Focused ion beam (FIB) slicing is a widely used technique to prepare ultrathin slices for the microanalysis of geological and environmental samples. During our investigations of the manganese oxidation states in rock varnish slices, we found an FIB-related reduction of manganese(IV) to manganese(II) at the samples’ surfaces. This study characterizes the observed reduction artifacts and emphasizes that caution is needed in the analysis of transition metal oxidation states upon FIB preparation.

To better understand the influence of sample geometry on laboratory measurements of permeability, the permeabilities of sandstone samples with different lengths and diameters were measured. Despite the large range in length, aspect ratio, and volume, the permeabilities of the samples are near identical. This is due to a homogeneous porosity structure and the small grain/pore size with respect to the minimum tested diameter and length. More tests are now needed to help develop such guidelines.

This work presents the progressive steps which led to the successful setup of such measurements at the new magnetic observatory in Choutuppal (CPL) of CSIR-NGRI, Hyderabad, India. Iterative tuning of the setup led to the generation of good quality data from 2016 onward. The processes of commissioning this setup in low-latitude conditions, with the aim of producing 1 s definitive data, and the characteristics of the data from this new instrument are presented here.

This paper focuses on major issues related to data reliability and MOBNET network performance in the AlpArray seismic experiments. We present both new hardware and software tools that help to assure the high-quality standard of broadband seismic data. Special attention is paid to issues like a detection of sensor misorientation, timing problems, exchange of record components and/or their polarity reversal, sensor mass centring, or anomalous channel amplitudes due to imperfect gain.