Applications of 6DoF sensors in seismology - from building monitoring to dynamic tilt correction

The application of 6 Degrees of Freedom (6DoF) sensors (sensitive to three orthogonal axis of rotational in addition to the classical three axis of translational motion) is an emerging new field of research in seismology. Especially when taking advantage of the inertia-free measurement principle in fiber optic gyroscopes, observation of pure rotational motion is possible. In this contribution, first, we show how the 6DoF sensor concept opens new paths in building monitoring by observing toroidal modes and interstory drift without an external reference frame. Second, we want to introduce a new approach to building monitoring combining a 6DoF sensor network and the concept of coda wave interferometry for damage detection and safety evaluation. Third, we describe and discuss new methods for dynamic tilt correction with directly measured rotational motions (recorded with a blueSeis3A, manufactured by iXblue, France). Simple correction in the time-domain as well as frequency-domain correction with a coherency threshold and correction using wavelet-coherency show their advantages and disadvantages in reproducible, well controllable laboratory experiments, in a synthetic experiment with simulated near-field recordings of volcanic long period events and in their application to real-world data sets.