Ground Penetrating Radar
Presented by Steve O'Gorman

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Dr. Harry Jol, Dr. Phil
Reeder, and Dr. Jack Shroder
using GPR at Bethsaida

Ground Penetrating Radar (GPR) is a tool archaeologists will
use more and more for excavations in the 21st century. GPR
allows archaeologists to survey archaeological sites in a short
amount of time with precision and without digging.

GPR works by sending electromagnetic waves from a transmitter
antenna through the ground. The electromagnetic waves bounce
off buried objects and are collected through a receiver antenna.
The signals are then stored in a computer that analyzes the data
and can depict the information in a variety of ways.

The depth of useable resolution depends on certain factors like
the content of minerals in the soil, how much clay and moisture
is in the soil, as well as the surface of the ground.

The frequency of the antenna is another factor that
determines the depth and resolution available. The longer
the wavelength the greater the depth but the resolution of
the buried objects is not as good as having a shorter
wavelength antenna.


First Overview

City Gates of Bethsaida

GPR was recently used at the ancient city of Bethsaida in Northern
Israel. Two thousand years ago, Bethasia was an active fishing
community by the sea of Galilee. It is the site where Jesus healed
a blind man and walked on water near its shore.

Recently, Dr. Harry Jol, professor of geography at the University of
Wisconsin - Eau Claire, used Ground Penetrating Radar to map an
area by the city gates of Bethsaida.


Excavations at Bethsaida

Movie: Antenna Run Through

The majestic Nahal Hever

Ground Penetrating Radar was used to map
possible excavation sites in the Cave of Letters.

Located in Nahal Hever, a canyon by the Dead
Sea, the Cave of Letters was where many
artifacts such as coins, clothes, and letters were
found mentioning the jewish leader Bar-Kokhba,
who fought against the Romans around the
middle of the first century CE.


The Cave is located 200 meters
above the canyon bed.

Once the data is collected it can be viewed and analyzed in several ways.
Programs can synthesize 3D models of the data as well as 2D images.


Beth tunnel
On the right side of the profile there is a
diffraction feature - a bump. We were
looking for possible tunnels - this might be one
that came up in the radar profile.

The horizontal layers would indicate layers of
stones/rocks that were laid down at this site.


Synthenized 3D model of data
collected at the Cave of Letters.



Email to:

Dr. Harry Jol
Assistant Professor of Geography
University of Wisconsin - Eau Claire

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