Earthquakes in Crete: “Silent” gentleman worries seismologists [images]


A snapshot of the catastrophic earthquake that struck Kos in 2017 / Photo: EUROKINISSI / NIKOLOPOULOS ANTONIS
The last catastrophic earthquake in Crete occurred nine decades ago. Today, seismologists are considering the possibility of approaching a powerful new “hitting” of Enceladus to the giant.

A strong earthquake, as explained by NeaKriti Research Director of the National Observatory of Athens, President of the Northwest Atlantic and Mediterranean Tuna Warning System, UNESCO and a candidate for the European Parliament with the River, Gerasimos Papadopoulos, are made in depths of more than 50 km.

Usually, as noted, Dr. Papadopoulos meets in areas where we have collision of lithospheric plates and precipitation of one beneath the other, one of the main causes of earthquakes.

When earthquakes become extremely dangerous
In the case of Crete, as Gerasimos Papadopoulos emphasizes in NeaKriti, the African plaque is submerged under the Eurasian Seaward to the North, from the South Cretan Sea to the Aegean Sea.

Unlike surface earthquakes, which have a focal depth of up to 50 kilometers and release seismic energy that spreads roughly evenly in all directions, the depths of depth have different characteristics, making them extremely dangerous.

According to Dr. Gerasimos Papadopoulos, the seismic energy that releases this kind of earthquakes does not spread evenly but selectively from the earthquakes of the southern Aegean to the Mediterranean side, ie Crete, the Dodecanese and even farther north of Egypt, operating as a “magnifying glass”.

What Happens When You Exceed the 7 Richters?
This is why, when these earthquakes are large in size over 7 Richters, they become extremely destructive in these areas. In addition, in surface earthquakes, the sea is proven to be life-saving as it has weakened, until energy is transferred to land.

But in the case of mid-range earthquakes, things are different.

A catastrophic earthquake of this kind has to happen from the strong vibration of 1926.

And, according to experts, this is the reason why serious concerns arise.

Is the next big earthquake coming?
Gerasimos Papadopoulos, according to “New Crete”, had described a certain principle that says “the longer the time since the previous earthquake, the greater is the probability of approaching the next”, and on the other hand given that separated from the last catastrophe of Enceladus 93 years, has radically changed the structure of the environment. ”

During the earthquake of 1926 the buildings that dominated the landscape were one-storeyed with stone, bricks and wood, while today are the blocks of flats and the high-rise hotels of reinforced concrete.

In the case of an intermediate-earthquake, these buildings are vibrating in about a second, that is, going from one side to the other.

The worrying is that exactly the same period of oscillation has the seismic waves of these earthquakes, which co-ordinates them with the multi-storey buildings as they behave after a hit of Enceladus of this form.

What happens to buildings and the possibility of a tsunami
Given the absence of experience after 90 years of a similar phenomenon, scientists are concerned about how current buildings could behave in dangerous areas, and so on our island, in the form of a devastating earthquake of intermediate depth.

There are, however, also optimistic new ones. According to NeaKriti, on the one hand, one does not rule out the case that the behavior of buildings is not synonymous with an imminent disaster, and on the other hand, the peculiarities of the mid-earthquakes are that they do not cause a tsunami, and they do not have an aftershock. This very need for a good knowledge of the phenomenon is a prerequisite for our fortification against the visible danger to the future.

A terrible image of the 6.4 Richter earthquake that hit Taiwan in February 2018 / Photo: AP IMAGES
That is why, as Mr Papadopoulos points out, the country’s anti-seismic protection system should see with particular interest this hot, without exaggeration, issue, and close cooperation between seismologists and civil engineers is required. One of the main concerns is the creation of a scenario of such an earthquake to predict the behavior of the buildings against the hit of Enceladus. And this is a necessity for our region, as the earthquakes with these characteristics are exclusively related to the region of Crete, Rhodes and Peloponnese, while on the other side of the northern Aegean, Attica and the rest of the mainland the spread of seismic energy is greatly reduced, and consequently the mid-depth earthquakes are not disastrous.

The terrible earthquakes of 1856 and 1926
In Crete, two are the most devastating blows in historical times from earthquakes of intermediate depth. One of the most terrifying was the one on October 12, 1856, according to the new calendar, which had a focal point in the Cretan Sea and an estimated magnitude of 7.6 on the Richter scale.

As evidenced by many testimonies and historical documents, the earthquake devastated Heraklion, causing widespread disasters in the rest of Crete and Rhodes.

About 550 people were killed in Heraklion and more than 630 injured, while the damage was terrifying. It is estimated that only 8 buildings in the city remained intact.

Scene of destruction in ’26
The same disaster scenario resumed on June 26, 1926, when a similar earthquake , of magnitude 7.4 on the Richter scale and a 115 km focal depth, again hit Crete, Rhode Island and areas of the eastern Mediterranean. According to Mr. Papadopoulos, in Heraklion and other areas of Crete hundreds of houses, churches and other buildings were destroyed. No victims were reported, but the homeless reached about 10,000. Damages were also suffered by Saint Minas and Saint Titus.

In Rhodes, the earthquake caused many deaths, and the disaster was also extensive. The damage zone has again expanded to Cairo and other parts of the eastern Mediterranean. It is of particular historical interest that the earthquake, as shown by a letter by Arthur Evans, seems to have influenced how the Knossos excavator who experienced it in Heraklion has incriminated the earthquake activity for the collapse of Minoan civilization.
Source – iefimerida.gr 

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