A Measurement Node for the continuous gravity and tilt observations in an active

geodynamic area of southern Italy: the Calabrian Arc system

Anna Albano¹, Vincenzo Carbone¹, Francesco Lamonaca²

¹Dipartimento di Fisica, Università della Calabria, Arcavacata di Rende (CS), Italy

²Dipartimento di Ingegneria Informatica, Modellistica, Elettronica e Sistemistica,
Università della Calabria, Arcavacata di Rende (CS), Italy

Calabria (southern Italy) is a site of considerable seismic activity related to the ongoing evolution of the Calabrian Arc system, where a complex lithospheric structure is present. For over a century the Calabrian region has been going through a period of relative seismic quietness, yet its seismic hazard is at the highest levels in the Mediterranean basin due to several catastrophic earthquakes present in the historical records. In order to strengthen the geophysical monitoring of this region, a gravity and tilt recording station was set up in the premises of the University of Calabria. The measurement node is composed by the gravimeter G-1089 from LaCoste & Romberg; the tilt-meter Model 714 from Applied Geomechanics; a 6 and ½ digits multimeter Agilent 34970A data acquisition and switching unit used to converts the analog signals of the gravimeter and tilt-meter in the corresponding digital ones; a computer used to store, elaborate and present the signals. The delay among the input channels of the multimeter is evaluated and the optimal configuration is achieved in order to make such a delay negligible for the time correlation of the input signals. The measurement node is positioned on the ground of the cube 41C. Finally, the information about the temperature and the atmospheric pressure is obtained by the nearby environmental station positioned on the roog of cube 41B. The recorded signals should allow to estimate a tidal anomaly, possibly correlated with the difference between some local feature of the lithosphere or geodynamic activity and the corresponding characteristics of the model used to calculate the reference gravity tide. A reliable model of the gravity tide is necessary for accurate processing of discrete absolute and relative gravimetric measurements and to detect in the gravity signals possible components correlated to major seismic activity. The Ocean Tide Load (OTL) effect was accounted for in the determination of the tidal field spectral parameters. The most widespread DDW99/ NH Earth’s model, adopted here as reference, fits the obtained results well enough.

How to cite: Albano, A., Carbone, V., and Lamonaca, F.: A Measurement Node for the continuous gravity and tilt observations in an activegeodynamic area of southern Italy: the Calabrian Arc system, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8485, https://doi.org/10.5194/egusphere-egu23-8485, 2023.

Strainmeters measure the change in length between two known fixed points and are used primarily to identify and estimate tectonic strain. In addition to tectonic strain, these instruments also record changes in strain caused by other phenomena such as Earth tides and fluctuations of meteorological signals like changes in groundwater levels caused by precipitation, which may be much larger than tectonic strain and thus mask its signals. To avoid meteorological influences as far as possible, horizontal strainmeters often are maintained in galleries such that tectonically induced strain signals are not affected by other sources of noise.

At Moxa Geodynamic Observatory, located in central Germany, two laser strainmeters with a base length of 26 m each are maintained in galleries oriented north-south and east-west. Their resolution is in the nano-scale and sampling rate is 0.1 Hz. Mountain overburden in the gallery is comparatively low at approx. 30 m and in addition, the hydrogeological situation of the subsurface surrounding the observatory, is very heterogeneous. Therefore, amplitudes of meteorological phenomena are still quite high. In order to correct meteorological influences in the recorded strain time-series, they first need to be better understood. For doing so, long time-series - a decade at least – are needed. As the laser strainmeters continuously record since summer 2011, these are now available.

We present the results of weighting various meteorological parameters on the strainmeter recordings by training Long Short Term Memory Networks and perturbing input parameters for the test data. In this way, the contribution of each parameter to the meteorologically induced strain signals can be estimated. This knowledge is subsequently used to eliminate meteorological influences from the time-series recordings of strain.

How to cite: Kasburg, V., Breuer, A., Bücker, M., and Kukowski, N.: Influence of Environmental Parameters on Highly Sensitive Instruments at Moxa Geodynamic Observatory, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3968, https://doi.org/10.5194/egusphere-egu23-3968, 2023.

