Parallel bands of seismicity at the Mid-Atlantic Ridge, 12-14 degrees N | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Parallel bands of seismicity at the Mid-Atlantic Ridge, 12-14 degrees N

Publication Type:

Journal Article

Source:

{GEOPHYSICAL RESEARCH LETTERS}, Volume {30}, Number {12} (0)

Abstract:

{{[}1] Seismicity distribution along the Mid-Atlantic Ridge ( MAR), monitored with the Autonomous Underwater Hydrophone (AUH) array, shows a band of seismicity similar to70 km west of the axis between similar to11.9 degreesN and 14.2 degreesN. Available focal mechanisms at the off-axis seismic band show extension directions consistent with the accommodation of the North-American (NA) and South-American ( SA) relative plate motion. Axial seismicity shows a gap at similar to14 degreesN, coinciding with the 14 degreesN hotspot-like region, and the focal mechanisms near this region are consistent with spreading of the African (AF) and the NA or SA plates. We speculate that the triple junction between the AF, NA and SA plates is close to the 14 degreesN seismic gap. The westward continuation of the NA-SA plate boundary is unconstrained, but could initiate at similar to13degreesN, at the south end of the off-axis seismic band, or be diffuse between similar to12degreesN and similar to15degreesN.}