Locating the Past

November 17th, 2021 |

In October, Historic Bethlehem Museums & Sites partnered with Lehigh University’s Dr. Mariah Hoskins, adjunct professor and postdoctoral researcher in the Earth and Environmental Sciences Department, to use Ground Penetrating Radar (GPR) to explore the Colonial Industrial Quarter.

HBMS contacted Lehigh University’s Seismology class to help discover remains of the old tawry, oil mill, and butchery in the Colonial Industrial Quarter, along the Monocacy Creek. The relative locations of the torn down buildings are known due to exceptional record keeping. We hope that uncovering the foundations of these long-gone buildings will further understanding and enhance the education of the public on the life of the 18th century Moravians.

The Colonial Industrial Quarter can be considered America’s earliest industrial park with 35 crafts, trades and industries operating there in 1747. Today this area is part of Historic Moravian Bethlehem National Historic Landmark District. Unfortunately, by the 1950s, this area became home to a junk yard and over the years through the restoration and preservation efforts HBMS has been transformed to an important place to share the stories of early industry in Bethlehem and one of the most photographed locations in the Lehigh Valley.

I joined Dr. Hoskins and eight of her students from the Seismology: The Earth and the Environment class on an unseasonably warm and sunny day at the Colonial Industrial Quarter.

They cordoned off an area, with flags and measuring tapes, to use a GPR device to get a look at what is beneath the surface. This area was located between the gravel path south of the springhouse that goes to the second floor of the Waterworks and the large tree just north of the Waterworks. 

I was able to learn more about Dr. Hoskins, who received a BS in Geology at Brigham Young University in 2016, and went directly to Lehigh University, where she earned a PhD in seismology, focusing on the north Ecuador subduction zone and major earthquakes there. She completed her PhD last year, and began postdoctoral research at Lehigh, continuing research in seismology and mentoring graduate students. This semester, she gets to pass on her enthusiasm for seismology to undergraduate students at Lehigh. Passionate about teaching and science communication, Dr. Hoskins also enjoys writing for Temblor Earthquake News. She hopes to inspire others with curiosity and greater understanding of the earth and natural hazards.

The seismology course is described as “An examination of how earthquakes and active source seismology are used to understand the Earth beneath our feet.”  Dr. Hoskins told me, “The Ground Penetrating Radar (GPR) survey is similar to a CAT scan of the ground. Through GPR, we can, without disturbing the ground at all, find evidence of the walls of buildings and other disturbances beneath the ground and map their locations.”

I watched as they calibrated the machine and took notes. One student wore a large console, while other students helped to place, align, and move the radar along the path marked. They brought the machine back to the starting area, switched out students, and then resumed moving along the next section.

I learned that by pulsating electromagnetic waves into the ground, a high-resolution image of the subsurface could be made and then analyzed. While I did not stay for the entire scan of the area, I did check back with Dr. Hoskins to see what results they found in their analysis.

The report sent to me indicated that the GPR image was able to capture differences in subsurface materials based on their differing electromagnetic properties. From analyzing the different reflections of the electromagnetic waves, the exact location of the tawry foundation was found, along with a known underground pipe. The tawry was one of the key industries in 1700s Bethlehem because it supplied the soft leather for various purposes such as book bindings, gloves, pocketbooks, and knee breeches for the community. 

The Lehigh survey located one of the foundation walls for the 1768 structure. The entire foundation was not discovered during the survey. The report indicated more time and data collection is necessary in order to locate the other walls of the foundation. This is good news, because now there is a solid starting point to locate where this building once stood.

Of the collaboration between Historic Bethlehem Museums & Sites and Lehigh University, Dr Hoskins told me, “It is a great opportunity for us to work with Historic Bethlehem Museums & Sites. The collaboration is a chance for the students to put what they are learning in the classroom into practice and, even better, to contribute to their community. Education is good, but its true power comes when students can turn to benefit themselves and those around them with the knowledge they have gained. This collaboration provides one of those crucial bridges between the classroom and application that contributes to society.”

This collaboration has been a fruitful endeavor for all involved and we can’t wait to see what the future brings as we continue to learn more about our Moravian forebearers. This is an especially exciting time as we embark on a joint serial nomination to the World Heritage List with international Moravian Sites – Herrnhut, Germany and Gracehill, Northern Ireland, UK.

Tara Henninger is the new Marketing Coordinator at Historic Bethlehem Museums & Sites.

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