The Pieniny Klippen Belt is located in the middle part of the zone between the Inner Carpathians and Outer Carpathians. Researches at the Pieniny Geodynamic Test Field dates back to the 1960s.

Previous geodynamic studies in the area of the Pieniny Klippen Belt  have indicated neotectonic activity. Currently, starting in 2004, a GNSS survey campaign is held annually in early September.

The subject of the study was to check whether the Pieniny Klippen Belt (PKB) shows neotectonic activity in the relation to the surrounding structures - the Podhale Flysh (FP) and the Magura Nape (MN).

This study was based on the  survey of the movement of stations located in the area of the aforementioned three structures, which create the Pieniny Geodynamic Test Field.

The Pieniny Geodynamic Test Field consists of 15 GNSS stations, including 6 stations inside the PKB, 5 stations within the MN and 4 stations within the FP. The whole geodynamic test field is supplemented by 4 GNSS stations located in the Tatra Mountains.

To determine the horizontal movements of the geodynamic units, the results of satellite measurements made between 2004 and 2020 were processed. The coordinates and velocities of the stations were determined in two reference systems - IGb08 and IGb14.

To define the IGb08 and IGb14 systems, 24 EUREF stations (Euref Parmanent GNSS Network) were used. The stations were selected based on the following criteria: location, length of available data and the fewest number of discontinuities. The stations were basign to be located at the shortest distance from the Pieniny Geodynamic Test Field, as well as to be distributed evenly. Data from the CODE Analysis Center was used to process the GNSS data. GNSS datasets were processed using Bernese 5.2 GNSS Software. The adjustment was prefared in two variants due to inconsistencies between the orbits of the satellites and the IGb14 system. The differences between the ITRF2008 and ITRF2014 are quite small and are due to new or updated antenna calibrations.

Then, the obtained velocities were converted to ETRF2014. Station velocities were determined in two ways-analytically, using transformation parameters between the ITRF and ETRF2014 systems for the 2010.0 epoch, and using the EPN CB Coordinate Transformation Tool shared by the EUREF Permanent Network (EPN).

Horizontal coordinates were determined in both short-period solutions - daily and long-period solutions - covering sixteen measurement epochs.

To check the validity of the adjustment, a comparison of the velocities calculated for the reference stations with the EUREF model was performed.

The velocities of stations located in the Pieniny Geodynamic Test Field were also compared with those obtained in a study done in 2016.

The realized comparison of calculations allowed us to conclude that the performed alignment does not deviate from the solutions presented in the model and in the previous study.

The obtained results shows the tectonic activity of the Pieniny Klippen Belt and surrounding units. Horizontal point movements are small, i.e. 0.2 - 0.7mm/year, although changes in the position of points show a linear character. The trend in the direction of these changes and their magnitude is also preserved.

How to cite: Staniszewska, D.: Geodynamic studies in the Pieniny Klippen  Belt in  2004-2020, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7450, https://doi.org/10.5194/egusphere-egu23-7450, 2023.

It is postulated that a pressure gauge has potential for detection of vertical crustal deformation associated with plate convergence since the measurement resolution is higher than the expected deformation. However, it has been long known that the sensor drift being a few of hPa (cm) per year or larger rate is identified in the long-term pressure observation at the seafloor. We have investigated the sensor drift of pressure gauges pressurized by a pressure balance in the laboratory. Two types of pressure gauges were examined; one is quartz resonant pressure gauges which are traditionally used for in-situ pressure observations and the other is silicon resonant pressure gauges which can be used for oceanographic observations in the future. Full scale of all pressure gauges examined in the present experiment is 70 MPa. Pressure calibration curves were obtained by applying the standard pressure from zero to full scale to characterize hysteresis and repeatability of pressure gauges. Comparing pressure calibration curves under the different temperature condition, only zero offset is changed for the tested quartz pressure gauges, whereas both zero offset and span are changed for some silicon pressure gauges. Then, static pressure of 20 MPa equivalent to 2000 m water depth is applied to the pressure gauges simultaneously for a period of approximately 100 days under the low temperature condition. Some silicon pressure gauges were pressurized under the normal temperature condition. Pressure calibrations were conducted about 50 times repeatedly by providing the standard pressure of 20 MPa using the pressure balance during the experiment. Differences between the standard pressure and the sensor’s output over time were calculated to evaluate the sensor drift. The results suggest that the lower ambient temperature can contribute to the shorter relaxation time (i.e., the elapsed time to disappear initial abrupt change) and the smaller sensor drift (i.e., the linear trend) in the both types of pressure gauges. The sensor drift between the quartz and the silicon pressure gauges were comparable except for the specific silicon pressure gauges. It is noted that the quartz pressure gauges are more sensitive to temperature than the silicon pressure gauges in the present experiment.

