Journal Summary Geofizika is an diamond open-access (CC-BY-NC 4.0 license), peer-reviewed international journal Geofizika issues contributions dealing with topics concerning physics of the atmosphere, the sea and the Earth's interior The journal is published by the Andrija Mohorovičić Geophysical Institute (Department of Geophysics, Faculty of Science, University of Zagreb, Croatia) JCR (WoS) - Journal Impact Factor (2024) = 1.1 ; JIF quartile = Q3 (Geochemistry & Geophysics) Editor-in-Chief : Ivica Vilibić (Ruđer Bošković Institute, Division for Marine and Environmental Research, Zagreb, Croatia; Institute for Adriatic Crops and Karst Reclamation, Split, Croatia)
Andrija Mohorovičić Geophysical Institute, Department of Geophysics, Faculty of Science, University of Zagreb
Copyright (c) 2025 G e o f i z i k a https://creativecommons.org/licenses/by-nc/4.0
Seismic activity and gravity field interpretation for subsurface fault detection on Mount Pandan, Indonesia
Indonesia experiences intense volcanic and tectonic activity due to its strategic location between 6° N–11° S latitude and 95° E–141° E longitude, where several major tectonic plates converge. Physiographically, Mount Pandan is located in the modern Sunda Arc region within the Anticlinorium or Kendeng Zone. Previous research recorded a minor earthquake in 2016, indicating ongoing tectonic activity in the Kendeng Zone, connected to sub-magmatic activity observed in several hot springs in Banyukuning, Jari, and Selogajah. Using gravity data, we identify the relationship between tectonic and magmatic activity through 3D inversion modelling of subsurface structures. This analysis correlates with fault fracture density (FFD) for surfaces with faults or fractures. Identifying the focal mechanism is essential for constructing the fault model of the earthquake source. The movement of Earth’s crust along the Kendeng Fault influences underlying magmatic processes. Evidence of this interaction includes low-density zones and sub-magmatic features, such as the presence of hot springs. Earthquakes around the mountain with magnitudes below 4.0 SR suggest a relationship between the movement of strike-slip faults and oblique reverse faults with magma ascent. 3D inversion modelling reveals four layers: At a depth of 0–0.46 km, with an estimated density range of 1.69–2.69 g/cm³, we interpret the layer as caprock, composed of pyroxene and host rock types. The layer at 0.46–1.14 km, with a density range of 1.31–2.23 g/cm³, is interpreted as a reservoir containing sand and clay rock types. Andesite and volcanic breccia rocks make up the layer at 1.14–1.59 km, with a density range of 2.4–2.8 g/cm³. It is thought to be caprock and intrusion (active fault). We interpret the layer at 1.59–2.43 km, with a density range of 1.43–3.45 g/cm³, as a heat source with basalt rock types and magma content. These findings provide new insights into the subsurface structure and fault dynamics of the Kendeng Zone, contributing to a better understanding of tectono-magmatic interactions in seismically active regions.
The Baranja earthquakes of 1922 and 1924
In regions of low seismicity, such as Baranja in northeastern Croatia, seismic hazard assessments rely heavily on the detailed characterization of the few largest known earthquakes. This study focuses on the two strongest historical earthquakes in the area, which occurred on 24 November 1922 and 12 August 1924. We re-evaluated these events using newly collected macroseismic data from Bosnia and Herzegovina, Croatia, Hungary, and Serbia, expanding the number of intensity observations from 106 to 278 for the earthquake of 1922, whereas the previously macroseismically not analysed event of 1924 is decribed by 14 data points. Using a modified Kövesligethy–Jánosi model that accounts for intensity anisotropy in the epicentral area, we inverted the macroseismic fields to relocate the epicentres and estimate focal depths and magnitudes. Both events were relocated near the village of Zmajevac, within the Bansko Brdo tectonic unit, close to its boundary with the Drava depression. The 1922 epicentre moved 13 km north-northeast of the original location in the Croatian Earthquake Catalogue (CEC), while the 1924 epicentre shifted 22 km westward. Revised moment magnitudes are Mw 5.3 and Mw 4.4 for the 1922 and 1924 events, respectively. Estimated focal depths are shallower than previously listed: 11 km and 8 km, compared to the 18 km and 14 km in CEC. These results indicate that significant seismicity in Baranja is confined to the Bansko Brdo unit, with no evidence of strong earthquakes or faults with sufficient seismogenic potential in the Drava Depression or Northern Baranja–Bačka units. This has important implications for regional seismic hazard estimates. Furthermore, we find no instrumental support for the largest catalogued aftershock of the 1922 event and propose its removal. Finally, we interpret the 1924 earthquake as a late aftershock of the 1922 mainshock, suggesting a dependent relationship between the two.
