A larger form of
tsunami caused by a truly
gigantic landslide, such as a collapsing
island, into a body of water, such as an
ocean or
sea. Such a
tsunami can reach hights of 100 meters, can reach
jet speed and they can reach up to 12km inland, and possibly more in
low-lying regions.
The
possibility of such
colossal disasters was first observed in
Alaska by two
geologists searching for
oil, when they
observed evidence of unusually
large waves in the nearby
bay. Five years later,
landslides were revealed to be the source of the
waves. These
landslides would hit the
water so fast that the
displaced water could not settle before the
rocks had, which increased the
strength of the resulting
wave. Subsequently, this was found to pertain to much larger
landslides as well, including
collapsing island masses.
The
geological record shows that events such as mega tsunamis are very rare, but are extremely
devastating to anything near the receiving
shore when they do occur. The last such event (that we know of) occured approximately 4000 years ago on
Réunion Island, to the east of
Madagascar.
The most likely
candidate for the next mega tsunami is the island of
La Palma, in the
Canary Islands. If the
Cumbre Vieja on
La Palma were to
collapse, the result would be a
massive wave headed straight for the
eastern coast of the
United States, and the
aftermath would hold obvious implications for the stability of the
government and
economy of the world. While potentially not as devastating as a
supervolcano, a mega tsunami would be a very tragic disaster in whatever region of the
world it occured.
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