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NH4.1

Short-term Earthquakes Forecast (StEF) and multi-parametric time-Dependent Assessment of Seismic Hazard (t-DASH)

From the real-time integration of multi-parametric observations is expected the major contribution to the development of operational t-DASH systems suitable for supporting decision makers with continuously updated seismic hazard scenarios. A very preliminary step in this direction is the identification of those parameters (seismological, chemical, physical, biological, etc.) whose space-time dynamics and/or anomalous variability can be, to some extent, associated with the complex process of preparation of major earthquakes.
This session wants then to encourage studies devoted to demonstrate the added value of the introduction of specific, observations and/or data analysis methods within the t-DASH and StEF perspectives. Therefore, studies based on long-term data analyses, including different conditions of seismic activity, are particularly encouraged. Similarly welcome will be the presentation of infrastructures devoted to maintain and further develop our present observational capabilities of earthquake related phenomena also contributing in this way to build a global multi-parametric Earthquakes Observing System (EQuOS) to complement the existing GEOSS initiative.
To this aim this session is not addressed just to seismology and natural hazards scientists but also to geologist, atmospheric sciences and electromagnetism researchers, whose collaboration is particular important for fully understand mechanisms of earthquake preparation and their possible relation with other measurable quantities. For this reason, all contributions devoted to the description of genetic models of earthquake’s precursory phenomena are equally welcome.

Co-organized by EMRP1/ESSI1/GI5/SM3, co-sponsored by JpGU and EMSEV
Convener: Valerio Tramutoli | Co-conveners: Pier Francesco Biagi, Carolina Filizzola, Nicola Genzano, Iren Adelina Moldovan
Presentations
| Fri, 27 May, 08:30–11:47 (CEST), 13:20–14:05 (CEST)
 
Room M2

Fri, 27 May, 08:30–10:00

Chairpersons: Valerio Tramutoli, Nikolaos Sarlis, Carolina Filizzola

08:30–08:33
Session I - Introduction

08:33–08:40
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EGU22-3610
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ECS
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Virtual presentation
Kiriha Tanaka et al.

The mechanism of seismic-electromagnetic phenomena (SEP) encouraged as precursors of earthquake forecast remains unrevealed. The previous studies reported that the surface charges of the frictional and fractured quartz are enough to cause electric discharge due to the dielectric breakdown of air. To verify the discharge occurrence, friction experiments between a diamond pin and quartz disk were performed under nitrogen gas with a CCD camera and UV-VIS photon spectrometer (e.g., Muto et al., 2006). The photon emission was observed at the pin-to-disk gap only during the friction. The photon spectra obtained from a friction experiment (normal stresses of 13-20 MPa, a sliding speed of 1.0×10-2 m/s, and a gas pressure of 2.4×104 Pa) showed that the photon was emitted through the second positive band (SPB) system of neutral nitrogen and the first negative band (FNB) system of ionized nitrogen. The estimated potential difference at the gap gave the breakdown electric field and surface charge density on the frictional surface at a gap, where photon was the most intense. These values were enough to cause dielectric breakdown of air. Therefore, the above results demonstrated that frictional discharge could occur on a fault asperity due to dielectric breakdown of ambient gases by frictional electrification. However, the details of electronic transition during the discharge and its type are unknown.
This study discussed the details of the gas pressure dependency for the photon emission intensity and distribution, and the discharge type using the electronic transition theory. Moreover, we compared the surface charge density estimated from the potential difference with that estimated from electron and hole trapping centre concentrations in the frictional quartz subsurfaces measured by electron spin resonance. From this comparison, we also discussed the possibility for the trapping centres to be the sources of the discharge. We could explain the nitrogen gas pressure dependency for the photon emission intensity and vibration temperature observed during our friction experiments using the electron transition theory. For example, Miura et al. (2004) reported that the gas pressure decreases with increasing vibration temperature of the SPB system and the relative intensity in the SPB system to the FNB system. This result showed that the vibration temperature and the relative intensity were about 2800 K and 0.1 during the friction experiment under a pressure of 2.4×104 Pa. The FNB system is related to negative glow charge and the discharge observed during the friction experiments was spark and/or glow discharges. The gas pressure decreases with increasing vibration temperature and molecule density as shown in several previous studies and decrease with increasing electron temperature and density as explained the electron transition theory. This implies that the increase in the free path of excited molecules as gas pressure decreases can result in the photo emission pattern change. The surface charge density of a frictional quartz surface estimated from the potential difference to be 5.5×10-5 C/m2 included in the range of 6.51×10-6–6.4×10-3 C/m² estimated from the trapping centre concentrations. Hence, the trapping centres can be the sources of the frictional discharge.

How to cite: Tanaka, K., Muto, J., and Nagahama, H.: Mechanism of frictional discharge plasma at fault asperities, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3610, https://doi.org/10.5194/egusphere-egu22-3610, 2022.

08:40–08:47
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EGU22-10961
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ECS
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Virtual presentation
Hong-Jia Chen et al.

Electromagnetic anomalies have become promising for short-term earthquake forecasting. One forecasting algorithm based on statistical moments of geoelectric data was developed and applied in Taiwan. The objective of our research was to investigate such a reliable, rigorously testable algorithm to issue earthquake forecasts. We tested the applicability of the forecasting algorithm and applied it to geoelectric data and an earthquake catalog in Kakioka, Japan with a long-term period of 26 years. We calculated the variance, skewness, and kurtosis of the geoelectric data each day, determined their anomalies, and then compared them with earthquake occurrences through the forecasting algorithm. We observed that the anomalies of variance, skewness, and kurtosis significantly precede earthquakes, suggesting that the geoelectric data distributions deviate from normal distributions before earthquakes. Furthermore, the forecasting algorithm can select robust optimal models and produce explicit forecasting probability for two-thirds of all experimental cases. Therefore, we concluded that the forecasting algorithm based on statistical moments of geoelectric data is universal and may contribute to short-term earthquake forecasting.

How to cite: Chen, H.-J., Hattori, K., and Chen, C.-C.: Regional applicability of earthquake forecasts using geoelectric statistical moments: Application to Kakioka, Japan, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10961, https://doi.org/10.5194/egusphere-egu22-10961, 2022.

08:47–08:54
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EGU22-12349
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Highlight
Katsumi Hattori et al.

Recently, there are many papers on electromagnetic pre-earthquake phenomena such as geomagnetic, ionospheric, and atmospheric anomalous changes. Ionospheric anomaly preceding large earthquakes is one of the most promising phenomena. Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) model has been proposed to explain these phenomena. In this study, to evaluate the possibility of chemical channel of LAIC by observation, we have installed sensors for atmospheric electric field, atmospheric ion concentration, atmospheric Rn concentration, soil radon Rn concentration (SRC), and weather elements at Asahi station, Boso, Japan. Since the atmospheric electricity parameters are very much influenced by weather factors, it is necessary to remove these effects as much as possible. In this aim, we apply the MSSA (Multi-channel Singular Spectral Analysis) to remove these influences from the variation of GRC and estimate the soil Rn flux (SRF). We investigated the correlations (1) between SRF and precipitation and (2) between SRF and the local seismic activity around Asahi station. The preliminary results show that SRF was significantly increased by heavy precipitations of 20 mm or more in total for 2 hours. We proposed two types of models, a rainwater load model and a rainwater infiltration model, and it is appropriate for both models to work and (2) between SRF and local seismicity within an epicenter distance of 50 km from the station.

 

How to cite: Hattori, K., Nemoto, K., Kojina, H., Kitade, A., kaneko, S., Yoshino, C., Mogi, T., Konishi, T., and Ouzounov, D.: Multi-channel singular spectrum analysis of soil radon concentration, Japan: Relationship between soil radon flux and precipitation and the local seismic activity, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12349, https://doi.org/10.5194/egusphere-egu22-12349, 2022.

08:54–09:01
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EGU22-3194
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ECS
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Virtual presentation
Chen Huang et al.

Operational earthquake forecasting (OEF) provides timely information about the time-dependent earthquake probabilities, which facilitates resilience-oriented decision-making. This study utilized the tools developed within the TURNkey (Towards more Earthquake-Resilient Urban Societies through a Multi-Sensor-Based Information System enabling Earthquake Forecasting, Early Warning and Rapid Response Actions) project funded by the European Union’s Horizon 2020 research and innovation programme to demonstrate the benefits of OEF to the decision support system.  The considered tools are developed based on the state-of-the-art knowledge about seismology and earthquake engineering, involving the Bayesian spatiotemporal epidemic-type aftershock sequence (ETAS) forecasting model, the time-dependent probabilistic seismic hazard assessment, the SELENA (SEimic Loss EstimatioN using a logic tree Approach) risk analysis, cost-benefit analysis and the multi-criteria decision-making methodology. Moreover, the tools are connected to the dense seismograph network developed also within the TURNkey project and, thus, it is capable of real-time updating the forecasting based on the latest earthquake information and observations (e.g., earthquake catalogue). Through a case study in a synthetic city, this study first shows that the changes in the earthquake probabilities can be used as an indicator to inform the authorities or property owners about the heightened seismicity, based on which the decision-maker can, for example, issue a warning of the potential seismic hazard. Moreover, this study illustrates that OEF together with the risk and loss analysis provides the decision-maker with a better picture of the potential seismic impact on the physical vulnerabilities (e.g., damage, economic loss, functionality) and social vulnerabilities (e.g., casualty and required shelters). Finally, given the decision-maker’s preference, this study shows how the hazard and risk results are used to help the decision-maker to identify the optimal action based on cost-beneficial class and the optimality value computed based on the multi-criteria decision-making methodology.

