Summary of the long term data taking, related to one of the proposed next generation ground-based gravitational detector’s location is presented here. Results of seismic and infrasound noise, ...electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gyöngyösoroszi, Hungary. The collected seismic data of more than two years is evaluated from the point of view of the Einstein Telescope, a proposed third generation underground gravitational wave observatory. Applying our results for the site selection will significantly improve the signal to noise ratio of the multi-messenger astrophysics era, especially at the low frequency regime.
The Nógrád-Gömör Volcanic Field (NGVF) is one of the five mantle xenolith bearing alkaline basalt locations in the Carpathian Pannonian Region. This allows us to constrain the structure and ...properties (e.g. composition, current deformation state, seismic anisotropy, electrical conductivity) of the upper mantle, including the lithosphere-asthenosphere boundary (LAB) using not only geophysical, but also petrologic and geochemical methods. For this pilot study, eight upper mantle xenoliths have been chosen from Bárna-Nagykő, the southernmost location of the NGVF. The aim of this study is estimating the average seismic properties of the underlying mantle. Based on these estimations, the thickness of the anisotropic layer causing the observed average SKS delay time in the area was modelled considering five lineation and foliation end-member orientations. We conclude that a 142–333 km thick layer is required to explain the observed SKS anisotropy, assuming seismic properties calculated by averaging the properties of the eight xenoliths. It is larger than the thickness of the lithospheric mantle. Therefore, the majority of the delay time accumulates in the sublithospheric mantle. However, it is still in question whether a single anisotropic layer, represented by the studied xenoliths, is responsible for the observed SKS anisotropy, as it is assumed beneath the Bakony–Balaton Highland Volcanic Field (Kovács et al.
2012
), or the sublithospheric mantle has different layers. In addition, the depths of the Moho and the LAB (
25
±
5
,
65
±
10
km
, respectively) were estimated based on S receiver function analyses of data from three nearby permanent seismological stations.
SUMMARY
We infer seismic azimuthal anisotropy from ambient-noise-derived Rayleigh waves in the wider Vienna Basin region. Cross-correlations of the ambient seismic field are computed for 1953 station ...pairs and periods from 5 to 25 s to measure the directional dependence of interstation Rayleigh-wave group velocities. We perform the analysis for each period on the whole data set, as well as in overlapping 2°-cells to regionalize the measurements, to study expected effects from isotropic structure, and isotropic–anisotropic trade-offs. To extract azimuthal anisotropy that relates to the anisotropic structure of the Earth, we analyse the group velocity residuals after isotropic inversion. The periods discussed in this study (5–20 s) are sensitive to crustal structure, and they allow us to gain insight into two distinct mechanisms that result in fast orientations. At shallow crustal depths, fast orientations in the Eastern Alps are S/N to SSW/NNE, roughly normal to the Alps. This effect is most likely due to the formation of cracks aligned with the present-day stress-field. At greater depths, fast orientations rotate towards NE, almost parallel to the major fault systems that accommodated the lateral extrusion of blocks in the Miocene. This is coherent with the alignment of crystal grains during crustal deformation occurring along the fault systems and the lateral extrusion of the central part of the Eastern Alps.
AlpArray is a large collaborative seismological project in Europe that includes more than 50 research institutes and seismological observatories. At the heart of the project is the collection of ...top-quality seismological data from a dense network of broadband temporary seismic stations, in compliment to the existing permanent networks, that ensures a homogeneous station coverage of the greater Alpine region. This Alp Array Seismic Network (AASN) began operation in January 2016 and will have a duration of at least 2 years. In this work we report the Swiss contribution to the AASN, we concentrate on the site selection process, our methods for stations installation, data quality and data management. We deployed 27 temporary broadband stations equipped with STS-2 and Trillium Compact 120 s sensors. The deployment and maintenance of the temporary stations across 5 countries is managed by ETH Zurich and it is the result of a fruitful collaboration between five institutes in Europe.
