Thanks to MagellanTV for sponsoring today’s
video. Since late December, the Hunga Tonga-Hunga
Ha'apai volcano has seen a lot of activity in a series of pretty big eruptions. On the 14th January, it was spotted erupting
again by local scientists. This seemingly huge eruption shot ash 20km
into the atmosphere, creating a pillar which stretched high above their view. But this is all about perspective, the impressive
sight from a ground view only appeared like a tiny little pillar from space. The next day, this happened. This eruption, seen by both the GOES West
and Himawari-8 geostationary satellites, show the biggest explosion captured on camera,
perhaps ever. Initial reports state this could dwarf even
the biggest man-made nuclear explosion, and it’s not hard to see why. Just look at how big the ash cloud is. If we overlay it over Europe, we can see that
it covers an impressive surface area. Sorry Luxembourg. Not visible in the satellite images, but detected
with radio wave listening instruments, more than 200,000 lightning flashes were counted
in the plume. Volcanic lightning is still an ongoing topic
of study, and we don’t exactly know the processes that cause it due to the difficulty
in studying it, but scientists are starting to suspect that positively charged particles
come from the eruption itself as well as interactions with ash and the atmosphere. While the island itself was uninhabited, the
islands nearby are. Damage from volcanoes comes in many different
forms. The most obvious is the ash cloud. The nearby islands around Tonga have been
blanketed, with some news reports saying it looks like a grey moonscape on these islands
now, covered by a thin blanket of ash. These before and after satellite images are
revealing. Residents here were all told to stay indoors
while the ash was falling, as breathing it in can be damaging to the lungs. Ash has settled on fresh water supplies, contaminating
them. And what was once a green and colourful place
now looks like what would happen if you turned the saturation on an image all the way down. This isn’t great for plants initially, as
it will block the Sun’s rays from hitting their leaves. Although eventually, it will be good for the
soil of the islands as volcanic ash is a natural fertiliser, containing many important minerals. However, the lightest ash particles didn’t
just go horizontally across the atmosphere but they have also certainly penetrated the
stratosphere. Typically, the Earth’s troposphere and stratosphere
don’t mix that well, so if ash gets into the stratosphere, it will stay there and circulate
around the globe for months to years. The tiniest ash aerosols contain sulphuric
acid, hydrogen sulphide and hydrochloric acid. Interestingly, this may have a very slight
cooling effect on the Earth as a whole, as sulphuric acid, for instance, is known to
reflect sunlight back into space. However, the negative consequences are that
eventually these particles will come back down into the troposphere, where they will
return to the surface in rain droplets, or in other words, acid rain. The next thing you’ll notice is this incredible
shockwave blasting away from the volcano. The fascinating view is seen best in the infrared,
as infrared is better at detecting the slight change in atmospheric temperature caused by
the pressure wave. The pressure wave travelled faster than the
speed of sound, and it was loud. This video may give you some idea of the scale
of this shockwave as it passed by an island 65km away. To be honest, we can be grateful that everyone’s
eardrums didn’t rupture. However, there have been reports that windows
from residences were blasted out by the shockwave. This pressure wave is believed to have travelled
around the world at least 4 times, as detected by weather stations in various countries. Across the US, the shockwave wasn’t audible,
but the effects could be seen in the slight fluctuations in air pressure as it passed
over the country. However, the shockwave was heard in places
as far away as New Zealand and Australia, even in Alaska. Generally speaking, underwater volcanic eruptions
don’t cause tsunamis, but simply due to the scale and sudden nature of this one explosion,
it did in fact cause a tsunami, although not a very big one in the end. It was still enough to do some damage across
the Pacific, however, to coastal regions facing the eruption. When news came that a tsunami was possible,
boats and ships were put out to sea the face the wave head on. As tsunamis reach shore, the amplitude of
the wave increases causing it to look much more visible to a tsunami far out at sea,
which is why the wave looks so big here. These boats are not too far from shore. The last damage I want to examine is to the
volcanic island itself. This island is very new, it’s only been
in existence since 2014. This is because it lies right on the Pacific
and Indo-Australian convergent plate boundary, a tectonically active area. Before 2014, it consisted of 2 mostly submerged
islands, with the caldera around 150m below sea level in between them. It had since erupted, filling the gap, merging
the two islands. As a result, it has actually been studied
by NASA themselves to better understand how water impacts volcanoes, as there are plenty
of old volcanoes on Mars that would have also been surrounded by water. Scientists wanted to track the erosion of
this newly formed island formed in the ocean to see if there are similarities to the erosion
patterns on the literal fields of Martian volcanoes, potentially providing additional
evidence that certain Martian volcanoes were once also surrounded by oceans of water. It’s also interesting for scientists to
be able to tell exactly how analogous planets like Earth and Mars really are, despite their
differences. As for Hunga Tonga-Hunga Ha’apai, the ash
building the island initially was easily washed away by the lapping sea water like a sandcastle
disappearing to the tide, however after about 6 months the erosion stopped as the ash and
seawater actually combined to produce a harder, more resistant type of rock. And had volcanic activity stopped for good,
Hunga Tonga-Hunga Ha’apai would probably have remained a small island for many years
to come. However, the force of the January 15th eruption
has absolutely decimated the island. What was one stretch of land only last year
is now two separate islands again, with the caldera disappearing back below the sea level. However just imagine if one day, Earth was
to meet a similar fate to Mars and its sea was completely drained. What now looks like a tiny little island to
us would still look like a towering 2000m high mountain from the sea floor. While volcanoes on our own planet are pretty
intimidating, we can take solace in the fact that an explosion of this size could have
been a lot worse for us humans. Moreover, this particular island will likely
continue to be examined by NASA for years yet, helping us understand our own planet
but also our neighbours in the solar system. And why should we care? Well, volcanic activity at this scale can
have global impacts, and by understanding their interactions with the atmosphere and
oceans, we not only can help predict our futures, but understand the past on planets like Mars. I’m guessing that you must find volcanoes
interesting if you clicked on this video, and if you want to know more about other volcanoes
around the world, MagellanTV has some great documentaries on some. One that I enjoyed is called “Guatemala:
Volcanoes on Mayan Territory” where they talk about the Santiaguito volcano, which
despite its size, has only existed for the last 100 years due to its constant eruptions. What impresses me so much about volcanoes
and this one in particular is how they can rise up for thousands of metres above the
surrounding landscape. Just look at this view from the top - breath-taking. MagellanTV is a subscription streaming platform
containing over 3000 documentaries, with more being added weekly, covering a variety of
topics like space and science. If you want to check out this documentary
I mentioned or any like it, you can watch it for free by using my link in the description,
which will give you MagellanTV for a month, so why not give it a go? Thanks for watching! Usually, my videos are more space related,
but this view of the eruption from space, plus the connection with Mars meant I just
couldn’t pass this topic up. If you liked this video, then I hope I earned
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