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On the Statistical Significance of Foreshock Sequences in Southern California
Author(s) -
Ende M. P. A.,
Ampuero J.P.
Publication year - 2020
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 - 10.1029/2019gl086224
Subject(s) - foreshock , induced seismicity , seismology , geology , earthquake prediction , statistical analysis , aftershock , geophysics , statistics , mathematics
Earthquake foreshocks may provide information that is critical to short-term earthquake forecasting. However, foreshocks are far from ubiquitously observed, which makes the interpretation of ongoing seismic sequences problematic. Based on a statistical analysis, Trugman u0026 Ross (2019) suggested that as much as 72% of all mainshocks in Southern California are preceded by foreshock sequences. In this study, we re-assess the analysis of Trugman u0026 Ross (2019), and we evaluate the impact of the assumptions made by these authors. Using an alternative statistical approach, we find that only 15 out of 46 mainshocks (33%) are preceded by significantly elevated seismicity rates. When accounting for temporal fluctuations in the background seismicity, only 18% of the analysed foreshock sequences remain unexplained by the background seismicity. These results imply that even in a highly complete earthquake catalogue, the majority of earthquakes do not exhibit detectable foreshock sequences.