Tsunamis are some of the most feared natural phenomena in the world, and there’s a good
reason why.
These large waves of water can wash away and destroy just about anything in their path,
including ships, cities, and people.
It can also magnify the death and destruction of an already existing catastrophic situation.
This is because the driving force behind tsunamis is usually another powerful and potentially
destructive phenomenon such as an earthquake or a volcanic eruption.
To make matters worse, there are megatsunamis, which are huge waves that are created in a
landslide involving large amounts of dirt and other materials falling into a body of
water.
While typical tsunamis have a wave height of up to 33 feet (10 meters), megatsunamis
have significantly higher wave heights than can range from hundreds or even thousands
of meters.
We will discuss ten of the largest and strongest tsunamis of all time in this episode of The
Infographics Show, “The Biggest Tsunamis Ever.”
10.
2011 Tohoku Tsunami On March 11, 2011, a magnitude 9.0 earthquake
occurred off the east coast of Japan.
A Guardian article describes it as the “fourth most powerful in the history of seismology.”
The earthquake was so strong that “it knocked the Earth six and a half inches off its axis,”
so it is not surprising that the tsunami it created had enormous strength too, reaching
a wave height of 131.2 feet (40 m).
The tsunami killed 18,000 people and devastated coastal communities.
Live Science describes how “waves overtopped and destroyed protective tsunami seawalls
at several locations” and that the “massive surge destroyed three-story buildings where
people had gathered for safety.”
Another potentially dangerous effect of the tsunami is that it “caused a cooling system
failure at the Fukushima Daiichi Nuclear Power Plant, which resulted in a level-7 nuclear
meltdown.”
Besides physical damage, the tsunami and earthquake caused great “financial damage” to Japan
as well.
The World Bank estimates that the “total economic cost could reach up to $235 billion,
. . . making it the costliest natural disaster in world history.”
9.
1883 Krakatoa Tsunamis The August 1883 volcanic eruption of Krakatoa
in what is now Indonesia created a series of powerful tsunamis.
NOAA’s National Centers for Environmental Information states that the “largest wave
was estimated at 135 feet (41 meters) high.”
When the tsunamis ended, not much was left on the islands near Krakatoa.
Vegetation, homes, and people were washed away by the waves.
NOAA estimates that “of the 36,000 people who died, 34,000 of them lost their lives
due to tsunamis.”
8.
1946 Aleutian Islands Tsunami This tsunami was caused by an 8.6 magnitude
earthquake that occurred near Unimak Island, one of Alaska’s Aleutian Islands.
NOAA states that the “waves reached as high as 42 m or about 138 ft.”
The tsunami wiped out a lighthouse on Unimak Island and killed its five occupants, but
there were more casualties.
Oddly enough, the tsunami caused more destruction outside of Alaska than in it.
Hawaii was hardest hit.
A Live Science article describes how the “Hilo waterfront was destroyed” and “surges
as tall as two- and three-story buildings pounded several coastal villages.”
The tsunami “killed 159 people in Hawaii and caused $26 million in damage – in 1946
dollars.”
7.
2004 Indian Ocean Tsunami The 2004 Indian Ocean Tsunami earned a spot
on our list because of its tragic trinity of high power, high wave height, and high
destruction.
This tsunami was caused by the massive Sumatra-Andaman earthquake, which ranged in magnitude between
9.1 and 9.3.
National Geographic estimates that the earthquake “released the energy of 23,000 Hiroshima-type
atomic bombs,” and this energy created powerful waves.
According to Australian Geographic, the 2004 Indian Ocean Tsunami attained a wave height
of almost 164 feet (50 m).
It decimated coastal areas and was one of the deadliest natural events on record.
This tsunami killed about 230,000 people, and Australian Geographic states that it caused
an estimated $10 billion in damage.
6.
1771 Great Yaeyama Tsunami According to NOAA’s National Centers for
Environmental Information, an earthquake with a magnitude of 7.4 shook the Ryukyu Islands
in Japan on April 24, 1771.
The earthquake did less damage than the tsunami it produced.
One source estimates that the wave height of the tsunami at one of the Ryukyu Islands,
Ishigaki, ranged between 131.2 to 262.5 feet (40 to 80 meters) high and that the number
of dead and missing was 12,000 people.
5.
1792 Mount Unzen Tsunami Mount Unzen is a group of stratovolcanoes
located in southern Japan.
On May 21, 1792, the collapse of one of Mount Unzen’s lava domes caused a landslide that
covered the city of Shimabara before crashing into the Ariaka Sea.
According to Popular Science, the 1792 collapse caused “300-foot-high (91.4 m) waves.”
