:25But scientists say that there is not enough magma yet for a disaster to occur.
07:30In Bolivia, the Uturunku volcano is also waking up.
07:34It is part of a group of volcanoes that have been talked about in the past.
07:37Since the 1960s, the ground around the Uturunku has risen,
07:41but the last eruption dates back to 250,000 years.
07:44Even if the magma rises, there is no place to worry for the moment.
07:48The probability that a super-eruption will occur during our lifetime is 1 in 1,400,
07:53which is quite low.
07:55And there is therefore no reason to be overly alarmed.
07:58But just as someone wins the lottery every week with very little chance,
08:02a super-eruption could happen one day or another.
08:05And when it happens, we absolutely have to be ready.