FN Archimer Export Format
PT J
TI Seismicity and active accretion processes at the ultraslow-spreading Southwest and intermediate-spreading Southeast Indian ridges from hydroacoustic data
BT 
AF TSANG-HIN-SUN, Eve
   ROYER, Jean-Yves
   PERROT, Julie
AS 1:1,2;2:1,2;3:1,2;
FF 1:;2:;3:;
C1 Univ Brest, Lab Domaines Ocean, Brest, France.
   CNRS, Lab Domaines Ocean, Brest, France.
C2 UBO, FRANCE
   CNRS, FRANCE
UM LGO
IF 2.414
TC 12
UR https://archimer.ifremer.fr/doc/00340/45165/44559.pdf
LA English
DT Article
CR MD 189 / INDIEN SUD 2
   MD 193 / LOGIPEV
   OHA-SIS-BIO - OBSERVATOIRE HYDROACOUSTIQUE
BO Marion Dufresne
DE ;Seismicity and tectonics;Acoustic properties;Mid-ocean ridge processes;Indian Ocean
AB Volcanic and tectonic events are the main processes involved in the generation of the oceanic crust and responsible for the seismicity associated with seafloor spreading. To monitor this activity, usually not or poorly detected by land-based seismological stations, we deployed from February 2012 to February 2013 a network of autonomous hydrophones to compare the behaviour of the ultraslow-spreading Southwest (SWIR) with that of the intermediate-spreading Southeast Indian ridges (SEIR). The rate of seismicity is similar for both ridges, suggesting that there is no systematic relationship between seismicity and spreading rates. The along-axis distribution of the seismic events, however, does differ, reflecting the rate-dependence of accretion modes. Earthquakes are sparse and regularly spaced and scattered along the SWIR, reflecting prevailing tectonic processes. By contrast, along the SEIR, events are irregularly distributed and focus at ridge-segment ends and transforms faults, reflecting the ridge segmentation; only two swarms occurred at a segment centre and are probably caused by a magmatic event. This seismicity distribution thus looks controlled by segment-scale crustal heterogeneities along the SEIR and by regional-scale contrasting accretion processes along the SWIR, probably driven by different lithospheric and asthenospheric dynamics on either side of the Melville FZ. The comparison of hydroacoustic and teleseismic catalogues shows that, along these spreading ridges, the background seismicity observed in one year by a hydroacoustic network is representative of the seismicity observed over two decades by land-based networks.
PY 2016
PD AUG
SO Geophysical Journal International
SN 0956-540X
PU Oxford Univ Press
VL 206
IS 2
UT 000379772500034
BP 1232
EP 1245
DI 10.1093/gji/ggw201
ID 45165
ER

EF