How to cite: Huang, C., Bolin, H., Refsum, V., and Meslem, A.: Using Operational Earthquake Forecasting Tool for Decision Making: A Synthetic Case Study , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3194, https://doi.org/10.5194/egusphere-egu22-3194, 2022.

09:01–09:08
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EGU22-8924
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Highlight
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Virtual presentation
Gaohua Zhu et al.

Foreshocks may provide valuable information on the nucleation process of large earthquakes. The 2021 Ms 6.4 Yangbi, Yunnan, China, earthquake was preceded by abundant foreshocks in the ~75 hours leading up to the mainshock. To understand the space-time evolution of the foreshock sequence and its relationship to the mainshock nucleation, we built a high‐precision earthquake catalog using a machine-learning phase picker—EQtransformer and the template matching method. The source parameters of 17 large foreshocks and the mainshock were derived to analyze their interaction. Observed “back-and-forth” spatial patterns of seismicity and intermittent episodes of foreshocks without an accelerating pattern do not favor hypotheses that the foreshocks were a manifestation of a slow slip or fluid front propagating along the mainshock’s rupture plane. The ruptured patches of most large foreshocks were adjacent to one another with little overlap, and the mainshock eventually initiated near the edge of the foreshocks’ ruptured area where there had been a local increase in shear stress. These observations are consistent with a triggered cascade of stress transfer, where previous foreshocks load adjacent fault patches to rupture as additional foreshocks, and eventually the mainshock.

How to cite: Zhu, G., Yang, H., Tan, Y. J., Jin, M., Li, X., and Yang, W.: The Cascading Foreshock Sequence of the Ms 6.4 Yangbi Earthquake in Yunnan, China, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8924, https://doi.org/10.5194/egusphere-egu22-8924, 2022.

09:08–09:18
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EGU22-6296
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solicited
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Virtual presentation
Mengxuan Fan et al.

In this paper, based on the Non-negative Tensor Decomposition (NTD), we analyzed the Y-component ionospheric magnetic field data as observed by Swarm Alpha and Charlie satellites before, during and after the 2015 (Mw=7.8) Nepal earthquake (April 25, 28.231°N 84.731°E). All the observation data were analyzed, including the data collected under quiet and strong geomagnetic activities. For each investigated satellite track, we can obtain a tensor, which is decomposed in three components. We found that the cumulative number of the inside anomalous tracks for one component of decomposition components (i.e., hs1, whose energy and entropy are more concentrated inside the earthquake-sensitive area, shows an accelerated increase which conforms to a sigmoid trend from 60 to 40 days before the mainshock. After that till the day before the mainshock, the cumulative result displays a weak acceleration trend which obeys a power law trend and resumed linear growth after the earthquake. According to the basis vectors, the frequency of the ionospheric magnetic anomalies is around 0.02 to 0.1 Hz, and by the skin depth formula the estimated depth of the mainshock is similar to the real one.

In addition, we did some confutation analysis to exclude the influence of the geomagnetic activity and solar activity on the abnormal phenomenon of the cumulative result for the hs1 component, according to the ap, Dst and F 10.7 indices. We also analyzed another area at the same magnetic latitude with no seismicity and find that its cumulative result shows a linear increase, which means that the accelerated anomalous phenomenon is not affected by the local time or due by chance.

At lithosphere, the cumulative Benioff Strain S also shows two accelerating increases before the mainshock, which is consistent with the cumulative result of the ionospheric anomalies. At the first acceleration, the seismicity occurred around the boundary of the research area not near the epicenter, and most of the ionospheric anomalies offset from the epicenter. During the second acceleration, some seismicity occurred closer to or on the mainshock fault, and the ionospheric anomalies appeared nearby the two faults around the epicenter, as well.

Furthermore, we considered combining with other studies on Nepal earthquake. Therefore, we noticed that the ionospheric magnetic field anomalies began to accelerate two days after the subsurface microwave radiation anomaly detected by Feng Jing et al. (2019). The spatial distribution of some ionospheric anomalies is consistent with the atmospheric Outgoing Longwave Radiation (OLR) anomalies found by Ouzounov et al. (2021). The latter occurred around two faults near the epicenter and the atmospheric anomalies occurred earlier than the ionospheric anomalies.

Considering the occurrence time of the anomalies in different layers, the abnormal phenomenon appeared in lithosphere, then transferred to the atmosphere, and at last occurred in the ionosphere. These results can be described by the Lithosphere Atmosphere Ionosphere Coupling model.

All these analyses indicate that by means of the NTD method, we can use all observed multi-channel data to analyze the Nepal earthquake and obtain a component whose anomalies are likely to be related to the earthquake. 

How to cite: Fan, M., Zhu, K., De Santis, A., Marchetti, D., Cianchini, G., Piscini, A., Perrone, L., He, X., Wen, J., Wang, T., Zhang, Y., Chen, W., Zhang, H., Zhang, D., and Cheng, Y.: Analysis of Swarm Satellite Magnetic Field Data before and after the 2015 Mw7.8 Nepal Earthquake Based on Non-negative Tensor Decomposition, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6296, https://doi.org/10.5194/egusphere-egu22-6296, 2022.

09:18–09:25
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EGU22-3337
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ECS
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Virtual presentation
Dedalo Marchetti et al.

Earthquake prediction has always been a challenging task, and some researchers have proposed that it is an even impossible goal, concluding earthquakes are unpredictable events. Such a conclusion seems too extreme and in contrast with several pieces of evidence of alterations recorded by several instrumentations from the ground, atmosphere, and more recently by Earth Observation satellite. On the other side, it is clear that searching the “perfect precursor parameter” doesn’t seem to be a good way, since the earthquake process is a complex phenomenon. In fact, a precursor that works for one earthquake does not necessarily work for the next one, even on the same fault. In some cases, another problem for precursors identification is the recurrency time between the earthquakes, which could be very long and, in such cases, we don’t have comparable observations of earthquakes generated by the same fault system.

In past years, we concentrated mainly on two aspects: statistical and single case study; the first one consists of some statistical evidence on ionospheric disturbances possibly related to M5.5+ earthquakes (e.g., presented at EGU2018-9468, and published by De Santis et al., Scientific Report, 2019), furthermore, some clear signals in the atmosphere statistically preceded the occurrence of M8+ events (e.g., presented at EGU2020-19809). On the other side, we also investigated about 20 earthquakes that occurred in the last ten years, some of them by a very detailed and multiparametric investigation, like the M7.5 Indonesia earthquake (presented at EGU2019-8077 and published by Marchetti et al., JAES, 2020), or the Jamaica earthquake investigation presented at the last EGU2021-15456. We found that both approaches are very important. Actually, the statistical studies can provide proofs that at least some of the detected anomalies seem to be related to the earthquakes, while the single case studies permit us to explore deeply the details and the possible connections between the geolayers (lithosphere, atmosphere and ionosphere).

In this presentation, we want to show an update of the statistical study of the atmosphere and ionosphere, together with a new statistical investigation of the seismic acceleration before M7.5+ global earthquakes.

Finally, we demonstrate that it is essential to consider the earthquake not as a point source (that is the basic approximation), but in all its complexity, including its focal mechanism, fault rupture length and even other seismological constraints, in order to try to better understand the preparation phase of the earthquakes, and the reasons for their different behaviour. These studies give hope and fundamental (but not yet sufficient) tools for the possible achievement, one day, of earthquakes prediction capabilities.

How to cite: Marchetti, D., Zhu, K., De Santis, A., Campuzano, S. A., Zhang, D., Soldani, M., Wang, T., Cianchini, G., D’Arcangelo, S., Di Mauro, D., Ippolito, A., Nardi, A., Orlando, M., Perrone, L., Piscini, A., Sabbagh, D., Shen, X., Zhima, Z., and Zhang, Y. and the Zhu Kaiguang's earthquake research group in Jilin University: Multiparametric and multilayer investigation of global earthquakes in the World by a statistical approach, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3337, https://doi.org/10.5194/egusphere-egu22-3337, 2022.

