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Slip‐weakening distance estimated at near‐fault stations
Author(s) -
Fukuyama Eiichi,
Mikumo Takeshi
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl029203
Subject(s) - slip (aerodynamics) , seismology , geology , seismogram , fault plane , geodesy , smoothing , waveform , earthquake rupture , fault (geology) , physics , mathematics , statistics , quantum mechanics , voltage , thermodynamics
We estimated the slip‐weakening distance from the seismograms recorded at near‐fault stations, considering the effect of spatio‐temporal filtering for a continuous propagation of rupture. This effect is usually observed at some distance away from the fault. We used a Green's function for 2‐D anti‐plane rupture propagating with constant rupture velocity and instantaneous slip at the crack tip. As a source time function, we used a regularized Yoffe function which is a kinematically good approximation of dynamic slip‐weakening behavior. By convolving these functions, near‐fault waveforms are computed. As a proxy of slip‐weakening distance ( D c ), we used D c ′, which is defined as a slip at the time of peak slip velocity. Then, D c ′ values can be computed as a function of the distance from the fault. This procedure is applied to the observation of the 2000 western Tottori, Japan, earthquake ( M W 6.6) as well as the 2002 Denali, Alaska, earthquake ( M W 7.9). We estimated D c ′ at about 0.3 m at GSH station (∼100 m away from the fault) for the Tottori earthquake and that at about 2.5 m at PS10 station (∼3 km away from the fault) for the Denali earthquake. We confirmed that both estimates are not affected by the spatio‐temporal smoothing.