Gravity observation at continental borderlands (Russia, Primorie, Cape Shults)

Abstract

The paper is focused on different kinds of gravity results obtained in Shults Cape Observatory for 2010–2015. Gravity observation is interpreted together with GPS observation data which was obtained from 2012 to 2015 at the same station. The station is situated on Gamov peninsular (42.58° N, 131.15° E, Russia) at the coast of Japan Sea. This region constitutes the eastern boundary of Eurasia. This major continental tectonic feature is associated with a seismic activity, high heat flow and anomalous thickness of earth's crust. The goal of the observation was the investigation of gravity variation with time and seismicity situation monitoring. Gravity observation was developed at special basement by absolute gravimeter (GABL type) and by spring gravimeter (SCINREX CG-5and gPhone type). Tidal models were tested by results of observation with spring gravimeters. Reduction task was solved, as the experimental data received from different points of Shults Cape Observatory was used. Applied reduction coefficient is 203.3 μGal m−1, and agrees with theoretical calculation. Next goal was studying structure of earth's crust by means of gravity models. Gravity anomaly varied from 30 mGal to 46 mGal, which also depend on difference reference system. Experimental results were used for testing of the structure of continental boundary, which also depends on the sea bottom flexion. Thickness of elastic layer was estimated from 12 km to 18 km by using different models.