Speaker
Description
The seismic wave field is fully described by six components: three components of translation and of rotation (6 degrees of freedom, 6-DoF). As rotational amplitudes are small, for a long time, seismology confined itself to half of the available information by using only translation. However, since roughly two decades, rotational ground motions are observable. Since a couple of years, even portable sensors exist. Although the methods used for OSI activities are stipulated, we want to show how they might profit from the inclusion of rotational measurements. These benefits include: determining structural models, especially for the shallow sub-surface (site characterisation), which in turn improve event localisation; dynamic tilt correction of horizontal translational components; wave field decomposition by 6-DoF polarisation analysis; improved resolution of seismic moment tensors; overcoming long-standing problems in active seismic experiments such as coherent-noise suppression and sampling requirements. Probably the most important aspect is the fact that with new processing techniques we can obtain similar information from a single 6-DoF station where traditionally an entire array of translational sensors would be necessary. Therefore, efforts in terms of hardware, maintenance, human power, and time can be reduced drastically. All these are key factors in OSI activities.
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