After the eruption Devastation and ash in Tonga, the last kingdom of Polynesia
Interview Maurizio Ripepe: "Our goal is to predict an eruption weeks in advance"
As the days go by, more details are known about the magnitude of the eruption that affected Tonga on Saturday, a remote Pacific archipelago made up of more than 170 islands that has been practically cut off, covered in ash and with large areas devastated after the explosion recorded on Saturday at the Hunga Tonga-Hunga Ha'apai volcano.
In addition to the three confirmed dead in Tonga, two people drowned in Peru (some 10,000 kilometers away from the site of the eruption) due to the high waves that were recorded in the Pacific after the explosion.
Also in the South American country, the strong waves caused an oil spill that affected beaches in the province of Callao.
This underwater but shallow (shallow) volcano joined the two small islands (Hunga-Ha'apai and Hunga-Tonga) that give it its name, fortunately uninhabited, since they almost disappeared from the map after the eruption, considered the most powerful since the del Pinatubo (Philippines) in 1991. The energy released on Saturday was about 10 megatons (each megaton is equivalent to one million tons of explosive TNT), according to an estimate by NASA scientists.
The geologist Stavros Meletlidis, from the National Geographic Institute (IGN), explains why the eruption has been so explosive: "The magma in the Tonga volcano is more evolved than the one we have in the Canary Islands. It remains in a shallow reservoir for a long time. time until enough pressure builds up for an eruption, that's why they are so explosive," he says in a telephone conversation from Tenerife.
Lava and water, an explosive combination
To the greater explosiveness that characterizes this type of magma, another factor has been added, water, since it is an underwater caldera, although not very deep.
"
When lava comes into contact with water there are three possible scenarios.
That the volume of water is much greater than that of the lava, which is what happened on La Palma, and there are almost no effects; that the interaction is in equal parts, and a certain explosiveness is produced but not very great; or what has happened in Tonga: that there is more lava than water. The water evaporates suddenly and the pressure of these water vapors is added to the pressure of the volcano, multiplying the pressure and multiplying the explosiveness", summarizes the Greek geologist, who compares this volcano in Tonga with that of the most famous Greek island : "Imagine the caldera of Santorini and submerge it in the sea. Thousands of years from now, Tonga will be like Santorini."
The Hunga Tonga-Hunga Ha'apai volcano
had erupted sporadically on several occasions since 2009
.
The most recent activity had begun at the end of last December, with intermittent emissions of ash, steam and tephra (or pyroclasts, that is, the solid fragments of material expelled).
A large explosion was already recorded on January 13, but it was far surpassed two days later, on Saturday the 15th, with an eruption that gave rise to
an atmospheric wave that has traveled the entire planet (
at a speed of between 1,000 and 1,200 kilometers per hour approximately)
and has made two turns.
And it is that, as José Miguel Viñas, meteorologist at Meteored / tiempo.com, explains, the eruption generated "a train of pressure waves through the air that has spread throughout the atmosphere, causing
sudden oscillations in pressure as it passes through the weather stations around the world
", including Spain, where these variations ranged between 1 and 2 hectopascals.
As detailed by Cayetano Torres, spokesman for the State Meteorological Agency (Aemet),
the atmospheric wave generated by the eruption was recorded in our country at 9:00
p.m. (Spanish peninsular time) on Saturday.
The main signal was measured around 11 p.m. and the disturbances lasted until 7 a.m. on Sunday the 16th.
Volcano blast wave Tonga 2022
The atmospheric shock wave spread the sound of the violent explosion to areas as far away as Alaska, to the point that it is believed to have been the most felt on the entire planet since the Krakatau in 1883, in Indonesia.
At the same time, says Viñas, the eruption generated a train of marine waves that has spread throughout the Pacific basin, causing a catastrophic tsunami in the Tonga archipelago and rises in sea level in other coastal areas bathed by that ocean.
The surprise for Viñas has been the meteotsunamis that it has generated even in the Mediterranean, that is,
"the expansive wave that crosses the atmosphere has caused a variation in sea level"
such as that generated by some meteorological phenomena.
40 cm in Minorca
As detailed by the veteran meteorologist Agustí Jansà, former director of the Aemet Meteorological Center in the Balearic Islands, that variation in sea level recorded in the Mediterranean after the eruption in Tonga reached about 40 centimeters in the port of Ciutadella, Menorca.
"It is not an exaggerated meteotsunami,
because in the Balearic Islands every year we usually have between 5 and 10 meteotsunamis caused by storms or by internal gravitational waves of the atmosphere. Occasionally they exceed one meter or even reach two meters. There were two catastrophic episodes singular, in 1984 and 2006, with more than three meters of unevenness. What
I had never measured in my 50 years of work had been a meteotsunami caused by a volcanic eruption.
This does not mean that it had not happened before but we had not measured it ", clarifies Jansà by phone from Palma de Mallorca.
No effects on the weather
On the other hand, the first measurements from meteorological satellites indicate that
the column of material emitted by the volcano would have reached up to 39 kilometers in altitude
, according to Simon Proud, a researcher at the University of Cambridge and the National Center for the Earth. From United Kingdom. If that measurement is confirmed, Proud says, "it would be the tallest cloud of material we've ever seen."
Despite this, José Miguel Viñas
does not believe that this emission of material is going to have an effect on the climate,
as has happened after other eruptions, such as that of Pinatubo in 1991. "On that occasion there were several eruptions and they lasted for days, like that the volcano emitted much more material into the atmosphere and it did cause cooling. It doesn't look like it's going to happen now because although this backfire has emitted a lot of sulfur dioxide, it's not likely to be reflected in this year's temperatures."
Conforms to The Trust Project criteria
Know more
Science and Health
science
HBPR
AstronomyWhat has NASA really said about asteroid 2009 JF1?
ScienceSasha Sagan, on the 25th anniversary of Carl Sagan's death: "My father did not believe in life beyond death, but it seems that he is still among us"
PaperJames Webb: the most sophisticated space telescope will 'travel back in time' to see how it all began
See links of interest
Last News
covid
What
Check Christmas Lottery
Work calendar 2022
The reading
Apothecary Garcia
Celta de Vigo - Osasuna
Real Sociedad - Atletico Madrid
Barcelona - Vallecano Ray
Valencia CF - Seville
Unics Kazan - Barca