Interview with Thomas A. Tombrello - Caltech Oral Histories

Tombrello–239
picked Motorola’s 6800 chip. I think we made the right choice. It was a four-bit
microprocessor. It had minimal memory, but it was a computer. You could run a robot with it.
So we put these things out there. They ran on batteries, but we continuously charged the
batteries from the power lines. And because people tend to break into things or shoot them—we
had a few cases of that—we bought little Sears utility sheds and sited them near forest ranger
stations. We put the instrumentation into army-surplus fiberglass boxes and bought them a
phone number. It cost $7 a month to communicate with them, so it was a step forward in
gathering data in an efficient way. Remember, this is now over a third of a century ago. It was
efficient. It was cheap. In 1979, I went to China and talked to the state seismological people
about this project. They said, “How many people work on this?” I said, “We have one full-time
equivalent.” They said, “In China we have the human sea.” Well, as it turned out, people were
cheap. They would site instruments out in remote locations and have somebody living in a hut
next to it. Alan Rice, who is now the division administrator in PMA, was one of the people we
had who really, really was roughly our full-time equivalent for a while there. We had a network
of something like a dozen of these things. That was one of the projects that some of the people
in Kellogg truly hated.
ASPATURIAN: It sounds like you were taking, or trying to take, the lab in a more interdisciplinary
direction.
TOMBRELLO: I was trying to explore the boundaries to see if there were things that would catch
people’s imagination and would not just be applied but might also eventually lead to some new
science. Were they successful? Yes, but most of the successful things—particularly in the
materials science and analysis stuff—occurred after I left Kellogg and was on my own. I think
I’ve told that story. The seismic radon project died for an interesting reason. I had friends who
backed it. Frank Press liked the idea very much. He was a true believer. We were all true
believers, until we took enough data to realize that most of the signal was just noise. We thought
we saw signals of precursors, but in reality the signal was just not something that stood out the
way the Chinese claimed it did. We discovered that most of the Chinese data, and virtually all of
ours, was related to geochemical signals that had to do with aquifer mixing, changes in
temperature, and other phenomena that depended on very small changes in atmospheric pressure.
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