The mechanism of tidal triggering of earthquakes at mid-ocean ridges

Christopher H Scholz, Yen Joe Tan, Fabien Albino

Research output: Contribution to journalArticle (Academic Journal)peer-review

16 Citations (Scopus)
112 Downloads (Pure)

Abstract

The strong tidal triggering of mid-ocean ridge earthquakes has remained unexplained because the earthquakes occur preferentially during low tide, when normal faulting earthquakes should be inhibited. Using Axial Volcano on the Juan de Fuca ridge as an example, we show that the axial magma chamber inflates/deflates in response to tidal stresses, producing Coulomb stresses on the faults that are opposite in sign to those produced by the tides. When the magma chamber's bulk modulus is sufficiently low, the phase of tidal triggering is inverted. We find that the stress dependence of seismicity rate conforms to triggering theory over the entire tidal stress range. There is no triggering stress threshold and stress shadowing is just a continuous function of stress decrease. We find the viscous friction parameter A to be an order of magnitude smaller than laboratory measurements. The high tidal sensitivity at Axial Volcano results from the shallow earthquake depths.

Original languageEnglish
Article number2526
Number of pages6
JournalNature Communications
Volume10
Issue number1
DOIs
Publication statusPublished - 7 Jun 2019

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