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Bilinear Magnitude‐Frequency Distributions and Characteristic Earthquakes During Hydraulic Fracturing
Author(s) -
Igonin Nadine,
Zecevic Megan,
Eaton David W.
Publication year - 2018
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 - 10.1029/2018gl079746
Subject(s) - magnitude (astronomy) , geology , hydraulic fracturing , seismology , bilinear interpolation , superposition principle , fault (geology) , range (aeronautics) , earthquake magnitude , geotechnical engineering , statistics , mathematics , geometry , physics , mathematical analysis , materials science , astronomy , composite material , scaling
Previous studies show that a temporal drop in the b value (slope) of magnitude‐frequency distributions observed during hydraulic‐fracturing operations could signify the activation of a preexisting fault system. Based on a new data set from Alberta, Canada, we provide a case study wherein events induced during hydraulic fracturing are localized within spatial clusters with a range of b values from ∼1.0 to ∼2.5. The distribution in b values is related to the orientation and depth distribution of these clusters. As a consequence of the superposition of spatially varying clusters, the catalog for the entire data set yields a bilinear magnitude distribution with exceptionally low apparent b value at larger magnitude levels. Several clusters are compatible (at 95% confidence level) with the characteristic‐earthquake hypothesis, a controversial model for some fault systems wherein episodic large ruptures occur significantly above the maximum‐likelihood Gutenberg‐Richter relationship.