Open AccessTemporal changes in attenuation of S waves through a fault zone in a South African gold mine
Author(s) -
Yoshimitsu Nana,
Kawakata Hironori,
Yamamoto Akihito,
Ogasawara Hiroshi,
Iio Yoshihisa
Publication year - 2012
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2012.05678.x
Subject(s) - attenuation , seismology , geology , fault (geology) , seismic wave , scattering , san andreas fault , seismic zone , induced seismicity , optics , physics
SUMMARY We investigated the temporal changes in the seismic attenuation of a fault zone using near‐source recordings of S waves from repeating microearthquakes that occurred both before and after M ∼ 2 earthquakes in the Bambanani gold mine, South Africa. Because the source locations and the mechanisms of repeating earthquakes can be regarded as identical, the attenuation change can be estimated using the spectral ratios for repeating earthquake pairs. We found an increase in the S‐ wave attenuation parameter on the vertical component which is positively correlated with frequency, corresponding to times before and after the M ∼ 2 earthquakes. This increase can be explained by scattering attenuation, with a typical scale of damage in the fault zone of ∼3 m.