A Beautiful Place with a Frightening Reality

After living in California on the San Andreas fault, I never realized how many people did not know how dangerous it was and all of the misconceptions people had about the fault. Before I started taking geology classes, I was definitely one of those people. I knew that it was there, but I really did not know much about it. I didn’t know the risks or even what would happen when it ruptures. When there would be a minor earthquake people would be paranoid for a day and then return to their normal lives. Of course, I am one of those people who is extremely afraid of earthquakes, and living on the San Andreas Fault was too unsettling, so I moved. Every time I go to California, I am terrified of the fault rupturing. This fear stems from the fact that earthquakes are very unpredictable. We do not know when the fault will rupture and when it does, it will be disastrous. Buildings and structures will be severely damaged, pipelines will break, fires will break out, and mass hysteria will fill the streets. These are just some of the many things that could happen, and that is not something I would like to experience if and when the fault ruptures.

When I first learned about this trip, I knew I had to get over my fears and pursue my passion for geology in another country. This is my major in college. This is probably not the last hazardous place I will visit either. So here I am living in a place with an active volcano and two major faults running through it. Coming into this trip we were briefly told of the hazards like earthquakes, tsunamis, rockfall, landslides, and of course, the volcano exploding; but I had no idea what the extent of the hazards were until now.

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Figure 1. Many boats dock and travel right over the magma chamber. Most people who travel in the caldera, have no idea that they pass over the magma chamber. 

Imagine sitting on a boat right over Santorini’s magma chamber (3.3 to 6.3 km below the seafloor) and finding out that just 6 years ago, Santorini had significant warning signs that an eruption could happen. The look on my face when I found out was characterized by disbelief and amazement. Not only was I worried about being incinerated from a possible eruption, but I was also amazed because I had never been able to study this hands-on in an area that is volcanically active.

From January 2011 to May 2012, the volcano started to awaken. In January 2011, earthquakes of less than a magnitude of 3.5 were occurring in the caldera. This is the first time since the 1950s, with modern technology, that seismic activity like this was occurring. It was also occurring on a fault line that runs vertically beneath Nea Kameni and Palea Kameni. This is the same location previous eruptive events stemmed from (1). The seafloor inflated by 20 centimeters, meaning it is due to hydrothermal activity or the magma was pushing upwards. If it was hydrothermal activity, the inflation should have gone down. If it was due to magma pushing to the surface, it is more permanent. Since this incident, only a small fraction has deflated. The magma was degassing and escaping through the seafloor, thus changing the water chemistry. The gases exsolve to form bubbles and then escape through the path of least resistance. This indicates one of the steps of magma ascent to the surface before an eruption. The hot springs temperatures increased by 4 degrees Celsius. This is due to new magma intruding. The estimated volume of new magma is 14 million cubic meters (1). Santorini had been in a state of unrest for over a year and many locals and tourists had no idea because of the risk of losing money from tourism. Many locals still do not know the dangers of even living on this island, as shown by Sarah Kitchen’s blog, “What do people know about where they are?”. Luckily, there was not an eruption, but all of the warning signs were there, and no one knew or attempted to evacuate. Even if the eruption was minor, anyone visiting Nea Kameni would have been incinerated or severely injured.

I know that the Crisis Period did not directly affect me because I am here 6 years after it happened; however, if there was volcanic activity occurring right now, I am not sure if I would even know about it. The information regarding the Crisis Period was not publicly advertised. It was mainly kept to scientific articles and journals. To me, this is frightening. I would like to know if I am putting myself at risk even more than just living on a volcano for a month.

While on the boat, I also learned about the type of eruptions Santorini could have in the near and far future. It came down to the event that is most probable to occur, the most destructive event to occur in short mid-term, and maximum expected event to occur. All of these possible volcanic eruptions are extremely dangerous and can cause significant harm to life on Santorini and surrounding areas.

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Figure 2. The image above shows what the 1924-1925 eruption looked like, a Vulcanian eruption driven by hydrothermal processes. This is the most probable event to occur in Santorini (2).

