Satellites can identify 8,000-year-old settlements

Satellites can identify 8,000-year-old settlements

Archaeologists discover a method to identify ancient human settlements on a large scale.

Hidden in the fertile crescent-shaped landscape of the Middle Eastscientists say that a series of small settlements that guard vital keys of ancient civilizations.

Beyond the impressive mounds of earth, known as accounts in Arabic, that locate lost cities, researchers have found a way to give archaeologists a broader perspective of the old landscape. Combining photos taken by spy satellites obtained in the 60s with modern multispectral images and digital maps of the Earth's surface, researchers have created a new method of making patterns on large-scale maps of human settlements. The method, which is used to locate some 14,000 settlements spanning eight millennia in 23,000 square kilometers of northeastern Syria, is published today in The Procedures of the National Academy of Sciences.

Traditional archeology goes straight to large settlements, such as palaces or cities, but tends to ignore settlements at the other end of the social scale.”Says Jason Ur, an archaeologist at Harvard University in Cambridge, Massachusetts, a co-author of the study. "People who migrate to cities come from somewhere; we have to put those people on the map”.

These detailed maps promise discover long-term trends in urban activity. “This type of novel large-scale application is what remote sensing has been promising archeology for some years now; it will certainly help to focus our attention on the big picture”Says Graham Philip, an archaeologist at the University of Durham, UK.

Signs on the ground.

Satellite methods are based on the fact that human activity leaves a distinctive signature on the ground called astrosols. Made up of organic waste and rotting mud brick architecture, astrosols are infused with higher levels of matter organic and have a finer texture and lighter appearance than undisturbed soil, leading to resulting properties that can be seen by satellites.

To scrutinize satellite imagery for those signals, co-author Bjoern Menze, an affiliate researcher in computer science at the Massachusetts Institute of Technology in Cambridge, based it on his everyday skills. identifying tumors on clinical images.

Menze created a program to detect wavelengths characteristics of known astrosols in images spanning 50 years of seasonal differences. This automation is the key. "You can do this with the naked eye using Google Earth looking at sites, but this method takes the subjectivity outside of it by defining the spectral features that revolve around archaeological sites.”Says Ur.

Menze and Ur have also used digital elevation data collected in 2000 by the space shuttle as part of NASA's Shuttle Radar Topography (SRTM) Mission. This information allows the authors to estimate the volume of amplitude of the reservoirs from the outset, and also use this volume to relate it to its longevity. The bigger the settlement, longer survived.

Tony Wilkinson, an archaeologist at Durham University and Ur's former mentor, says that power measure the volume of many reservoirs in remote areas it's a great find. However, Philip cautions that the resolution of the SRTM data could be too thick to provide an accurate measurement of the volume of the smallest settlements. However, you expect this method to cause new archaeological discoveries in different regions.

New life for old hypotheses

The method has already renewed speculations about the importance of water for the development of the city. Surprisingly, the study has found a group of unexpectedly large sites, since they are not near rivers or areas with abundant rainfall. "The settlement known as Tell Brak, for example, is too big for what you would expect in such a marginal position, ”says Ur.“ This is where things get interesting”.

Jennifer Pournelle, a landscape archaeologist at the University of South Carolina at Columbia, agrees. "These findings validate the hypotheses I introduced in southern Iraq that irrigation is a side effect of urbanization.", He says. "It is not what allows a city to evolve; it's what helps you get by after the soil moisture has run out”.

Pournelle says she will try to adopt this method as soon as possible, and notes that it offers a valuable way of learning over large regions, particularly when they are remote and difficult to access by local conflicts.

Images: Nature

With a degree in Journalism and Audiovisual Communication, since I was a child I have been attracted to the world of information and audiovisual production. Passion for informing and being informed of what is happening in every corner of the planet. Likewise, I am pleased to be part of the creation of an audiovisual product that will later entertain or inform people. My interests include cinema, photography, the environment and, above all, history. I consider it essential to know the origin of things to know where we come from and where we are going. Special interest in curiosities, mysteries and anecdotal events in our history.


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