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Missing links in earthquake clustering models
Author(s) -
Wang Qi,
Jackson David D.,
Zhuang Jiancang
Publication year - 2010
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 - 10.1029/2010gl044858
Subject(s) - aftershock , cluster analysis , magnitude (astronomy) , seismology , geology , sequence (biology) , missing data , remotely triggered earthquakes , statistics , earthquake swarm , induced seismicity , mathematics , physics , astronomy , biology , genetics
Many clustering models imply two kinds of earthquakes: spontaneous ones and those triggered by previous earthquakes. The pair‐wise links from earlier to later earthquakes control the estimates of the clustering parameters. However, earthquake catalogs are limited in time, space, and magnitude, so that triggers of some cataloged earthquakes may be unknown. Thus some links are unrecognized and some triggered events appear spontaneous. Here we present a method for identifying such earthquakes and reducing the bias from missing links. We treat earthquakes probably affected by missing links as potential triggers, but we exclude them in evaluating modeled effects. We use an Epidemic‐type Aftershock Sequence (ETAS) model to examine specifics. The most affected parameter is the proportion of spontaneous earthquakes. The most important missing links apparently follow earthquakes below the magnitude threshold, before the start, and outside the spatial boundaries of the catalog, in that order.