Etna Tsunami Impact Analysis

This is another story about when and not if. There seems to be a scientific consensus that the south eastern flank of Mount Etna is breaking off or (best case) sliding into the sea. Most of the old Roman coastal empire (Africa is included) is going to take in some serious flooding due to the resulting Tsunami.

The event will be bad enough which until a few months ago I was totally unaware.. I post this for the latest animations showing where the devastation is likely to occur and the time frame to "Run Away" after it happens !


youtu.be...

a reply to: 727Sky

I found the paper that is shown at the beginning of this video.

The southeastern flank of Etna volcano slides into the Ionian Sea at rates of centimeters per year. The prevailing understanding is that pressurization of the magmatic system, and not gravitational forces, controls flank movement, although this has also been proposed. So far, it has not been possible to separate between these processes, because no data on offshore deformation were available until we conducted the first long-term seafloor displacement monitoring campaign from April 2016 until July 2017. Unprecedented seafloor geodetic data reveal a >4-cm slip along the offshore extension of a fault related to flank kinematics during one 8-day-long event in May 2017, while displacement on land peaked at ~4 cm at the coast. As deformation increases away from the magmatic system, the bulk of Mount Etna’s present continuous deformation must be driven by gravity while being further destabilized by magma dynamics. We cannot exclude flank movement to evolve into catastrophic collapse, implying that Etna’s flank movement poses a much greater hazard than previously thought. The hazard of flank collapse might be underestimated at other coastal and ocean island volcanoes, where the dynamics of submerged flanks are unknown.

The above is the abstract.

What is said in the paper regarding the potential for tsunamis:

Catastrophic collapses of ocean island volcanoes or those built at the shoreline pose the largest threat as the sudden displacement of large amounts of material in water can trigger tsunamis with extreme effects (4, 5).

Here are the two papers that are cited:

Island Edifice Failures and Associated Tsunami Hazards

Hazard potential of volcanic flank collapses raised by new megatsunami evidence

Neither of which speak specifically about this event happening at Etna.

Going back to the paper mentioned above:

Notably, the observed length change in the network of ~4 cm provides a minimum estimate of the true slip along the fault during the May 2017 event.

What does this boil down to?

A slip of 4 cm corresponds to a moment magnitude release equivalent to a Mw of 4.3 to 5.3 earthquake (26). Since the initiation of instrumental seismic recording at Etna in the 1980s, no earthquake with a magnitude larger than 4 has been observed in the area (27). Hence, the main style of deformation of the offshore volcanic flank is episodic and aseismic sliding rather than seismic rupture.

This is saying that the deformation and motion of the ground is happening in a more or less continuous, drawn out event rather than is a short time period as we are familiar with most earthquakes happening.

Slow slip faulting is a type of earth movement over a period of hours to days and it happens gradually rather than in an abrupt rupture as we are used to seeing with quakes.

In the case of Mount Etna, our shoreline-crossing deformation analysis implies a greater hazard for flank collapse than previously assumed, as deep-seated gravitational sliding can potentially lead to catastrophic collapse (2, 3, 16).

So, it would seem as though the possibility at Etna is indeed present and potentially greater than first considered.

Gravitational collapse of Mount Etna’s southeastern flank

What would be needed would be research into the sedimentation layers along the potentially affected shorelines to determine if something like this has occurred in the past. Tsunamis of the size indicated here leave signs that are easily read tens of thousand of years after the event.

a reply to: 727Sky

That is assuming that it all falls into the sea at once, which is the worse case scenario.

It may just slide down a bit at a time which would be Meh.

Well, as long as you are not in the small city.

P

a reply to: jadedANDcynical

Thank you for adding content to the thread. Hopefully the deformation will continue at the 4 or 5 cm level with no large/sufficient earthquake in the foreseeable future to cause the worse case scenario as presented in the video.

a reply to: 727Sky

Wellll, No.

Especially after the part about Malta being 'partially protected'...

Someone needs to take a look at a map.

peace