thumbnail

Velocity anomalies: An alternative explanation based on data from laboratory experiments

Pure and Applied Geophysics PAGEOPH

By:
,
DOI: 10.1007/BF00876537

Links

Abstract

Locations and velocities were calculated for microseisms occurring in samples of rock subjected to triaxial loading and injection of pore fluid. This was accomplished by analyzing arrival times of acoustic emission using an automatic first arrival picker. Apparent velocity anomalies were observed prior to both failure of intact samples and violent slip in samples containing saw cuts. Further analysis revealed that these fluctuations in calculated velocity were not due to changes in the true seismie velocity. Instead, variations in calculated velocity are shown to be related to sampling errors in picking first arrivals. The systematic picking of late first arrivals for small magnitude events was found to be a persistent bias resulting in low calculated velocities. This has encouraged the reexamination of earthquake records to determine how important sampling biases are in contributing to reported velocity anomalies. ?? 1978 Birkha??user Verlag.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Velocity anomalies: An alternative explanation based on data from laboratory experiments
Series title:
Pure and Applied Geophysics PAGEOPH
DOI:
10.1007/BF00876537
Volume
116
Issue:
4-5
Year Published:
1978
Language:
English
Publisher location:
Birkha??user-Verlag
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Pure and Applied Geophysics PAGEOPH
First page:
765
Last page:
772
Number of Pages:
8