HR: 1340h
AN: NG33B-0179    [Abstracts]
TI: Observational Strategy of ACROSS towards the Time-evolving Natures in the Lithosphere
AU: * Kumazawa, M
EM: m-kumazawa@eps.nagoya-u.ac.jp
AF: Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 Japan
AU: Fujii, N
EM: fujii@seis.nagoya-u.ac.jp
AF: Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602 Japan
AU: Kasahara, J
EM: junz_kshr@ybb.ne.jp
AF: Faculty of Scoence, Shizuoka Univ., 836 Ootani, Suruga-ku, Shizuoka, 422-8529 Japan
AB: ACROSS (Accurately Controlled, Routinely Operated Signal System) is aiming at the detection of very small changes in physical states in the lithosphere, particularly for the focal region of the anticipated huge earthquakes as demanded socially. Our technical challenge is to device an ideal methodology to enable us to acquire the ideal observation data towards the real understanding of the EarthOs interiors even under the inherent noise and physical limitations. We need light to illuminate the dark EarthOs interiors, eyes to observe them and a brain to interpret the result: The light should be designed well to be really coherent, the eyes with high fidelity should be accurately synchronized to the light transmission and the brain should be smart enough to evolve by itself. In order for the whole system to be robust against noise, we have to devise all that can be done. In addition, a significant demand is imposed onto us; non-destructiveness against our environment. The recent progress of technology makes it possible what was impossible several years, so that we try to find out the ideal way to go. We have spent about 10 years for developmental works, which started a moment before the disastrous Kobe earthquake of 1995. Now we believe that the background theory has been known in addition to some of the basic technology elements, whereas the user-friendly hardware and other auxiliary tools including practical theory and software have not been acquired yet. The examples of the field observation have started to accumulate for demonstration as reported by companion papers. The data acquired by ACROSS in seismology is not seismogram but tensor transfer function (Green function) in frequency domain. The data carry substantially new information with high quality and rigorous estimate of reliability. The availability of ACROSS would change the strategy for underground study in the coming years. We would like to call for your attention and discussion to the next way to go: (1) Combined use of both elastic and electromagnetic waves: (2) Necessity of super-array or array of dense arrays of sensors, the network of ACROSS transmitters, mobile transmitters both on land and on the ocean surface: (3) Protocol of transmitting signals and data format: (4) Software for efficient data processing: (5) New targets of inversion and its methodology to utilize the new type of transfer function data to full extent: (6) Monitoring strategy for prediction of highly non-linear events.
DE: 4494 Instruments and techniques
DE: 7218 Lithosphere (1236)
DE: 7294 Seismic instruments and networks (0935, 3025)
DE: 7299 General or miscellaneous
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005