Visit to School of Science-Affiliated Facilities

Vol.2 GCRC (Geochemical Research Center)

  • Written by Kenji Notsu (Director of Geochemical Research Center, Professor) in 2007

Translated into English in August 2010

How GCRC was named

GCRC (Geochemical Research Center), or The Laboratory for Earthquake Chemistry (old name for the Center used until March 2010 from its establishment), which was established in April 1978 as a new affiliated facilities of the School of Science, marks its 30th anniversary next year. The Japanese name “Chikaku Kagaku” is an easy-to-pronounce and easy-to-remember name for the Japanese. However, it is not a scientific field that can be found in a physical or chemical science dictionary or in a geosciences dictionary, and no English name for the field exists. I would venture to call it “Chemistry of Crust”. Its meaning, however, is different from that of “Earthquake Chemistry” in the old English name of GCRC. Behind this naming of the Center, we can see the efforts of the members involved in the establishment of the Center.

Figure 1

Figure 1: Cover of the GCRC brochure published in 1998

The history of the Center dates back to 1973, which was about 5 years before the establishment of the Center. Prof. Toshi Asada of the Department of Earth and Planetary Physics, Faculty of Science, wanted to start a study of geochemistry aimed at earthquake prediction, and he began research on radon dissolved in underground water. Hiroshi Wakita, a research associate at the Radioisotope Laboratory, was a leading member of the research group. At that time, the freshness and importance of geochemical research on earthquakes started to garner world-wide recognition. And in line with a proposal called “Partial Revision of the 3rd Earthquake Prediction Plan” announced by the Geodesy Council of the Ministry of Education (presently the Ministry of Education, Culture, Sports, Science and Technology) in July 1975, the Center was established under the leadership of Kenji Tamaru, the Dean of the School of Science. With the prospect that the research field would broaden in the future, those involved in the establishment at first wanted to name the Center “Geochemistry Research Facility.” I heard, however, that they chose the current Japanese name because the research areas of geochemistry are far too wide, and a “Research Facility” would mean research on a temporary basis. Still, the current name, which means “Chemistry of Crust”, does not deliver the true meaning of our research considering the fact that earthquakes occur in the mantle, which is located in a deeper part of the Earth than the Earth's crust. Our spirit of promotion on the chemical study of the Earth with the study of the Earth's crust as a main field is described on the cover of our brochure (Fig. 1), which was first published on the 10th anniversary of the Center's establishment. And I think the Center has now realized the description. I hear they chose the English name of the Center, “Laboratory for Earthquake Chemistry” because they thought it would show the research field in four words, although they felt unsure about it to a certain degree.

Outline

When the Center was set up in 1978, there were only two faculty members: Hiroshi Wakita (associate professor) and Yuji Nakamura (assistant professor). Not only did they improve the geochemical observation network aimed at earthquake prediction, but they focused on the basic study of geochemistry. The following are some of our achievements from those days: clarification of discharge of mantle-derived helium through earthquake faults; detection of Radon density anomaly in underground water prior to the occurrence of the Izu-Oshima Coastal Earthquake in 1978; and elucidation of hydrogen formation as a result of the reaction of water with fractured rock in active faults.

The Center has been reorganized four times since 1982. In 1995, the Center was organized with two professors, two assistant professors, three research assistants, and an engineering official (temporary member at that time). The members are unchanged since then except for the engineering official, who quit the Center. As we had expected, our research field broadened into a variety of areas of geochemistry (e.g., volcano chemistry, ocean-floor chemistry, and deep earth chemistry), which made the Center grow into a unique research and education organization that clarifies various phenomena occurring on the Earth and planets, from a chemical perspective.

Figure 2

Figure 2: Group photo taken in April 2007

Figure 3

Figure 3: Kamakura Observatory

Currently, the Center has six faculty members, a part-time administrative staff member, a researcher, a member for research promotion, JSPS fellows, postdoctoral researchers supported by the Grants-in-Aid for Scientific Research, and several administrative assistants as well as more than a dozen graduate students and a few undergraduate students working on their graduation researches.

