1. Department of Physics Kumamoto University Kumamoto 860-8555 Japan
2. Materials Dynamics Laboratory RIKEN SPring-8 Center Hyogo 679-5148 Japan
3. Department of Earth and Planetary Science The University of Tokyo Tokyo 113-0033 Japan
4. Earth-Life Science Institute Tokyo Institute of Technology Tokyo 152-8550 Japan
5. Japan Synchrotron Radiation Research Institute Hyogo 679-5198 Japan