Open AccessThe effects of crack anisotropy on the hypocentral locations of local earthquakes
Author(s) -
Doyle Mark,
McGonigle Robert,
Crampin Stuart
Publication year - 1982
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1982.tb04940.x
Subject(s) - anisotropy , geology , seismology , fault plane , spurious relationship , dilatant , focal mechanism , earthquake location , magnitude (astronomy) , hypocenter , fault (geology) , geodesy , induced seismicity , physics , geotechnical engineering , optics , astronomy , machine learning , computer science
Summary. Exact modelling of the earthquake location process in regions of dilatancy‐anisotropy shows that failure to take account of the velocity anisotropy in the determination of local hypocentres can result in erroneous and misleading locations. In particular, the locations can indicate spurious migrations of foci from the true epicentral positions and the true depths of foci. These spurious locations may indicate planes of hypocentres deviating from the true fault plane. Observations of such phenomena have been noted several times in the literature. However, once the anisotropic model is known, a simple location program, incorporating the anisotropic velocity‐variations, permits accurate location of local earthquakes using P and first S ‐wave arrival times.