Triggering of New Madrid seismicity by late-Pleistocene erosion

E. Calais*, A. M. Freed, R. Van Arsdale, S. Stein

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

97 Scopus citations

Abstract

The spatiotemporal behaviour of earthquakes within continental plate interiors is different from that at plate boundaries. At plate margins, tectonic motions quickly reload earthquake ruptures, making the location of recent earthquakes and the average time between them consistent with the faultsĝ€™ geological, palaeoseismic and seismic histories. In contrast, what determines the activation of a particular mid-continental fault and controls the duration of its seismic activity remains poorly understood. Here we argue that the concentration of magnitude-7 or larger earthquakes in the New Madrid seismic zone of the central United States since the end of the last ice age results from the recent, climate-controlled, erosional history of the northern Mississippi embayment. We show that the upward flexure of the lithosphere caused by unloading from river incision between 16,000 and 10,000 years ago caused a reduction of normal stresses in the upper crust sufficient to unclamp pre-existing faults close to failure equilibrium. Models indicate that fault segments that have already ruptured are unlikely to fail again soon, but stress changes from sediment unloading and previous earthquakes may eventually be sufficient to bring to failure other nearby segments that have not yet ruptured.

Original languageEnglish (US)
Pages (from-to)608-611
Number of pages4
JournalNature
Volume466
Issue number7306
DOIs
StatePublished - Jul 29 2010

ASJC Scopus subject areas

  • General

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