- JSPS Award Recipient
Prof. Kurt Lambeck
Research School of Earth Sciences
The Australian National University
- Period of the Stay
February 17, 2005 to March 9, 2005 (21 days)
- Host Institution
Department of Earth and Planetary Sciences
Graduate School of Science
The University of Tokyo
- Report given by the JSPS award recipient
Report to the Japan Society for the Promotion of Science by Professor Kurt Lambeck, recipient of a JSPS Award for Eminent Scientists.
The JSPS Eminent Scientist Award provided a wonderful opportunity to develop a more in depth knowledge of Japan Science than was hitherto the case. My previous understanding of both Japan and its scientific efforts was limited to information gleaned during infrequent and short visits, and through Japanese visitors to the Research School of Earth Sciences of the Australian National University, both as students and research staff. Though the JSPS sponsored visit was relatively brief in time, it was concentrated and I was able to visit a number of geoscience research institutes, in addition to the University of Tokyo, and to talk to scientists in diverse sub-disciplines of geoscience. The program was the following:
University of Tokyo, 17-22 February
National Astronomical Observatory of Japan, Mitaka, 23 February
National Astronomical Observatory of Japan, Mizusawa, 23-25 February
Kyushu University, 26 February ? 1 March
Kyoto University, 1-3 March
Okayama University, Misasa, 3-7 March
University of Tokyo, 7-9 March.
In addition to the symposium organised to coincide with my visit, held on 21 February, the time at Tokyo University from 17 to 22 February was predominantly occupied by scientific discussions with staff from the Department of Earth and Planetary Science, the Earthquake Research Institute and the Center for Climate System Research. The highlight of course was the symposium with its two themes: climate and mantle dynamics. This not only gave me the opportunity to talk to a wider audience than would otherwise have been possible in the time available, but it also showcased Japanese contributions in two important areas of geoscience. This juncture of the two sub-disciplines was more than an excuse to cover some of my current research interests but reflects the role of mantle dynamics in understanding aspects of climate change. The two lectures were given, entitled: Earth rheology from glacial rebound analysis: Evidence for complex spatial structure and non-linear behaviour? and Ice History during the last glacial cycle: What can we learn from sea-level analyses?
A number of discussions were arranged for the days after the symposium which led to potentially important outcomes. Of particular note were the discussions with Drs A. Abe-Ouchi, F. Saito and Y. Yokoyama on the ice-climate coupling in the modelling of palaeo climate. This work complements the field-based work carried out at ANU and we arranged that I will supply my ice models and crustal deflection results and that we will run our rebound models for different climate scenarios to establish whether we can develop an effective and efficient method for coupling the climate model to the earth deformation model.
At the Earthquake Research Institute I had discussions with Drs S. Okubo, Vice Director, and J. Okuno on a range of geophysical matters including the results of geodetic observations at the Japanese Antarctic Base Syowa. (This was also discussed later at the National Institute for Polar Research (NIPR), see below.) These observations, together with geological data for rebound (raised shorelines) and ice cover (cosmogenic dating) over longer time intervals present possibly the most complete data set for understanding the deglaciation history of this part of Antarctica in the past and at present. Yet the interpretation of the data remains ambiguous and further modelling is warranted. We discussed avenues for doing this and I anticipate that some joint research will occur in the near future. A second issue discussed was the use of absolute gravity measurements for monitoring crustal deformation. A fascinating example was shown to me for the Asama Volcano where the changes in gravity during magma dyke injection, but equally important for me was to be able to discuss the accuracies that are achievable with this kind of measurement and whether there is a role for these instruments along with geodetic positioning and tide gauge measurements to separate crustal motion from sea level change.
A range of other climate-related research projects were discussed with Dr Y. Yokoyama including the evolution of the Japan Sea during glacial cycles. Some earlier joint work has led to geographic reconstructions of sea level and shorelines of the Japan Sea and we were able to compare the outcomes of the model productions with recent analyses of sediment cores. This work, as well as further studies of rapid sea level change events during glacial periods will provide the basis for further collaboration, which in fact occurred immediately after my visit with a visit by Dr Yokoyama to Australia to discuss these projects at ANU and at Geoscience Australia.
While in Tokyo I also visited NIPR because of common scientific research interests, including previous visits by NIPR staff to Australia to conduct absolute gravity measurements and because one of my responsibilities is Chair of the Antarctic Science Advisory Committee which advises the Australian Government on Antarctic Science matters. I was able to discuss the absolute gravity project with Dr K. Shibuya as well as review some of the geological data with Dr K Moriwaki and, as discussed above, this is likely to lead to further collaboration.
The ANU has operated a superconducting gravimeter for the National Astronomical Observatory of Japan (NAOJ) for a number of years as part of a cooperative program. With Dr T. Sato of Mizusawa approaching retirement the future of the program will be reviewed in Japan, and with my own retirement looming at ANU the program there will also need to be reviewed at a future time. Thus it was timely to visit NAOJ, both at Mitaka and at Mizusawa to discuss the project’s future with the Director General, Dr N. Kaifu and the Director, Dr S. Manabe. It is my fervent wish that the project can continue for some years yet because, as the gravity reverberations produced by the Sumatra earthquake are beginning to show, much and unexpected information about the deep structure of the earth can be produced with long records from these instruments. At Mitaka, I also visited the gravity-wave experiment and the 4-D visualization facility. Both represent very impressive developments that Japan can be proud of.