Statistical analysis of magnetic susceptibility variations in the flotation tailing of the Rudnik Mine, Republic of Serbia
Mine tailings are increasingly recognized as potential valuable mineral resources. This study applies magnetic susceptibility analysis to three boreholes in flotation tailings from dumps at the Pb-Zn Rudnik Mine, Serbia. The samples were obtained over a small spatial distance (10 cm), allowing for the application of various statistical methods with the obtained dataset. The results indicate that the mutual similarity among boreholes cannot be established with statistical significance; however, certain zones between boreholes exhibit some similarities. These variations are attributed to anthropogenic deposition, where local materials were intermixed and arbitrarily deposited during mining and processing, preventing clear statistical correlations. The study identifies key zones of interest in all three boreholes for further geochemical and mineralogical investigations.
Study on the response characteristics of source parameters for strong mining tremors
Mine tremors are a significant factor contributing to safety accidents in mining areas, and studying the characteristics of the rupture process at the source of mine tremor is crucial for improving the understanding of the disaster mechanism caused by mine tremors.This paper conducts an in-depth analysis and study of 69 strong mine tremor in Shandong mining areas in China using a combination of numerical simulation and theoretical analysis.Firstly, the waveform recording of strong mine tremors is processed using Fast Fourier Transform (FFT). Subsequently, the noise term, instrument response, path effect, and site response of the monitoring station are eliminated from the waveform recording.Finally, based on the Brune source model, a genetic algorithm is utilized to fit and obtain the source parameters, the response characteristics of source parameters for strong mining tremors are analyzed, and the scale of focal rupture as well as the characteristics of regional stress release are revealed.The results showed that the calculated corner frequencies, seismic moments, moment magnitudes, and stress drops of these strong mining tremors were in the ranges of 0.9-3 Hz, 10¹³-10¹⁵ N·m, 2.7-3.7, and 0.009-0.065 MPa, respectively. The results showed that the mine tremors exhibited cross-correlation relationships between the source parameters similar to those of earthquakes.. This demonstrates that various source parameters of mine tremors have the same physical significance as those of earthquakes in representing the scale of focal rupture and magnitude of regional stress.However, the stress drops of strong mining tremors were orders of magnitude lower than those of earthquakes, indicating that the background stresses of the mining tremors were far smaller than those of earthquakes. This signifies that even relatively small changes in regional stress can potentially trigger the occurrence of mining tremors, we need to pay close attention to factors that can cause regional stress changes during the resource extraction process in mining areas. Meanwhile, compared to earthquake of the same magnitude, mine tremors exhibit a larger rupture scale of the focal body, which may also be one of the reasons why the surface ground motion is often more intense than those caused by earthquakes of the same size. This provides theoretical support for the monitoring and assessment of the risk associated with strong mine tremors.
Geological structural mapping using aeromagnetic data to predict zones of rare earth minerals potential
The application of aeromagnetic anomalies to rare earth mineral (lepidolite) exploration in Ijero-Aramoko pegmatite field Southwestern Nigeria, has been carried out with a view to determining the locations and depth to the lineaments hosting the pegmatite bodies. The methodology adopted involved Euler deconvolution technique applied to the 2-D profile and gridded potential field data to obtain estimates of locations and depths of causative bodies. The data was upward continued to a height of 12 km and the regionals was subtracted to yield the residual aeromagnetic map with enhanced shallow magnetic sources (structures) and anomalies of intrests. The 2-D geomagnetic sections developed along two section lines across the study area delineated suspected fault/fracture zones that area characterized by low magnetic succesptibilty. Euler deconvolution methods was applied to the data with SI values 0.5, 1 and 2. Euler solution for structural indices and the power spectral analysis gave depth values which ranged from < 10 – 50 m for shallow sources, 50 – 250 m for intermediate magnetic sources and 250 – 770 m for deeper sources. The Euler solution for structural indices of 0.5 and 1.0 gives the best solutions. The results of this study showed that pegmatite rich rare earth mineralisation occurs as a magnetic source which exhibited low magnetic intensity at relatively shallow depth. The existence of mining sites close to the lineaments further confirms the evidence of mineralisation of some the geologic structures delineated in the study area.
