Localized seismic deformation in the upper mantle revealed by dense seismic arrays

Asaf Inbal*, Jean Paul Ampuero, Robert W. Clayton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Seismicity along continental transform faults is usually confined to the upper half of the crust, but the Newport-Inglewood fault (NIF), a major fault traversing the Los Angeles basin, is seismically active down to the upper mantle. We use seismic array analysis to illuminate the seismogenic root of the NIF beneath Long Beach, California, and identify seismicity in an actively deforming localized zone penetrating the lithospheric mantle. Deep earthquakes, which are spatially correlated with geochemical evidence of a fluid pathway from the mantle, as well as with a sharp vertical offset in the lithosphere-asthenosphere boundary, exhibit narrow size distribution and weak temporal clustering. We attribute these characteristics to a transition from strong to weak interaction regimes in a system of seismic asperities embedded in a ductile fault zone matrix.

Original languageEnglish
Pages (from-to)88-92
Number of pages5
Issue number6308
StatePublished - 7 Oct 2016
Externally publishedYes


FundersFunder number
Signal Hill Petroleum and Breitburn Energy
National Science FoundationEAR-1520081, EAR-1214912, 1520081


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