UDC

550.34

Authors

Mikhaylova Yana Aleksandrovna
Institute of Ecological Problems of the North, Ural Branch of the Russian Academy of Sciences Naberezhnaya Severnoy Dviny, 23, Arkhangelsk, 163000, Russian Federation;
e-mail: mikhailovayana@gmail.com
Morozov Aleksey Nikolaevich
Institute of Ecological Problems of the North, Ural Branch of the Russian Academy of Sciences Naberezhnaya Severnoy Dviny, 23, Arkhangelsk, 163000, Russian Federation;
e-mail: morozovalexey@yandex.ru
Fedorenko Irina Valentinovna
Institute of Ecological Problems of the North, Ural Branch of the Russian Academy of Sciences Naberezhnaya Severnoy Dviny, 23, Arkhangelsk, 163000, Russian Federation;
e-mail: fedorenko.irina.v@yandex.ru

Abstract

At the present time there are detailed bathymetric, gravimetric, magnetometric, petrological, and seismic (mb > 4) data for the Gakkel Ridge. However, so far not enough information has been obtained on the distribution of small-magnitude earthquakes (or microearthquakes) within the ridge area due to the absence of a suitable observation system. With the ZFI seismic station (80.8 °N, 47.7 °E), operating since 2011 at the Frantz Josef Land Archipelago, we can now register small-magnitude earthquakes of 1.5 ML and more within the Gakkel Ridge area. This article elaborates on the results and analysis of the ZFI station seismic monitoring obtained within the area of the ridge between 6 °W and 30 °E for the period from December 2011 to October 2014. We have calculated the parameters of the seismic setting and their variations. The Gakkel Ridge is seismically active, regardless of the lowest spreading velocity among the global mid-ocean ridges. Earthquakes within the Gakkel Ridge were registered unevenly in time and space. Quiet periods alternated with the periods of higher seismic activity. The largest number of earthquake epicenters are assigned to the Sparsely Magmatic Zone, the area between 1.5 °E and 19.0 °E. The Benioff graph allowed us to reveal trends in release of seismic energy within the Gakkel ridge in time. In the first approximation we can highlight the stabilization period of seismic energy release of one year duration. The dip calculations of cumulative recurrence curve for the period from 2012 to 2014 also indicate the uneven existence of weak seismicity in time.

Keywords

Gakkel ridge, seismicity, seismic setting

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