Fig. 2 is a group photo taken in April this year, which shows all the members of the Center. Thanks to the academic characteristics of our research, we have been conducting active international exchanges, we have conducted joint researches with more than ten countries (including Italy, Spain, UK, USA, China, Republic of Korea), and international researchers and graduate students are working with us at the Center on a daily basis.

The most distinctive feature of the Center compared to other School of Science-Affiliated Facilities is that there is no mother-department that handles the Center's research field in the School of Science. Dovetailed with the fact that geochemistry was born after a union of geology and chemistry in the early 1900s, the Center was born as a research organization that covers the integrated academic areas constituting chemistry, geophysics, and geology. Being an institute with a unique research field gave us many advantages such as being able to maintain our distinctiveness, but at the same time we were left holding out on our own and were forced to course a difficult navigation.

As for educational activities, the Center set up a geochemical laboratory as well as a planetary chemistry laboratory in response to the estimation of the maximum number of graduate students in the Department of Chemistry as a collaborative research unit between the Center and the Department of Chemistry, when the School of Science placed a strategic focus on graduate education in 1993. In addition, we share undergraduate education with the Department of Chemistry through lectures, experiments and postgraduate research. Since we share the student education with the Department of Earth and Planetary Science as well, students from two different departments are studying together in the Center. However, our laboratories are dispersed throughout the Chemistry Buildings (West, Main, and East Buildings), which makes it hard for us to work efficiently. We hope to have our laboratories in one place some day in the future. Also, we have an observatory on the School of Science-owned ground in Yuigahama, Kamakura City as the basis of our observatory research.

Members

During the 30-year history of the Center, personnel transfer has made us change the research subjects. Currently there are four ongoing research subjects in the Center. Research activities of the Center are conducted mainly by the six full-time researchers. However, much of our research has been supported by collaborative research conducted through collaboration with researchers of the related fields both in Japan and abroad, which has helped us to play a role as a base of geochemistry research. Majors, specialized fields and the work experiences of our researchers vary, because the research of the Center is in interdisciplinary areas that are considered as surrounding areas that cover the research fields of the existing departments. This has formed the diversity of our organization and has become the source of our research activities. Let me introduce the six main scientists of the Center.

First of all, let me introduce myself (Kenji Notsu, professor). My major was chemistry but I started in cosmochemistry, which covers meteorite isotopes, hoping to study in a less populated research field. Since then I have changed my research subjects in 10-year cycles from volcanic isotope chemistry, chemical observation on volcanoes to active fault chemistry. Every time I have changed my research subject, I have changed my research methods accordingly.

Prof. Keisuke Nagao has an opposite approach to research than I have. He learned the first thing about mass spectrometer production at an experimental physics laboratory and has stuck with noble gas mass spectrometry up to the present. While making new discoveries in high- sensitivity and high- accuracy measurement, he has contributed to creating a new academic field. Since he was transferred to the University of Tokyo, he has been working on the development of noble gas mass spectrometry in the micro region and micro specimen, using lasers. He discovered the noble gas concentrated in E-chondrite and chondrules, and proved that strong irradiation of the solar wind occurred during the evolution process of the early solar system. He has also made it possible to measure the noble gas isotopes of each cosmic dust grain, which is as small as a microgram, and he is trying to find out where they are from. Based on these achievements of ultralow volume isotope analysis, he was appointed as a member of the initial analysis team to conduct the noble gas analysis when the samples of the asteroid Itokawa were brought to the Earth. Prof. Nagao also loves fieldwork and goes out to collect samples of volcano/hot spring gas while visiting countries such as Cameroon, Republic of Korea, China, Greece, and Turkey as well as Antarctica. Through his fieldwork, he has made many research achievements.

Hirochika Sumino, assistant professor, is the youngest faculty member of the Center. Even though his major was chemistry, he has made a significant contribution to the improvement of mass spectrometers. He has made achievements in fields of material circulation in the Earth's interior to clarify mantle structure based on noble gas isotopes. He is expected to be back in Japan after a year-long research in England by the time this article appears in the School of Science Newsletter.