Characteristics of the 2025 Santorini-Amorgos seismic swarm
This study investigates the spatiotemporal evolution and scaling characteristics of the 2025 seismic swarm in the Santorini–Amorgos region, one of the most seismically and volcanically active zones in the Aegean arc. Using a high-resolution earthquake catalog including 1,601 events (ML ≥ 2.9), we analyze variations in key statistical parameters—including b-value, fractal dimension (Dc), scaling exponent (αb), and the q-parameter—within cumulative time windows. Our findings reveal a marked decrease in b-value and simultaneous increase in Dc during the swarm’s activation phase, consistent with an inverse energy cascade and progressive rupture. The spatial extent of the seismic swarm (L) contracts significantly before expanding during the decay phase, and vertical migration of the seismic barycenter suggests a fluid-triggered nucleation process. 3D visualizations confirm fault-aligned clustering and upward migration patterns, supporting a hybrid rupture mechanism governed by both tectonic faulting and fluid diffusion. These results provide critical insights into the complex dynamics of swarms in extensional volcanic environments and highlight the relevance of fractal and scaling analysis for short-term seismic hazard assessment.
Microearthquake identification and seismicity analysis of the M4.7 Feidong earthquake sequence in Anhui
On September 18, 2024, an M4.7 earthquake struck Feidong County in Hefei, Anhui Province. Located at the complex junction of the Tanlu fault zone, this event exhibited a clear foreshock–mainshock–aftershock evolution, attracting widespread attention. To investigate the aftershock activity and seismogenic structure of this earthquake sequence, this study employs deep learning methods applied to continuous waveform data from the Anhui seismic network for automatic detection. Coupled with precise earthquake relocation, a comprehensive and high-precision seismic catalog was constructed. The relocation results indicate that the Earthquake sequence are mainly distributed along a linear trend in the NE–SW direction, extending approximately 12 km, with hypocentral depths concentrated between 8 and 13 km. Notably, both the mainshock and most aftershocks occur at a depth of about 10.5 km. Focal mechanism solutions reveal that the dominant earthquakes in the region exhibit right-lateral strike-slip rupture on steeply dipping faults trending NE, which is highly consistent with the orientation and structural characteristics of the primary Zhuding–Shimenshan fault in the area. In conjunction with observational evidence of fluid intrusion, it is inferred that fluids may have migrated from the southwest into the seismogenic zone through structural pathways such as the Zhuding–Shimenshan fault and accumulated within a depth range of approximately 10 km near the fault. This fluid accumulation likely induced local stress concentration, which may be the primary trigger for the Feidong earthquake sequence.
Meteorological data-driven approach for soil passability modeling in GIS using machine learning
Vehicle mobility across different terrains depends on a multitude of geographical and meteorological variables. Traditional approaches rely on labor-intensive manual field measurements to assess soil conditions for military or humanitarian vehicle passage. In this study, we aimed to explore novel methods for parameterizing the Cone Index, a fundamental metric for assessing passage feasibility, leveraging meteorological data from the global numerical model GFS. Focusing specifically on chernosols, primarily agricultural soils found in flat, open regions conducive to military operations, we utilized machine learning methods to assess how soil conditions affect vehicle mobility. Through rigorous exploratory analysis, we investigated correlations, model performance metrics, and the relative importance of predictors in Cone Index modeling. Our findings highlight the comparative efficacy of different modeling approaches, particularly emphasizing the utility of the Random Forest method. We identified key environmental conditions under which the model reliably predicts the Cone Index. This sets the baseline for spatial modelling in GIS. Despite these insights, our study is constrained by data limitations and the inherent resolution constraints of the GFS model. The obtained solution lays the initial groundwork for implementing the model in a GIS environment to predict the trafficability of chernosols across the broader European region. Future research will aim to expand the dataset, spatial relationships, and employ models with higher resolution for more robust and accurate predictions.
Research on applying deep learning technology to classify earthquakes and blasting events using a Lightweight Convolutional Neural Network
This paper proposes a lightweight convolutional neural network model to identify the types of natural earthquake and blasting events quickly and accurately. Since an event is generally recorded by several stations, it is necessary to preprocess and classify the data based on the event beforehand. This ensures that different station waveforms of the same event do not appear in any two of the training sets, validation sets, and test sets. With the three-component waveforms recorded by stations after preprocessing as the input, the network model and hyperparameters are optimized by analyzing the average and variance in the accuracy and loss values of the verification set in the fivefold cross-validation, and the accuracy and loss curves in the training process. Finally, the classification results of all stations that achieve a certain signal-to-noise ratio for each event are taken as the output of this event type based on the principle that the majority prevails over the minority. This study uses 2,190 natural and blasting events recorded by the Hainan Seismic Network before August 2022, which includes 53,067 waveforms, to train and test the effectiveness of the model. Twenty percent of those events are selected randomly as the test set. The results showed that out of 438 randomly selected events, 427 were correctly identified, resulting in an accuracy rate of 97.48%. Specifically, the accuracy rate for seismic events was 95.59%, with a recall rate of 89.04%, while the accuracy rate for blasting events was 97.84%, with a recall rate of 99.18%. In conclusion, the convolutional neural network model proposed in this paper can rapidly and accurately identify natural and blasting types in Hainan.