09:25–09:32
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EGU22-5375
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ECS
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Highlight
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On-site presentation
Yiting Cai and Maxime Mouyen

Non-tectonic processes, namely solid earth tides and surface loads such as ocean, atmosphere, and continental water, constantly modify the stress field of the Earth's crust. Such stress perturbations may trigger earthquakes. Several previous studies reported that tides or hydrological loading could modulate seismicity in some areas. We elaborate on this idea and compute the total Coulomb stress change created by solid earth tides and surface loads together on active faults. We expect that computing a total stress budget over all non-tectonic processes would be more relevant than focusing on one of these processes in particular. The Coulomb stress change is a convenient approach to infer if a fault is brought closer to or further from its critical rupture when experiencing a given stress status. It requires to know 1) the fault's rake and geometry and 2) the value of the stress applied on it, which we retrieve from a subduction zone geometry model (Slab2) and a loading-induced Earth's stress database, respectively. In this study, we focus on the Coulomb stress variations on the Kuril-Japan fault over the few last years. By applying this method to the entire Slab2 catalogue and other known active faults, we aim at producing a database of non-tectonic-induced Coulomb failure function variations. Using earthquakes catalogues, this database can then be used to statistically infer the role of the non-tectonic process in earthquakes nucleation.

How to cite: Cai, Y. and Mouyen, M.: Non-tectonic-induced stress variations on active faults, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5375, https://doi.org/10.5194/egusphere-egu22-5375, 2022.

09:32–09:39
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EGU22-1505
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ECS
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Highlight
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On-site presentation
Behnam Maleki Asayesh et al.

Large earthquakes are always followed by aftershocks sequence that last for months to years. Sometimes, these aftershocks are as destructive as the mainshocks. Hence, accurate and immediate prediction of aftershocks’ spatial and temporal distribution is of great importance for planning search and rescue activities. Despite large uncertainties associated with the calculation of Coulomb failure stress changes (ΔCFS), it is the most commonly used method for predicting spatial distributions of aftershocks. Recent studies showed that classical Coulomb failure stress maps are outperformed by alternative scalar stress quantities, as well as a distance-slip probabilistic model (R) and deep neural networks (DNN). However, these test results were based on the receiver operating characteristic (ROC) metric, which is not well suited for imbalanced data sets such as aftershock distributions. Furthermore, the previous analyses also ignored the potential impact of large secondary earthquakes.

In order to examine the effects of large events in spatial forecasting of aftershocks during a sequence, we use the 2017-2019 seismic sequence in western Iran. This sequence started by Azgeleh M7.3 mainshock (12 November 2017) and followed by Tazehabad M5.9 (August 2018) and Sarpol-e Zahab M6.3 (November 2018) events. Furthermore, 15 aftershocks with magnitude > 5.0 and more than 8000 aftershocks with magnitude > 1 were recorded by Iranian seismological center (IRSC) during this sequence (12.11.2017-04.07.2019). For this complex sequence, we applied the classical Coulomb failure stress, alternative stress scalars, and R forecast models and used the more appropriate MCC-F1 metric to test the prediction accuracy. We observe that the receiver independent stress scalars (maximum shear and von-Mises stress) perform better than the classical CFS values relying on the specification of receiver mechanisms (ΔCFS resolved on master fault, optimally oriented planes, and variable mechanism). However, detailed analysis based on the MCC-F1 metric revealed that the performance depends on the grid size, magnitude cutoff, and test period. Increasing the magnitude cutoff and decreasing the grid size and test period reduces the performance of all methods. Finally, we found that the performance of all methods except ΔCFS resolved on master fault and optimally oriented planes improve when the source information of large aftershocks is additionally considered, with stress-based models outperforming the R model. Our results highlight the importance of accounting for secondary stress changes in improving earthquake forecasts.

How to cite: Maleki Asayesh, B., Zafarani, H., Hainzl, S., and Sharma, S.: Testing spatial aftershock forecasts accounting for large secondary events during on going earthquake sequences: A case study of the 2017-2019 Kermanshah sequence, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1505, https://doi.org/10.5194/egusphere-egu22-1505, 2022.

09:39–09:46
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EGU22-8280
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ECS
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Virtual presentation
Zahra Pak Tarmani et al.

The site effect has a great impact on seismic hazard assessment in urban and industrial regions.
For instance, a layer of soft soil with a thickness of several meters amplifies seismic waves from
1.5 to 6 times relative to the underlying bedrock. Therefore, investigating the main characteristics
of Quaternary deposits such as the granulometry and mechanical layering is crucial in site effect
studies. These parameters are directly related to the local geologic/geomorphic setting and genesis
processes of the Quaternary deposits. Nevertheless, large cities in development countries have 
rapidly been enlarged covering Quaternary terrains before being evaluated for the site effect. This
rather rapid growth in urbanization interested us to take advantage of ancient aerial photographs
reprocessed with new image processing techniques in order to provide 3D terrain models from
such kind of areas before the recent urbanization. It helped us in the geomorphic terrain
classification and the detection of regions with different site effects originally caused by the
geomorphic setting and genesis of the Quaternary terrains. For example, site effect in a river flood
plain will be different from surrounding areas underlined by alluvial conglomerates or bedrock.
The main target of this study is investigating the primary-level site effect in Urmia city using 3D
geomorphic models derived from ancient aerial photos taken in 1955. Urmia in NW Iran is one of
the populated high-risk areas according to the standard regulations of earthquake in Iran, and
covers a wide region from mountainous areas to the ancient coast of Lake Urmia, with the Shahr
Chai River as the axial drainage. We created the 3D terrain model through the Structure from
Motion (SfM) algorithm. We have provided a detailed geomorphic map of Plio-Quaternary terrains
using the 3D Anaglyph view, Digital Elevation Model (DEM), and orthophoto-mosaic of the
region. It was complemented by granulometry and mechanical layering information from the
available geotechnical boreholes to reconstruct a shallow soil structure model for the area. It
allowed us establishing a primary-level site effect zoning for Urmia. Our results reveal the
presence of five distinct geomorphic zones, with different genesis processes and soil characteristics
from piedmont to coastal zones, which represent different soil structures and probable site effects.
This zoning paves the way for performing complementary site effect investigations with lower
time consummation and cost. The developed method, proposes a sophisticated tool to evaluate
primary site effect in areas covered by urbanization subjected to future natural hazards like
earthquake, landslide and flood before designing geophysical networks for the measurement of
quantitative site effect parameters such as Nakamura microtremor H/V and Multichannel Analysis
of Surface Waves.
Key words: Earthquake hazard, Site effect, Image Processing, Aerial photos, Quaternary geology, Structure from
Motion 

How to cite: Pak Tarmani, Z., Masoumi, Z., and Shabanian, E.: Primary-level Site Effect Zoning in Developing Urban Areas Through the Geomorphic Interpretation of Landforms, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8280, https://doi.org/10.5194/egusphere-egu22-8280, 2022.

09:46–09:53
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EGU22-12275
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Virtual presentation
Taner Sengor

Some samples are given illustrating possible influences of the natural hazards those will occur in the future times for the seismic activities those occur at the present time in [1]. Those samples force to ask whether there exist operational connections originating from future time’s naturel events, NEs on the present time’s NEs or do not. The analytical basics orienting such cooperation are derived in here [2]-[3].

Both the past time’s NEs and the future time’s NEs are not exist at the present time’s NEs topology when we want to observe and measure all them at the same location in the present time as a matter of the event for the present time’s temporal and spatial metric or in a space-time differential displacement with other words [4]. This situation brings the fact on the absence and/or presence of NEs in a temporal topology as a principle about the occurrence of NEs in their specific manifolds [4]. The very simple example in below may be helpful to understand the fact:

Example 1: If you want to be a medical doctor in your future then you have to study and learn medical facts in an official way. Without doing this in your past times and present times you cannot earn the medical doctor degree in your future times.

Result 1: The future time’s NEs present cooperation in both the past and future time’s NEs.

Example 1 and connected result 1 illustrate the future time’s event of being medical doctor operates the past and present time’s event of learning medicine so the principle 1 in below brings the processes designing the cooperation among past, present, and future NEs:

Principle 1: There is either definitive and/or fuzzy cooperation among the NEs in the future time, pas time, and present time for NEs’ topology.

The retarded potential in gauge form is split into two parts: The first part is a part of Fourier transform given the future time’s NEs and the second part is a Fourier sinus transform. The first part involves the ingredients of future time’s NEs. The second part involves the ingredients of both NEs of past time and present time. The first part has the property as a forwarded potential. The second part fits to the properties as the events at the past and/or the present.

The principle 1 is checked during several earthquakes received in 1999-2004 [5]- [6] and some important results are shared in [1]. The present writer calls virtual earthquake (VEQ) future time’s earthquake activities cooperating with the past and/or present time’s seismic activities and presents the topological processes with their analytical extractions from the above-mentioned observations.

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1Sengor T, http://meetingorganizer.copernicus.org/ EGU2020/EGU2020-22589.pdf.

2Sengor T, Helsinki University of Tech., Electromagnetics Lab. Report 344, Nov. 2000, ISBN 951-22-5258-9, ISSN 1456-632X.

3Sengor T, Helsinki University of Tech., Electromagnetics Lab. Report 347, Dec. 2000, ISBN 951-22-5274-0, ISSN 1456-632X.

