National Observatory

Abstract A better understanding of the near‐surface aquifer system of the Caxambu Water Park, located in the Minas Gerais State, Brazil, has been achieved. The study aimed to identify groundwater reservoirs and flow patterns and contribute to the hydrogeological conceptual model using a multi‐scale geophysical approach. Audiomagnetotellurics and electrical resistivity tomography methods were employed, in addition to surface and structural geology. Structural contrasts at different depths were identified, allowing the characterization of the key geometric parameters of the aquifer system. The obtained geophysical models satisfactorily mapped the resistivity of the alluvial deposits, the crystalline basement and the base of the Caxambu Hill at depths of up to 200 m. The results revealed a distinctive brecciated groundwater reservoir containing conductive mineralized water beneath the mineral water springs of the Caxambu Water Park and the adjacent hill. Furthermore, it was possible to identify a deformation domain of the Caxambu Shear Zone that transports mineral water from depths greater than 190 m to the near‐surface fractured and porous aquifers. The presence of a conductor in the alluvial sedimentary layer indicates that the porous aquifer connects with the fractured aquifer and contains mineralized water. According to previous chemical and isotopic studies in the Caxambu Water Park, the original construction method of the water fountains prevents the external contamination. These results contribute to the sustainable exploitation of the resource and provide essential information for the effective management of regional water systems, ensuring the preservation of the therapeutic characteristics of the Caxambu water.

Abstract We investigate and update observational constraints on cosmological parameters within the $$\Lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Λ</mml:mi> </mml:math> CDM and dynamical dark energy frameworks, using a new compilation of the transverse (or 2D) BAO data, measurements that provide a relatively model-independent estimate of the BAO angular scale at a given redshift. Firstly, we assess the consistency of this compilation with CMB-Planck data and recent BAO results from the DESI collaboration. After confirming minimal tension with CMB data, we perform a series of joint analyses combining CMB data with the 2D BAO compilation, as well as with several recent Type Ia supernova (SNIa) samples. In all cases, we compare the constraining power of the 2D BAO data with that of DESI DR2 data (3D BAO). Our results indicate that combining 2D BAO with CMB and SNIa data provides observational constraints that are in agreement with those obtained using DESI DR2 data. Although the precision of DESI DR2 results remains higher, as expected due to the more accurate 3D measurements, the 2D BAO compilation combined with other probes yields strong constraints. For example, in the $$\Lambda $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>Λ</mml:mi> </mml:math> CDM context, we find (CMB + 2D BAO): $$H_0 = 68.16^{+0.41}_{-0.37} \,\,\, \text {km s}^{-1}\,\text {Mpc}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>H</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>68</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mn>16</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>0.37</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.41</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace/> <mml:mspace/> <mml:mspace/> <mml:mtext>km</mml:mtext> <mml:mspace/> <mml:msup> <mml:mtext>s</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mspace/> <mml:msup> <mml:mtext>Mpc</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> and $$\Sigma m_{\nu } &lt; 0.081~\textrm{eV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Σ</mml:mi> <mml:msub> <mml:mi>m</mml:mi> <mml:mi>ν</mml:mi> </mml:msub> <mml:mo>&lt;</mml:mo> <mml:mn>0.081</mml:mn> <mml:mspace/> <mml:mtext>eV</mml:mtext> </mml:mrow> </mml:math> (95% CL). These results are consistent with analogous analyses using DESI DR2. Several other cases are investigated and discussed in the main text. Our results show that this new 2D BAO compilation is robust and delivers meaningful cosmological constraints. Parameters from 2D BAO alone agree with CMB-only results, with no significant tension. Overall, 2D and 3D BAO provide consistent and complementary information when combined with other probes.

Landslides in the Western Corinth Rift reflect a mix of long-term “set-up” conditions—such as terrain, rock type, and fault-related structure—and short-term triggers linked to transient deformation and changing rainfall patterns. To represent these interacting processes in a clear and interpretable way, we propose a two-phase, multi-scale landslide susceptibility workflow based on explainable XGBoost. At Phase 1 (watershed scale) we develop a baseline susceptibility model using a standardized set of conditioning factors. These include (i) terrain and geomorphometric variables (elevation, slope, aspect, profile curvature, plan curvature and topographic wetness index (TWI) and (ii) lithological and structural controls (lithology and hydrolithology classes, distance from river network and fault-influence proxies such as distance to faults). The model is trained using historical landslide inventories, whereas interpretability was built in through explainable AI tools, such as SHAP, allowing us to quantify both global and site-specific contributions of conditioning factors, including key interactions. The result is a set of susceptibility maps paired with readable diagnostics that explain why certain areas are critical. At Phase 2 (local refinement and activity confirmation) focuses on the Krini–Gkrekas–Pititsa sector, where observations are denser and more reliable. Here, we evaluate whether susceptibility hotspots from Phase 1 align with evidence of ongoing or emerging instability. We add dynamic indicators and independent validation using: European Ground Motion Service InSAR ground motion, SBAS historical InSAR data; GNSS trend metrics and antecedent precipitation indices from station data. The goal is not just to refine local interpretation, but to test whether predicted patterns make physical sense, by checking consistency between (a) areas predisposed by lithology and structure and (b) present-day deformation signals and rainfall forcing. The workflow aims to produce decision-ready, interpretable outputs at two complementary scales: (1) watershed-scale susceptibility that highlights where failures are more likely based on relatively stable controls, and (2) a localized assessment that strengthens confidence where susceptibility coincides with measured deformation and hydrometeorological conditions. This improves trust and usability of AI-assisted landslide hazard assessment in tectonically active landscapes.KeywordsLandslide susceptibility; XGBoost; explainable AI; SHAP; multi-scale modeling; watershed analysis; lithology; active faults; EGMS; InSAR ground motion; GNSS; antecedent precipitation index; Western Corinth Rift.

