Travel-time residuals of teleseismic P-waves at the Rodriguez Triple Junction in the Indian Ocean using ocean-bottom seismometers

1996 ◽  
Vol 23 (7) ◽  
pp. 713-716 ◽  
Author(s):  
Toshinori Sato ◽  
Kei Katsumata ◽  
Junzo Kasahara ◽  
Naoshi Hirata ◽  
Ryota Hino ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Travel Time ◽  
Triple Junction ◽  
Ocean Bottom ◽  
P Waves ◽  
Ocean Bottom Seismometers ◽  
The Indian Ocean

scholarly journals Microearthquake seismicity and focal mechanisms at the Rodriguez Triple Junction in the Indian Ocean using ocean bottom seismometers

2001 ◽  
Vol 106 (B12) ◽  
pp. 30689-30699 ◽  
Author(s):  
Kei Katsumata ◽  
Toshinori Sato ◽  
Junzo Kasahara ◽  
Naoshi Hirata ◽  
Ryota Hino ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Focal Mechanisms ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometers ◽  
The Indian Ocean

Shallow Nonvolcanic Tremor Activity and Potential Repeating Earthquakes in the Chile Triple Junction: Seismic Evidence of the Subduction of the Active Nazca–Antarctic Spreading Center

2019 ◽  
Author(s):  
Miguel Sáez ◽  
Sergio Ruiz ◽  
Satoshi Ide ◽  
Hiroko Sugioka
Keyword(s):  
Triple Junction ◽  
Local Maximum ◽  
Time Correlation ◽  
Spreading Center ◽  
Ocean Bottom ◽  
P Waves ◽  
South American Plate ◽  
Repeating Earthquakes ◽  
Ocean Bottom Seismometers ◽  
Chile Triple Junction

ABSTRACT In southern Chile, at ∼46.2°S and ∼75.2°W, the active spreading center between the Nazca and Antarctic plates is colliding with the South American plate, forming the Chile triple junction (CTJ). For 1 yr, from March 2009 to February 2010, five ocean‐bottom seismometers (OBSs) were deployed over the CTJ. We used a portion of the OBS data to study the seismic signatures of the subduction of the active Nazca–Antarctic spreading center. Using the envelope technique, we detected long episodes of shallow nonvolcanic tremor (NVT) activity. To improve the identified location of the NVT activity, we cross‐correlated the vertical and horizontal components of all located NVTs. In different months, we measured the local maximum of the lag‐time correlation near 2 s, which is associated with the lag between the S and P waves (S−Ptime). Furthermore, we observed that in the days with intense tremor activity, the maxima corresponding to S−Ptime emerged in windows without observable NVTs. We suggest that days with intense tremor activity correspond to an almost continuous slow slip, which may accelerate and decelerates nearly randomly, with spatial and temporal heterogeneity. In addition, we detected some potential repeating earthquakes with an S−Ptime near 2 s, as well as NVTs. The detected NVT activity and potential repeating earthquakes suggest the existence of a shallow region close to the CTJ that is able to generate brittle (earthquakes) and brittle–ductile (potential repeating earthquakes and NVTs) ruptures.

Segmentation of the Central Indian Ridge between 12°12′ S and the Indian Ocean Triple Junction

1993 ◽  
Vol 15 (4) ◽  
pp. 265-282 ◽  
Author(s):  
Lindsay M. Parson ◽  
Philippe Patriat ◽  
Roger C. Searle ◽  
Anne R. Briais
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Central Indian Ridge ◽  
The Indian Ocean ◽  
Indian Ridge

scholarly journals Eocene to recent development of the South-west Indian Ridge, a consequence of the evolution of the Indian Ocean Triple Junction

1981 ◽  
Vol 64 (3) ◽  
pp. 587-604 ◽  
Author(s):  
John G. Sclater ◽  
Robert L. Fisher ◽  
Phillippe Patriat ◽  
Christopher Tapscott ◽  
Barry Parsons
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
West Indian ◽  
The South ◽  
South West ◽  
The Indian Ocean ◽  
Indian Ridge

scholarly journals Tomography of crust and lithosphere in the western Indian Ocean from noise cross-correlations of land and ocean bottom seismometers

2019 ◽  
Vol 219 (2) ◽  
pp. 924-944 ◽  
Author(s):  
Sarah Hable ◽  
Karin Sigloch ◽  
Eléonore Stutzmann ◽  
Sergey Kiselev ◽  
Guilhem Barruol
Keyword(s):  
Indian Ocean ◽  
Group Velocity ◽  
Western Indian Ocean ◽  
Spreading Ridge ◽  
Ocean Bottom ◽  
Depth Range ◽  
La Réunion ◽  
Velocity Measurements ◽  
Ocean Bottom Seismometers ◽  
Cross Correlations