4Sengor T, Invited paper. doi:10.23919/URSI- ETS.2019.8931455

5Sengor T, http://meetingorganizer.copernicus.org/EGU2019/EGU2019-17127.pdf.

6Sengor T, Helsinki University of Tech., Electromagnetics Lab. Report 368, May. 2001, ISBN 951-22-5275-1, ISSN 1456-632X.

How to cite: Sengor, T.: Virtual Earthquakes Cooperating with Natural Hazards and Simultaneously Scheduled Seismic Activities, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12275, https://doi.org/10.5194/egusphere-egu22-12275, 2022.

09:53–10:00
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EGU22-10209
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On-site presentation
Monika Sobiesiak et al.

Applying the software BackTrackBB (Poiata et al., 2016) for automated detection and location of seismic events to data sets from Rudna Deep Copper Mine, SW Poland, lead to an enhancement of existing routine catalogs by about a factor of 10.000 in number of events. Following our hypothesis that all types of seismic events contribute to seismic hazard in a mine, we included all events from major mine collapses (M>3), recorded blasting works and detonations, to machinery noise. These enhanced data sets enabled a detailed spatio-temporal distribution of seismicity in the mine and a short-term hazard assessment on a daily basis.

In this study, we focus on the data from two days with major mine collapses: the 2016-11-29 Mw=3.4, and the 2018-09-15 Mw=3.7 events. The spatio-temporal distribution of seismicity of both days deciphered detailed horizontal and vertical structures and revealed the increase of seismic activity after the daily blasting work. The daily histograms exhibit similar patterns, suggesting the dominant influence of explosions on the overall seismicity in the mine. Using the enhanced data sets for short-term hazard assessment, we observed gaps in the activity rates before the main shocks. They were followed by sudden increase of seismicity, a simultaneous drop in seismic b-value, and an increase in exceedance probability for the assumed largest magnitude events. This demonstrates the usefulness of enhanced data sets from surface networks for revealing precursory phenomena before destructive mine collapses and suggests a testing strategy for early warning procedures.

How to cite: Sobiesiak, M., Leptokaropoulos, K., Staszek, M., Poiata, N., Bernard, P., and Rudzinski, L.: Enhancing Data Sets From Rudna Deep Copper Mine, SW Poland: Implications on Detailed Structural Resolution and Short-Term Hazard Assessment, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10209, https://doi.org/10.5194/egusphere-egu22-10209, 2022.

Fri, 27 May, 10:20–11:50

Chairpersons: Pier Francesco Biagi, Nicola Genzano, Lisa Pierotti

10:20–10:27
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EGU22-8426
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Highlight
Gerasimos Chouliaras et al.

Earthquake nowcasting [1] (EN) is a modern method to estimate seismic risk by evaluating the progress of the earthquake cycle in fault systems [2]. EN employs natural time [3], which uniquely estimates seismic risk by means of the earthquake potential score (EPS) [1,4] and has found many useful applications both regionally and globally [1, 2, 4-10]. Among these applications, here we focus on those in Greece since 2019 [2], by using the earthquake catalogue of the Institute of Geodynamics of the National Observatory of Athens[11–13] (NOA) for the estimation of the EPS in various locations: For example, the ML(NOA)=6.0 off-shore Southern Crete earthquake on 2 May 2020, the ML(NOA)=6.7 Samos earthquake on 30 October 2020, the ML(NOA)=6.0 Tyrnavos earthquake on 3 March 2021, the ML(NOA)=5.8 Arkalohorion Crete earthquake on 27 September 2021, the ML(NOA)=6.3 Sitia Crete earthquake on 12 October 2021. The results are promising and reveal that earthquake nowcast scores provide useful information on impending seismicity.

[1] J.B. Rundle, D.L. Turcotte, A. Donnellan, L. Grant Ludwig, M. Luginbuhl, G. Gong, Earth and Space Science 3 (2016) 480–486. dx.doi.org/10.1002/2016EA000185

[2] J.B. Rundle, A. Donnellan, G. Fox, J.P. Crutchfield, Surveys in Geophysics (2021). dx.doi.org/10.1007/s10712-021-09655-3

[3] P.A. Varotsos, N.V. Sarlis, E.S. Skordas, Phys. Rev. E 66 (2002) 011902. dx.doi.org/10.1103/physreve.66.011902

[4] S. Pasari, Pure Appl. Geophys. 176 (2019) 1417–1432. dx.doi.org/10.1007/s00024-018-2037-0

[5] M. Luginbuhl, J.B. Rundle, D.L. Turcotte, Pure and Applied Geophysics 175 (2018) 661–670. dx.doi.org/10.1007/s00024-018-1778-0

[6] M. Luginbuhl, J.B. Rundle, D.L. Turcotte, Geophys. J. Int. 215 (2018) 753–759. dx.doi.org/10.1093/gji/ggy315

[7] N.V. Sarlis, E.S. Skordas, Entropy 20 (2018) 882. dx.doi.org/10.3390/e20110882

[8] S. Pasari, Y. Sharma, Seismological Research Letters 91 (6) (2020) 3358–3369. dx.doi.org/10.1785/0220200104

[9] J. Perez-Oregon, F. Angulo-Brown, N.V. Sarlis, Entropy 22 (11) (2020) 1228. dx.doi.org/10.3390/e22111228

[10] P.K. Varotsos, J. Perez-Oregon, E.S. Skordas, N.V. Sarlis, Applied Sciences 11 (21) (2021) 10093. dx.doi.org/10.3390/app112110093

[11] G. Chouliaras, Natural Hazards and Earth System Sciences 9 (3) (2009) 905–912. dx.doi.org/10.5194/ nhess-9-905-2009

[12] G. Chouliaras, N.S. Melis, G. Drakatos, K. Makropoulos, Advances in Geosciences 36 (2013) 7–9. dx.doi.org/10.5194/adgeo-36-7-2013

[13] A. Mignan, G. Chouliaras, Seismological Research Letters 85 (3) (2014) 657–667. dx.doi.org/10.1785/0220130209

How to cite: Chouliaras, G., Skordas, E. S., and Sarlis, N.: Earthquake nowcasting: Retrospective testing in Greece 2019 - 2021, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8426, https://doi.org/10.5194/egusphere-egu22-8426, 2022.

10:27–10:34
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EGU22-11299
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ECS
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Virtual presentation
Andrea Carducci et al.

The frequency-magnitude relation of earthquakes, with particular attention to the b-value of Gutenberg-Richter law, is computed in Southern California. A three-dimensional grid is employed to sample relocated focal mechanisms and determine both the magnitude of completeness and the b-value for each node. Sampling radius and grid size are appropriately chosen accordingly to seismogenic source dimensions. The SCEC Community Fault Model is used for comparison of the main fault systems along with the calculated 3D distributions.

The b-values are compared to Aλ, a streamlined kinematic fault quantification, which does not use inversion processes since directly depends on individual rakes of focal mechanisms. Potential relationships between the two quantities are then computed through multiple regressions at increasing depth ranges: they may help to evaluate seismic hazard assessment in relating the frequency and size of earthquakes to kinematic features. The rheological transition from elastic to plastic conditions is computed, assuming different physical constraints, and its influence on b-value and Aλ is also analyzed. Among proposed linear, polynomial, and harmonic equations, the linear model is statistically valued as the most probable one to relate the two parameters at different depth ranges. b-values against Aλ results are implemented into a 3D figure, where point data are interpolated by “Lowess Smoothing” surfaces to visually check the constancy depending on depth.

How to cite: Carducci, A., Petruccelli, A., De Santis, A., de Nardis, R., and Lavecchia, G.: b-value and kinematic parameters from 3D focal mechanisms distributions in Southern California, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11299, https://doi.org/10.5194/egusphere-egu22-11299, 2022.

10:34–10:41
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EGU22-4417
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Virtual presentation
Iren Adelina Moldovan et al.

Diurnal geomagnetic variations are generated in the magnetosphere and last for about 24 hours. These can be seen on the recordings of all magnetic observatories, with amplitudes of several tens of nT, on all magnetic components. The shape and amplitude of diurnal variations strongly depend on the geographical latitude of the observatory. In addition to the dominant external source from the interaction with the magnetosphere, the diurnal geomagnetic variation is also influenced by local phenomena, mainly due to internal electric fields. External influence remains unchanged over distances of hundreds of kilometers, while internal influence may differ over very short distances due to the underground conductivity. The ration of the diurnal geomagnetic variation at two stations should be stable in calm periods and could be destroyed by the phenomena that can occur during the preparation of an earthquake, when at the station inside the seismogenic zone, the underground conductivity would change or additional currents would appear. The cracking process inside the lithosphere before and during earthquakes occurrence, possibly modifies the under- ground electrical structure and emits electro-magnetic waves.