deep learning; classification; earthquake; blasting; CNN-convolutional neural network
Copyright (c) 2025 Geofizika Journal https://creativecommons.org/licenses/by-nc/4.0/
Using empirical methods, GIS and bathymetric survey for assessing the siltation of Sidi-Yacoub Dam (northwestern Algeria)
The silting of dams is a critical issue that requires immediate solutions through a participatory approach involving diverse territorial stakeholders. This approach aims to mitigate sediment inputs and preserve the intrinsic qualities of water resources within dams. In this context, the present study evaluates the siltation rate of the Sidi-Yacoub Dam, located in the Oued El Ardjem watershed, and identifies the primary causes contributing to this phenomenon. The methodology employed combines the analysis of thematic maps with the application of the sedimentation prediction model Previsioni Interimento Serbatoi Artificiali (PISA) to calculate various parameters. The annual average of solid inputs reaching the reservoir is estimated at 376.74 m³/km²/year, corresponding to an overall siltation rate of 0.46 Mm³/year. The preservation of this hydraulic infrastructure is critical to optimizing water resource utilization in the region and supporting its economic and social development. This study underscores the importance of integrating empirical methods, Geographic Information Systems, and bathymetric surveys to achieve a comprehensive understanding of siltation dynamics. The findings indicate that the dam experienced a significant loss of approximately 32.22 Hm³ of capacity between 1985 and 2004, representing an 11.6% reduction in its initial storage volume. These results highlight the urgent need for effective sediment management strategies to ensure the long-term sustainability of water resources in Algeria and other regions confronting similar challenges.
In memoriam: Dragutin Skoko, F.C.A. (24 July 1930 – 6 September 2024)
Utilizing Remote Sensing for Monitoring Land Cover Changes and Land Surface Temperature Fluctuations
Land cover change detection supports many kinds of environmental and human development initiatives in both developed and developing countries over the past twenty-three years, Laos has experienced massive changes in land use resulting in corresponding increases in surface temperature. These changes have been little studied or evaluated empirically. To address this gap, this research study focused on tracking land cover change detection (LCCD) and Land surface temperature (LST) change in the study area of Thakhet Laos. Landsat 5, 8, and Modis datasets were used to analyze the relationship between land use and LST from 2000 to 2023. According to the LCCD results, the forest area decreased from 46,912 km² in 2000 to 33,955 km² in 2023, likely due to human activities and urban transition, while bare land increased and agricultural land decreased. In 2000 the LST values in the study area varied widely. The lowest recorded value is 24°C while the highest is 33°C. In 2023, the LST values ranged from 20°C to 41°C, this indicates an increase in temperatures compared to the previous years overall. The observed increase in urban areas, such as population movement, economic development, industrialization, and urban job creation could be a factor driving the LCCD and LST change.
Human thermal load on foggy and cloudless mornings in the cold season
We investigated the human thermal load in Martonvásár (Hungarian lowland, Carpathian region) in anticyclonic weather conditions in the morning, when a) the sky was completely clear and on the other hand, when b) there was fog. A customizable clothing thermal resistance-operative temperature model was used. The body mass index and the basal metabolic flux density values of the person in the simulations were 25 kgm-2 and 40 Wm-2, respectively. During the observations, weather data was provided by the automatic station of the HungaroMet company and it was accessible on the company's website. We had 77 observations in foggy weather, while we had 46 observations under clear sky conditions in the period between 2019–2023. The following main results should be highlighted: 1) clothing thermal resistance (rcl) varied between 0.5-2.5 clo in the case of fog, while in clear-sky cases rcl was between 0.9-3.5 clo. 2) Based on our data analysis, we estimated that the warming effect of the morning fog was around 0.8 clo. 3) We also showed that the effect of inter-personal variability on rcl was significant when the heat deficit was high (rcl ≥ 2.5 clo) and at this time it was comparable with the degree of the warming effect of fog. It should be mentioned that the analysis of typical weather situations from the point of view of human thermal load is a new field of research, since there is little information available on this subject.