SUMMARY We use seismic noise cross-correlations to obtain a 3-D tomography model of SV-wave velocities beneath the western Indian Ocean, in the depth range of the oceanic crust and uppermost mantle. The study area covers 2000 × 2000 km2 between Madagascar and the three spreading ridges of the Indian Ocean, centred on the volcanic hotspot of La Réunion. We use seismograms from 38 ocean bottom seismometers (OBSs) deployed by the RHUM-RUM project and 10 island stations on La Réunion, Madagascar, Mauritius, Rodrigues, and Tromelin. Phase cross-correlations are calculated for 1119 OBS-to-OBS, land-to-OBS, and land-to-land station pairs, and a phase-weighted stacking algorithm yields robust group velocity measurements in the period range of 3–50 s. We demonstrate that OBS correlations across large interstation distances of >2000 km are of sufficiently high quality for large-scale tomography of ocean basins. Many OBSs yielded similarly good group velocity measurements as land stations. Besides Rayleigh waves, the noise correlations contain a low-velocity wave type propagating at 0.8–1.5 km s−1 over distances exceeding 1000 km, presumably Scholte waves travelling through seafloor sediments. The 100 highest-quality group velocity curves are selected for tomographic inversion at crustal and lithospheric depths. The inversion is executed jointly with a data set of longer-period, Rayleigh-wave phase and group velocity measurements from earthquakes, which had previously yielded a 3-D model of Indian Ocean lithosphere and asthenosphere. Robust resolution tests and plausible structural findings in the upper 30 km validate the use of noise-derived OBS correlations for adding crustal structure to earthquake-derived tomography of the oceanic mantle. Relative to crustal reference model CRUST1.0, our new shear-velocity model tends to enhance both slow and fast anomalies. It reveals slow anomalies at 20 km depth beneath La Réunion, Mauritius, Rodrigues Ridge, Madagascar Rise, and beneath the Central Indian spreading ridge. These structures can clearly be associated with increased crustal thickness and/or volcanic activity. Locally thickened crust beneath La Réunion and Mauritius is probably related to magmatic underplating by the hotspot. In addition, these islands are characterized by a thickened lithosphere that may reflect the depleted, dehydrated mantle regions from which the crustal melts where sourced. Our tomography model is available as electronic supplement.

The tectonic evolution of the Indian Ocean Triple Junction, anomaly 6 to present

1993 ◽  
Vol 98 (B2) ◽  
pp. 1793-1812 ◽  
Author(s):  
Neil C. Mitchell ◽  
Lindsay M. Parson
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
Tectonic Evolution ◽  
The Indian Ocean

Microseismicity near the Indian Ocean triple junction

1977 ◽  
Vol 4 (12) ◽  
pp. 597-600 ◽  
Author(s):  
Sean C. Solomon ◽  
Paul J. Mattaboni ◽  
Richard L. Hester
Keyword(s):  
Indian Ocean ◽  
Triple Junction ◽  
The Indian Ocean

Tsunami Travel Time Atlas for the Indian Ocean

2006 ◽  
pp. 273-291 ◽  
Author(s):  
T Murty ◽  
A Rao ◽  
A Chaudhuri ◽  
A Gangopadhyay ◽  
S Dube ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Travel Time ◽  
Tsunami Travel Time ◽  
The Indian Ocean

scholarly journals Morphotectonics of the Mascarene Islands

1998 ◽  
Vol 41 (2) ◽  
Author(s):  
R. Hantke ◽  
A. E. Scheidegger
Keyword(s):  
Indian Ocean ◽  
Stress Field ◽  
Fracture Zone ◽  
Hot Spot ◽  
Ocean Bottom ◽  
Fracture Zones ◽  
Mascarene Islands ◽  
The Indian Ocean ◽  
Close Fit

A study is made of the orientations (strikes/trends) of joints, valleys, ridges and lineaments, i.e. of the (potentially) morphotectonic features, of the Mascarene Islands (Reunion, Mauritius and Rodrigues) in the Indian Ocean. It turns out that a connection exists between these features on all islands. For the joints alone, the results for Mauritius as a whole agree closely with those for Rodrigues as a whole, and also partially with those of Reunion. Inasmuch as the trends of the valleys, ridges and lineaments are related to the trends (strikes) of the joints, a common morphotectonic predesign seems to be present for all features studied. The morphotectonic orientations on the island also agree closely with the trends of fracture zones, ridges and trenches in the nearby ocean bottom; which has had a bearing on the theories of the origin of the Mascarene Islands. Generally, a hot-spot origin is preferred for Reunion, and may be for Mauritius as well, although differing opinions have also been voiced. The dynamics of a hot-spot is hard to reconcile with the close fit of the joint strikes in Réunion with the trends of the Madagascar and Rodrigues fracture zones. The closely agreeing joint maxima in Mauritius and Rodrigues í across the deep Mauritius trench í also agree with the trend of that trench and with the trend of the Rodrigues fracture zone. Thus, it would appear as most likely that the trends of joints and of fracture zones are all part of the same pattern and are due to the same cause: viz. to action of the neotectonic stress field.

Sign in / Sign up

Export Citation Format

Share Document