Present-day surface deformation of the Alpine region inferred from geodetic techniques

We provide a present-day surface-kinematics model for the Alpine region and surroundings based on a high-level data analysis of about 300 geodetic stations continuously operating over more than 12 years. This model includes a deformation model, a continuous surface-kinematic (velocity) field, and a strain field consistently assessed for the entire Alpine mountain belt. Special care is given to the use of the newest Global Navigation Satellite Systems (GNSS) processing standards to determine high-precision 3-D station coordinates. The coordinate solution refers to the reference frame IGb08, epoch 2010.0. The mean precision of the station positions at the reference epoch is ±1.1&thinsp;mm in N and E and ±2.3&thinsp;mm in height. The mean precision of the station velocities is ±0.2&thinsp;mm&thinsp;a−1 in N and E and ±0.4&thinsp;mm&thinsp;a−1 in height. The deformation model is derived from the point-wise station velocities using a geodetic least-squares collocation (LSC) approach with empirically determined covariance functions. According to our results, no significant horizontal deformation is detected in the Western Alps, while across the Southern and Eastern Alps the deformation vectors describe a progressive eastward rotation towards Pannonia. This kinematic pattern also makes evident an increasing magnitude of the deformation from 0.1&thinsp;mm&thinsp;a−1 in the western part of Switzerland up to about 1.3&thinsp;mm&thinsp;a−1 in the Austrian Alps. The largest shortening is observed along the southern front of the Eastern Alps (in the northern area of the Venetian-Friuli Basin) and in the northern part of the Apennine Peninsula, where rates reach 2 and 3&thinsp;mm&thinsp;a−1, respectively. The average accuracy of the horizontal deformation model is ±0.2&thinsp;mm&thinsp;a−1. Regarding the vertical kinematics, our results clearly show an ongoing average uplift rate of 1.8&thinsp;mm&thinsp;a−1 of the entire mountain chain, with the exception of the southern part of the Western Alps, where no significant uplift (less than 0.5&thinsp;mm&thinsp;a−1) is detected. The fastest uplift rates (more than 2&thinsp;mm&thinsp;a−1) occur in the central area of the Western Alps, in the Swiss Alps, and in the Southern Alps in the boundary region between Switzerland, Austria, and Italy. The general uplift observed across the Alpine mountain chain decreases towards the outer regions to stable values between 0.0 and 0.5&thinsp;mm&thinsp;a−1 and, in some cases, to subsidence like in the Liguro-Provençal and Vienna basins, where vertical rates of −0.8 and −0.3&thinsp;mm&thinsp;a−1 are observed, respectively. In the surrounding region, three regional subsidence regimes are identified: the Rhône-Bresse Graben with −0.8&thinsp;mm&thinsp;a−1, the Rhine Graben with −1.3&thinsp;mm&thinsp;a−1, and the Venetian-Friuli Basin with −1.5&thinsp;mm&thinsp;a−1. The estimated uncertainty of our vertical motion model across the Alpine mountain belt is about ±0.3&thinsp;mm&thinsp;a−1. The strain field inferred from the deformation model shows two main contrasting strain regimes: (i) shortening across the south-eastern front of the Alps and the northern part of the Dinarides and (ii) extension in the Apennines. The pattern of the principal strain axes indicates that the compression directions are more or less perpendicular to the thrust belt fronts, reaching maximum values of 20×10−9&thinsp;a−1 in the Venetian-Friuli and Po basins. Across the Alpine mountain belt, we observe a slight dilatation regime in the Western Alps, which smoothly changes to a contraction regime in western Austria and southern Germany, reaching maximum shortening values of 6×10−9&thinsp;a−1 in north-eastern Austria. The numerical results of this study are available at https://doi.pangaea.de/10.1594/PANGAEA.886889.</p

Present-day surface deformation of the Alpine Region inferred from geodetic techniques (data)

We provide a present-day surface-kinematics model for the Alpine region and surroundings based on a high-level data analysis of a network of about 300 continuously operating GNSS (GPS+GLONASS) stations with observations collected over 12.4 years. Based on the network station velocities, a continuous kinematic field is derived using a geodetic least-squares collocation approach with empirically determined covariance functions. Main results are (1) a deformation model, (2) a continuous surface-kinematic (velocity) field, and (3) a strain field consistently assessed for the entire Alpine mountain belt. The core contribution of this work is the homogeneous analysis of a large number of freely available data from GNSS stations located in the Alpine region, using unified processing standards and a common reference frame for the complete time-span covered by the observations. The GNSS network solution refers to the reference frame IGb08, epoch 2010.0. The mean precision of the station positions at the reference epoch is ±1.1 mm in N and E and ±2.3 mm in height. The mean precision of the station velocities is ±0.2 mm/a in N and E and ±0.4 mm/a in the height. The averaged accuracy of the horizontal and vertical deformation models inferred from the pointwise station velocities are ±0.2 mm/a and ±0.3 mm/a, respectively. The deformation model as well as the continuous velocity and strain fields are given in a grid of 25 km x 25 km covering the region between longitudes 4°E and 16°E and latitudes 43°N and 49°N

A high-Q superconducting toroidal medium frequency detection system with a capacitively adjustable frequency range >180 kHz

We describe a newly developed polytetrafluoroethylene/copper capacitor driven by a cryogenic piezoelectric slip-stick stage and demonstrate with the chosen layout cryogenic capacitance tuning of ≈60 pF at ≈10 pF background capacitance. Connected to a highly sensitive superconducting toroidal LC circuit, we demonstrate tuning of the resonant frequency between 345 and 685 kHz, at quality factors Q > 100 000. Connected to a cryogenic ultra low noise amplifier, a frequency tuning range between 520 and 710 kHz is reached, while quality factors Q > 86 000 are achieved. This new device can be used as a versatile image current detector in high-precision Penning-trap experiments or as an LC-circuit-based haloscope detector to search for the conversion of axion-like dark matter to radio-frequency photons. This new development increases the sensitive detection bandwidth of our axion haloscope by a factor of ≈1000

Receiver Antenna Phase Center Models and Their Impact on Geodetic Parameters

Evaluating the impact of receiver antenna phase centre corrections (PCCs) in geodetic positioning and timing applications in a general way is quite challenging, because several estimation concepts, implementation philosophies as well as different sets of PCCs exist and interact with each other and their contributions are not identifiable. In this paper, the authors present a methodology, based on investigations of Geiger (GPS-techniques applied to geodesy and surveying. Lecture notes in earth sciences, vol 19. Springer, New York, pp 210–222, 1988) and Santerre (Manuscr Geodaet 16:28–53, 1991), to classify PCCs and forecast their impact on all geodetic parameters, i.e. not only the position but also the receiver clock and troposphere parameter in a phase based precise point positioning (PPP) approach. In a first step, we introduce the mathematical model and generic PCC patterns. In the second step, simulation studies are carried out. Findings are evaluated by empirical studies using differences of PPP results to isolate the impact of different patterns. In parallel, the software impact is analysed since every software handles the observation modelling and parameter estimation differently, e.g., Kalman filter versus least squares approach. We show that all geodetic parameters are affected by PCC and that the impact on the parameters can be even amplified compared to the magnitude of the generic patterns. The final publication is available at Springer via https://doi.org/10.1007/1345_2016_233