A brief analysis of the supercell storm in Croatia on 19 July 2023
Supercell storms, or super-Cb, are powerful and long-lasting convective systems that can form within statically unstable air mass in favourable dynamic conditions. These severe storm types are characterized by one or more rotation updrafts, usually supported by environmental vertical wind shear. Severity of these systems is usually reflected in heavy precipitation, large hail, hurricane wind gusts and sometimes derecho or tornado events. During July 19th, 2023, super-Cb event hit Croatia, including the capital city, Zagreb. It originated in the western Po River valley, Italy, progressed over Slovenia, Croatia, and finally dissipated over Serbia. Its track crossed about 700 km long path and lasted approximately 9 h, leading to human casualties and heavy property damages. The synoptic and mesoscale conditions leading to the formation of the super-Cb is analysed and discussed. Regular official station data, synoptic charts, upper air soundings, radar, and satellite observations are deployed as well as WRF model simulation performed for this case scenario. This study contributes to better understanding of such phenomena and their destructive potential in the broader region of Croatia and adds to somewhat scarce research field of such weather in this part of the world.
Croatian catalogue and database of focal mechanism solutions, characteristic mechanisms, and stress field properties in the Dinarides and the surrounding regions
This report presents the CroFMS catalogue and database of focal mechanism solutions (FMS). It is based on the first-motion polarity data for earthquakes in Croatia and the neighbouring regions, collected over last four decades. The current catalogue version contains FMS for 410 earthquakes that were computed consistently, using the same programs, velocity models, and sets of parameters. Its content is described in terms of distributions of the time and origin of polarity picks, magnitudes, epicentral distances of stations, the quality marks, the phases used, azimuthal gap and distance to the closest station. It was also shown that solutions from the CroFMS catalogue and those independently obtained from the moment tensor inversions are generally consistent. Comparison of observed FMS with the latest European model of active fault sources (EFSM20) revealed several inconsistencies, most notably in the Zagreb and Petrinja epicentral areas, the greater Rijeka region, the Central Adriatic archipelago, and in the zone of surface traces of the thrust fronts of the East-Bosnian–Durmitor and Drina–Ivanjica nappes in Bosnia and Herzegovina. Spatial averaging of FMS over the whole study area produced maps of characteristic focal mechanisms, which may be found useful in the seismic hazard assessment in the areas where active faults are not identified or characterised. A formal stress inversion of the focal mechanism solutions produced a map of maximum horizontal stress orientations across the study area, revealing localized lateral variations that had not been identified in previous studies. Electronic supplement: Three FMS catalogues in the form of Excel-files are available for free download: The CroFMS catalogue ­– file: CroFMS_2024.xlsx The catalogue of characteristic focal mechanisms based on first-motion polarity solutions only – file: Characteristic_FMP_2024.xlsx The catalogue of characteristic focal mechanisms based on the first-motion polarity solutions and the best double-couple solutions by the moment inversion – file: Characteristic_FMP_MTI_2024.xlsx The first row is the header: N – Serial number of FMS; Year; Month; Day; Hour; Minute; Second; Lat. – latitude °N; Lon. – longitude °E: Depth – in km; M­ – magnitude ML; NP1str – strike of nodal plane 1; NP1dip – dip of nodal plane 1; NP1rake – rake of nodal plane 1; NP2str – strike of nodal plane 2; NP2dip – dip of nodal plane 2; NP2rake – rake of nodal plane 2; Pst – strike of the P-axes; Pdip – dip (plunge) of the P-axes; Tst – strike of the T-axes; Tdip – dip (plunge) of the T-axes; Qual – Quality of solution (1–5). None of the two nodal planes is the preferred one. The catalogues are up to date until 30 June 2024.
Spatial variation of the source mechanisms in the Egyptian continental margin
The spatial variability of the focal mechanism solutions in the NW Egypt Cyrenaica and Levant-north Egypt domains of the Egyptian Continental margin is investigated based on the polarity of the P-wave first motions of eleven earthquakes with local magnitudes ML ranging from 4.2 to 6.2. The identified focal mechanism solutions in the Levant-north Egypt domain are evaluated in two sub-provinces with different geological settings. The first sub-province shows strike-slip faulting mechanisms with right-lateral motion along the NE-trending Rosetta-Qattara fault zone, while the NW-trending Temsah fault zone produces left-lateral strike-slip motion. The inland extension of the Rosetta-Qattara fault zone towards the Western Desert reflects the same sense of motion. Strike-slip faulting with thrust components dominates the focal mechanisms in the second sub-province but with a different stress orientation. A single thrust faulting mechanism event which occurred on the periphery of the continental shelf shows the same common orientation of the stress field at the Hellenic Arc. This type of mechanism in this locality can be explained by the mean of compressional stress transfer towards the coast generated by the accelerated southwest retreat of the Hellenic Trench. The complex regional stress along the Cyprian and Hellenic arcs, the current local structure features, and the dominant orientation of the pre-existing fault are the factors that contribute to the changeable stress pattern field in the Levant-north Egypt domain. A single event in the second domain, the NW Egypt Cyrenaica, is a strike-slip with a right-lateral sense of motion on a WNW-oriented plane, consistent with motion along the WNW tectonic fault which separates the continental shelf from the oceanic crust.
