Archeologists surveying the rail route before construction begins, are using cutting edge technology to help map the area.
It's a sequence that’s being repeated along the 20-mile rail route from Kapolei to Ala Moana.
The work crews are working in tandem. Surveyors mark out the area where rail utilities and support columns will go along the route. Archeologists follow up with ground-penetrating radar.
"It only identifies anomalies. It doesn't tell us what's there," said Cultural Surveys Hawaii Project Manager McDermott.
The system looks a lot like a lawnmower, but it shoots energy waves down below the surface and records signals that come back up at different rates.
So far, it has been able to give archeologists a glimpse anywhere from 3 to 6 feet down below before they open up the ground.
"We are basically putting together a catalog of signatures that we are trying to put together. We don't have that yet, we are still being surprised by what we are find," but as we go along we are able to get these signatures with greater and greater accuracy," said McDermott.
The radar has been helpful in identifying where underground utilities are located,
It's particularly useful as the crew heads into the urban core.
But no one really knows what they will find, until crews actually open up the ground.
Last week, the first bone fragment was found on Halekauwila Street, and more time- consuming hand digging and sifting is expected.
"What we dealing with in Kakaako, is different types of sediment, multiple layers of fill and we are also near the water table, all of which inhibits the use of GPR," said McDermott.
When the work is complete it will be the most comprehensive study to date of what's down beneath the ground, thanks to the improvements with low frequency technology.
“Very low frequency, more than a cellphone, but not that much more," said McDermott.