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Parallel bands of seismicity at the Mid‐Atlantic Ridge, 12–14°N
Author(s) -
Escartín Javier,
Smith Deborah K.,
Cannat Mathilde
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017226
Subject(s) - induced seismicity , geology , seismology , ridge , triple junction , plate tectonics , focal mechanism , geodesy , tectonics , geophysics , paleontology
Seismicity distribution along the Mid‐Atlantic Ridge (MAR), monitored with the Autonomous Underwater Hydrophone (AUH) array, shows a band of seismicity ∼70 km west of the axis between ∼11.9°N and 14.2°N. 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 ∼14°N, coinciding with the 14°N 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°N seismic gap. The westward continuation of the NA‐SA plate boundary is unconstrained, but could initiate at ∼13°N, at the south end of the off‐axis seismic band, or be diffuse between ∼12°N and ∼15°N.