TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 60 (No. 11), pp. 1137-1141, 2008


Seismic scaling relation of the 2007 Off Mid Niigata, Japan, earthquake (Mw 6.6) sequence in comparison with two other earthquake (Mw 6.6) sequences

Reiko Tajima and Fumiko Tajima

Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagami-yama, Higashi-Hiroshima 739-8526, Japan

(Received November 15, 2007; Revised January 15, 2008; Accepted January 30, 2008; Online published November 18, 2008)

Abstract: The relationship of seismic moment (M0) to corner frequency (fc) of the 2007 Off Mid Niigata prefecture (Chuetsu-oki) earthquake sequence is examined in comparison with that of two other earthquake sequences. The M0-fc relation of this sequence (3.4 ≤ Mw ≤ 6.6) is M0fc-3.87, which deviates from M0fc-3. The relatively large deviation from fc-3 may reflect the influence of fluids identified in tomographic studies around the source region of the tectonic strain concentration. Moreover, the lower fcs of the small events (3.4 ≤ Mw ≤ 3.8) in this sequence are similar to those of off-main-fault events in the 2004 Mid Niigata prefecture earthquake sequence. The characteristics in the scaling relation may be interpreted in the context of the event locations, which are either on- or off-main faults, and may have implications for the seismogenic conditions.
Key words: The 2007 Off Mid Niigata earthquake, seismic scaling, seismogenic conditions.

Corresponding author E-mail: re-ko-is-loving-it@hiroshima-u.ac.jp

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