Greece and Volcanoes

Around the smaller islands that make up Greece, there are ten different volcanoes, both active and extinct. The relatively high number of volcanoes around Greece is caused by the large volcanic arch surrounding it, called the Hellenic Arc. The most well-known active volcanoes in Greece are the Santorini Volcano, the Nisyros Volcano, the Methana Volcano, and the Milos Volcano. (1) However even though these volcanoes are considered active, there has not been a volcanic eruption in Greece was the 1950 eruption of the Santorini Volcano. Greece has a long history of natural disasters caused by volcanoes, the earliest instance of a volcanic eruption there recorded as early as 1646 BCE in Thera, which is present day Santorini. (2) The force of the eruption is hypothesized to be about the same as 40 atomic bombs, or 100 times stronger than the eruption in Pompeii. This eruption itself was completely devastating in terms of geographic destruction and in mortality. Not only did this eruption blow out the interior portion of the Santorini island, it also killed 20,000 people and buried  the settle completely. (3)

(Picture of Santorini now)

A volcano itself is "a vent in the crust of the Earth... from which issue eruptions of molten rock, hot rock fragments, and hot gases." (4) The geology of a volcanic eruption can made up of an accumulation of gassy magma, causing emissions of steams from opening in the ground. However volcanic eruptions may also cause earthquakes and a rise of magma, be it either a thin fluid lava or even shooting up in the air like a fountain. (5) The size of destruction and loss of life can vary from virtually none at all to complete devastation, depending on the actual strength of it. As stated above, the last time there was a volcanic eruption was in 1950 so volcanic activity in Greece is not as frequent as other natural disasters, regardless of its number of active volcanoes.

Given how many volcanoes are in such close proximity to Greece, the country has implemented a warning system as it has for earthquakes. In the case of Greece, there is a geospatial warning system for several active volcanoes such as Nisyros, established by Copernicus, previously known as the Global Monitoring for Environment and Security. The objective of it is to "achieve early warning of volcanic activities by monitoring measurable changes in geophysical and geochemical parameters." (6) It established correlations and runs 2D and 3D simulations and integrates its results to improve the country's ability to warn hazards and potential eruptions. They have also created an interactive multimedia tool available for citizens through CDs and the internet which include warnings risks and emergency plans for eruptions.






Sources:
Image 1: http://www.historymuseum.ca/cmc/exhibitions/civil/greece/images/gr0004b.jpg


Source 1: http://www.greeka.com/greece-holiday/nature/volcanoes/

Source 2 and 3: http://www.historymuseum.ca/cmc/exhibitions/civil/greece/gr1040e.shtml

Source 4 and 5: https://www.britannica.com/science/volcano

Source 6: http://www.copernicus.eu/projects/geowarn

Greece and Earthquakes

Of all natural disasters, the second most commonly occurring one in Greece are earthquakes. However that being said, earthquakes actually are the number one natural disaster in terms of their mortality rate. Furthermore, earthquakes in Greece are also the natural disaster that cause the highest percentage of economic by a substantial margin. (1) In the past 365 days alone, Greece has experienced 116 earthquakes, the largest one being a 5.5 magnitude in Kalpaki. (2)

(Charts of Greece's natural disaster mortality and economic issue rate)

To preface, seismicity is defined as "the worldwide distribution of earthquakes in space, time, and magnitude... the measure of the frequency of earthquakes in a region." (3) Every region of the earth has its own specified and measured seismicity, monitors in put in place to track seismic activity. Greece's seismicity is one of the most active among the regions of the world, actually ranking as the sixth most active region globally, and even considered the most seismically active part of Europe. (4) Even before Greece's seismic activity was scientifically monitored and measured, the country had been notorious for its deadly earthquakes, even being recorded by ancient accounts as far back at 550 BCE.

(Destruction of a theater in the ancient Greek city of Cyrene, by an earthquake that occurred in a 365 AD earthquake)

Because earthquakes have been so prevalent in Greece for centuries, the country has put into place different plans for how people can be safe in the event of one. For example, the country has two main axes of antiseismic policy which are "the pre-earthquake of measures of prevention, preparedness, and awareness" as well as "the measures after the occurrence of an earthquake for the effective treatment and management of emergencies. (5) There are two different services that have been made to implement these axes which are the Organization for Antiseismic Planning and Protection, which focuses on the pre-measures, and the The Earthquake Rehabilitation Service for after. The organizations' goals are to gather relevant scientific seismic information, to establish regular seismic monitoring, and to promote social awareness of seismic risks through public awareness, educational programs, and training workshops. On a literal level, these organizations have established a requirement for an enhancement in "seismic capacity of the constructed environment," meaning buildings and houses. (6)


Sources:

• Image 1: http://www.preventionweb.net/countries/grc/data/

• Image 2: http://www.drgeorgepc.com/Tsunami365ADeEastMedSea.html

• Source 1: http://www.preventionweb.net/countries/grc/data/

• Source 2: earthquaketrack.com/p/greece/recent

• Source 3: https://www.britannica.com/science/seismicity

• Source 4:

https://www.researchgate.net/publication/226748777_Seismicity_and_Seismic_Hazard_Assessment_in_Greece

• Source 5 and 6: http://www.misrar.nl/UserFiles/File/Good_practice_epirus%20earthquake.pdf

Greece Plate Boundaries

Greece is located in an area of the world where there are multiple plate boundaries, sitting in between Europe and Asia. Because Greece's setting, it sits on the Aegean Sea Plate, however this small plate, which can also be called the Hellenic Plate, is near both the Eurasian Plate and the African Plate. That being said, Greece is near the plate boundaries of both the Eurasian Plate and the African Plate. (Image below)

The southern part of the Aegean Plate, near Crete, is considered a subduction zone because the African Plate pushes beneath is. (1) As a refresher, a subduction zone is a "place where two lithospheric plates come together, one riding over the other." (2) In the case of Greece, the southern part of the Aegean Plate 'rides over' the northern part of the African Plate. Because of this motion, there are many shallow and normal earthquakes along this southern Aegean plate boundary, as well as having caused the formation of the Hellenic Arc which is made up of both active and inactive volcanoes. (3)  For example, the Santorini Volcano, one of the most active ones, last erupting in 1950.

(Image of the Santorini Volcano eruption)

(Image of the aftermath of Athens 5.2 earthquake)

At the north part of the Aegean Plate is the Eurasian Plate, there is a divergent boundary, which is when "two tectonic plates that are moving away from each other" and this creates a space that is filled with new crustal material sourced from molten magma that forms below. (4) This kind of seismic activity not only causes earthquakes but also caused the formation of the Gulf of Corinth. (5)

Sources:

• Image 1: http://earthguide.ucsd.edu/earthguide/maps/basemaps/

• Image 2: http://www.greece-is.com/born-of-fire/

• Image 3: http://www.express.co.uk/news/world/583178/Greece-earthquake-violent-5-2-magnitude-tremor-rattles-capital-Athens

• Source 1: https://www.revolvy.com/topic/Aegean%20Sea%20Plate&uid=1575

• Source 2: https://earthquake.usgs.gov/learn/glossary/?term=subduction%20zone

• Source 3: https://watchers.news/2012/01/28/increasing-seismic-activities-in-aegean-sea-greece-with-tectonic-summary/

• Source 4 and 5: https://www.revolvy.com/topic/Divergent%20boundary&item_type=topic