The Buried Aegean

On the island of Thera in the central southern Aegean, an enormous caldera filled with deep blue ocean stands as a reminder of one of the most destructive volcanic eruptions in modern history. Once a nucleus for maritime civilization, the Minoan culture that occupied Thera until 1628 b.c. disappeared in a cataclysmic event that has left us with only a remnant of the island's human debris and former topography. Through advanced geological and geophysical techniques, we are, for archaeology, reconstructing the island as it was in the Late Bronze Age, and for volcanology, reinterpreting the volcanic eruption.
--Dr. Floyd McCoy, University of Hawaii, Kaneohe

Objectives

Some 30 years ago, archaeologists near Akrotiri, Greece on the island of Thera unearthed what Christos Doumas (the excavation's current director) has called the "Pompeii of the Late Bronze Age." Here, frozen in time, lay the largest Minoan city yet to be found preserved beneath the tens of meters of pumice and ash deposited in 1628 b.c. by one of the largest, most violent eruptions in modern history.

The blast-twice that of Krakatau and 40 times that of Mount St. Helens-destroyed the island's civilization, and through tidal waves, destroyed Minoan cities on surrounding shores, especially on Crete. Beneath five distinct layers of pumice and ash lies evidence of this cultural and spiritual center of Minoan culture: pastures then cultivated with crops and orchards, each field divided by rock walls and shelters; uncultivated uplands with wild animals; gentle streams and valleys incised into soft volcanic rock; multistoried buildings with internal plumbing; and country villas scattered across the landscape. The cataclysmic eruption brought about the abrupt transition from the Minoan to the Mycenean culture-documented in various legends from the area-and perhaps even accounts for the stories of Atlantis and Exodus.

Today, volcanic hazards increasingly affect civilization, especially since populations occupy the slopes and innards of volcanoes. Surrounding landscapes are at risk as well, considering the potential for eruptions to change global climates and decimate vast areas of land. In order to prepare for future eruptions, we are working towards better understanding volcanic behavior. What causes volcanoes to be so explosive? What triggers the blasts? Can we predict such eruptions and consequent hazards? Are there any mitigative measures?

Because of the incredible explositivity of many eruptions, scientists are unable to remain on site during an eruption; volcanoes have killed 13 volcanologists in the past 5 years. To increase our ability to understand these natural disasters, we are using the best possible instruments for hindsight. With ground-penetrating radar, we are analyzing the buried landscape of Thera in order to recreate the pre-blast island. By mapping the layers of volcanic debris blanketing the landscape, we can trace the eruption, understand the progression of events and variability in explosiveness, then relate all this to what happened and why.

Fieldwork

To map the buried Minoan level of Thera, we had to take long treks across the modern landscape and document geologic and archaeologic phenomena through the use of sophisticated surveying and geophysical equipment. To establish the course of the flow, we used laser-ranging surveying equipment (Electronic Distance Measuring, or EDM theodolites). To dicipher eruptive volcanics, we made thorough observations of the pumice, ash, rock fragment, fossils, and other components within the deposit. To determine subsurface stratification, including the topographical relief and human-made debris from 17th-century b.c. Thera, we used Ground-Penetrating Radar, or GPR. When hauled across the ground, the GPR shoots down an electromagnetic beam, which reflects off both volcanic and human-made objects. EarthCorps volunteers helped haul equipment, develop and record data, photograph sites, and tend donkeys that were used for transportation.

Results

We now understand the mechanics of this eruption. We know why it went through four major blasts with minor perturbations. We are beginning to picture what this island looked like during the Minoan occupation: we've mapped major stream valleys, the coastline, seacliffs, and soils and traced how the ash, mud, and pumice covered natural and human-made objects.

Our dramatic results demonstrate the effectiveness of GPR in mapping volcanic terrains. Incredible pictures of the subsurface show the features of the buried landscape and traces of its extinct population. These are facsimile depictions-at best open to interpretation-but that is part of the excitement.

Our present focus is to continue mapping the island, district by district, and to continue compiling all of our data onto computers. Our goal is to eventually recreate a computer-simulated eruption, which demonstrates each episode and its affects across the landscape. We will map the island as it was during Minoan occupation, and then destroy it in one cataclysmic event.

Since many modern societies are within proximity of dangerous volcanoes, the hazard remains today. Our research on Thera demonstrates the magnitude of what did-and can-happen, while broadening our understanding of the eruption process.

Further Reading

Acknowledgments

I would like to thank my field assistants Meg Watters and Eleni Argy, our friend on Thera Niko Yannaros, our surveyors Andrew Browne and B.J. McKinney, and my wife Anne.

Contacts

For more information about these or other project results, please email: info@earthwatch.org and reference "The Homol'ovi Research Program".

The Buried Aegean is currently running in the 1996 field season.



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