‘Hierro’, a volcano and island of the Canary Islands of Spain (named ‘El Hierro’), summits at 1500 meters (4,900 feet), and has gone through periods of highly active earthquake swarms – which leads some to believe that someday ‘something’ may happen. A tsunami.
About El Hierro: Massive Landslide
After three successive eruptions, and consequent accumulations, the island emerged from the ocean as an imposing triangular pyramid volcano.
El Hierro has the largest number of volcanoes in the Canaries with over 500 open sky cones, another 300 covered by the most recent outflows, and some 70 caves and volcanic galleries.
130,000 years ago (some reports say 50,000 years ago), seismic tremors produced massive landslides at El Hierro as a giant piece of the island split off and crashed down into the ocean, scattering along the seafloor.
The submarine landslide, which consisted of approximately 300 cubic kilometers of earth, resulted in the creation of the huge amphitheater of the El Golfo valley, and more importantly caused a super tsunami that most likely rose over 100 meters high, 300 feet, and probably reached as far away as the American coast.
300 Foot Tall Tsunami
Trying to imagine a 300 foot tall tsunami is nearly unimaginable. Knowing the devastation that was caused by the tsunamis in Indonesia and Japan which themselves reached heights ranging between 20 and 50 feet, and the devastation that followed…
The reality is that the odds of such an occurrence is low at any given time. However we cannot escape the fact that sometimes the seemingly random behavior of the geophysical world that we live in — will occasionally unleash devastation.
‘If’ Hierro were to shake itself to the point where another huge chunk of the island plunged into the sea, the potential super tsunami would reach European shorelines in an hour or a few, while the United States east coast would probably be hit in about 6 hours time.
Knowing that the March-2011 major tsunami that tragically hit Japan also traveled 4,000 miles the other direction across the Pacific to produce an approximate 3 foot tsunami on some areas of the United States west coast, the approximate ratio was 10:1 as the wave finally reached the United States coastline.
There are many factors that are at work to determine tsunami height, and this is highly over-simplifying the formula.
But the point is that if a Hierro submarine landslide and subsequent tsunami hit the United States east coast (which is 3,000 miles from the Canary Islands), the tsunami height could potentially be 30 to 40 feet at a minimum (in my estimation) – while some suggest much higher depending on the terrain leading up to the shoreline.
A tsunami like this might completely cover most of Long Island New York, Cape Cod Massachusetts, much of New York City, Boston, and countless other cities and towns up and down the highly populated east coast harboring millions upon millions of people. How about the state of Florida which is only feet about sea level… Unthinkable.
Why mention this at all, and what can we do about it anyway?
It’s good to simply be aware of the possibilities, which may lead to further preparedness by some who’ve never thought of it before.
While doing our best to temper any ‘doom and gloom’, at the same we understand the unpredictability of some things – while also weighing the odds.
Given the the tremors and swarms that sometimes occur at Hierro, and although the odds are low, who’s to say more of the island won’t slump into the sea one day and produce a tsunami scenario?