Copyright (c) 2024 Geofizika Journal https://creativecommons.org/licenses/by-nc/4.0/
Results of the magnetometer inter-comparisons during the 2nd Cycle of Geomagnetic Information Renewal in the Republic of Croatia
Between 2017 and 2021, the 2nd Geomagnetic Information Renewal Cycle was carried out on the Croatian Geomagnetic Repeat Stations Network (CGRSN). On several occasions, before and after the survey at CGRSN, the magnetometers used in the survey were tested at the Lonjsko Polje Geomagnetic Observatory (LON). This paper presents the methods and results of these tests. The results verified the correctness of the used magnetometers and confirmed that their absolute accuracy is within the targeted measurement accuracy at the secular point. Despite the favourable results, a detail analysis revealed the presence of a small magnetic offset. This offset was introduced during the comparison process and did not affect the CGRSN measurements results in any way. In this paper, we share our experience which could be instructive for other observers performing similar work. Further testing is needed to determine the exact direction and magnitude of this systematic offset.
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Drought monitoring in Croatia using the standardized precipitation-evapotranspiration index
Several periods of drought in the 21st century have severely affected large parts of Europe and caused considerable economic losses, particularly in the agricultural and energy sectors. While rainfall deficits are one of the main causes of droughts, high temperatures in the summer months exacerbate their development, which can have devastating consequences. This was the case in 2022, when long dry spells were accompanied by several heat waves. In this study, climatological drought monitoring using the Standardized Precipitation Evapotranspiration Index (SPEI) is analyzed with the primary goal of finding the best theoretical distribution for adjusting the water balance (defined as the difference between precipitation and potential evapotranspiration) in Croatia before the index is officially introduced into the operational drought monitoring. Although the SPEI is widely used for drought monitoring, the underlying theoretical distribution of the water balance may differ between regions. The study is based on monthly precipitation amounts and monthly mean values of daily minimum and maximum temperatures observed at 31 main meteorological stations for the period 1961–2022. The analysis is carried out for different time scales, ranging from 1 to 24 months. Among the five distributions considered, a generalized logistic distribution with three parameters (GLO) proves to be the most appropriate. There is general agreement between SPEI and SPI time series, both in terms of sign and intensity. However, in periods with a light to moderate lack of precipitation and high air temperatures, a tendency towards higher drought intensity prevails in the SPEI. A comparative analysis of the 2022 drought in Croatia confirmed the ability of the SPEI to detect a drought earlier than the SPI, which also suggests that a larger area of the country was affected by the drought due to consistent air temperature excesses.
Quo vadis scientia? The tales of recent Croatian publications in geodesy and geophysics
Research publications are a key indicator in evaluations of both the careers of scientists and the performance of research institutions and science systems. However, unprecedented changes in publishing have been made in recent decades following the development of solutions that can be helpful in managing publications and the conjoined peer-review process. In that spirit, we performed a comparative study of research articles reported by the Croatian Committee of Geodesy and Geophysics between two 4-year periods, 2019-2022 and 2015-2018, focusing in particular on the changes in journals and publishers between these periods. Apparently, there is a dramatic change in articles between these two periods, directed toward publishers that have much shorter evaluation times, such as MDPI and Frontiers. In almost all subcategories, the percentage of articles in the MDPI increased several times, reaching approximately 65% in hydrology and physical limnology and 30% in geodesy. We argue that these changes are worsening the reliability of science, driven by the national rules that favor the ‘publish or perish’ principle over the quality of research. Furthermore, we propose a way to cope with this problem at the national level, which should include a transition toward reliable publishers and peer-review assessments implemented during research evaluations.
Croatian publications - geodesy and geophysics
Copyright (c) 2024 Geofizika Journal https://creativecommons.org/licenses/by-nc/4.0
Night sky brightness trends above Zagreb, 2012–2022
The night sky brightness at the RGN site (near the centre of Zagreb, Croatia) was monitored from January 2012 to August 2022. The first data set, covering the period 2012 to 2017, has already been analysed and the conclusions were published in Andreić (2018). The main conclusions are repeated here for comparison and completeness. The results of the analysis of the second dataset, covering the period from January 2018 to July 2022, are reported here. The first data analysis showed that the average night sky brightness did not change significantly from 2012 to 2017, excluding differences due to annual variations in meteorological parameters. The second data set (2018 to 2022) showed a slight decrease in night sky brightness compared to the first data set. The difference is small, about 0.2 mag/arcsec2 (mean values). In the second data set, there is a trend toward darker nights in later years that began three or four years ago (around 2019 or 2020). It is attributed to the modernisation of the public lighting network, where old, often very poor lighting fixtures are slowly being replaced by modern LED lighting fixtures, and to the effects of climatic changes leading to warmer winters with more clear nights.
