The seismic hazard from hydrocarbon exploration in the Ionian Sea

John Protonotarius Professor at the School of Civil Engineering of the National Technical University of Athens (NTUA). specializing in Soil Mechanics – Seismic Engineering at MIT.

The following text comes from Yannis Protonotariou’s speech at the Lefkada Frontier Action event on Saturday, February 8th.

As the Greek Governments, as well as international oil giants, are known, they are planning research to discover and then exploit hydrocarbons in Ionian and neighbouring areas, as well as in areas of Crete and the south.

However, it is also known that areas of the Ionian islands, as well as neighbouring land areas (eg Preveza, Kyllini, etc.) are the most earthquake-prone areas in Europe and one of the most seismically active areas on the planet.

For this reason, these areas have been thoroughly explored for years now by specialist Greek scientists at universities and research institutes.

In these areas there have been many earthquakes ranging in magnitude from 6.0 to 7.0 R, but also some earthquakes around 7.5 R. The reason for the large earthquakes here is that the western branch of the Aegean arch is crossed by the area, that is, the arc along which the African tectonic plate collides with and sinks beneath it.

Thus in the islands of Lefkada, Kefalonia, Ithaca, seismic intensities above 9 on the Mercalli scale have been recorded, sometimes even 10+.

These intensities correspond to vibrations for maximum accelerations in the range of 0.70 to 1.20 g. For this reason, these areas are classified in zone 4 on the seismic map of the New Earthquake Regulation (NEAK) for which an active design acceleration of 0.36g is envisaged.

These vibrations have long dominant idioms (even over 1.0 sec). However high-end structures such as exploration and extraction platforms also have large idioms, so they respond to such vibrations in a particularly intense manner due to synchronization phenomena.

It is therefore certain that in the event of an earthquake, they will not be able to withstand such intense tensions and, as a result, collapse, creating enormous pollution in the surrounding marine and inland areas. In addition, drilling pipes and hydrocarbon transport pipelines will burst under pressure releasing large amounts of hydrocarbons.

It is characteristic that, for similar reasons, platforms have never been installed in the Gulf of Mexico, near Mexico on the Atlantic or Pacific Ocean, despite the abundant hydrocarbons found. It is still possible to note the blowout, as has happened in the Gulf of Mexico but also in the state of Oklahoma where a magnitude 5.7R earthquake occurred when drilling was done.

So instead of attempting to pump hydrocarbons from very deep wells, which are economically questionable (perhaps only for the large energy groups that exploit them), it would be much more useful to pursue renewable energy plants.

We therefore believe that the installation of exploration or hydrocarbon platforms in these areas is totally unacceptable as it involves such a high seismic hazard.

(*)   Professor at the School of Civil Engineering of the National Technical University of Athens (NTUA). specializing in Soil Mechanics – Seismic Engineering at MIT.

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