Segmentation of transform systems on the East Pacific Rise: Implications for Earthquake processes at fast-slipping oceanic transform faults

Patricia M. Gregg, Jian Lin, Deborah K. Smith

Research output: Contribution to journalArticlepeer-review

Abstract

Seven of the eight transform systems along the equatorial East Pacific Rise from 12° N to 15° S have undergone extension due to reorientation of plate motions and have been segmented into two or more strike-slip fault strands offset by intratransform spreading centers (ITSCs). Earthquakes recorded along these transform systems both teleseismically and hydroacoustically suggest that segmentation geometry plays an important role in how slip is accommodated at oceanic transforms. Results of thermal calculations suggest that the thickness of the brittle layer of a segmented transform fault could be significantly reduced by the thermal effect of ITSCs. Consequently, the potential rupture area, and thus maximum seismic moment, is decreased. Using Coulomb static stress models, we illustrate that long ITSCs will prohibit static stress interaction between transform segments and limit the maximum possible magnitude of earthquakes on a given transform system. Furthermore, transform earthquakes may have the potential to trigger seismicity on normal faults flanking ITSCs.

Original languageEnglish (US)
Pages (from-to)289-292
Number of pages4
JournalGeology
Volume34
Issue number4
DOIs
StatePublished - Apr 2006
Externally publishedYes

Keywords

  • Clipperton transform fault
  • Earthquake stress triggering
  • East Pacific Rise
  • Seismology
  • Siqueiros transform fault
  • Transform faults

ASJC Scopus subject areas

  • Geology

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