Hiroyuki Kagi, associate professor (presently Professor), has a strong presence in the Center. He studied Chemistry but in the middle of his doctoral course, he started working in the Graduate School of Engineering, which shows that he is a so-called “child of material science”. Since he was employed by the University nine years ago, he has been working on the atomic level observations of crystal surface, and the clarification of the local structure around impurity elements aimed at understanding of mineral-fluid reaction as well as spectral measurement under high-pressure and diffraction chrystallography research for the clarification of the state of materials in the Earth's deep interior. In particular, he deserves attention for the fact that he was the first to clarify the state of water in the silicate minerals that make up the Earth's deep interior through the neutron diffraction experiments under extreme high pressure. Prof. Kagi also demonstrated a talent for obtaining competitive funds, and this year he managed to start research supported by the Grant-in-Aid for Creative Scientific Research that promotes the neutron science under extreme high pressure. Besides, he showed his leadership by organizing a group of researchers to build a beam line for high-temperature and high-pressure experiments specialized for geoscience research in the pulsed neutron source, JSNS (The Japan Spallation Neutron Source), in J-PARC (Japan Proton Accelerator Research Complex).

Associate Prof. Toshiya Mori is the one who is supporting the field science in the Center. He graduated from the Department of Earth and Planetary Physics, Faculty of Science. For research observations, he visits volcanoes not only in Japan but overseas. He has commanded the respect of overseas researchers in the method of remote spectroscopic observations of volcanic gas since he was a graduate student. Recently, he has succeeded in the visualization of sulfur dioxide emitted from volcano craters, using a self-made device that has made it possible to see the dynamic state of volcanic gas emission clearly and to track time variation of the discharge volume with high time-resolution.

Another member who is also supporting the field science is Fumiaki Tsunomori, assistant professor, who studied applied physics. He started out in the field of polymer science and progressed to geochemistry. He has good skills in making measuring devices and information- processing; he has developed a new method to observe the emission of volatile substances relating to seismic activity, and has achieved successful results in rock fracture experiments that serve as a basis for such phenomenon.

Future of the Center

GCRC has achieved satisfactory results in geochemistry research and education activities that are a fresh departure for the research fields the existing departments of the School of Science cover. While expanding the research field from the chemical research on volcanoes, we have carried out a mission to develop new research fields as one of the School of Science-Affiliated Facilities trying to create something new from existing knowledge. The Center will be supporting a new research project called the “Development of Ultra-high Pressure Material Science Utilizing Intense Pulse Neutron Source” that was adopted as one of the FY 2007 - 2011 Grant-in-Aid for Creative Scientific Research projects. In 2006, we went through an external evaluation after conducting self-inspection of the Center, and we received a high evaluation for the on-going research subjects. However, there are various opinions on what direction the Center should work toward in the future. Based on these opinions, we have started discussing possible measures for further advancement. Even though specific research subjects change with the flow of the times, our basic policy does not change; we study and teach the phenomena occurring on the Earth based on chemical methods. A great number of researchers from both within and outside the University and both from Japan and overseas have visited the Center for joint research. We wish to work on creating a system that will make our previous activities work organically.

  1. Geochemical research associated with seismic activity
    • Development of simultaneous-continuous analysis of ground water dissolved gas multi-component & application to seismic observation
    • Detection of mantle-derived helium emitted from active faults and deep low frequency micro-motion areas
  2. Research on volcanic activity with volcanic fluid
    • Development of remote measurement of chemical composition of volcanic gas based on the infrared absorption spectroscopy
    • Detection of change in the diffusely emitted carbon dioxide flux induced by volcanic activity.
    • Development of visualization method for sulfur dioxide contained in volcanic gas
  3. Research on geochemistry using noble gas element and isotopes
    • Detection of chondrules that show the solar wind irradiation in the early solar nebula
    • Verification of noble gas circulation in the subduction zone using mantle-derived substances and volcanic rocks
  4. Material scientific research associated with the chemical phenomena in the Earth's interior
    • Determination of hydrogen position in hydrated minerals using neutron diffraction under high pressure
    • Estimation of depth where rocks originated based on the Raman Spectrum of CO2 fluid inclusion in the rocks
    • Scanning near-field optical microscope production and inter-granular /trans-granular residual pressure mapping

GCRC Web site:http://www.eqchem.s.u-tokyo.ac.jp/index_e.html