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Magnitude‐based discrimination of man‐made seismic events from naturally occurring earthquakes in Utah, USA
Author(s) -
Koper Keith D.,
Pechmann James C.,
Burlacu Relu,
Pankow Kristine L.,
Stein Jared,
Hale J. Mark,
Roberson Paul,
McCarter Michael K.
Publication year - 2016
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 - 10.1002/2016gl070742
Subject(s) - coda , seismology , magnitude (astronomy) , induced seismicity , geology , tectonics , amplitude , earthquake magnitude , geometry , physics , mathematics , quantum mechanics , astronomy , scaling
Abstract We investigate using the difference between local ( M L ) and coda/duration ( M C ) magnitude to discriminate man‐made seismic events from naturally occurring tectonic earthquakes in and around Utah. For 6846 well‐located earthquakes in the Utah region, we find that M L ‐M C is on average 0.44 magnitude units smaller for mining‐induced seismicity (MIS) than for tectonic seismicity (TS). Our interpretation of this observation is that MIS occurs within near‐surface low‐velocity layers that act as a waveguide and preferentially increase coda duration relative to peak amplitude, while the vast majority of TS occurs beneath the near‐surface waveguide. A second data set of 3723 confirmed or probable explosions in the Utah region also has significantly lower M L ‐M C values than TS, likely for the same reason as the MIS. These observations suggest that M L ‐M C is useful as a depth indicator and could discriminate small explosions and mining‐induced earthquakes from deeper, naturally occurring earthquakes at local‐to‐regional distances.