S U M M A R YMud volcanoes are geological systems often characterized by elevated fluid pressures at depth deviating from hydrostatic conditions. This near-critical state makes mud volcanoes particularly sensitive to external forcing induced by natural or man-made perturbations. We used the Nirano mud volcanic field as a natural laboratory to test pre-and post-seismic effects generated by distant earthquakes. We first characterized the subsurface structure of the Nirano mud volcanic field with a geoelectrical study. Next, we deployed a broad-band seismic station in the area to understand the typical seismic signal generated by the mud volcano. Seismic records show a background noise below 2 s, sometimes interrupted by pulses of drumbeatlike high-frequency signals lasting from several minutes to hours. To date this is the first observation of drumbeat signal observed in mud volcanoes.In 2013 June we recorded a M4.7 earthquake, that occurred approximately 60 km far from our seismic station. According to empirical estimations the Nirano mud volcanic field should not have been affected by the M4.7 earthquake. Yet, before the seismic event we recorded an increasing amplitude of the signal in the 10-20 Hz frequency band. The signal emerged approximately two hours before the earthquake and lasted for about three hours. Our statistical analysis suggests the presence of a possible precursory signal about 10 min before the earthquake.

Induced polarization data recorded at the field scale are usually processed using techniques based on isotropy. We study the effect of anisotropic complex conductivities in the frequency domain, with a particular emphasis on the polarization properties (i.e., phase angles). We consider anisotropy to be caused by a thin layering of isotropic media. Based on this, we derive corresponding mixing laws for the phase angles parallel and perpendicular to the layering and show that in cases of anisotropic layering, phase angles can only exist if the complex conductivity magnitudes are also anisotropic. We modified an existing isotropic finite‐element forward modelling code to support anisotropic complex conductivities. Based on an isotropic 2D inversion of a synthetic data set generated for an anisotropic model, we show that ignoring anisotropy may lead to artefacts and poor model recovery. Finally, we investigate a field data set recorded over a fault system in Germany, where anisotropic conductivities are expected. The isotropic 2D inversion of this data set yields a complex image that is difficult to interpret. We suggest an alternative interpretation based on trial‐and‐error forward modelling with anisotropic complex conductivities, using geological a priori information to constrain the model. The obtained model has a much simpler structure, consistent with the anticipated geology but yet is able to explain the measured data.

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Abstract. Controlling virtual characters in AR games for modern smartphones is even more challenging than controls for 'pure' VR games because the player has to keep the AR world in view. We propose six interaction concepts based on combinations of both physical and virtual buttons and sensor input and suggest an evaluation according to game experience criteria.