<p>In recent years, the field of geodetic monitoring is undergoing a profound transformation driven by the transition from GPS-only positioning to a fully multi-GNSS environment. With Galileo, BeiDou, and modernized GPS & GLONASS constellations now operational, a wealth of new signals and frequencies provides enhanced opportunities for high-precision positioning and real-time monitoring. However, these advances present challenges: the integration of heterogeneous receivers across local and campaign-based networks, the continued reliance on outdated RINEX 2 workflows, and the discontinuation of the <code>teqc</code> utility in 2019 have all disrupted well proven, long-standing GNSS pre-processing pipelines. While the <i>International GNSS Service</i> (IGS) community has smoothly adopted RINEX <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">3</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="260af46f346b63c527387f7858f175c2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gi-15-89-2026-ie00001.svg" width="20pt" height="14pt" src="gi-15-89-2026-ie00001.png"/></svg:svg></span></span> and alternative pre-processing tools, smaller research-oriented networks have often struggled to keep pace, leaving a gap between available technology and operational monitoring practices.</p>
<p>In this paper, we present two complementary tools designed to address these challenges in the context of volcanological and seismological observatories. The first, <code>rinexmod</code> (for <i>RINEX Modification</i>), is a lightweight utility for editing RINEX headers, renaming files, and enriching metadata. It replaces critical <code>teqc</code> functionalities while supporting modern RINEX <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">3</mn><mo>/</mo><mn mathvariant="normal">4</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="eb581bee290aca91043393d5ba11d8f5"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gi-15-89-2026-ie00002.svg" width="20pt" height="14pt" src="gi-15-89-2026-ie00002.png"/></svg:svg></span></span> conventions, long-file naming schemes, and direct sitelog integration. The second, <code>autorino</code> (for <i>Assisted Unloading, Treatment and Organization of RINEX Observations</i>), implements a flexible multi-step workflow for automated acquisition of raw GNSS data from heterogeneous receivers and conversion to a common standard RINEX format. By integrating official manufacturer converters, handling file splicing/splitting, and linking directly with <code>rinexmod</code>, it provides a unified pipeline capable of near real-time operation (down to 5-minute intervals). Together, these tools modernize GNSS workflows across networks that are both technically diverse and geographically remote, ensuring interoperability with IGS standards while preserving operational robustness in challenging field conditions.</p>
<p>We illustrate their deployment at the <i>Institut de physique du globe de Paris</i>’s volcanological observatories and monitoring networks in Guadeloupe, Martinique, La Réunion, and Mayotte, where they enable continuous monitoring of volcanic and tectonic processes. Beyond local applications, these tools contribute to bridging the gap between global GNSS standards and regional network realities, supporting the long-term sustainability of GNSS-based geo-hazard monitoring.</p>
Abstract Ultra-thick soft-hard (UTSH) composite coal seams, composed of alternating layers of soft and hard coal, frequently experience severe rockburst accidents during roadway excavation under shallow burial depths (< 500 m). However, research on the mechanisms underlying such rockbursts remains limited. This study simulates the failure process of surrounding rock in roadways excavated through UTSH composite coal seams under shallow depth conditions using true triaxial low axial pressure unloading tests. Through a comprehensive analysis of failure characteristics, mechanical properties, and acoustic emission (AE) parameters of soft coal, hard coal, and multi-layered soft-hard coal composite specimens (2–4 alternating layers), the mechanism of rockburst induced by excavation unloading in shallow depths UTSH composite coal seams is revealed. Results demonstrate that under low axial pressure unloading conditions, composite specimens exhibit higher crack quantities and lengths compared to the hard coal specimen, with energy accumulation ranging from 70.2 to 120.7 kJ/m3, significantly exceeding the 66.6 kJ/m3 observed in the hard coal specimen. AE parameters further confirm that composite specimens undergo more severe damage than the hard coal specimen. A three-stage failure mechanism is proposed: (1) low-stress shear failure in soft coal layers, (2) interface shear failure induced by concentrated stress, and (3) shear failure in hard coal layers caused by stress transfer. This sequential process explains rockburst occurrences in shallow depths of composite coal seams, and a mechanical criterion is established accordingly. The findings provide theoretical foundations for monitoring, early warning, and prevention of rockburst hazards in roadways excavated through UTSH composite coal seams.
