English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Most earthquake ruptures propagate with speeds smaller than the Rayleigh wave velocity of the medium. These are called sub- Rayleigh ruptures. However, under suitable conditions, segments of otherwise sub- Rayleigh seismogenic ruptures can occasionally accelerate to speeds higher than the local shear wave velocity, giving rise to so-called supershear ruptures. The occurrence of supershear ruptures is usually associated with a locally higher value of pre-stress on the fault segment compared to the sub-Rayleigh segments of the same fault. Additionally, shear stress changes generated by the supershear rupture are radiated out unattenuated to distances comparable to the depth of rupture instead of rapidly decaying at much smaller distances from the rupture. This leads to aftershocks being distributed away from the fault on the supershear segment. This study attempts to verify whether these pre- and postseismic stress conditions and the resultant spatial aftershock distributions lead to discernible features in the statistical properties of the aftershock sequences of the earthquakes known to be associated with supershear ruptures. We analyze the Gutenberg-Richter scaling, the modified Omori law and Båth’s law for the aftershock sequences of two supershear mainshocks: the 1979 MW 6.5 Imperial Valley (California) and 2002 MW 7.9 Denali (Alaska) earthquakes. We observe that the b-value is always higher in the supershear zone than the rest of the sequence. We also observe that there is no systematic trend in the exponent of the modified Omori law when comparing the aftershocks in the supershear zone with the rest of the aftershocks. We argue that the b-value anomaly can be explained in terms of the off-fault distribution of aftershocks around the supershear segment of the rupture

Anomalous statistics of aftershock sequences generated by supershear ruptures