In this paper, we study how the diurnal geomagnetic field variations are related to Mw>4.9 earthquakes occurred in Vrancea, Romania. For this purpose, we use two magnetometers situated at 150 km away from each other, one, the Muntele Rosu (MLR) observatory of NIEP, inside the Vrancea seismic zone and the other, the Surlari (SUA) observatory of IGR and INERMAGNET, outside the preparation area of moderate earthquakes. We have studied the daily ranges of the magnetic diurnal variation, R=DBMLR/DBSUA, during the last 10 years, to identify behavior patterns associated with external or internal conditions, where DB= Bmax-Bmin, during a 24 hours period.

As a first conclusion, we can mention the fact that the only visible disturbances appear before some earthquakes in Vrancea with Mw> 5.5, when we see a differentiation of the two recordings due to possible local internal phenomena at MLR. The differentiation consists in the decrease of the value of the vertical component Bzmax-Bzmin at MLR compared to the USA a few days before the earthquake and the return to the initial value after the earthquake. These studies need to be continued in order to determine if it is a repetitive behavior, or if it is just an isolated phenomenon.

Acknowledgments:

The research was supported by: the NUCLEU program (MULTIRISC) of the Romanian Ministry of Research and Innovation through the projects PN19080102 and by the Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI) through the projects PN-III-P2-2.1-PED-2019-1693, 480 PED/2020 (PHENOMENAL) and PN-III-P4-ID-PCE- 2020-1361, 119 PCE/2021 (AFROS).

How to cite: Moldovan, I. A., Toader, V. E., Carnini, M., Petrescu, L., Placinta, A. O., and Enescu, B. D.: The study of the geomagnetic diurnal variation behavior associated with Mw>4.9 Vrancea (Romania) Earthquakes, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4417, https://doi.org/10.5194/egusphere-egu22-4417, 2022.

10:41–10:48
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EGU22-7107
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Highlight
Dragos Armand Stanica

A very strong earthquake of magnitude Mw8.2 struck the coastal zone of Alaska (USA), on July 29, 2021. This earthquake was felt around the Gulf of Alaska, on a wide offshore area belonging to USA and Canada. In order to identify an anomalous geomagnetic signal before the onset of this earthquake, we retrospectively analyzed the data collected on the interval June 17 - July 31, 2021, via internet (www.intermagnet.org), at the two geomagnetic observatories, College (CMO) - Alaska and Newport (NEW)-USA, by using the polarization parameter (BPOL) and the strain effect–related to geomagnetic signal identification. Thus, for the both observation sites (CMO and NEW), the daily mean distribution of the BPOL and its standard deviation (STDEV) are carried out using an FFT band-pass filtering in the ULF range (0.001-0.0083Hz). Further on, a statistical analysis based on a standardized random variable equation was applied to emphasize the following: a) the anomalous signature related to Mw8.2 earthquake on the both time series BPOL*(CMO) and BPOL*(NEW); b) the differentiation of the transient local anomalies associated with Mw8.2 earthquake from the internal and external parts of the geomagnetic field, taking the NEW observatory as reference. Consequently, on the BPOL*(NEW-CMO) time series, carried out on the interval 07-31 July, 2021, a very clear anomaly of maximum, greater than 1.2 STDEV, was detected on July 22, with 7 days before the onset of Mw8.2 earthquake.

How to cite: Stanica, D. A.: ANOMALOUS GEOMAGNETIC SIGNAL EMPHASISED BEFORE THE Mw8.2 ALASKA EARTHQUAKE OCCURRED ON JULY 29, 2021, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7107, https://doi.org/10.5194/egusphere-egu22-7107, 2022.

10:48–10:55
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EGU22-2152
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Virtual presentation
Victorin - Emilian Toader et al.

The Romanian National Institute of Earth Physics (NIEP) developed a radon monitoring network mainly for Vrancea seismic are characterized by deep earthquakes (a rectangle zone in longitude/ latitude 25.050/ 46.210 - 27.950/ 44.690, 60 Km – 250 Km). Few stations were relocated after a year of operation following inconclusive results regarding the relationship between radon and seismic activity. To the 5 stations that are in the Vrancea area (Bisoca, Nehoiu, Plostina, Sahastru and Lopatari) we added others positioned in areas with surface seismicity (Panciu, Râmnicu Vâlcea, Surlari and Mangalia). The last two are on the Intramoesica fault, which will be monitored in the future along with the Fagaras - Câmpulung fault. Radon together with CO2 - CO is monitored at Râmnicu Vâlcea within the SPEIGN project near a 40 m deep borehole in which the acceleration in three directions, temperature and humidity are recorded. The same project funded the monitoring of radon, CO2 and CO in Mangalia, which is close to the Shabla seismic zone. The last significant earthquake in the Panciu area with ML = 5.7 R occurred on 22.11.2014. The area is seismically active, which justified the installation of a radon detector next to a radio receiver in the ULF band within the AFROS project. Within the same project, radon monitoring is performed at Surlari, following the activity of the Intramoesica fault. In this location we also measure CO2, CO, air temperature and humidity. The first results show a normal radon activity in Panciu. The measurements in Surlari have higher values than those in Panciu, possibly due to the forest where the sensors are located. A special case is Mangalia where the data indicate more local pollution than the effects of tectonic activity. Radon CO2 and CO values vary widely beyond normal limits. The source of these anomalies may be the local drinking water treatment plant or the nearby shipyard. We also recorded abnormal infrasound values that are monitored in the same location. Determining the source of these anomalies requires at least one more monitoring point.

The purpose of expanding radon monitoring is to analyze the possibility of implementing a seismic event forecast. This can be done in a multidisciplinary approach. For this reason, in addition to radon, determinations of CO2, CO, air ionization, magnetic field, inclinations, telluric currents, solar radiation, VLF - ULF radio waves, temperature in borehole, infrasound and acoustics are made.

This research helps organizations specializing in emergencies not only with short-term earthquake forecasts but also with information on pollution and the effects of climate change that are becoming increasingly evident lately. The methods and solutions are general and can be applied anywhere by customizing them according to the specifics of the monitored area.

The main conclusion is that only a multidisciplinary approach allows the correlation of events and ensures a reliable forecast.

How to cite: Toader, V.-E., Ionescu, C., Moldovan, I.-A., Marmureanu, A., Lingvay, I., and Ciogescu, O.: Extension of the radon monitoring network in seismic areas in Romania, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2152, https://doi.org/10.5194/egusphere-egu22-2152, 2022.

10:55–11:02
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EGU22-11511
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Highlight
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Virtual presentation
Lisa Pierotti et al.

Since late 2002, a network of six automatic monitoring stations is operating in Tuscany, Central Italy, to investigate possible geochemical precursors of earthquakes. The network is operated by the Institute of Geosciences and Earth Resources (IGG), of the National Research Council of Italy (CNR), in collaboration and with the financial support of the Government of the Tuscany Region. The areas of highest seismic risk of the region, Garfagnana, Lunigiana, Mugello, Upper Tiber Valley and Mt. Amiata, are currently investigated. The monitoring stations are equipped with multi-parametric sensors to measure temperature, pH, electric conductivity, redox potential, dissolved CO2 and CH4 concentrations in spring waters. The elaboration of long-term time series allowed for an accurate definition of the geochemical background, and for the recognition of a number of geochemical anomalies in concomitance with the most energetic seismic events occurred during the monitoring period (Pierotti et al., 2017).

In an attempt to further exploit data from the geochemical network of Tuscany in a seismic risk reduction perspective, here we present a new statistical analysis that focuses on the possible correlation between low to moderate seismic events and variations in the chemical-physical parameters detected by the monitoring network. This approach relies on the estimate of a conditional probability for the forecast of earthquakes from the correlation coefficient between seismic events and signals variations (Fidani, 2021).

Seismic events (EQ) are classified according to a magnitude threshold, Mo. We set EQ = 0, if no seismic events were observed with M < Mo, and EQ = 1, if at least a seismic event was observed with M > Mo. Chemical-physical (CP) events were defined based on their appropriate amplitudes threshold Ao, being CP = 0 if the amplitude A < Ao, and CP = 1 if A > Ao. Digital time series were elaborated from data collected over the last 10 years, where EQs were declustered and CPs detrended for external influences. The couples of events with the same time differences TEQ – TCP, between EQs and CPs, were summed in a histogram. Then, a Pearson statistical correlation coefficient corr(EQ,CP) was obtained starting from the covariance definition.

A conditional probability for EQ forecasting is estimated starting from the correlation coefficient in an attempt to use data from CP network of Tuscany in a seismic risk reduction framework. The approach consists in an evaluation of EQ probability in a defined area, given a CP detection by the station in the same area. The conditional probability P(EQCP), when a correlation between EQs and CPs exists and time difference is that evidenced by the correlation, is increased by a term proportional to the correlation coefficient as

 

with respect to the unconditioned probability P(EQ) when a CP event is detected, where P(CP) is the unconditioned probability of CP.

 

 

Fidani, C. (2021). Front. Earth Sci. 9:673105.

Pierotti, L. et al. (2017). Physics and Chemistry of the Earth, Parts A/B/C, 98, 161-172.

