A decade of short-period earthquake rupture histories from multi-array back-projection

&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;Teleseismic&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; back-projection has emerged as a widely-used tool for understanding the rupture histories of large earthquakes. However, its application often suffers from artifacts related to the receiver array geometry, notably the `swimming' artifact. We present a &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;teleseismic&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; back-projection method with multiple arrays and combined P and &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;pP&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; waveforms. The method is suitable for defining arrays ad-hoc in order to achieve a good azimuthal distribution for most earthquakes&amp;lt;/span&amp;gt;.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;We present a catalog of&amp;lt;/span&amp;gt; &amp;lt;span&amp;gt;short-period&amp;lt;/span&amp;gt; &amp;lt;span&amp;gt;rupture histories (0.5-2.0 Hz) &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;containing &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; 54 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;events &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;from 2010 to 2021 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;M&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;w&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;&amp;amp;#160;&amp;lt;/span&amp;gt;&amp;amp;#8805;&amp;lt;span&amp;gt; 7.5&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;including &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;recent &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;and significant&amp;lt;/span&amp;gt; &amp;lt;span&amp;gt;earthquake ruptures&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;,&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; e.g., 2021 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Mw 8.3 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;South of Sandwich Islands, 2021 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Mw 8.2 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Chignik, 2021 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Mw 8.1 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Kermadec Islands, &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;and 2020 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Mw 7.8 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Simeonof Island&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;.&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;&amp;lt;span&amp;gt;The method provides semi-automatic estimates of rupture length, directivity, speed, and aspect ratio, which are related to the complexity of large ruptures. We determined short-period rupture length scaling relations that are in good agreement with previously published relations based on estimates of total slip. Rupture speeds were consistently in the sub-Rayleigh regime for thrust and normal earthquakes, whereas strike-slip events propagated in the unstable &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;supershear&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; range. Many of the rupture histories exhibited complex behaviors such as rupture on conjugate faults &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;2018 Mw 7.9 Gulf of Alaska&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, bilateral ruptures &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2017 Mw 7.8 Komandorsky Islands)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, and dynamic triggering by a P wave &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2016 Mw 7.9 Solomon Islands)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;. For &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;megathrust&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt; earthquakes, ruptures encircling asperities were frequently observed, with down-dip &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2021 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Mw 8.1 &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;Kermadec Islands)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, up-dip &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2016 Mw 7.8 Pedernales)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, double encircling &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2015 Mw 8.3 Illapel)&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, and segmented &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;(e.g., 2020 Mw 7.8 Simeonof Island) &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;patterns. Although there is a preference for short-period emissions to emanate from central and down-dip parts of the &amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;megathrust&amp;lt;/span&amp;gt;&amp;lt;span&amp;gt;, emissions up-dip of the main asperities are more frequent than suggested by earlier results.&amp;lt;/span&amp;gt;&amp;lt;/p&amp;gt;