Seismic properties of the Eltanin Transform System, South Pacific

Emile A. Okal, Amy R. Langenhorst

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We present a compilation of the seismic properties of the Eltanin Transform Fault (TF) system, compelled by the recent discovery of the Hollister Ridge and the possibility of a change of plate kinematics pattern in the region. The Hollister Ridge is a major volcanic system located on the Western flank of the Pacific-Antarctic Ridge (PAR), immediately south of the Eltanin Fracture Zones (FZs). We find or confirm two anomalous characteristics: the occurrence of seven normal faulting events on the transform segments, expressing extension across the plate boundary in the azimuth N26°W, and more than 90% deficiency in the seismic moment released during strike-slip events on the transforms, as compared to the rate expected from kinematic models. Other seismic properties are typical of the seismicity of a fast-spreading mid-ocean ridge (MOR) system. In particular, we could not document a single teleseismically recorded event on the Hollister Ridge; earthquakes are confined to narrow TFs with no activity present on the ridge segments. The transform events have regular frequency-moment statistics, and we could not document any significantly slow sources. These seismic properties generally support conventional plate tectonics models such as NUVEL-1, and cannot be reconciled with a proposed reorientation of the Pacific plate 4 Ma ago. (C) 2000 Elsevier Science B.V. All rights reserved.

Original languageEnglish (US)
Pages (from-to)185-208
Number of pages24
JournalPhysics of the Earth and Planetary Interiors
Volume119
Issue number3-4
DOIs
StatePublished - May 2000

Keywords

  • Eltanin Transform System
  • Seismic properties
  • South Pacific

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Geophysics
  • Physics and Astronomy (miscellaneous)
  • Space and Planetary Science

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