 

How to cite: Pierotti, L., Fidani, C., Facca, G., and Gherardi, F.: Earthquake forecasting probability by statistical correlations between low to moderate seismic events and variations in geochemical parameters , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11511, https://doi.org/10.5194/egusphere-egu22-11511, 2022.

11:02–11:09
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EGU22-7148
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ECS
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Virtual presentation
Sofia Peleli et al.

Among the different parameters, the fluctuations of Earth's thermally emitted radiation, as measured by sensors on board of satellite systems operating in the Thermal Infra-Red (TIR) spectral range and Earth's surface deformation as recorded by satellite radar interferometry, have been proposed since long time as potential earthquake precursors. Nevertheless, the spatiotemporal relationship between the two different phenomena has been ignored till now.

On September 27, 2021, a strong earthquake of magnitude M5.8 occurred in Crete, near the village of Arkalochori at 06:17:21 UTC, as the result of shallow normal faulting. The epicenter of the seismic event was located at latitude 35.15 N and longitude 25.27 E, while the focal depth was 10 km. Since the beginning of June, almost 4 months earlier, more than 400 foreshocks ranging in magnitude from M0.5 to M4.8 were recorded in the broader area while the strongest aftershock (M 5.3) occurred on September 28th at 04:48:09 UTC.

10 years of MODIS Land Surface Temperature and Emissivity Daily L3 Global 1km satellite records were incorporated to the RETIRA index computation in order to detect and map probable pre-seismic and co-seismic thermal anomalies in the area of tectonic activation. At the same time, SAR images of the Sentinel-1 Copernicus satellite in both geometries of acquisition were used to create the differential interferograms and the displacement maps according to the Interferometric Synthetic Aperture Radar (InSAR) technique. Then, the two kinds of datasets (i.e thermal anomaly maps and crustal deformation maps) were introduced into a Geographic Information System environment along with geological formations, active faults, and earthquakes’ epicenters. By overlapping all the aforementioned data, their spatiotemporal relation is explored.

How to cite: Peleli, S., Kouli, M., and Vallianatos, F.: Investigating the spatiotemporal relationship between thermal anomalies and surface deformation; The Arkalochori Earthquake sequence of September 2021, Crete, Greece., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7148, https://doi.org/10.5194/egusphere-egu22-7148, 2022.

11:09–11:16
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EGU22-9690
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ECS
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Highlight
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Virtual presentation
Valeria Satriano et al.

In the recent years, in order to evaluate the possible spatial-temporal correlation among anomalies in Earth’s thermally emitted InfraRed radiation and earthquakes occurrence, several long-term studies have been performed. Different seismically active areas around the world have been this way investigated by using TIR sensors on board geostationary (e.g. Eleftheriou et al. 2016, Genzano et al., 2020, Genzano et al., 2021, Filizzola et al., 2022) and polar (e.g. Zhang and Meng, 2019) satellites.  Since the study of Filizzola et al. (2004) the better S/N ratio achievable by the geostationary sensors (compared with the polar ones) made this kind of sensors the first choice for this kind of long-term analyses.

In this paper the lesson learnt after 20 years of satellite TIR analyses are critically analyzed in the perspective of the possible inclusion of such anomalies among the parameters usefully contributing to the construction of a multi-parametric system for a time-Dependent Assessment of Seismic Hazard.

The more recent results achieved by applying the RST (Tramutoli et al., 2005, Tramutoli 2007) approach to long-term (>10 years) TIR satellite data collected by the geostationary sensors SEVIRI (on board MSG) - over Greece (Elefteriou et al., 2016), Italy (Genzano et al, 2020) and Turkey (Filizzola et al., 2022) – and  by JAMI and IMAGER (on board MTSAT satellites) over Japan (Genzano et al., 2021) will be also presented and discussed.

References

Eleftheriou, A., C. Filizzola, N. Genzano, T. Lacava, M. Lisi, R. Paciello, N. Pergola, F. Vallianatos, and V. Tramutoli (2016), Long-Term RST Analysis of Anomalous TIR Sequences in Relation with Earthquakes Occurred in Greece in the Period 2004–2013, PAGEOPGH, 173(1), 285–303, doi:10.1007/s00024-015-1116-8.

Filizzola, C., N. Pergola, C. Pietrapertosa, V. Tramutoli (2004), Robust satellite techniques for seismically active areas moni-toring: a sensitivity analysis on September 7, 1999 Athens’s earthquake. Phys. Chem. Earth, 29, 517–527. 10.1016/j.pce.2003.11.019

Filizzola C., A. Corrado, N. Genzano, M. Lisi, N. Pergola, R. Colonna and V. Tramutoli (2022), RST Analysis of Anomalous TIR Sequences in relation with earthquakes occurred in Turkey in the period 2004–2015, Remote Sensing, (accepted).

Genzano, N., C. Filizzola, M. Lisi, N. Pergola, and V. Tramutoli (2020), Toward the development of a multi parametric system for a short-term assessment of the seismic hazard in Italy, Ann. Geophys, 63(5) doi:10.4401/ag-8227.

Genzano, N., C. Filizzola, K. Hattori, N. Pergola, and V. Tramutoli (2021), Statistical correlation analysis between thermal infrared anomalies observed from MTSATs and large earthquakes occurred in Japan (2005–2015). JGR: Solid Earth, 126, e2020JB020108, https://doi.org/10.1029/2020JB020108

Tramutoli, V. (2007), Robust Satellite Techniques (RST) for Natural and Environmental Hazards Monitoring and Mitigation: Theory and Applications, in 2007 International Workshop on the Analysis of Multi-temporal Remote Sensing Images, pp. 1–6, IEEE. doi: 10.1109/MULTITEMP.2007.4293057

Tramutoli, V., V. Cuomo, C. Filizzola, N. Pergola, C. Pietrapertosa (2005), Assessing the potential of thermal infrared satellite surveys for monitoring seismically active areas: The case of Kocaeli (İzmit) earthquake, August 17, 1999. RSE, 96, 409–426. https://doi.org/10.1016/j.rse.2005.04.006

Zhang, Y. and Meng, Q. (2019), A statistical analysis of TIR anomalies extracted by RSTs in relation to an earthquake in the Sichuan area using MODIS LST data, NHESS, 19, 535–549, https://doi.org/10.5194/nhess-19-535-2019, 2019

How to cite: Satriano, V., Colonna, R., Corrado, A., Eleftheriou, A., Filizzola, C., Genzano, N., Katsumi, H., Lisi, M., Pergola, N., Filippos, V., and Tramutoli, V.: Lesson learnt after long-term (>10 years) correlation analyses between satellite TIR anomalies and earthquakes occurrence performed over Greece, Italy, Japan and Turkey, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9690, https://doi.org/10.5194/egusphere-egu22-9690, 2022.

11:16–11:23
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EGU22-1438
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ECS
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Highlight
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Virtual presentation
Abdennasser Tachema

The interest of this research work is focused on the detection of possible pre-seismic perturbations related to medium-sized earthquakes (5≤Mw≤5.9) occurring in the upper ionized atmosphere (about 350 km above the Earth, ionospheric F2-region). For this specific purpose, we have exploited several geodetic data, derived through signal processing of dual-frequency permanent ground-based Global Positioning System (GPS)/Global Navigation Satellite Systems (GNSS) receivers, located at the Euro-Mediterranean basin.

To find out whether the ionospheric F2-layer is responsive to the energy released during the preparation periods of medium magnitude earthquakes, the Lorca seismic event (May 11th, 2011, Mw 5.1, Murcia region) was taken as an initial sample. For this shallow-focus earthquake (4 km depth), the longitude-latitude coordinates of the epicenter are 1.7114° W, 37.7175° N. As result, modeling regional ionosphere using GPS/GNSS-total electron content (TEC) measurements over the epicentral area through spherical harmonic analysis, allowing us to identify pre-earthquake ionospheric irregularities in response to the M5.1 Lorca event. After discerning the seismo-ionospheric precursors from those caused by space weather effects, via wavelet-based spectral analysis, these irregularities were identified about a week before the onset of the mainshock.

The seismo-geodetic technique adopted in this study validates our hypothesis that stimulates the existence of a strong correlation between deep lithospheric deformations and pre-seismic ionospheric anomalies due to moderate magnitudes.

Keywords: Murcia earthquake, Seismo-ionospheric precursors, Spherical harmonic analysis, Wavelet transform, GPS/GNSS-TEC, Lithospheric deformations, Regional F2-ionosphere maps.

How to cite: Tachema, A.: Could the moderate-sized earthquakes trigger pre-seismic ionospheric irregularities? Study of the 2011 Murcia earthquake in the Mediterranean region (SE-Spain)., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1438, https://doi.org/10.5194/egusphere-egu22-1438, 2022.

11:23–11:33
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EGU22-2979
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solicited
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Virtual presentation
Michael E. Contadakis et al.

