HR: 08:00h
AN: S31C-01    [Abstracts]
TI: Japanese Strategy and Technology of Active Monitoring of the Earth's Interiors
AU: * Kumazawa, M
EM: mkumazawa@eps.nagoya-u.ac.jp
AF: School of Environmental Science, Nagoya University, Chikusa, Nagoya, 464-8601 Japan
AU: * Kumazawa, M
EM: mkumazawa@eps.nagoya-u.ac.jp
AF: Tono Geoscience Center, Akeyo-cho, Mizunami, 509-6132 Japan
AB: The difficulty of the research towards the highly nonlinear phenomena such as earthquakes motivated us to explore an essential tool demanded inevitably beyond the level of technology and budget available at present. Intuitively it must be the extensive and intensive monitoring of the target with higher resolution. Naturally it is the remote sensing by utilizing actively and continuously all possible types of `wave', i. e., seismic wave and electromagnetic wave. The developmental study of the active tools has been made since 1994 in Japan for the precise structure exploration and continuous state monitoring targeted to the tectonically active parts in the Earth's lithospheres. It was promoted after the disastrous Kobe Earthquake of 1993. Basic necessity for the technology is the robustness against the natural and artificial noise in remote observation to obtain data with larger S/N under non-destructive condition for environments. The data to be obtained is the transfer function between many transmitter sites and many receiver sites. We believe that our science would change drastically, once we come to obtain the highly reliable data with reliable estimate of observational error smaller than before by one order of magnitude. The technical demand is the precision of transmitting signal and receiving device, which are stable and accurate enough both in synchronization and reproducibility so as to allow the effective data stacking of long period of time in obtaining the transfer function data between the source and receiver. A special emphasis is placed on the polarization and dispersion (color) of the transfer function, in order to extract the data of anisotropy, scattering and attenuation that are expected to carry the information on the physical states within the polycrystalline rocks bearing the structural sensitivity under stress. A review is made on the current state of the technology called ACROSS (Accurately Controlled Routinely Operated Signal System) and several applications in Japan and also a proposal is made for establishing the underground monitoring system of Japanese islands. The relevant test site is set to Tokai area, where a disastrous Earthquake is expected to take place at the plate boundary between Philippine Plate and Asian Plate.
DE: 7260 Theory and modeling
DE: 7294 Instruments and techniques
DE: 7209 Earthquake dynamics and mechanics
SC: Seismology [S]
MN: 2004 AGU Fall Meeting