The visit to Mizusawa, was of particular interest because I first visited the Observatory in 1971 and I was impressed by the progress made in the field of space geodesy with the development of the ‘VERA’ VLBI program. The area of Space Geodesy is one in which I have worked intermittently for forty years so I chose to review progress made in this time with my lecture on: Forty Years of Satellite Geodesy: Contributions to the understanding of the solid Earth. I also had detailed discussions with Dr T. Sato about the gravity program including the review of one of their scientific papers recently submitted for publication, and from this I gained a much better understanding of their Svalbard project. I have proposed that one of my students at ANU work with the Svalbard data collected by the gravity, VLBI, and GPS measurements and this should ensure longer-term collaboration. I was pleased to meet Dr K. Matsumoto whose work on the modeling of ocean tides is important as it provides an independent calculation of the effect of ocean tides on the deformation of the earth as recorded by gravity and other geodetic techniques. I look forward to be able to use his results in our own high-precision GPS analyses.
I was also introduced to the Japanese program for the mapping of the Lunar gravity field. This is a scientifically important program as it completes something started by NASA several decades ago but whose incompletion has left major unknowns in our understanding of the structure and history of the Moon. I wish this program success and look forward to seeing the results. I was pleased that the launch of the Japanese meteorological satellite the week following my visit was successful.
The visit to the Department Earth and Planetary Sciences of Kyushu University at Fukuoka allowed me to renew contact with Professor M. Nakada, who was a Research Fellow at ANU in the 1980’s, and to develop new links with other staff, including Professor K. Takahashi with whom I was able to have a constructive discussion on possible Australian participation in the Integrated Ocean Drilling Program. I also gave a lecture entitled: Earth, Ice and Ocean: What can we learn about Earth rheology and ice sheet history from sea level analyses?
(By coincidence I had been collaborating with a Japanese scientist, K. Uehara, on paleo-tides in the North Sea who was at the University of Wales under JSPS sponsorship. I was unaware that he is now at Kyushu University in the Institute for Applied Mechanics and I did not meet him there. But I have since then suggested that he contact Professor Nakada to see whether similar palaeo-tide modelling can be done for the Japan Sea, as this would make a nice compliment to the sedimentological studies of Dr Yokoyama.
The visit to Kyoto University was to the Department of Geophysics where I gave a lecture on: Mantle Viscosity: What can we learn about Earth rheology from glacial rebound analyses? I also had discussions with Dr Y. Fukuda and Professor S. Takemoto primarily about absolute gravity measurements at Syowa in Antarctica. The periodic program of absolute gravity measurements in Antarctica have been important in Australia because during most transits from Japan to Antarctica it has been possible to take measurements at the site of the superconducting gravimeter at Mt Stromlo, ANU, for calibration of the relative gravity meter and for monitoring whether the site is undergoing long-term slow changes in gravity. This turned out to be particularly important for the calibration after the Stromlo fires. For as long as the superconducting gravimeter remains at Mt Stromlo it is desirable that the absolute gravity measurements are repeated.
The visit to the Institute for Study of the Earth’s Interior of Okayama University at Misasa coincided with a conference on ‘Origin, Evolution and Dynamics of the Earth — Present & Future Research’ and with a special program to honour Professor M. Kono. For the latter I gave the keynote address, entitled: Earth rheology from glacial rebound analysis in keeping with the broader theme of the conference. Prior to the conference I visited the laboratories at ISEI and was impressed not just by the remarkable resources that have been collected together but also by the range of outstanding and difficult scientific questions being addressed. I was also pleased to meet several former students and post doctoral fellows who had been trained in the high-pressure and isotope laboratories of the ANU.
It transpires that I have been visiting Japan at -11 year intervals since my first visit in 1971 and the most obvious change that I have seen over these periods is the rise of the young scientists in the Earth Sciences. Not only are they more visible but they are more ready to engage in debate and able to hold their own in scientific debate. This is true not only in Tokyo but also at the other institutes visited and at all places a very substantial part of the audience was made up of young scientists who were prepared to question even an ‘eminent’ scientist and to present me with their latest papers. I enjoyed this exchange and learnt new things and from the reactions received I think that this was reciprocated. It not only made for a productive and busy schedule but it reminded me of the global contributions being made to Earth Science by Japanese scientists. In a twenty-first century where technological developments dominate, it is easy to overlook that Earth Science, concerned with the workings of the planet’s interior and of its fluid envelope, is clearly important to Japan. The talent and enthusiasm displayed to me by Japan’s geoscientists, particularly the younger element, indicates that this science is in a healthy shape and will contribute significantly to Japan’s future welfare and international standing. I certainly look forward to seeing Japanese science continue to go forward in leaps and bounds and I hope that it will be possible to participate in this through the foundations laid by the JSPS program.
On a more personal side, I express my great appreciation to JSPS and the University of Tokyo for making this visit possible, in particular the former for their generous support. It was a pleasure to be able to meet with the Presidents of both institutions to personally thank them for the distinct honour they bestowed on me. Not only was the science part impressive. My wife and I enjoyed the tremendous hospitality offered at all times by our hosts and the institutions that they represent: Dr Yokoyama and University of Tokyo, Dr Sato and NAOJ, Professor Nakada and Kyushu University, Dr Fukuda and Kyoto University, and Professor Kono and ISEI. Not only did they provide the key to look at Japan’s future science but they also provided us with an insight into Japanese life, history and culture that will remain with us. I hope that it will not be another 11 years before we return.
Professor of Geophysics
The Australian National University