This paper is one of a series of papers dealing with the investigation of  the Lower ionospheric variation on the occasion of an intense tectonic activity.In the present paper, we investigate the TEC variations during the intense seismic activity in Arkalochori of Crete on December 2021 over Europe. The Total Electron Content (TEC) data are been provided by the  Hermes GNSS Network managed by GNSS_QC, AUTH Greece, the HxGN/SmartNet-Greece of Metrica S.A, and the EUREF Network. These data were analysed using Discrete Fourier Analysis in order to investigate the TEC turbulence band content. The results of this investigation indicate that the High-Frequency limit fo of the ionospheric turbulence content, increases as aproaching the occurrence time of the earthquake, pointing to the earthquake epicenter, in accordane to our previous investigations. We conclude that the Lithosphere Atmosphere Ionosphere Coupling, LAIC, mechanism through acoustic or gravity waves could explain this phenomenology.

 

Keywords: Seismicity, Lower Ionosphere, Ionospheric Turbulence, Brownian Walk, Aegean area.

How to cite: Contadakis, M. E., Arabelos, D. N., Pikridas, C., Bitharis, S., and Scordilis, E. M.: TEC variation over Europe during the intense tectonic activity in the area of  Arkalochori of Crete on December of 2021, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2979, https://doi.org/10.5194/egusphere-egu22-2979, 2022.

11:33–11:40
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EGU22-10222
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ECS
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Virtual presentation
Roberto Colonna et al.

Near the end of the last century and the beginning of the new, different types of geophysical parameters (components of the electromagnetic field in several frequency bands, thermal anomalies, radon exhalation from the ground, ionospheric parameters and more) have been proposed as indicators of variability potentially related to the earthquakes occurrence. During the last decade, thanks to the availability of historical satellite observations which has begun to be significantly large and thanks to the exponential growth of artificial intelligence techniques, many advances have been made on the study of the seismic-related anomalies detection observed from space.

In this work, the variations in Total Electron Content (TEC) parameter are investigated as indicator of the ionospheric status potentially affected by earthquake related phenomena. In-depth and systematic analysis of multi-year historical data series plays a key role in distinguishing between anomalous TEC variations and TEC changes associated with normal ionospheric behavior or non-terrestrial forcing phenomena (mainly dominated by solar cycles and activity).

In order to detect the differences between the two types of variation, we performed an optimal setting of the methodological inputs for the detection of seismically related anomalies in ionospheric-TEC using machine learning techniques and validating the findings on multiple long-term historical series (mostly nearly 20-year). The setting was optimized using techniques capable of combining multi-year time series of TEC satellite data and multi-year time series of seismic catalogues, simulating their behaviors in tens of thousands of possible combinations and classifying them according to criteria established a priori. Input setup and validation were done by investigating possible links between TEC anomalies and earthquake occurring over Italy and Mediterranean area. We will show and comment the results of both, optimal input setting and statistical correlation analyses consequently performed, and we will discuss the potential impact of these on future developments in this field.

How to cite: Colonna, R., Filizzola, C., Genzano, N., Lisi, M., Pergola, N., and Tramutoli, V.: Optimized setup and long-term validation of anomaly detection methods for earthquake-related ionospheric-TEC (Total Electron Content) parameter over Italy and Mediterranean area, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10222, https://doi.org/10.5194/egusphere-egu22-10222, 2022.

11:40–11:47
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EGU22-10488
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On-site presentation
Yuriy Rapoport et al.

The work continues one presented by us in 2021, which included the identification of three groups of periods in the VLF amplitude variations in the waveguide Earth-Ionosphere (WGEI) according to data of Japan receivers, obtained in 2014–2017. Periods of 5–10 minutes correspond to the fundamental mode of acoustic-gravity waves (AGW) near the Brunt–Väisälä period and were firstly revealed in VLF signals. Apart from these values, periods of 2–3 hours and possibly 1 week were also detected; the weekly periodicity is caused by anthropogenic influence on the VLF data. The problem with penetration of the ULF electric field to the ionosphere is investigated both within the dynamic simulation of the Maxwell equations and within the quasi-electrostatic approach. It is demonstrated that in the case of open field lines the results of dynamic simulations differ essentially from the quasi-electrostatic approach, which is not valid there. In the case of closed field lines, the simulation results are practically the same for both approaches and correspond to the data of measurements of plasma perturbations in the ionosphere. It is shown that the diurnal cycle is most clearly visible in the variations of the VLF amplitudes. Disturbances from various phenomena also appear in the VLF data series. One of the strongest geomagnetic storms during the analyzed time range was the event of St. Patrick's Day (March 17, 2015), which is not reflected in Japanese data because this event occurred at night for East Asia. The use of information entropy in the VLF signal processing was tested with the determination of the main features of information entropy. Variations in information entropy at different stations are discussed in detail. It has been found that information entropy shows maxima near sunrise and sunset. The location of these peaks relative to the moments of sunrise and sunset changes with the seasons that is probably connected with the solar terminator passage at the heights of the VLF signal propagation. A study of 109 earthquakes during 2014-2017 did not show a clear dependence of information entropy when using the superposed epoch analysis, although a slight decrease in information entropy was observed before a part of the earthquakes. The effect of solar flares on information entropy has been established, but this issue needs further study. We have developed a model describing the penetration into the ionosphere of a nonlinear AGW packet excited by a ground source. Complex modulation of the initial AGW includes acoustic waves with closed frequencies and random phases. The model is important for the interpretation of atmosphere–ionosphere coupling along with seismoionospheric one. We are working on the application of this model to the spectrum of the VLF waves in the WGEI and unified models of the atmosphere–ionosphere coupling due to AGW and electromagnetic field excited by the same source in the lower atmosphere. This model would be important for the understanding seismogenic and tropical cyclone influence on the ionosphere.

How to cite: Rapoport, Y., Reshetnyk, V., Grytsai, A., Liashchuk, A., Fedorenko, A., Hayakawa, M., Grimalsky, V., and Petrishchevskii, S.: Results of the analysis of VLF and ULF perturbations and modeling atmosphere-ionosphere coupling, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10488, https://doi.org/10.5194/egusphere-egu22-10488, 2022.

Fri, 27 May, 13:20–14:50

Chairpersons: Iren Adelina Moldovan, Vallianatos Filippos, Katsumi Hattori

13:20–13:30
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EGU22-10371
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solicited
Yuval Reuveni et al.

The scientific use of ground and space-based remote sensing technology is inherently vital for studying different lithospheric-tropospheric-ionospheric coupling mechanisms, which are imperative for understanding geodynamic processes. Current remote sensing technologies operating at a wide range of frequencies, using either sound or electromagnetic emitted waves, have become a valuable tool for detecting and measuring signatures presumably associated with earthquake events. Over the past two decades, numerous studies have been presenting promising results related to natural hazards mitigation, especially for earthquake precursors, while other studies have been refuting them. While highly impacting for geodynamic processes the controversy around precursors that may precede earthquakes yet remains significant. Thus, predicting where and when natural hazard event such as earthquake is likely to occur in a specific region of interest still remains a key challenging task in geo-sciences related research. Recently, it has been discovered that natural hazard signatures associated with strong earthquakes appear not only in the lithosphere, but also in the troposphere and ionosphere. Both ground and space-based remote sensing techniques can be used to detect early warning signals from places where stresses build up deep in the Earth’s crust and may lead to a catastrophic earthquake. Here, we propose to implement a machine learning Support Vector Machine (SVM) technique, applied with GPS ionospheric Total Electron Content (TEC) pre-processed time series estimations, extracted from global ionospheric TEC maps, to evaluate any potential precursory caused by the earthquake and is manifested as ionospheric TEC anomaly. Each TEC time series data was geographically extracted around the earthquake epicenter and calculated by weighted average of the four closest points to evaluate any potential influence caused by the earthquake. After filtering and screening our data from any solar or geomagnetic influence at different time scales, our results indicate that with large earthquakes (> 6 [Mw]), there is a potentially high probability of gaining true negative prediction with accuracy of 85.7% as well as true positive prediction accuracy of 80%. Our suggested method has been also tested with different skill scores such as Accuracy (0.8285), precision (0.85), recall (0.8), Heidke Skill Score (0.657) and Tue Skill Statistics (0.657).

How to cite: Reuveni, Y., Asaly, S., Inbar, N., and Gottlieb, L.: Utilizing machine learning techniques along with GPS ionospheric TEC maps for potentially predicting earthquake events, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10371, https://doi.org/10.5194/egusphere-egu22-10371, 2022.

13:30–13:37
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EGU22-3138
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Virtual presentation
Angelo De Santis et al.

