Technology gives archeologists a peek at the past

Israeli algorithms offer a clearer picture of what’s underground, saving spadework.

Forget Machu Pichu or Angkor Wat, many of the world’s archeological sites are located close to cities, if not inside them, and suffer the encroachments of roads, homes and factories.
If there isn’t a road, farm or a factory on the site already, an archeologist is likely to face objections from property developers or government officials anxious to get on with business or building. Technology exists that lets scientists see below the surface for signs of structures and artifacts of the past, but it has severe limitations. Everything from electric power to water mains can disrupt the results while sites with artifacts from multiple historical periods appear as a jumble.
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Now, an Israeli team led by Lev Eppelbaum, a geophysicist at Israel’s Tel Aviv University, says it has developed an algorithmic toolkit that addresses these problems. It lets researchers process archeological data collected by using magnetic and other geophysical fields in finer detail than previously possible while eliminating all the so-called “noise” that has confounded surveys until now.
“In urban development, many archeological sites are damaged or disturbed,” Eppelbaum told The Media Line. “But, making geophysical observations and analyses of sites before they build new roads or factories will allow us to see what there is underground. It can answer the question, ‘Do we need to excavate this site or is it secondary?’”
Israel alone may have some 20,000 archeological sites in a country of some 22,000 square kilometers (8,500 square miles). Many of the most potentially important findings are under the streets of Jerusalem, the site of much Biblical history, not to mention Roman, Byzantine, Islamic, Crusader and later periods. Today it’s a bustling city of 750,000 people.
Israel is so replete with archeological history that builders can’t begin construction until the archeologists have been called in. That’s an extensive and time-consuming process. Further complicating matters are religious sensitivities. Key sites, like the Temple Mount, or Haram al-Sharif in Jerusalem’s Old City, are off-limits to archeological digging altogether.
Eppelbaum says conducting an examination using his Multi-PAM (physical archeological models) systems can cut the cost of surveying a site by 30 or 40 times.
Even where there are no problems of urban sprawl, archeologists typically don’t have the resources to explore more than 5% of a site over a period of many years. Geophysical methods can save them a lot of spadework, telling them where they can expect to find remains and to a large extent what they can expect to find. It can also provide a library of sites for future excavation.