The USGS states that this tsunami traveled “along the adjacent shorelines of Shimabara
Peninsula” and “17-23 km (10.5-14.3 mi.)across the Ariaka Sea in neighboring provinces.”
The USGS calls the 1792 Mount Unzen landslide and tsunami “Japan’s worst historical
volcanic disaster.”
A total of 15,000 people died, but one source estimates that 10,000 out of the 15,000 deaths
were due to the tsunami.
Australian Geographic states that “the cost of damages to agriculture and fish facilities
was estimated at $17.4 billion yen (roughly $150 million).”
4.
2017 Greenland Megatsunami On June 17, 2017, part of the Karrat Fjord
in Greenland gave way, causing a large landslide that cascaded into the ocean.
The science journal Nature reports that rocks and other material fell into the water with
such force that they generated a “seismic signal suggestive of a magnitude-4.1 earthquake”
and a megatsunami with a wave height of 328.1 feet (100 m).
A Daily Mail article states that the waves of this megatsunami “far surpassed the height”
of those caused by the 2011 tsunami in Japan, and they even “sent huge icebergs hurtling
ashore.”
Nature adds that the megatsunami was strong enough to inundate the small fishing village
of Nuugaatsiaq , which is located “on an island within the fjord about 20 kilometers
(12.4 miles) away.”
Eleven houses were lost, and “four people are presumed dead.”
While it did not cause a lot of death and destruction, Nature calls the 2017 Greenland
Megatsunami “one of the tallest tsunamis in recorded history.”
3.
Pico do Fogo Megatsunami Approximately 73,000 years ago, Pico do Fogo,
a 9,300-foot (2834.6 km) volcano on one of the Cape Verde Islands, erupted with such
force that part of it collapsed and crashed into the sea.
A BBC article reports that the impact of the falling debris “created a 240 m (800 ft.)
tsunami wave that engulfed Santiago island 34 miles away.”
It is highly unlikely human lives were lost in this megatsunami because the “Cape Verde
Islands were uninhabited until the mid-1400s.”
Because no human records are available, scientists reconstructed the effects of the Pico do Fogo
Megatsunami on Santiago Island based on geologic evidence.
Some of this evidence indicates that it “inundated the island up to 900 feet (274.3 m) above
sea level” according to a Popular Science article.
Scientist Ricardo Ramalho and his research team were able to confirm through field work
and rock-dating techniques that huge boulders found on Santiago Island were transported
by the tsunami.
This was no small feat because these boulders weighed “up to 770 tonnes (1,697,559.4 lbs.)”
according to a Guardian article.
Ramalho also speculated that “it is highly probable that any (or at least most) of the
flora and fauna within this zone were completely wiped out.”
2.
1980 Spirit Lake Megatsunami When Mount St. Helens erupted in 1980, a collapse
of the upper top of the mountain caused a huge landslide that sent rocks and debris
tumbling into nearby Spirit Lake.
The landslide displaced water in the lake, creating a megatsunami that was 820.2 feet
(250 m) high.
One source states that this wave height was “over 6 times the height of the devastating
tsunami unleashed by the Krakatoa eruption in 1883.”
The damage caused by the megatsunami was limited to the area close to Spirit Lake.
The megatsunami took out nearby trees and debris and deposited them into the lake.
Three people, two amateur volcanologists and a lodge owner, were known to be near Spirit
Lake when Mount St. Helens erupted.
Most sources presume they were killed by the landslide and not the megatsunami.
However, what happened to them will probably never be fully known because their bodies
were never recovered.
1.
1958 Lituya Bay Megatsunami On June 17, 1958, a magnitude 7.8 earthquake
triggered seismic activity along the Fairweather Fault in Alaska.
The earthquake caused a landslide.
Rocks, dirt, and other materials from slopes near the fault tumbled into a nearby body
of water called Lituya Bay, resulting in a megatsunami.
Geologist Don Miller did an aerial inspection of the damage.
According to the Alaska Earthquake Center, Miller searched for the trimline, which is
the water line that marks the highest point that the tsunami reached, and found it to
be 1,720 feet (524.3 m).
Below the trimline, the destruction was described as “absolute.”
Miller saw that “trees and earth had been stripped away to clean bedrock.”
However, the loss of human life and property was minimal due to the fact that the megatsunami
swept through a remote area.
Five people died, and a nearby lighthouse, cabin, and mountaineers’ camp site were
swept away without a trace.
A Smithsonian article calls the 1958 Lituya Bay Megatsunami the “tallest tsunami ever
documented.”
What other tsunamis do you think should be on this list?
Let us know in the comments!
Also, be sure to check out our other video called Biggest Earthquakes Ever!
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See you next time!