Long-term seismicity of the Reykjanes Ridge (North Atlantic) recorded by a regional hydrophone array.

• Published in: Geophysical Journal International
• Main Authors: Goslin, Jean, Lourenco, N., Dziak, R. P., Bohnenstiehl, D.R., Haxel, J., Luis, J.
• Other Authors: Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2005
• Subjects: earthquake sequences; long-term observations; mid-ocean ridges; seismicity; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; Mid-Atlantic Ridge; Reykjanes; North Atlantic
• Online Access: https://hal.science/hal-00112614; https://hal.science/hal-00112614/document; https://hal.science/hal-00112614/file/162-2-516.pdf; https://doi.org/10.1111/j.1365-246X.2005.02678.x

The seismicity of the northern Mid-Atlantic Ridge was recorded by two hydrophone networks moored in the sound fixing and ranging (SOFAR) channel, on the flanks of the Mid-Atlantic Ridge, north and south of the Azores. During its period of operation (05/2002–09/2003), the northern ‘SIRENA' network, deployed between latitudes 40° 20′N and 50° 30′N, recorded acoustic signals generated by 809 earthquakes on the hotspot-influenced Reykjanes Ridge. This activity was distributed between five spatio-temporal event clusters, each initiated by a moderate-to-large magnitude (4.0–5.6 M) earthquake. The rate of earthquake occurrence within the initial portion of the largest sequence (which began on 2002 October 6) is described adequately by a modified Omori law aftershock model. Although this is consistent with triggering by tectonic processes, none of the Reykjanes Ridge sequences are dominated by a single large-magnitude earthquake, and they appear to be of relatively short duration (0.35–4.5 d) when compared to previously described mid-ocean ridge aftershock sequences. The occurrence of several near-equal magnitude events distributed throughout each sequence is inconsistent with the simple relaxation of mainshock-induced stresses and may reflect the involvement of magmatic or fluid processes along this deep (>2000 m) section of the Reykjanes Ridge.