Professor helps preserve Church of Nativity
Experts work to stabilize site of Christ’s birth
Millions of pilgrims travel to the Church of the Nativity in Bethlehem each year, particularly at Christmas, because of its historical and religious significance as the site of Jesus Christ’s birth.
University of Wisconsin-Madison associate professor Dante Fratta was unlike most tourists visiting the site. He brought ground-penetrating radar and electrical resistivity equipment. He brought his camera, too.
Fratta was part of a team of experts called to the Church of the Nativity to learn buried secrets without lifting a shovel. Following a recent archaeological excavation in a section of the church known as the Hall of St. Jerome, authorities worried about the structural integrity of the church, first built in A.D. 339.
That prompted the survey by an international team of experts from Peru, Portugal and the United States last summer. Fratta, an expert on near-surface geophysical techniques, was asked to join the project.
“It was a neat experience,” Fratta said in a phone interview from his campus office Friday. “I’m not religious, but this is the center of many religions of the world. We had opportunities to go places tourists don’t go. I consider myself very lucky to have the opportunity.”
Fratta is adept at using ground-penetrating radar to send electromagnetic waves into the ground and wait for reflections that can detect the presence of nails or water or other substances, as well as evaluate walls and rocks. The equipment measured the depth of the foundations of the columns down to the bedrock to help evaluate the church’s stability and provide more information about the underlying geology for future excavations.
The team spent a week in July at the Bethlehem church, measuring as much as it could to protect the fragile structure from further damage. Team members placed sensors, measured vibrations and scanned surfaces with lasers, installed a network of sensors for long-term monitoring of the church and created virtual 3D maps of the Hall of St. Jerome, detailing cracks and damage.
“The challenge of this site is that construction has been going on for more than 1,000 years. You see at different depths different types of construction and foundations — a wall that was built by the Crusaders, a wall built 500 years ago — which is very difficult to evaluate. Technically, that’s been the challenge for us,” Fratta said.
The Argentina native has taught at UW since 2004. Fratta teaches classes on applied geophysics and soil mechanics to students studying to become geologists and geological and civil engineers.
Fratta’s research at the site showed there’s quite a bit of limestone that’s fairly close to the surface underneath the Church of the Nativity. Most of the buildings in Bethlehem have a yellowish tint because they were built or fabricated using the abundant limestone.
A church was first built at what is believed to be the site of Jesus Christ’s birth by Constantine the Great and his mother, Helena. The original basilica was destroyed by fire in the sixth century. A new basilica was built by the Byzantine emperor Justinian in 565 and was used as the primary coronation site by Crusader kings in the 1100s. The church has undergone numerous construction and restoration efforts since then.
In 2010 Palestinian authorities announced plans for a multimillion dollar restoration of the Church of the Nativity, but called a halt to the digging when excavators came dangerously close to undermining the support beneath a structural column in the Hall of St. Jerome, named after the man who translated the Bible from Hebrew and Greek into Latin.
Four denominations oversee the Church of the Nativity — Roman Catholic, Greek Orthodox, Armenian Apostolic and Syriac Orthodox. Even though the Hall of St. Jerome is under the auspices of the Armenian Church, all four churches need to grant approval for the team’s survey.
Fratta said the team recommended retrofitting one of the columns in the Hall of St. Jerome to improve the integrity and stability of the church.