HR: 1340h
AN: S23B-0320    [Abstracts]
TI: Coherence Characteristics Of Body Waves From Local Events
AU: * Kinoshita, S
EM: kkk001@yokohama-cu.ac.jp
AB: A fundamental issue in seismology and earthquake engineering is the coherence characteristics of body waves from local events that propagate in a sedimentary layer - basement system. To respond this issue, we investigated down-hole array recordings including deep-borehole seismograms obtained in the Kanto region, central Japan and obtained the following results: (1) Coherence characteristics of body waves traveling in a sedimentary layer - basement system are modeled by omega-square model. (2) Corner frequency in the omega-square model decreases as increasing in travel time. However, there is a critical corner frequency that becomes a constant independent of travel time. For example, the critical corner frequencies are about 6Hz and 3Hz for P- and S-waves, respectively. This means that bedrock motions recorded in the pre-Tertiary basement are incoherent in frequencies higher than these critical corner frequencies.
DE: 7203 Body wave propagation
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2004 AGU Fall Meeting