I always find myself trailing behind the rest of the class, whether this be on hikes or walks to get gelato. I can’t help but be intrigued with everything I see… On the hike to the town of Oia, I gaze up and see the other ten of my classmates scribbling in their notebooks. Some students are frantically writing down everything my professor says, others are writing while carrying on side conversations about what they see. As for me, I step back and peer around the rim of the caldera. It wasn’t until this moment when I thought, “When will there be another volcanic eruption in Santorini?”
For three weeks, professor Skinner has taught us about the past eruptions that have occurred on Santorini. We have learned about the first eruption that occurred, all the way to the last eruption in 1950. Sixty-six years later an eruption still hasn’t happened, but when will it?
It is nearly impossible to predict the next volcanic eruption . Volcanoes may show signs of an eruption such as steam or earthquakes. Although, geologists cannot assume a volcano is going to erupt based on these factors. Steam or gas from the vent or crater may be it just “clearing its throat” or “waking up” after years of being in rest. The volcano is making its presence known, then goes back to being dormant for years. Its just like waking up in the middle of the night, turning over, and then falling back into deep sleep. However, a volcano doesn’t always go back to sleep, it can decide to stay up and really make its presence known by having a powerful eruption.
Although, steam and earthquakes aren’t the only indication of a near eruption. There may be signs of a volcanic eruption within the ocean. For example, subsidence of the shoreline may occur, meaning to recede or move back. If subsidence occurs, this means a tsunami will happen during the volcanic eruption. Additionally, there may be a change of color in seawater. Seawater may become warmer with a green tint. The water changes from a bright cerulean blue, to a dull, murky jade green due to the addition of heat (Figure 1).
While there may be clear signs of an eruption, these signs do not always indicate an eruption is near. Geologists may use monitoring to help identity when the next eruption will occur. Through short-term monitoring, it can be assumed that the next eruption will take place in the year 2573. The most probable event to occur would be similar to the 1925-1926 eruption. The eruption was a phreatomagmatic eruption, meaning seawater was present during the eruption. Seawater interacts with magma, creating it to be a “cooler” eruption in temperature. The temperature ranges from 200-300 degrees Celsius. Even though this is considered to be a cool eruption, 200-300 degrees Celsius is still extremely hot.
The most destructive event to occur is similar to the 1650 eruption. The 1650 eruption resulted in pyroclastic flows, which are dense clouds of hot gases and volcanic material being ejected out of the vent or crater of a volcano. In addition to hot volcanic material, such as ash and pumice, a tsunami also occurred during the eruption. Hot gases, volcanic material and the tsunami wiped out lives, villages, and livestock.
The two predictions are only short term predictions. It is very difficult to forecast what will occur in the future. This is what makes volcanoes so unpredictable. We never know what will happen thousands of years from now. It is is daunting to think that the two predictions may occur in 2573. It is also possible that nothing will happen at this time and not for another thousand years.
Even more so, it is difficult to rely on monitoring to predict the next eruption. Rather than utilizing this method, geologists use equipment such as seismographs and CO2 (carbon dioxide) flux monitoring stations (Figure 2). Seismographs record seismic activity that occur, it identifies any unusual or hyperactive patterns. Seismic activity is the movement of Earth’s crust due to the accumulation of stress or tension. CO2 flux monitoring stations record the amount of gas that is released from vents in a volcano. There two CO2 flux stations on Nea Kameni, the most volcanically active and youngest island of Santorini. Every ten minutes data is sent to Firostefani, a town midwest of Thera, the main island of Santorini. This data is then sent to Athens. Geologists are very cautious and diligent with monitoring gas flow on Nea Kameni, this is evident through how often data is sent to the main island.
Upon standing on Nea Kameni, I was quite confused with what I saw coming out of a large crater (Figure 3). There were bursts of gases flowing out of the air. At first I thought it was ash or stream, but I was wrong. Imagine opening the restroom door after a very hot shower, you see stream flow around you, that is exactly what it was like. At one point, I was actually standing on a vent that was releasing gas and I wasn’t even aware until a classmate told me! I should have known I was near a vent. The smell was unbearable. I can still feel the putrid scent of sulfur and rotten eggs overwhelming my nose. The CO2 flux station was monitoring this awful smelling gas. It was monitoring the amount of gas being released and sending this data back to Firostefani. If you happen to smell that nearby, see if you’re standing near a vent on a volcano!
There are ways to predict if a volcanic eruption is near based on monitoring, seismic activity and unusual characteristics in the ocean such as change in color. These methods may not be useful in long-term prediction. Geologists use seismographs and CO2 flux stations to focus on long-term eruptions. Even though geologists use dating and equipment to predict the next eruption, the next volcanic eruption could occur at any time and day. It could erupt tomorrow (let’s hope not) or it could erupt hundreds of years from now. Volcanoes are a very unpredictable geological feature, it’s almost as if they have a mind of their own.
 Friedrich, Walter, L, 2009, Santorini: Denmark, Aarthus University Press, 312.