Alan Witten teaching about the day's geophysics results at the UCSD Archaeology Field School in Jordan, 2002.
Thomas E. Levy
Department of Anthropology, University of California, San Diego
Over the past 16 years, I had the good fortune of working closely with Alan Witten on a number of archaeology projects in Israel and Jordan. Over this period of time, Alan developed a passion for applying his knowledge of geophysics to the interdisciplinary goals of archaeology. By the time of his tragic death, Alan had left us with the proofs of this impressive Handbook of Geophysics and Archaeology that you hold in your hands. This book will be a lasting tribute to Alan Witten's brilliance as a scientist, scholar, researcher and teacher. Alan's far ranging talents carried him to the Middle East where he unleashed his intellect to become one of the leading advocates, innovators and leaders in the field of geophysics and archaeology. Some of the highlights of the handbook will be touched on below in the context of a small appreciation of Alan Witten.
Alan and I spent more time together in the field than we did back in the USA. In fact, our intercontinental collaboration was solely based on field work that translated into a number of published papers. These collaborations evolved over the years from the use of snail mail, faxes and Fed Ex to the internet. It is ironic that Alan, so gifted a physicist, didn't really like to use email but preferred the telephone. He liked the personal touch. Alan wanted to talk—not just about business but to find out how you and your family were really doing.
Our relationship started when Alan was working at the Oak Ridge National Laboratory in Tennessee and I was the assistant director of the Nelson Glueck School of Biblical Archaeology (NGSBA) at the Hebrew Union College in Jerusalem, Israel. Back in 1989, Avraham Biran, the noted Biblical Archaeologist and director of the NGSBA, handed me a series of letters from Alan regarding his interest in doing some geophysics at archaeology sites in Israel. Biran, who was in his 80s at the time and from the old school of archaeology, didn't appreciate what geophysics could do for archaeology so he let me deal with the letters. One of the letters included a copy some newspaper articles from The New York Times and The Wall Street Journal explaining how Alan, using geophysics, had discovered the largest dinosaur skeleton in the world which he called 'Siesmosaurus'. Alan used a geophysical tool that he helped pioneer called 'Geophysical Diffraction Tomography' (GTD, see Chapter 12, this volume) and if you saw the beginning of the Spielberg movie Jurassic Park—the geophysics portrayed there are based on Alan's work. Always one to take a gamble on 'high-tech' and archaeology, Alan Witten sounded like my kind of researcher.
Alan flew out to Israel in 1990 with a mountain of geophysics equipment and some colleagues to help him in the field. At the time, I was digging an unusual ancient settlement from the Chalcolithic period (ca. 4500-3600 BCE)—a time when metal working was first discovered, fruit growing developed, the earliest temples emerged and the first institutionalized social inequalities (chiefdoms) were formed (Chapter 12, this volume). At the ancient village of Shiqmim located in Israel's northern Negev desert (and in the middle of an Israeli army firing zone), we had found evidence of over twenty underground rooms and tunnels that represented a kind of 'troglodyte' community. The question was just how extensive were these subterranean complexes and what were they for? Alan had brought three different geophysical tools with him to the field but GTD worked the best. Even before he got on the plane, Alan had to improvise. Standard GTD as practiced at the time in the USA with large research budgets had the luxury of using truck-based drilling rigs and small explosive devices to produce the much needed sound source for subterranean imaging. We simply didn't have the funds to hire a truck in Israel. In addition, try getting an eight-gauge chassis mounted shot-gun through Israeli customs! Instead, Alan brought a hand auger, a metal sound plate and a sledge hammer for us to use. Studying his lap-top computer in the field, we immediately saw significant results—a long underground tunnel leading somewhere. However, time had run out as the army needed our area for their exercises.
Alan returned to Israel in 1993 to join me as part of a UCSD expedition to Shiqmim. I had just joined the faculty at the University of California, San Diego, as an assistant professor. Alan set up his equipment in an area over 300 meters from our main excavations to test just how extensive the underground architecture was at the site. That year, Alan borrowed a large Silicon Graphics computer unit from the company in Tel Aviv and operated it out of the rented minibus that he drove out to our desert site. As the data started to appear on the computer screen, we were amazed to see that the entire hill was catacombed with underground rooms. We did ground-truth tests by digging in those areas that Alan imaged and proved that his work was correct. These data were instrumental in proving the existence of a huge underground storage system that was central to the rise of chiefs in this ancient society. Our published results gained a great deal of scholarly and popular attention.
While Alan loved the deserts of the Middle East, he was also partial to a clean bed, warm shower and a healthy Israeli or Jordanian breakfast served at the best available hotels in our research areas. In all the years we worked together, Alan never slept under tent canvas. But Alan was no prima donna—he simply liked to ensure that he had a good night's sleep to maximize his performance in the field. Unlike many specialists who work with archaeologists, Alan always brought his own funding to our projects making him a unique independent scholar and true partner.
