<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Nicholas van der Elst</dc:creator>
  <dc:date>2021</dc:date>
  <dc:description>&lt;div class="article-section__content en main"&gt;&lt;p&gt;The earthquake magnitude-frequency distribution is characterized by the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value, which describes the relative frequency of large versus small earthquakes. It has been suggested that changes in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value after an earthquake can be used to discriminate whether that earthquake is part of a foreshock sequence or a more typical mainshock-aftershock sequence, with a decrease in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value heralding a larger earthquake to come. However, the measurement of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value during an active aftershock sequence is strongly biased by short-term incompleteness of the earthquake catalog and by data-windowing, and these biases have the same direction as the proposed signal. Here I develop a new estimator of the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b-&lt;/i&gt;value that is insensitive to transient changes in catalog completeness and that does not require data windowing. The new estimator “&lt;i&gt;b&lt;/i&gt;-positive” is based on the positive-only subset of the differences in magnitude between successive earthquakes, which are described by a double-exponential (Laplace) distribution with the same&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value as the magnitude distribution itself. The&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-positive estimator greatly improves the robustness of continuous&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value measurements during active earthquake sequences, as well as in historical catalogs with unknown or variable completeness. The new estimator confirms some of the observations of Gulia and Wiemer&amp;nbsp;(2019), although at a reduced level, showing a decrease and recovery of the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value during several recent foreshock sequences that cannot be attributed simply to measurement bias. However, the unbiased&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;b&lt;/i&gt;-value changes may be too subtle to use in a real-time earthquake alarm system.&lt;/p&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/2020JB021027</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>B-positive: A robust estimator of aftershock magnitude distribution in transiently incomplete catalogs</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>