[ghsc-seminars] GHSC Seminar, Tuesday July 10th @ 10am: Elizabeth Cochran, USGS, Pasadena

[Oliver Boyd]

*"Deciphering the evolutionary **behavior of induced earthquakes in
southern Kansas"*


*Elizabeth Cochran**Research Geophysicist*
*USGS, Pasadena, CA*

The timing of events in seismic sequences can provide insights into the
physical processes controlling fault slip. In southern Kansas, the rate of
earthquakes rose rapidly starting in 2013 following expansion of energy
production into the area, demanding the disposal of large volumes of
wastewater into deep wells. Seismicity catalogs that are complete to low
magnitudes can provide insights into the physical processes that induce
seismicity near wastewater disposal. We develop a catalog of over 130,000
earthquakes recorded in southern Kansas from mid-March 2014 through
December 2017 by applying a matched filter algorithm to an original catalog
of 5,831 template earthquakes. Detections have nearly identical waveforms
to template events and represent slip on nearly co-located sections of a
fault. We select template events with at least 100 associated detections
and examine the characteristics of these prolific families of earthquakes.
We find that families located close (< 10 km) to areas with significant
volumes of injected fluids tend to occur at a steady rate, have lower
median magnitudes, and remain active over longer durations compared to
families at greater distances from wells. We conclude that increasing pore
fluid pressures from nearby disposal of large volumes of wastewater is the
primary driver of these long duration episodes, with earthquake-earthquake
interactions driving sequences at greater distance from the wells.

*Tuesday, ​July 10th**, 2018*
*​10​​​​a​m​​*
*​  (Mountain Time)*
*USGS, 1711 Illinois Street, Golden, CO*
*Entry Level Seminar Room (204)*

*Note: Please arrive *~5 minutes early* and *bring photo ID* for
airport-style security measures now in place at the USGS building.

Thank you,
GHSC Seminar Committee

Mirus, Ben - bbmirus at usgs.gov
Josh Rigler - erigler at usgs.gov
Oliver Boyd - olboyd at usgs.gov <oboyd at usgs.gov>
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