Could you tell us a little bit about yourself?
I am a Professor Emeritus of the University of Texas at Austin, retired from the university in 2005. Born in Japan, graduated from Tohoku University, completed graduate study at Pennsylvania State University, I went to work for General Dynamics, an aircraft manufacturer, as a research scientist in various engineering projects.
Spending a year at the Lamont-Doherty Geological Observatory (now Lamont-Doherty Earth Observatory) of Columbia University, while on leave from General Dynamics, in the late 1960s led me to participate in the highly successful Apollo Passive Seismic Experiment (PSE) on the Moon as a team member. When the Lamont group moved to the University of Texas in Galveston in 1972, I joined the group full time and continued on analyzing the acquired seismic data.
I was also involved in the Viking project to acquire seismic data on Mars in the mid to late 1970s. After the Apollo data analyses were completed in early 1980s, I came back to Earth to study offshore structures in areas of tectonic interest such as Gulf of Mexico, Taiwan, New Hebrides and northwestern Australia.
Since the turn of the century, it became possible to reanalyze the decades old Apollo seismic data using highly powerful computers and new analysis techniques that became available. I am now trying to help young researchers in this renewed endeavor.
What are the most important recent developments in the field of research discussed in your chapter?
In my chapter I mainly discuss earlier results, and recent developments are discussed in other chapters. The most important recent development is in uncovering information hidden in the decades old Apollo lunar data using new analysis techniques. For example, seismic structure in the deep interior of the Moon has now been better defined than possible earlier, and more new discoveries are expected.
How can other seismologists, planetary scientists and astrophysicists learn from this area of research?
This book is a good starting point. If you need to learn more, I would recommend reading some of the original papers referenced therein.
Could you recommend some of your key research papers related to your book chapter? Could you tell us a bit more about the research?
A summary of the Apollo PSE results at the end of the project was given in reference (1) below. In addition, reference (2), which talks about the lunar internal structure, and reference (3), which talks about deep moonquakes, may be of interest.
(1) Nakamura, Y., G. V. Latham, and H. J. Dorman, Apollo lunar seismic experiment — Final summary, Proc. Lunar Planet. Sci. Conf., 13th, J. Geophys. Res. 87 suppl., A117-A123, 1982.
(2) Nakamura, Y., Seismic velocity structure of the lunar mantle, J. Geophys. Res. 88, 677-686, 1983.
(3) Nakamura, Y., A1 moonquakes: Source distribution and mechanism, Proc. Lunar Planet. Sci. Conf. 9th, 3589-3607, 1978.
How important is it for you to be involved in international, collaborative, interdisciplinary research linked to seismology?
It is very important because full understanding of what is being investigated and executing the needed data acquisition require collaboration beyond what a seismological community in a single country can provide.
Do you have any other messages to our readers?
The most important lesson we have learned and are still learning from the extraterrestrial data we acquired is that they always reveal something entirely unexpected from our extremely limited knowledge based on our experience on Earth. This in turn helps us tremendously to understand things happening here on Earth.
I am currently involved in retrieving and reanalyzing the Apollo data from the Moon and the Viking data from Mars. This is very important because we are now finding that these old data sets contain valuable information that the original investigators were not aware of. This applies not only to the seismic data but also to all the other experiments.