The analysis of long term seismological data collected underground in the
M\'atra Mountains, Hungary, using the facilities of the M\'atra Gravitational
and Geophysical Laboratory (MGGL) is reported. ...The laboratory is situated
inside the Gy\"ongy\"osoroszi mine, Hungary, 88m below the surface. This study
focuses on the requirements of the Einstein Telescope (ET), one of the planned
third generation gravitational wave observatories, which is designed for
underground operation. After a short introduction of the geophysical
environment the evaluation of the collected long term data follows including
the comparison of a two-week measurement campaign deeper in the mine. Based on
our analysis and considering the specialities of long term data collection,
refinements of the performance and evaluation criteria are suggested as well as
performance estimation of a possible M\'atra site.
The selection of sites for underground gravitational wave detectors based on spectral and cumulative characterisation of the low frequency seismic noise. The evaluation of the collected long term ...seismological data in the Mátra Gravitational and Geophysical Laboratory revealed several drawbacks of the previously established characteristics. Here we demonstrate the problematic aspects of the recent measures and suggest more robust and more reliable methodology. In particular, we show, that the mode of the data is noisy, sensitive to the discretization and intrinsic averaging, and the \(rms_{2Hz}\) is burdened by irrelevant information and not adapted to the technological changes. Therefore the use of median of the data instead of the mode and also the modification of the frequency limits of the \(rms\) is preferable.
The analysis of long term seismological data collected underground in the Mátra Mountains, Hungary, using the facilities of the Mátra Gravitational and Geophysical Laboratory (MGGL) is reported. The ...laboratory is situated inside the Gy\"ongy\"osoroszi mine, Hungary, 88m below the surface. This study focuses on the requirements of the Einstein Telescope (ET), one of the planned third generation gravitational wave observatories, which is designed for underground operation. After a short introduction of the geophysical environment the evaluation of the collected long term data follows including the comparison of a two-week measurement campaign deeper in the mine. Based on our analysis and considering the specialities of long term data collection, refinements of the performance and evaluation criteria are suggested as well as performance estimation of a possible Mátra site.
The European Physical Journal, Special Topics 228, 1693-1743
(2019) Summary of the long term data taking, related to one of the proposed next
generation ground-based gravitational detector's location ...is presented here.
Results of seismic and infrasound noise, electromagnetic attenuation and cosmic
muon radiation measurements are reported in the underground Matra Gravitational
and Geophysical Laboratory near Gy\"ongy\"osoroszi, Hungary. The collected
seismic data of more than two years is evaluated from the point of view of the
Einstein Telescope, a proposed third generation underground gravitational wave
observatory. Applying our results for the site selection will significantly
improve the signal to nose ratio of the multi-messenger astrophysics era,
especially at the low frequency regime.
Matra Gravitational and Geophysical Laboratory (MGGL) has been established near Gy\"ongy\"osoroszi, Hungary in 2015, in the cavern system of an unused ore mine. The Laboratory is located at 88~m ...below the surface, with the aim to measure and analyse the advantages of the underground installation of third generation gravitational wave detectors. Specialized instruments have been installed to measure seismic, infrasound, electromagnetic noise, and the variation of the cosmic muon flux. In the preliminary (RUN-0) test period, March-August 2016, data collection has been accomplished. In this paper we describe the research potential of the MGGL, list the installed equipments and summarize the experimental results of RUN-0. Here we report RUN-0 data, that prepares systematic and synchronized data collection of the next run period.
Summary of the long term data taking, related to one of the proposed next generation ground-based gravitational detector's location is presented here. Results of seismic and infrasound noise, ...electromagnetic attenuation and cosmic muon radiation measurements are reported in the underground Matra Gravitational and Geophysical Laboratory near Gy\"ongy\"osoroszi, Hungary. The collected seismic data of more than two years is evaluated from the point of view of the Einstein Telescope, a proposed third generation underground gravitational wave observatory. Applying our results for the site selection will significantly improve the signal to nose ratio of the multi-messenger astrophysics era, especially at the low frequency regime.
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