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WITHDRAWN: Source Duration of Stress‐ and Water‐Induced Seismicity as Derived from Experimental Analysis of P Wave Pulse Width in Granite
Author(s) -
Masuda Koji,
Satoh Takashi
Publication year - 2012
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 - 10.1029/2012gl054025
Subject(s) - induced seismicity , stress (linguistics) , pulse (music) , geology , seismology , waveform , fracture (geology) , fault (geology) , mineralogy , geotechnical engineering , optics , physics , linguistics , philosophy , quantum mechanics , voltage , detector
We used analyses of pulse widths of P waves in granite measured during a laboratory experiment to investigate source durations of rupture processes for water‐induced and stress‐induced microseismicity. Water was injected into a dry granite sample under constant axial stress of about 70% of fracture strength and a confining pressure of 40 MPa. After elimination of the effects of event size and hypocentral distance from observed pulse widths we obtained scaled source durations of 0.50 μs and 0.26 μs for stress‐induced and water‐induced microseismicity, respectively. This difference suggests that the rupture velocity of water‐induced microseismicity is greater than that of stress‐induced microseismicity or that fault geometry is more equidimensional in the wet state than in the dry state. Our results suggest that pulse‐width analysis of P waveforms can be used to distinguish water‐induced events from those induced by regional stress and to characterize the faulting process.