How to cite: Matsumoto, H., Kajikawa, H., and Araki, E.: Long-term sensor drift of pressure gauges characterized by a pressure balance, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4919, https://doi.org/10.5194/egusphere-egu23-4919, 2023.

Intermittency is a property of turbulent astrophysical plasmas, such as the solar wind, that implies non-uniformity in the transfer rate of energy carried by non-linear structures from large to small scales. We evaluate the intermittency level of the turbulent magnetic field measured by the Parker Solar Probe in the slow solar wind in the proximity of the Sun, at about 0.17 AU, during the probe’s first encounter. A quantitative measure of the intermittency of a time-series can be deduced based on the normalized forth order moment of the probability distribution functions, the flatness parameter. We observe that when dividing the data into contiguous samples of various lengths, from three to twenty-four hours, flatness differs significantly from sample to sample, suggestive of alternating intermittency-free time intervals with highly intermittent samples. In order to describe this variability, we apply an elaborate statistical test tailored to identify nonlinear dynamics in a time series which involves the construction of surrogate data that eliminate all nonlinear correlations contained in the dynamics of the signal but are otherwise consistent with an “underlying” linear process, i.e. the null hypothesis that we want to falsify. If a discriminating statistic for the original signal, such as the flatness parameter, is found to be significantly different than that of the ensemble of surrogates, then the null hypothesis is not valid, and we can conclude that the computed flatness reliably reflects the intermittency level of the underlying non-linear processes. We determine that non-stationarity of the time-series strongly influences the flatness of both the data and surrogates and the null hypothesis cannot be falsified. The intermittency level detected in such cases reflects the effects of isolated and, maybe, statistically not meaningful events, consequently, we stress upon the importance of careful data selection and evaluating the significance of the evaluated discriminating statistic.

How to cite: Teodorescu, E., Echim, M., Johnson, J., and Munteanu, C.: Estimating intermittency significance by means of surrogate data: implications for stationarity, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9762, https://doi.org/10.5194/egusphere-egu23-9762, 2023.

Long time series observations in the ocean are rare. In the Northeast Pacific, Ocean Networks Canada (ONC) of the University of Victoria operates a number of permanent cabled ocean observatories. The first was installed in 2006, and they have successfully produced many interdisciplinary high-resolution time series over the years, the longest being over 16 years in duration. The cabled observatories operated by ONC include the VENUS coastal observatory and the NEPTUNE off-shore deep-sea observatory. Each observatory has several sites where an observatory node provides continuous power and high bandwidth communications to a wide range of ocean and geophysical sensors. Various long high-resolution time series will be presented and the assessment of climate, decadal, inter-seasonal, annual, and even daily cycles, variations, and signals will be discussed. Such long time series, including environmental baselines, are key for evaluating physicochemical and biological change in the oceans in response to natural variations and climate change. In this way, recent efforts to leverage our time series data in robust monitoring, measurement, reporting, and verification (M2RV) frameworks in the context of different marine carbon dioxide removal (mCDR) approaches, will also be presented.

How to cite: Dewey, R., Scherwath, M., Milahy, S., Heesemann, M., De Leo, F., Muzi, L., Bauer, K., and Juniper, K.: Ocean Networks Canada: Long-term ocean observing on a Northeast Pacific cabled ocean observatory, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16971, https://doi.org/10.5194/egusphere-egu23-16971, 2023.