The M7.2 Kermadec Islands (New Zealand) large earthquake occurred on June 15, 2019 as the result of shallow reverse faulting within the Tonga-Kermadec subduction zone. This work deals with the study of the earthquake-related processes that occurred during the preparation phase of this earthquake. We focused our analyses on seismic (earthquake catalogues), atmospheric (climatological archives) and ionospheric data (from ground to space, mainly satellite) in order to disclose the possible Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). For what concern the ionospheric investigations, we analysed and compared the observations from the Global Navigation Satellite System (GNSS) receiver network and those from satellites in space. Specifically, the data from the European Space Agency (ESA) Swarm satellite constellation and from the China National Space Administration (CNSA, in partnership with Italian Space Agency, ASI) China Seismo-Electromagnetic Satellite (CSES-01) are used in this study. An interesting comparison is made with another subsequent earthquake with comparable magnitude (M7.1) that occurred in Ridgecrest, California (USA) on July 6 of the same year. Both earthquakes showed several multiparametric anomalies that occurred at almost the same times from each earthquake occurrence, evidencing a chain of processes that point to the moment of the corresponding mainshock. In both cases, it is demonstrated that a multiparametric and multilayer analysis is fundamental to better understand the LAIC in complex phenomena such as the earthquakes.

How to cite: De Santis, A., Perrone, L., Campuzano, S. A., Cianchini, G., D'Arcangelo, S., Di Mauro, D., Marchetti, D., Nardi, A., Orlando, M., Piscini, A., Sabbagh, D., and Soldani, M.: The Jun 15, 2019, M7.2 Kermadec Islands (New Zealand) earthquake as analyzed from ground to space, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3138, https://doi.org/10.5194/egusphere-egu22-3138, 2022.

13:37–13:44
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EGU22-10161
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Highlight
Mohammed Y. Boudjada et al.

We report in our study on earthquakes that occurred in Croatia and Slovenia in the period from 1 Jan. 2020 to 31 Dec. 2021. Those seismic events happened in a localized region confined between 13.46°E and 17.46°E in longitude and 45.03°N and 49.03°N in latitude. Maximum magnitudes Mw6.4 and Mw5.4 occurred, respectively, on 29 Dec. 2020, at 11:19 UT, and 22 March 2020, at 05:24 UT. We use two-radio system, INFREP (Biagi et al., 2019) and UltraMSK (Schwingenschuh et al., 2011) to investigate the reception conditions of LF-VLF transmitter signals. The selected earthquakes occurred at distances less than 300km from the Graz station (47.03°N, 15.46°E) in Austria. First, we emphasize on the time evolutions of earthquakes that occurred along a same meridian, i.e. at a geographical longitude of 16°E. Second, we study the daily VLF-LF transmitter signals that exhibit a minimum around local sunrises and sunsets. This daily variations are specifically considered two/three weeks before the occurrence of the two intense events with magnitudes Mw6.4 and Mw5.4. We discuss the unusual terminator time motions of VLF-LF signals linked to earthquakes occurrences, and their appearances at sunrise- or sunset-times. Such observational features are interpreted as disturbances of the transmitter signal propagations in the ionospheric D- and E-layers above the earthquakes preparation zone (Hayakawa, 2015).

 

References:

Biagi et al., The INFREP Network: Present Situation and Recent Results, Open J. Earth. Research, 8, 2019.

Hayakawa, Earthquake Prediction with Radio Techniques, John Wiley and Sons, Singapore, 2015.

Schwingenschuh et al., The Graz seismo-electromagnetic VLF facility, Nat. Hazards Earth Syst. Sci., 11, 2011

How to cite: Boudjada, M. Y., Biagi, P. F., Eichelberger, H. U., Galopeau, P. H. M., Schwingenschuh, K., Solovieva, M., Lammer, H., Voller, W., and Hayakawa, M.: Analysis of VLF and LF signal fluctuations recorded by Graz facility prior to earthquakes occurrences, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10161, https://doi.org/10.5194/egusphere-egu22-10161, 2022.

13:44–13:51
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EGU22-8420
Hans U. Eichelberger et al.

In this study we investigate electric field perturbations from sub-ionospheric VLF/LF paths which cross seismic and volcanic active areas. We use waveguide cavity radio links from the transmitters TBB (26.70 kHz, Bafa, Turkey) and ITS (45.90 kHz, Niscemi, Sicily, Italy) to the seismo-electromagnetic receiver facility GRZ (Graz, Austria). The continuous real-time amplitude and phase measurements have a temporal resolution of 1 sec, events are analyzed for the period 2020-2021. Of high interest in this time span are paroxysms of the stratovolcano Mt. Etna, Sicily, Italy. We show electric field amplitude variations which could be related to atmospheric waves, occurred at the active crater and propagated up to the lower ionosphere. This corresponds to vertical coupling processes from the ground to the E-region, the upper waveguide boundary during night-time. Ionospheric variations possibly related to earthquakes are discussed for events along the TBB-GRZ path, assumed is an area given by the so-called effective precursor manifestation zone [1,2]. The findings indicate statistical relations between electric field amplitude variations of the ITS-GRZ path in the VLF/LF sub-ionospheric waveguide and high volcanic activity of Etna. For earthquakes multi-parametric observations shall be taken into account to diagnose physical processes related to the events. In summary, VLF/LF investigations in a network together with automated data processing can be an essential component of natural hazards characterization.

References:

[1] Dobrovolsky, I.P., Zubkov, S.I., and Miachkin, V.I., Estimation of the size of earthquake preparation zones, PAGEOPH 117, 1025–1044, 1979. https://doi.org/10.1007/BF00876083

[2] Bowman, D.D., Ouillon, G., Sammis, C.G., Sornette, A., and Sornette, D., An observational test of the critical earthquake concept, JGR Solid Earth, 103, B10, 24359-24372, 1998. https://doi.org/10.1029/98JB00792

How to cite: Eichelberger, H. U., Schwingenschuh, K., Boudjada, M. Y., Besser, B. P., Wolbang, D., Solovieva, M., Biagi, P. F., Stachel, M., Aydogar, Ö., Schirninger, C., Muck, C., Grill, C., and Jernej, I.: Ionospheric perturbations related to seismicity and volcanic eruptions inferred from VLF/LF electric field measurements , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8420, https://doi.org/10.5194/egusphere-egu22-8420, 2022.

13:51–13:58
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EGU22-7309
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Virtual presentation
Dimitrios Z. Politis et al.

A VLF (10 – 47.5 kHz) radio receiver with call sign UWA has recently been installed at the University of West Attica in Athens (Greece) and is continuously monitoring the lower ionosphere by means of the receptions from many transmitters, in order to identify any possible pre-seismic signatures or other precursors associated with extreme geophysical and space phenomena. In this study, we examine the case of three very recent strong mainshocks with magnitude Mw ≥ 5.5 that happened in September and October of 2021 in the southeastern Mediterranean. The VLF data used in this work correspond to the recordings of one specific transmitter with the call sign “ISR” which is located in Negev (Israel). The borders of the 5th Fresnel zone of the corresponding sub-ionospheric propagation path (ISR-UWA) are close in distance with the epicenters of the two earthquakes (EQ), while the third one is located within the 5th Fresnel zone of the specific path. In this work, we computed the morlet wavelet scalogram of the nighttime amplitude signal in order to check for any embedded wave-like structures, which would indicate the existence of Atmospheric Gravity Waves (AGW) before each one of the examined EQs. In our investigation, we also checked for any other global extreme phenomena, such as geomagnetic storms and solar flares, which may have occurred close in time with the examined EQs and could have a contaminating impact on the obtained results. Our results revealed wave-like structures in the amplitude of the signal a few days before the occurrence of these three EQs.

How to cite: Politis, D. Z., Potirakis, S. M., Biswas, S., Sasmal, S., and Hayakawa, M.: Wave-like structures prior to very recent southeastern Mediterranean earthquakes as recorded by a VLF/LF radio receiver in Athens (Greece), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7309, https://doi.org/10.5194/egusphere-egu22-7309, 2022.

13:58–14:05
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EGU22-8718
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On-site presentation
Alejandro Ramírez-Rojas and Elsa Leticia Flores-Márquez

The visibility graph method has allowed to identify statistical properties of earthquake magnitude time series. So that, such statistical features in the time series have helped to classify the earthquakes sequences in different categories according with their tectonical sources related with their dynamical seismicity. The Tehuantepec Isthmus subduction zone, México, has showed different dynamical behavior before and after the M8.2 occurred on September 07, 2017. This behavior is associated with the temporal correlations observed in the magnitude sequences. With the aim to characterize these correlations we use the visibility graph method which has showed great potential to get the dynamical properties of studied system from the statistical properties in the network graph. In this study we investigate four periods: the first, between 2005 and 2012, the second (before the M8.2 EQ) from 2012 to 2017, the third from September 2017 to March 2018 corresponding to aftershocks period, and the fourth from April to December 2021, in order to find type of connectivity corresponding to each one, we have computed the distribution function P(k) of the connectivity degree k. Our results show the connectivity increases till the earthquake and decrease in the aftershocks period.

How to cite: Ramírez-Rojas, A. and Flores-Márquez, E. L.: Visibility graph analysis to identify correlations in the magnitude earthquake time series monitored in the Tehuantepec Isthmus subduction zone, México., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8718, https://doi.org/10.5194/egusphere-egu22-8718, 2022.