This article presents a gravity data integration and a regional geophysical overview of the geological framework in the State of Paraná, southern Brazil. For data processing, we used open-source computational tools based on Python libraries from the Fatiando a Terra Project. Data processing included determining theoretical gravity on the physical surface of the Earth, calculating the Gravity Disturbance, modeling topographic masses to obtain the complete Bouguer Disturbance, data gridding using the equivalent source method, and the application of enhancement techniques. The products obtained were compared with previous geological studies, revealing a robust correlation between our results and the main geological characteristics from literature. Some relatively high values of the Bouguer Disturbance indicate important structural features, such as the Paranapanema Block and the Ponta Grossa Arch. Additionally, enhancement techniques highlighted relevant geological structures, in both the Paraná Basin and the Proterozoic orogenic basement. Using the gravity method and open-source tools, this work aims to serve as a reference for future geophysical and geological investigations in the State of Paraná. The gravity maps of the Paraná are a valuable unified database for the scientific community and for future geophysical investigations. These data will be made available in an open repository, facilitating access and encouraging use in subsequent research and practical applications.

Abstract This book is a comparative—intergenerational and interregional—history of Asia Minor memories and identities of forced displacement that examines the multilayered relationship between contemporary attitudes and refugee past. Marking the centenary of the Asia Minor population transfer in the context of Greece’s contemporary migration crisis, the research questions that this book addresses are: how have memories of the 1922–24 forced displacement changed over time from one generation to the next? How do people with these memories and identities think about subsequent migration? Following a regional history approach and an oral history approach, this study draws upon literature from several disciplines and rests upon oral testimony. Specifically, it employs a methodology of collecting primary sources using oral testimonies (262 life history interviews) and archival evidence (five thousand oral testimonies) based on three regional case studies, namely the borderland island of Lesvos, Central Macedonia in northern Greece, and Attica. This book argues that refugee identity is a capacious and dynamic platform of ongoing understanding as well as a limited space of domination and competition. Elucidating the attitudes of refugee descendants and unfolding key patterns about the complex role of refugee memory and identity, it brings together the intersection of three interlocking elements: time (refugee generations), place (refugee locations), and subsequent migration (waves of other migrations). In short, A Century of Asia Minor Refugees in Greece sheds light on the convoluted relationship between contemporary attitudes and refugee past, providing a nuanced history of the 1922–24 memories and identities of forced displacement.

Abstract This chapter is devoted to the borderland island of Lesvos that constitutes an entry port, a transit point, and a place of settlement for significant past and contemporary migratory waves. The chapter draws upon seventy oral testimonies, in addition to family, associational, and archival evidence, and is based on the selected towns and villages. The proximity to the Asia Minor coast and the extreme and unexpected dimension of this displacement composed the uniqueness of this traumatic memory and the shaping of the islanders’ identity. The traumatic dimension of the Asia Minor displacement, the non-linear transfer of this memory, and the dynamic interplay of the various frameworks of remembrance shape strong intergenerational refugee identities in the context of Lesvos. Asia Minor refugee memory leads to completely different outcomes depending on how the subjects perceive their sense of identity, with Lesvians becoming gate-openers and building bridges with other histories of displacement.

Abstract This chapter brings together the three interlocking elements of this study: time (refugee generations), place (refugee locations), and subsequent migration (waves of other migrations), exploring the attitudes of Asia Minor descendants towards other migrants and refugees. Through the lens of comparative analysis, the question that this book addresses is: how do people with memories and identities of the 1922–24 forced displacement think about subsequent migration? Building on the richness and diversity of the oral history testimonies, as derived from the previous chapters, this chapter sheds light on the complex, nuanced, and multidirectional attitudes of people with refugee origins. In this context, the geographical and intergenerational perspectives of this research and ultimately their intersection reveal the continuities and discontinuities that characterize the Janus-faced attitudes of refugee descendants, leading to empathy, hostility, and competition.

Soil degradation driven by intensive management practices has become of increasing concern for olive cultivation, as trends for desertification and loss of arable land have emerged across the Mediterranean basin. Agroecological management practices, such as mulching made from olive tree pruning remains, have shown potential for improving soil structure, nutrient retention and biodiversity. This study aimed to enhance the understanding of how soil management influences soil properties and arthropod diversity in small-scale olive orchards in a heterogeneous landscape in south-west Greece. Soil was sampled from 11 orchards managed under one of two systems: conventional (herbicide use, tillage, mowing) and agroecological (cover cropping, mulching), encompassing a diversity of management practices. Physicochemical properties were measured alongside soil arthropod abundance and diversity, allowing for comparisons at two levels: between management systems and among practices nested within each system. When compared across broader systems, the agroecological orchards, compared to conventional orchards, had greater porosity (56.38% and 48.75%), and soil organic matter (8.99% and 6.87%), though differences in soil composition likely accounted for some of the variation. Additionally, metrics for arthropod diversity were improved under agroecological management, with 21% higher Shannon diversity and 16.8% greater evenness compared to conventional management. Ordination analysis and generalized linear models further supported these findings illustrating the relationship between agroecological management, soil health and arthropod diversity. These results support a growing body of research which illustrate the potential of agroecological management in enhancing soil health and biodiversity in olive orchards and contributing to the development of more resilient agroecosystems within the Mediterranean basin.