New data about small-magnitude earthquakes of the ultraslow-spreading Gakkel Ridge, Arctic Ocean

Morozov, A. N.; Vaganova, N. V.; Ivanova, Ekaterina V.; Konechnaya, Yana V.; Fedorenko, I.V.; Mikhaylova, Yana

doi:10.1016/j.jog.2015.11.002

Cited by 10 publications

(4 citation statements)

References 36 publications

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“…More recent data and interpretations of the Gakkel Ridge structure, mostly its western part, are presented in several studies (Schmidt-Aursch and Jokat, 2016;Morozov et al, 2016;Michael et al, 2003;Jokat et al, 2003;Urlaub et al, 2009;Jokat and Micksch, 2004;Cochran et al, 2003;Schlindwein et al, 2005Schlindwein et al, , 2015Jokat and Schmidt-Aursch, 2007;Cochran, 2008;Engen et al, 2009). Current knowledge indicates that the present day mid-ocean ridge has a very thin crust, c. 2-6 km thick (Urlaub et al, 2009;Schmidt-Aursch and Jokat, 2016), and is segmented in non-volcanic and sparselyvolcanic segments, with deep earthquakes in the amagmatic sections (at c. 35 km depth; Schlindwein and Schmid, 2016).…”

Section: Introductionmentioning

confidence: 98%

Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data

et al. 2018

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High Arctic new seismic data, collected by Russian Federation from 2011 to 2014, and additional geological and geophysical information, are used to interpret the basement and sedimentary structure of central and eastern Eurasia Basin, the Gakkel Ridge, and their transition into the Laptev Sea. We find that significant changes in basement topography occur in Nansen Basin at C20 (43.43 Ma) and in the Amundsen basins at C21 (45.7 Ma), and in both basins at C13 (33 Ma). A long seismic profile, that documents for the first time the structure of conjugate flanks and their margins in the central-eastern Eurasia Basin, confirms that oceanic accretion was asymmetric, with 10% less crust developed in the Amundsen Basin since continental break-up. In the eastern Amundsen Basin, we observe mid-ocean ridge uplift since C13 (33 Ma). We identify four distinct sedimentary packages in the Eurasia Basin: Early to Mid Eocene (c. 56 to 45.7 Ma), Mid Eocene to Early Oligocene (45.7 to 33.2 Ma), Early Oligocene to Early Miocene (33.2 to 19.7) and Early Miocene to Present (19.7 to 0 Ma); they are linked to the oceanic lithosphere age determined from magnetic data. The deepest part of the Gakkel Ridge (5215 m), situated close to the easternmost part of this mid ocean ridge, is imaged for the first time by seismic data that reveals volcanic constructions within the older axial ridges and on the flanks. Gakkel Ridge's asymmetric flanks with shallow, regularly-spaced, and rugged structure, typical to ultra-slow spreading ridges, imply periodicity of tectonic phases. The Khatanga-Lomonosov Fault between Lomonosov Ridge and the Laptev Sea region, is identified on few seismic profiles; kinematic models predict that it may have been active only for a maximum of 10 myr after continental break-up.

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Section: Introductionmentioning

confidence: 98%

Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data

et al. 2018

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“…For example, the spatial distribution of earthquakes (red circles) recorded by the SVZ station during 2017 and processed using wave forms from other seismic stations installed in the Arctic region is shown in Figure 3, in which the earthquake processing results recorded by the SVZ station only are presented also. Location of earthquake epicenters is reliant on the hodograph type which is absent for the central part of the Arctic Ocean; as a result, we use the NOES [19] or BARENTS [20] regional hodographs. As a result, we can determine the most likely areas of their location roughly.…”

Section: Results Of the Unified Seismic Catalog Which Makes Use Of Stmentioning

confidence: 99%

Recent Geodynamics and Seismicity of the European Arctic

Rogozhin¹,

Antonovskaya²,

Basakina³

et al. 2019

Arctic Studies - A Proxy for Climate Change

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The recent seismicity and heat flow density are indicators of geodynamic processes. For the European Arctic, the information of recent earthquakes were generalized and compiled on the general seismic catalog for 1998-2017 based on the new seismic data from stations opened in the region from 2011 to 2016. The general database of the heat flow from different data sources is compiled to obtain its spatial distribution for the European Arctic region. The relationships of heat flow values and seismic activity are discussed for this region, and combined geological and geophysical lithosphere cross sections are made in the latitudinal and meridional directions. The most geodynamic active structures and zones of tectonic stress concentration are distinguished; there are Gakkel Ridge and the Svalbard anticline in the Barents Sea region. Weak seismic events were recorded in the Novaya Zemlya region that reflect manifestations of recent tectonic activity.

