A Simple and Easy Math Problem

On June 13th we returned to the Cape Akrotiri lighthouse where we first looked at the domes that formed the Akrotiri peninsula. This time, Lisa wanted to show us the most massive block she’s ever seen. A block is a solidified rock that is thrown up into the air during an eruption, and can be any shape. This blocks shape was gigantic. 

We walked down the slope behind the Akrotiri lighthouse. Lisa pointed out the thin layer of pumice from Phase 1 of the eruption which consisted of pumice fall. On top of Phase 1 was the white lapilli and ash beds of Phase 2 that were deposited as a result of pyroclastic surges. Pyroclastic surges are turbulent clouds of ash and lapilli and lithic fragments that tumble across the landscape outward from the vent depositing the material according to density. Lithic fragments are usually deposited together in a pyroclastic surge because of their density. The giant block Lisa brought us down there to see was obviously too large to be carried by a pyroclastic surge. It wasn’t even close to the size of the lithic fragments carried by the surge. So how did it get there? 

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Look Closely: Every Layer is an Event

Layer upon layer of history, tragedy, and misfortune built up every wall that ascended as we hiked deeper into Cape Plaka on Friday (3 June). Each wall, exposed and vulnerable, waits for someone to hear the stories inscribed in every grain. As I gaze up at the colossal remnants of the countless catastrophes that took place here, I am no longer in my body. I can see history being made before my eyes, eruption after eruption, construction and erosion, life and death. Every layer is an event. I feel my feet slip on the loose rock beneath me and I snap back to 2016. Continue reading “Look Closely: Every Layer is an Event”

Ballistic Blocks, Steam Explosions, and Turbulent Flows?

From the point of view of a fictional Minoan character-

Sitting in our boats, miles from home, I look back to where we came from. I see my beloved island sitting on the horizon as life as I know it dissappeared. Everything happened so fast these past couple days that the events are starting to blur together into a swarm of panic, packing, and leaving. I yearn to go back to my beloved Santorini, back to before my life was interrupted by the ominous signs of our once-peaceful volcano…

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A Glimpse of the Past

Humans have learned to use rocks for many different purposes in life, such as for tools, jewelry, and even counter tops, but what intrigues me is the observation and inference of rocks that tell a story of the past. Even after taking multiple geology classes at NAU, I have only recently learned about one important characteristic of volcanic deposits that provides information on how an eruption occurred thousands of years ago; a block sag.  The geologic definition of a “block” is defined as an angular piece of lava (larger than 64mm) that was ballistically ejected from a volcanic vent. On the other hand, a block sag is a depressed or indented section of rock strata that was created by a ballistically ejected angular fragment of a volcano during an explosive eruption. The blocks that we’ve seen here on Santorini have had a wide variety of sizes, ranging up to two meters. We found an impressive two meter block on the edge of Cape Akrotiri, which is on the southwest tip of the island. (Observation Point 9 on the map below)

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