Implications of the neotectonics around the Laptev Sea Rift as a result from (micro-) seismicity analysis

Abstract

The Laptev Sea Rift offers an outstanding opportunity to study continental rifting. At the edge of the Laptev Sea, the ultra-slow spreading Gakkel Ridge encounters the continental slope, with the divergent motion continuing on the continent within the Laptev Sea Rift. Due to the isolated location of this unique region at the northern edge of the Arctic Circle in Siberia, geophysical investigations are still relatively rare. The study of earthquakes is a suitable method for exploring geodynamic processes. However, the global network of permanent seismic stations is relatively sparse above the Arctic Circle, resulting in only a vague understanding of the (micro-)seismic activity in the Laptev Sea region, as weaker seismic events simply cannot be detected. The global earthquake catalogue (until 2018) demonstrates a significant distribution of earthquakes clearly defined along the axes of the Gakkel Ridge. In the transition zone, where the ridge meets the continent, a decrease in activity is observed, dispersing into a wider area to the south. In this study, earthquake data recorded at stations of a local, temporary network and arrays were analysed. The data set spans a period of nine months, from August 2016 to April 2017. This study focuses on the neotectonic context to address whether the Laptev Sea Rift is still active and whether the rift region can be defined as a separate tectonic block, such as a microplate.