Copyright (c) 2024 https://creativecommons.org/licenses/by-nc/4.0
Report of the Croatian Committee of Geodesy and Geophysics on activities carried out between 2019 and 2022
Content: Introduction Geodesy in Croatia, 2019–2022 Geomagnetism and aeronomy in Croatia, 2019–2022 Hydrology and physical limnology in Croatia, 2019–2022 Meteorology in Croatia, 2019–2022 Physical oceanography in Croatia, 2019–2022 Seismology in Croatia, 2019–2022
Hydrology and physical limnology - Croatia
Copyright (c) 2023 Geofizika Journal https://creativecommons.org/licenses/by-nc/4.0
Mediterranean meteotsunamis of May 2021 and June 2022: Observations, data analysis and synoptic background
Meteorological tsunamis (i.e., tsunami-like waves of atmospheric origin) are regularly observed in the Mediterranean Sea. During a single event, destructive flooding usually occurs in one location or limited area. However, in May 2021 and June 2022, strong meteotsunamis hit several Mediterranean locations up to 500 km apart. In the morning hours of the 24th of May 2021, a meteotsunami hit Bonifacio on the island of Corsica (western Mediterranean, France) and in the afternoon hours of the same day, another meteotsunami hit Široka Bay on the island of Ist (Adriatic Sea, Croatia), 500 km away. About 13 months later, on the 26th of June 2022, a meteotsunami hit Ciutadella on the island of Menorca (Spain) and two days later Bonifacio, 400 km away. Sea-level and atmospheric pressure data and satellite imagery, as well as synoptic conditions, associated with both events were analysed in detail. It has been confirmed that in the Mediterranean, meteotsunamis occur when meteotsunamigenic synoptic conditions prevail over the area, with a strong southwesterly jet stream embedded in dynamically or convectively unstable atmospheric layers standing out as the most important condition. The meteotsunamigenic potential of each of the three bays (Ciutadella, Bonifacio, Široka Bay) was investigated by considering: (1) the potential for Proudman resonance on the shelves offshore of the bays, (2) the orientation of the mouth of the bay and (3) the frequency of meteotsunamigenic synoptic conditions over the area. The strongest and most frequent meteotsunamis occur at locations where the shelf characteristics (width, depth, orientation), bay mouth orientation and climatology of 500-hPa winds and atmospheric stability have characteristics that support the amplification of long-ocean waves and their propagation toward the bay mouth.
Short-term forecasting of PM10 and PM2.5 concentrations with Facebook's Prophet Model at the Belgrade-Zeleno brdo
We demonstrate the use of Facebook's Prophet (usually just called Prophet) model for short-term air quality forecasting at Belgrade-Zeleno brdo monitoring station. To address missing data, we applied minimally-altering data distribution imputation techniques. Linear interpolation proved effective for short-term gaps (1–3 hours), hourly mean method for mid-term gaps (24–26 hours), and Hermite interpolation polynomial for long-term gaps (132–148 hours). The most significant data change was a 3.4% shift in skewness. Partitioning the time series enabled a detailed quality assessment of the Prophet model, with PM2.5 predictions being more precise than PM10. Using the longest time series for forecasting yielded absolute errors of 6.5 μg/m3 for PM10 and 2.7 μg/m3 for PM2.5. Based on 173 forecasts, we anticipate Prophet model root-mean-square values under 6.26 μg/m3 and 9.99 μg/m3 for PM2.5 and PM10 in 50% of cases. The Prophet model demonstrates several advantages and yields satisfactory results. In future research, the results obtained from the Prophet model will serve as benchmark values for other models. Additionally, the Prophet model is capable of providing satisfactory air quality forecasting results and will be utilized in future research.
