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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7060
pubmed:dateCreated
2005-10-6
pubmed:abstractText
The 1992 magnitude 7.3 Landers earthquake triggered an exceptional number of additional earthquakes within California and as far north as Yellowstone and Montana. Since this observation, other large earthquakes have been shown to induce dynamic triggering at remote distances--for example, after the 1999 magnitude 7.1 Hector Mine and the 2002 magnitude 7.9 Denali earthquakes--and in the near-field as aftershocks. The physical origin of dynamic triggering, however, remains one of the least understood aspects of earthquake nucleation. The dynamic strain amplitudes from a large earthquake are exceedingly small once the waves have propagated more than several fault radii. For example, a strain wave amplitude of 10(-6) and wavelength 1 m corresponds to a displacement amplitude of about 10(-7) m. Here we show that the dynamic, elastic-nonlinear behaviour of fault gouge perturbed by a seismic wave may trigger earthquakes, even with such small strains. We base our hypothesis on recent laboratory dynamic experiments conducted in granular media, a fault gouge surrogate. From these we infer that, if the fault is weak, seismic waves cause the fault core modulus to decrease abruptly and weaken further. If the fault is already near failure, this process could therefore induce fault slip.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Oct
pubmed:issn
1476-4687
pubmed:author
pubmed:issnType
Electronic
pubmed:day
6
pubmed:volume
437
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
871-4
pubmed:year
2005
pubmed:articleTitle
Nonlinear dynamics, granular media and dynamic earthquake triggering.
pubmed:affiliation
Geophysics Group EES-11, Los Alamos National Laboratory of the University of California, MS D443, Los Alamos, New Mexico 87545, USA. paj@lanl.gov
pubmed:publicationType
Journal Article