Presently, climate change is an urging topic and mapping the effects of climate change is a crucial part. According to the evaluation by United Nations Development Programme, more than half of the territory of Kazakhstan exposed ecological crisis as drought, extreme weather events, fires and others. In this regard, this study is important for conducting research on both observation and visualization of the boundaries change of climatic zones on the land area of Kazakhstan. The Köppen climate classification was applied as a reference. In particular, such variables as temperature and precipitation were used for climatic zones classification. Extensive database of Google Earth Engine spatial analysis platform allows to leverage climate reanalysis datasets for many decades. Although, World Metereological Organization recommends considering 30-year period to witness the climate change, there is limited data access for the region of interest. Thus, only 21-year time frame was analyzed, specifically, time range between 2000 and 2021. Results are presented as time-series maps of classified climate zones and may benefit other researchers on their projects related to climate change.

How to cite: Yessimkhanova, K. and Gede, M.: Observing climate zones boundaries change: Kazakhstan's case study, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11340, https://doi.org/10.5194/egusphere-egu23-11340, 2023.

Statistical associations between variables of interest are commonly assessed by applying similarity measures like Pearson correlation to corresponding observational time series. Most traditional measures focus on continuous variables and their associated complete variability, while there is a vast amount of practical examples where only times with specific conditions (e.g. extreme events) are of interest. For the latter cases, concepts like event synchronization strength or event coincidence rates have been introduced as proper similarity measures, and have proven their broad applicability across many areas of research. However, recent work has shown that such event based similarity measures may have conceptual as well as practical limitations when studying co-occurrence statistics between temporally clustered or extended events that do not meet the common assumption of serially uncorrelated point processes.

In this work, we introduce and discuss a straightforward extension of event coincidence analysis (ECA) to studying statistical associations between sequences of persistent events, which we tentatively call interval coincidence analysis (InCA). Here, each event of interest corresponds to a well-defined time interval, and the discrete counts of event co-occurrences in ECA are replaced by the fractions of time during which event intervals in two sequences mutually overlap. A statistical significance test for the obtained interval coincidence rates is realized by block bootstrapping event and non-event intervals, retaining the event duration and waiting time distributions of the persistent events in both sequences.

We demonstrate the practical potentials of InCA, as well as its similarities and differences with ECA, for a specific case study on atmospheric dynamics. Specifically, we apply both methods to studying the likelihood of co-occurrences between boreal summer (June to August) heatwaves in different parts of the Northern hemisphere and hemispheric anomalies of the atmospheric circulation, such as a jet stream pattern exhibiting two distinct wind bands known as double-jet. Our analysis reveals large-scale regions of markedly elevated likelihood of co-occurrences over Northern Europe, Central to Eastern Siberia, Northeastern Canada as well as the Middle East, Eastern China, the Southwestern and Northeastern United States and Northwest Africa, indicating a particular vulnerability of those regions to the presence of double-jet patterns.

How to cite: Donner, R., Diedrich, D., Praast, S., and Di Capua, G.: Quantifying statistical associations among persistent events: Interval coincidence analysis between Northern hemisphere heatwaves and different types of circulation anomalies, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12070, https://doi.org/10.5194/egusphere-egu23-12070, 2023.

The Indian summer monsoon (ISM), which accounts for the majority of India’s yearly rainfall, has a significant influence on the nation’s economy. Understanding monsoonal dynamics is a challenge because of the related small-scale processes and their spatiotemporal complexity. Nevertheless, in the past decades, complex networks have become a key mathematical tool in the analysis of complex systems like the monsoon. However, multi-scale interactions and the coupling between rainfall and atmospheric circulation have remained underrepresented in the corresponding functional network studies. In this study, we exploit coupled rainfall networks to investigate simultaneous interactions of rainfall with other atmospheric variables. Firstly, rainfall networks are investigated by considering various network measures. Secondly, a coupled network is developed based on several atmospheric variables and their point-wise correlation with rainfall fields. Furthermore, the contrasts between the rainfall network and its coupled equivalent are emphasized. By comparison, the resulting coupled network includes both horizontal and vertical interconnections of the spatially enclosed time sequences, representing both the inherent structure of a single meteorological variable and the interaction structure with rainfall fields. It is expected to help with understanding the dynamics of monsoonal rainfall. This study, therefore, demonstrates the application of a complex network approach to studying highly dynamic phenomena such as the ISM. Our results are anticipated to provide the scientific community with new insights into how the interplay of the atmospheric systems leads to the heavy rainfall episodes that take place during the ISM.