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“…Improvements in the seismic network across the European Arctic have led to an increased monitoring capability over an extended region (Antonovskaya et al 2014). Seismicity on the Gakkel Ridge, north of Svalbard, has been analyzed teleseismically (Engen et al 2003;Korger & Schlindwein 2012), locally (Korger & Schlindwein 2013), and now with an improved prospect of monitoring with permanent regional stations (Morozov et al 2016). There is more diffuse seismicity along the coast of Greenland, on and around Svalbard and, for example, between the spreading ridge and the Continental Ocean Transition near Bear Island (Czuba et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Locating seismicity on the Arctic plate boundary using multiple-event techniques and empirical signal processing

Gibbons

Harris

Dahl‐Jensen

et al. 2017

Geophysical Journal International

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The oceanic boundary separating the Eurasian and North American plates between 70 and 84 degrees North hosts large earthquakes which are well recorded teleseismically, and many more seismic events at far lower magnitudes that are well recorded only at regional distances. Existing seismic bulletins have considerable spread and bias resulting from limited station coverage and deficiencies in the velocity models applied. This is particularly acute for the lower magnitude events which may only be constrained by a small number of Pn and Sn arrivals. Over the past two decades there has been a significant improvement in the seismic network in the Arctic: a difficult region to instrument due to the harsh climate, a sparsity of accessible sites (particularly at significant distances from the sea), and the expense and difficult logistics of deploying and maintaining stations. New deployments and upgrades to stations on Greenland, Svalbard, Jan Mayen, Hopen, and Bjørnøya have resulted in a sparse but stable regional seismic network which results in events down to magnitudes below 3 generating high quality Pn and Sn signals on multiple stations. A catalog of several hundred events in the region since 1998 has been generated using many new phase readings on stations on both sides of the spreading ridge in addition 2 S. J. Gibbons et al. to teleseismic P phases. A Bayesian multiple event relocation has resulted in a significant reduction in the spread of hypocenter estimates for both large and small events. Whereas single event location algorithms minimize vectors of time residuals on an event-by-event basis, the Bayesloc program finds a joint probability distribution of origins, hypocenters, and corrections to travel time predictions for large numbers of events. The solutions obtained favour those event hypotheses resulting in time residuals which are most consistent over a given source region. The relocations have been performed with different 1-D velocity models applicable to the Arctic region and hypocenters obtained using Bayesloc have been shown to be relatively insensitive to the specified velocity structure in the crust and upper mantle, even for events only constrained by regional phases. The patterns of time residuals resulting from the multiple-event location procedure provide well-constrained time correction surfaces for single-event location estimates and are sufficiently stable to identify a number of picking errors and instrumental timing anomalies. This allows for subsequent quality control of the input data and further improvement in the location estimates. We use the relocated events to form narrowband empirical steering vectors for wavefronts arriving at the SPITS array on Svalbard for azimuth and apparent velocity estimation. We demonstrate that empirical matched field parameter estimation determined by source region is a viable supplement to planewave f-k analysis, mitigating bias and obviating the need for Slowness and Azimuth Station Corrections (SASCs). A database of reference events and phase arrivals ...

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New data about small-magnitude earthquakes of the ultraslow-spreading Gakkel Ridge, Arctic Ocean

Cited by 10 publications

References 36 publications

Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data

Eurasia Basin and Gakkel Ridge, Arctic Ocean: Crustal asymmetry, ultra-slow spreading and continental rifting revealed by new seismic data

Recent Geodynamics and Seismicity of the European Arctic

Locating seismicity on the Arctic plate boundary using multiple-event techniques and empirical signal processing

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