Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean
With its remote location in the ice-covered Fram Strait, Lena Trough is a poorly known segment of the global mid-ocean ridge system. It is a prominent member of the ultra-slow spreading mid-ocean ridges but its spreading mechanisms are not well understood. We relocalized teleseismically recorded ear...
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fthighwire:oai:open-archive.highwire.org:gji:184/3/1354 2023-05-15T15:16:01+02:00 Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean Läderach, C. Schlindwein, V. Schenke, H.-W. Jokat, W. 2011-03-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/184/3/1354 https://doi.org/10.1111/j.1365-246X.2010.04926.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/184/3/1354 http://dx.doi.org/10.1111/j.1365-246X.2010.04926.x Copyright (C) 2011, Oxford University Press Seismology TEXT 2011 fthighwire https://doi.org/10.1111/j.1365-246X.2010.04926.x 2016-11-16T18:43:36Z With its remote location in the ice-covered Fram Strait, Lena Trough is a poorly known segment of the global mid-ocean ridge system. It is a prominent member of the ultra-slow spreading mid-ocean ridges but its spreading mechanisms are not well understood. We relocalized teleseismically recorded earthquakes from the past five decades to identify tectonic processes in Lena Trough and the adjacent Spitsbergen Fracture Zone (FZ). During two cruises with RV Polarstern in 2008 and 2009 we deployed seismic arrays on ice floes to record the local seismicity of Lena Trough. We could identify and localize microseismic events which we assume to be present in the entire rift valley. In contrast, our relocalization of teleseismically recorded earthquakes shows an asymmetric epicentre distribution along Lena Trough with earthquakes occurring predominately along the western valley flanks of Lena Trough. In 2009 February/March, several high-magnitude earthquakes peaking in an M b 6.6 event occurred in an outside-corner setting of the Spitsbergen FZ. This is the strongest earthquake which has ever been recorded in Fram Strait and its location at the outside-corner high of the ultra-slow spreading ridge is exceptional. Comparing the seismicity with the magnetic anomalies and high-resolution multibeam bathymetry, we divide Lena Trough in a symmetrically spreading northern part and an asymmetrically spreading southern part south of the South Lena FZ. We propose that a complex interaction between the former De Geer Megashear zone, which separated Greenland from Svalbard starting at Late Mesozoic/Early Cenozoic times, and the developing rift in the southern Lena Trough resulted an increasing eastward dislocation towards the Spitsbergen FZ between older spreading axes and the recent active spreading axis which we believe to be located west of the bathymetric rift valley flanks in a wide extensional plain. Text Arctic Arctic Ocean Fram Strait Greenland Svalbard Spitsbergen HighWire Press (Stanford University) Arctic Arctic Ocean Greenland Spitsbergen Fracture Zone ENVELOPE(0.875,0.875,79.875,79.875) Svalbard Geophysical Journal International 184 3 1354 1370 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Seismology |
spellingShingle |
Seismology Läderach, C. Schlindwein, V. Schenke, H.-W. Jokat, W. Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
topic_facet |
Seismology |
description |
With its remote location in the ice-covered Fram Strait, Lena Trough is a poorly known segment of the global mid-ocean ridge system. It is a prominent member of the ultra-slow spreading mid-ocean ridges but its spreading mechanisms are not well understood. We relocalized teleseismically recorded earthquakes from the past five decades to identify tectonic processes in Lena Trough and the adjacent Spitsbergen Fracture Zone (FZ). During two cruises with RV Polarstern in 2008 and 2009 we deployed seismic arrays on ice floes to record the local seismicity of Lena Trough. We could identify and localize microseismic events which we assume to be present in the entire rift valley. In contrast, our relocalization of teleseismically recorded earthquakes shows an asymmetric epicentre distribution along Lena Trough with earthquakes occurring predominately along the western valley flanks of Lena Trough. In 2009 February/March, several high-magnitude earthquakes peaking in an M b 6.6 event occurred in an outside-corner setting of the Spitsbergen FZ. This is the strongest earthquake which has ever been recorded in Fram Strait and its location at the outside-corner high of the ultra-slow spreading ridge is exceptional. Comparing the seismicity with the magnetic anomalies and high-resolution multibeam bathymetry, we divide Lena Trough in a symmetrically spreading northern part and an asymmetrically spreading southern part south of the South Lena FZ. We propose that a complex interaction between the former De Geer Megashear zone, which separated Greenland from Svalbard starting at Late Mesozoic/Early Cenozoic times, and the developing rift in the southern Lena Trough resulted an increasing eastward dislocation towards the Spitsbergen FZ between older spreading axes and the recent active spreading axis which we believe to be located west of the bathymetric rift valley flanks in a wide extensional plain. |
format |
Text |
author |
Läderach, C. Schlindwein, V. Schenke, H.-W. Jokat, W. |
author_facet |
Läderach, C. Schlindwein, V. Schenke, H.-W. Jokat, W. |
author_sort |
Läderach, C. |
title |
Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
title_short |
Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
title_full |
Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
title_fullStr |
Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
title_full_unstemmed |
Seismicity and active tectonic processes in the ultra-slow spreading Lena Trough, Arctic Ocean |
title_sort |
seismicity and active tectonic processes in the ultra-slow spreading lena trough, arctic ocean |
publisher |
Oxford University Press |
publishDate |
2011 |
url |
http://gji.oxfordjournals.org/cgi/content/short/184/3/1354 https://doi.org/10.1111/j.1365-246X.2010.04926.x |
long_lat |
ENVELOPE(0.875,0.875,79.875,79.875) |
geographic |
Arctic Arctic Ocean Greenland Spitsbergen Fracture Zone Svalbard |
geographic_facet |
Arctic Arctic Ocean Greenland Spitsbergen Fracture Zone Svalbard |
genre |
Arctic Arctic Ocean Fram Strait Greenland Svalbard Spitsbergen |
genre_facet |
Arctic Arctic Ocean Fram Strait Greenland Svalbard Spitsbergen |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/184/3/1354 http://dx.doi.org/10.1111/j.1365-246X.2010.04926.x |
op_rights |
Copyright (C) 2011, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.2010.04926.x |
container_title |
Geophysical Journal International |
container_volume |
184 |
container_issue |
3 |
container_start_page |
1354 |
op_container_end_page |
1370 |
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1766346334474862592 |