How to cite: Bishnoi, G., Donner, R., Dhanya, C. T., and Khosa, R.: Understanding monsoonal rainfall patterns with a complex network approach , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12560, https://doi.org/10.5194/egusphere-egu23-12560, 2023.

We perform a systematic and comparative analysis of the fractal dimension estimators as a proxy for data complexity. In particular, we focus on the analysis of the horizontal geomagnetic field components registered by four stations (Belsk, Hel, Sodankylä and Hornsund) at various latitudes during the period of 22 August–1 September, when the 26 August 2018 geomagnetic storm appeared. To identify the fractal scaling and to compute the fractal dimension, we apply and compare three selected methods: structure function scaling, Higuchi, and detrended fluctuation analysis. The obtained results show the temporal variation of the fractal dimension of horizontal geomagnetic field components, revealing differences between their irregularity (complexity). Moreover, the values of fractal dimension seem to be sensitive to the change of physical conditions related to interplanetary shock, the coronal mass ejection, the corotating interaction region, and the high-speed stream passage during the storm development. Especially, a significant decrease in the fractal dimension for all stations is observed immediately following the interplanetary shock, which was not straightforwardly visible in the geomagnetic field components data.

How to cite: Wawrzaszek, A., Modzelewska, R., Krasińska, A., Gil, A., and Glavan, V.: 26 August 2018 Geomagnetic Storm: Fractal Analysis of Earth Magnetic Field , EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10009, https://doi.org/10.5194/egusphere-egu23-10009, 2023.

Underground research laboratories provide advantageous conditions to observe a broad range of various rock parameters to characterise rock matrix and geological features, and to enhance knowledge of their dynamic behaviour, all under relatively undisturbed conditions. One of their favorable features is that the overburden protects against large environmental changes, although those influences cannot be mitigated in full. Especially for long term investigations, a holistic observation of ambient environmental parameters is necessary on the local scale and beyond.

The Swiss Mont Terri rock laboratory is situated in the Jura Mountains about 250 m below the surface. Starting in 1996, the international Mont Terri Consortium has conducted about 150 experiments in the native Opalinus Clay. Embedded in several of the ongoing in situ experiments, platform tiltmeters assist in the often interdisciplinary investigations. Two different types of biaxial instruments with resolutions of 0.1 urad and better than nrad are distributed throughout the laboratory, together forming a small, growing array, with the first tiltmeters installed in April 2019.

Tiltmeters observe the direct local deformation, they are exposed to near field but also far field impacts. Known local influences are mainly temperature, air pressure, and humidity. In Mont Terri, all of these parameters are registered directly at the location of the tilt sensors with the same relatively high sampling of once every few seconds. In addition, Mont Terri's comprehensive database imparts valuable complementing information. However, the detected deformation pattern is also influenced on a much larger spatial scale, e.g. far field, extensive changes in weather patterns, earth tides, and teleseismic events.

Therefore, to allow detection, identification, and realistic interpretation of complex signal responses on different spatial scales, it is mandatory to distinguish transient and long term signals, natural and anthropogenic disturbances. Their understanding is essential for the evaluation of stability and the safety of a rock laboratory for the benefit of its personnel and visitors. Obviously, long term, continuous data series require long term commitments. But the efforts pays off, not the least, as decade-long deformation studies contribute to multifaceted technical and scientific aspects of long term behavior of barrier rocks, and these are relevant for the exploitation of the deep geological subsurface such as nuclear waste disposal, geological storage of carbon dioxide, use of geothermal energy, or inter-seasonal thermal energy storage.

How to cite: Rebscher, D., Reichertz, F. G., and Schefer, S.: Long term investigations at the Mont Terri rock laboratory of tilt and their near and far field influences, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11304, https://doi.org/10.5194/egusphere-egu23-11304, 2023.