How radar technology is used to discover unmarked graves at former residential schools

Before the first electric waves hit the ground of a suspected residential school site, archaeologists may have collected important information from one of their most important sources: the survivors.

Survivors may have heard the news over the years or may have had accurate knowledge of the area, said Terence Clark, an assistant professor of archeology at the University of Saskatchewan.

“We have heard that it is usually the children who dig the graves of other children so they know exactly where the graves are,” he said. “It doesn’t make sense to make hundreds of meters around schools on all sides. It’s like a needle in a flat. But if we can talk to survivors who know some information, then we can narrow down our search.”

Understanding the process and technology of finding unmarked graves has become a major focus after the shocking announcement of Tk’emlúps te Secwépemc First Nation last week. He said the initial discovery of a yard survey at a former Kamloops Indian Residential School indicated that the remains of 215 children could be buried in the area.

That determination was made by a specialist who used ground radar (GPR), a geophysical research method to test the site. The technology commonly used on sites to determine the presence of underground canals, water pipes or gas or sewer lines. But it can also be used to scan historical cemeteries and unmarked tombs.

On Friday, Kukpi7 (Chief) Rosanne Casimir said they expected to have a final report by the end of the month about the findings of the study at the former school.

‘It’s a very difficult process’
“If you go to these places, I would like to say that the process is very difficult,” Dr. Kisha Supernant, a professor who works in the Department of Human Resources at the University of Alberta, told CBC Radio Day 6.

“Of course, no one wants to find an unmarked child’s grave. But at the same time, we want to find that because we want to give that back to the communities.”

Depending on the technology, test teams will use ground radar devices to navigate the earth’s surface. GPR is similar to medical ultrasound, but instead, very high frequency waves enter the ground and form a picture of what may be below, according to G.

The machine, a box about 20 inches [25 cm] wide and with wheels, is pushed or pulled by an expert who surveys the earth in rows in a manner that looks like “cutting the visible grass,” said Will Meredith, founder and GPR specialist at GeoScan.

The device includes a radar transmitter that sends high waves to the ground that will return to the receiver if it hits anything different from that ground.

In the days after The Tk’emlúps te Secwépemc First Nation reported that the remains of 215 children had been found during a pre-operation at a former school campus in Kamloops, BC, indigenous communities across Canada had requested similar searches at suspected locations. Three indigenous women consider the importance of accounting for all children who die in boarding schools and Kisha Supernant, a Métis archaeologist at the University of Alberta, explains how he uses the ground radar to help Indigenous communities do this work. 13:48
Supernant said his team would place a square grid, about 50 feet by 50 feet, and then drag the GPR box to the surface of the earth. He said they would try to make the lines very close together – the rule is separated by 25 inches.

“This ensures that we cover the entire world under the radar box itself. It’s a slow process,” he said.

The device itself must be able to touch the ground, which means that before any work can be done, either the brush or the long grass should be wiped to get the best result, Clark said.

“I was working on a project earlier this week at the unmarked cemetery and our team spent a lot of time removing the brambles and underbrush and all this so we could see the world.”

Clark said the computer can combine all those lines and view the results in three dimensions.

“It’s very deceptive. If you go through a very small grave and find a little of it in one pass, the next pass will find the rest. And then you can find out exactly what’s going on there,” he said.

Technology does not know biological ID
Technology, however, is unable to pick up living organisms, which means that they will not be able to determine if fossils lie below.

Over time, bones will absorb minerals from the soil and become more like soil, says Steve Watson, owner of Global GPR Services Inc. in Ontario.

With a new burial, within a few years, a specialist can identify the bones or identify what looks like a bone, he said.

“If you have something 50, 60 years or 100 years or 200 years, you won’t see the bones,” he said. .

Instead, experts will be looking for “turned soil,” Watson said.

The soil is made up of thin layers, and when a shovel is put into the ground, “it connects that soil electrically, it differs from the natural soil next to it,” he said.

“So that’s what we see about GPR, an area that has been turned into dust.”

Clark said the way they received the funeral was because they saw “a very consistent style, everything is the same.

“Then we basically see the stolen area,” he said. “So we find this a bit awkward. It looks a lot softer than the ground around it.”

However, inspecting unmarked, unplanned graves with no particular shape can be a challenge, Clark said.

“There are a lot of things close to the face like roots and gopher holes and all sorts of things that can confuse what is happening to that 30 or 40 officer

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