On becoming a professor in the Department of Geology and Geophysics at the University of Oklahoma (Norman) in the 1990s, Alan held the Schultz Chair in Geophysics. After many years at Oak Ridge, Alan was prepared to take the chance of leaving the security of his work with the government for a new life in academia. During this period, he joined me in a series of new archaeological projects in Jordan. Alan's practice of geophysics on archaeological sites was what he called the 'shot gun approach' where he would bring a truck load of different geophysical tools into the field in order to test which technique would yield the most fruitful results for the archaeologist. Alan's mastery of all aspects of shallow geophysics is highlighted in this handbook which aims to introduce the student and researcher to both the theory behind geophysics coupled with tested experiments at archaeological, paleontological and historical sites.
Witten begins by addressing one of the archaeologist's age old needs—to detect secret underground rooms and tombs beneath a surface structure. As Alan points out, this is also one of the most challenging problems in geophysics. This problem has been faced by a number of fields, and resulted in, for example, the early detection, of leaks in the bottom of large petroleum storage tanks, the presence of chambers beneath the great pyramids of Egypt, and, most recently, the detection of secret underground facilities in problem areas around the world. This can be solved using gravity measurements (Chapters 2 and 3). One of the more common geophysical tools, magnetometry, is discussed in detail in Chapters 4 and 5. In archaeology, magnetometry has been used to locate and identify non-metallic features such as stone or brick fire pits or fireplaces. This is because these objects have been exposed to heat to create 'thermoremnant' magnetization. Buried stone walls can be located if the stones that make up the wall are basalt with a high remnant magnetization. Walls containing low magnetic susceptibility rocks (Table 4.1) can, in some cases, be indirectly detected. In Chapter 5, a series of fascinating applications of magnetometry are presented including the discovery of tombs belonging to the offspring of the Egyptian Pharaoh Rameses II (ca. 1250 BCE) in an expedition led by Kent Weeks, and the complete mapping of an Early Bronze Age (ca. 2400/2300—2200/2100 BCE) small city known as Titrish Höyük located along a small tributary in the Upper Euphrates river basin of southeastern Turkey. This project, directed by Guillermo Algaze of UCSD, included an important magnetometry survey by Lewis Somers that produced stunning results that enabled the archaeologists to zero in and identify choice buildings and other features to sample (Chapter 5). From magnetometry, he moves on to introducing the basic concept of waves (Chapter 7), necessary for understanding the use of waves in geophysics applications.
Witten points out that Electromagnetic induction (EMI) has been used in geophysics for decades for the exploration of metallic ore bodies. He refers to it in this handbook as a new frontier, because EMI has only recently been exploited to take advantage of the power of this technique for the kind of shallow applications of interest to archaeologists. One reason that EMI methods Stagnated for many years is that some geophysicists considered EMI to be the most difficult of all the geophysical techniques. Witten, along with I.J. Won and others, helped pioneer the development of EMI for archaeology, homeland security and other applications. In Chapter 8, a number of fascinating EMI studies are presented including Witten's own work on a tunnel in Guthrie, Oklahoma, rumored to have dated to the 'OF West' period and used as a secret entrance to the town that led to a labyrinth of subterranean pathways beneath Guthrie. Witten carried out another EMI survey as part of a project to locate and identify the remains of a Captain Kidd's pirate ship m the harbor of a small island near Madagascar in the Indian Ocean. The EMI survey was carried out in an attempt to confirm a tunnel or a tunnel complex rumored to have been developed by Captain Kidd's pirate crew. In an effort at forensic anthropology, Witten used EMI to located evidence of the Tulsa Oklahoma Race Riots of 1921. Finally, he presents a series of EMI survey studies carried out at Pre-Pottery Neolithic and Iron Age sites in southern Jordan. These surveys were part of the University of California, San Diego—Department of Antiquities of Jordan (Jabal Hamrat Fidan) archaeological investigation of sites in the copper ore rich region of Faynan in the area of biblical Edom. Not only was Witten able to map the subterranean architecture at the Jordanian sites, he also detected important copper ore bodies below an ancient mining center in the research area. In all of the above examples, Witten's application of EMI technology helped solve important cultural and historical problems.
Ground Penetrating Radar, or GPR, is another method of subsurface investigation where short radio pulses are sent through the ground so that the 'echoes' send back important changes in the character of the soil or sediment. After presenting a thorough overview of the theory behind GPR (Chapter 9), the range of GPR instruments are discussed. This is followed by a series of case studies where GPR has been successful in modeling cave and cash deposits used by the nineteenth-century outlaw Jesse James during the mid-1800s to 1880 in southeast Oklahoma and additional data from the Tulsa Race Riot of 1921, The handbook ends with Witten's discussion of Geotomography (Chapters 11 to 13)—another sub-field of geophysics that he helped pioneer,
Although we spoke over the years, the last time I saw Alan was when he came to the field in Jordan in 2002 to help us by using geophysics to explore one of the largest Iron Age (ca. 1200—500 BCE) copper metal factories in the ancient Near East. The results of that work are published here in coordination with Alan's remarkable young sons, Seth and Ben, and with the support of their mother—Kathy. Seth had joined his father on that last expedition to jordan. As a university professor, Alan's gifts as a teacher and communicator grew every year. He could make the most complex physics concepts understandable for the 'science challenged'. This handbook, the first in our series, is a fitting tribute to this remarkable person.