Expected heat load of Dubrovnik, Osijek, Rijeka, Zadar and Zagreb based on the projections of regional climate models
This paper examines the expected future heat load in five Croatian cities: Dubrovnik, Zadar, Rijeka, Zagreb, and Osijek. The heat load is estimated by temperature-related climate indices and mean, maximum and minimum daily temperatures obtained by climate simulations using two different regional climate models (DHMZ-RegCM4 and SMHI-RCA4) with a horizontal resolution of 12.5 km, forced with two global climate models (EC-EARTH and MPI-ESM-MR/LR) for two different greenhouse gas concentration scenarios (RCP4.5 and RCP8.5). By comparing these variables for the period 2041–2070 with respect to the current climate (defined as that of the period 1991–2020), a significant increase in mean, maximum and minimum temperatures was observed in all analysed combinations of regional and global climate models for all analysed cities. Although there is a difference in results depending on the combination of regional and global models, the largest increase is mainly found in the warm part of the year (April-October), with the strongest warming of Dubrovnik and Rijeka. Due to similar trends in minimum and maximum temperatures, the trend in the daily temperature range is weak. Under warmer climate conditions, the number of days with a maximum air temperature above 25 °C increases in all considered cities (especially in Dubrovnik), as does the number of days with a minimum air temperature exceeding 20 °C (especially in Rijeka and Zadar). Furthermore, a reduction in the number of days with maximum and minimum temperatures below 0 °C is projected for all cities. Nevertheless, some differences are found between coastal and inland cities caused by local factors.
Application of the Random Forest method on the observation dataset for visibility nowcasting
Accurate visibility forecasting is essential for safe aircraft operations. This study examines how various configurations of the Random Forest model can enhance visibility predictions. Preprocessing techniques are employed, including correlation analysis to identify fundamental relationships in weather observations. Time-series data is transformed into a regular Data Frame to facilitate analysis. This study proposes a classification framework for organizing visibility data and phenomena, which is then used to develop a visibility forecast using the Random Forest method. The study also presents procedures for hyperparameter tuning, feature selection, data balancing, and accuracy evaluation for this dataset. The main outcomes are the Random Forest model parameters for a three-hour visibility forecast, along with an analysis of errors in low visibility forecasts. Additionally, models for one-hour forecasts and visibility forecasting under precipitation are also examined. The resulting models demonstrate a deterministic forecast accuracy of approximately 78%, with a false alarm rate of around 6%, providing a comprehensive overview of the capabilities of the Random Forest model for visibility forecasting. As anticipated, the model demonstrated limitations in accurately simulating fast radiative cooling or abrupt decreases in visibility caused by precipitation. Specifically, in relation to precipitation, the model achieved an accuracy of 79%, yet exhibited a false alarm rate of 19%. Additionally, this method sets a foundation for enhancing prediction accuracy through the inclusion of supplementary forecast data, while its implementation on real-world datasets expands the reach of machine learning techniques to the members of the meteorological community.
Statistical analogies between earthquakes, micro-quakes in metals and avalanches in the 1D Burridge-Knopoff model
Universalities and intriguing analogies in the statistics of avalanches are revealed for three physical systems defined on largely different length and energy scales. Earthquakes induced by tectonic scale dynamics, micro-scale level quakes observed from slipping crystallographic planes in metals and a one-dimensional, room-scale spring-block type Burridge-Knopoff model is studied from similar statistical viewpoints. The validity of the Gutenberg-Richter law for the probability density of the energies dissipated in the avalanches is proven for all three systems. By analysing data for three different seismic zones and performing acoustic detection for different Zn samples under deformation, universality for the involved scaling exponent is revealed. With proper parameter choices the 1D Burridge-Knopoff model is able to reproduce the same scaling law. The recurrence times of earthquakes and micro-quakes with magnitudes above a given threshold present again similar distributions and striking quantitative similarities. However, the 1D Burridge-Knopoff model cannot account for the correlations observed in such statistics.
The role of slope inclination, doline density and water budget analysis in delineation of complex karst catchment area of Slunjčica River (Croatia)
Due to the high vulnerability of the karst aquifer to the surface contaminants, a precisely defined catchment area has the highest priority. In this study, the influence of slope inclination, the doline density analysis, and the water budget analysis in the delineation process of a complex karst catchment area is discussed. To define hydrogeological role of lithological units, cross sections of slope inclination and doline density were combined with hydrogeological cross sections, while the degree of karstification was used to describe the permeability of rock units. The verification of karst catchment delineation area was performed with water budget analysis. The methodology used for the determination of hydrogeological behavior and delineation of a complex karst catchment area (Slunjčica River basin, Croatia) is shown with the flow diagram. It has been found that the highest doline density appears in the range from 0 to 1° of the slope inclinations, and that it decreases with a higher slope degree. Although the results of this study confirm that even with the relatively small number of input data it is possible to define the karst catchment area, it must be emphasized that the doline density analysis presents an indispensable tool in the research related to the definition of karst catchment areas.