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The 2017–2018 Maple Creek Earthquake Sequence in Yellowstone National Park, USA
Author(s) -
Pang Guanning,
Koper Keith D.,
Hale J. Mark,
Burlacu Relu,
Farrell Jamie,
Smith Robert B.
Publication year - 2019
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 - 10.1029/2019gl082376
Subject(s) - aftershock , geology , seismology , earthquake swarm , cluster (spacecraft) , sequence (biology) , induced seismicity , biology , computer science , genetics , programming language
We explore the detailed spatiotemporal evolution of 3,345 earthquakes that occurred near Maple Creek, Yellowstone, for the time period of 12 June 2017 to 13 March 2018. We generate high‐accuracy relocations and near source V P / V S ratios using 4.4 million P wave and S wave differential travel times derived from waveform cross correlation. The hypocenters can be subdivided geographically into two major subpopulations: a northern cluster with planar structures striking mainly NW‐SE and a southern cluster with planar structures striking mainly E‐W. We observe V P / V S ratios of 1.39–1.66 in the northern cluster and a steady ratio of 1.50 in the southern cluster, suggesting the presence of CO 2 ‐filled cracks. We interpret the northern earthquake cluster primarily as long‐lived aftershocks of the 1959 M w 7.2 Hebgen Lake earthquake but with some influence of magmatic fluids. We interpret the southern earthquake cluster as a more classic, swarm‐like sequence induced primarily by the migration of magmatic fluids.