The event that is most probable to occur is a Vulcanian style eruption like the one in 1924-1925. This is when steam builds up beneath preexisting rocks. When the pressure becomes too great, it explodes. Basically, anyone on Nea Kameni would be incinerated and anyone in the surrounding areas could be hit by blocks (large volcanic fragments). This was the eruption scientists thought could happen during the Crisis Period. Despite the information, Nea Kameni and the immediate areas were still open to tourists.

The most destructive event expected in short-midterm is a sub-Plinian explosive event. This would be devastating to Santorini. A sub-Plinian eruption has a sustained eruption column that can deposit tons of pyroclastic material laterally. This could potentially cover the island in a scalding hot material. This happened during the Minoan eruption, so we know that this volcano is capable of producing such eruption. Another example of this is what just happened in Guatemala. The eruption of Volcan de Fuego had pyroclastic flows that incinerated and destroyed everything in its path. Hundreds of people have died and hundreds more are still missing. However, Guatemala is not an island, so the people who weren’t in the pyroclastic flow immediate path were able to escape. This would not be the case in Santorini because it is an island. There would not be enough time or boats for thousands of people to evacuate.

The maximum expected event is another Minoan type event. This would be catastrophic not only to Santorini but the surrounding areas as well. This event is characterized by phases 0-4 that occur in an extremely fast manner. The Minoan eruption occurred in less than 24 hours. Each phase of the eruption is dangerous in its own ways. In phase 0, a small layer of ash and lapilli are deposited. These deposits are primarily controlled by wind, so not all of the island will have these deposits. Next, in phase 1, an unstable sub-Plinian eruption deposits scalding hot pumice. These deposits are also controlled by the wind. In Phase 2, water enters the vent and causes very violent explosions. Pyroclastic surges with intense turbulent flows cover the island with pyroclastic deposits. In phase 3, the vent opens up even more and pyroclastic flows are deposited all at once. Finally, in phase 4, the caldera excavates and collapses, blowing up everything in its path. For more information on how deadly and destructive this eruption is, check out the blog “Into the Air: a Sky Filled with Ash, Gas, and Glass”.

Not only is there Santorini to worry about but north is Koloumbo, a shallow submarine caldera that is more active than Santorini. Scientists expect a large eruption from there before Santorini has another caldera-forming eruption. An eruption from Koloumbo would produce a massive eruption column, a tsunami, and may even change the climate regionally. The deposits from an eruption like this would definitely reach Santorini especially if the winds were blowing in this direction.

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Figure 3. The image above shows satellite imagery of the Aegean sea. The areas circled in pink represent just some of the many volcanoes that are in this region of the world including Santorini. The places circled from left to right include Methana, Milos, Christiana Islands, Santorini, Koloumbo, Nysiros, and Kos.

Here I am in the Cyclades living on a volcano and surrounded by volcanoes. I’ve spent the past month learning about Santorini and the geologic hazards associated with it. Santorini is an active volcano. The Crisis Period just 6 years ago proves that Santroni is far from being done. Santorini also has the capability of producing many different types of eruption styles that all pose a great threat to life here. Despite my over-exaggerated fear of natural disasters, I would come back again. I have had such an amazing experience here. If this place has taught me one thing, it is to not worry as much. No matter where you travel or live there are going to be hazards associated with it. The best thing to do is to be prepared and informed on what’s going on. It is terrifying knowing what Santroni is capable of, but it is also relieving knowing that we have a plan if something does happen. The rest is out of our control.

Thanks Santorini for not blowing up while I was here. It has been a good one.

Sources:

  1. Newman, A, et al. 2012, Recent geodetic unrest at Santorini Caldera, Greece: Geophysical Research Letters, vol. 39, 1-5.
  2. “Santorini Volcano Eruptions 1925”. Santorini Hotels. Santorini Hotels. n.d. Web. 20 June 2018.

2 thoughts on “A Beautiful Place with a Frightening Reality

  1. Sarah,

    You provided an accurate and real account of the potential volcanic hazards Santorini may experience. Your third figure was helpful in understanding volcanos in the region as well as your references to other posts.

  2. Your post was quite informative, yet weaved in your own story/experience which made it enjoyable to read. Work on your transitions; showing how one idea leads to the next will help your reader follow. Nice use of graphics. Glad to hear you had such a wonderful experience!

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