Abstract The crack initiation stress (σ ci) and crack damage stress (σ cd) are two important stress thresholds for describing the progressive failure process of rocks. Accurately obtaining these two stress thresholds is crucial for analyzing the anisotropic characteristics of shale under the influence of bedding planes. The stress thresholds of rocks can be effectively obtained based on the response law of axial and circumferential strains during rock failure. Therefore, strain measurement methods have a significant impact on the stress threshold of rocks. Currently, there are mainly two methods to measure the axial strain of rock by displacement sensors, namely, axial extensometer and linear variable differential transformer (LVDT). To investigate the influence of strain measurement methods on σ ci and σ cd of shale, the stress thresholds and corresponding strain thresholds obtained by the extensometer and LVDT axial strain measurement methods were calculated based on the triaxial compression test results of Longmaxi shale under seven different bedding plane angles, and the differences in the calculation results based on the two methods were analysed. The discrete element method (DEM) was used to carry out numerical analysis, and the influence of the two measurement methods on the mechanical properties of rock was further studied. The research shows that the influence of strain measurement methods on the mechanical properties of shale is mainly reflected in deformation parameters, stress and strain thresholds and the post‒peak shape of the stress‒strain curve. For σ cd and its corresponding strain threshold, the calculation result of the extensometer is obviously smaller than that of the LVDT. In terms of σ cd, shale shows significant anisotropic characteristics.
Abstract Garhwal Himalaya is one of the most landslide-prone regions in the Himalayan Belt due to its seismo-tectonic background, geological complexity, climate, geomorphological setting and large-scale human interference. A gigantic rock avalanche happened on July 10, 2024, near Patalganga-Langsi Tunnel on the Badrinath Highway (NH-7) of the Chamoli district and disconnected the Joshimath, Badrinath, and Nanda Devi National Park for a few hours. This road corridor is a significant gateway for valued pilgrimage destinations and Indo-Tibet Border security. A detailed investigation has been done on the recent reactivated rock cum debris avalanche at the Patalganga-Langsi Tunnel site. The Artificial Neural Network (ANN) model identifies this area as a high landslide susceptible zone, and the entire Patalganga-Langsi is tectonically controlled by the Main Central Thrust (MCT) and other proximity minor thrusts. Rainfall and exposed slope conditions are the primary triggering factors behind this rock avalanche, and geologically, this slope is still vulnerable as the Factor of Safety (FoS) is near the threshold value (1.019). Subsequently, the Schmidt hammer rebound test showed poor rock strength (approximately 30 or sometimes below 30), and the rocks have numerous structural signatures, which make them more vulnerable. Results of kinematic analysis for the two studied road cut slopes (Slope 1 and 2) emphasized a tendency to wedge failure. After the geo-technical study and the hazard potential of the slide site, sustainable geo-environmental management techniques should be immediately executed to maintain the socio-economic lifeline as well as Indo-Tibetan Border security management. Geo-technical parameters of the Patalganga-Langsi site reflect that there is a very high probability of wedge-type rockfall and rock-cum-debris fall.
Abstract Metasomatized mantle xenoliths containing hydrous minerals, such as amphiboles, serpentine, and phlogopite, likely represent the potential mineralogical compositions of the metasomatized upper mantle, where low seismic velocities are commonly observed. This study presents the first experimentally determined single‐crystal elasticity model of an Fe‐free near Ca, Mg‐endmember amphibole tremolite at high pressure and/or temperature conditions (maximum pressure 7.3(1) GPa, maximum temperature 700 K) using Brillouin spectroscopy. We found that sound velocities of amphiboles strongly depend on the Fe content. We then calculated the sound velocities of 441 hydrous‐mineral‐bearing mantle xenoliths collected around the globe, and quantitatively evaluated the roles that amphiboles, phlogopite and serpentine played in producing the low velocity anomalies in the metasomatized upper mantle.
Abstract Extreme winds associated with tropical cyclones (TCs) can cause significant loss of life and economic damage globally, highlighting the need for accurate, high‐resolution modeling and forecasting for wind. However, due to their coarse horizontal resolution, most global climate and weather models suffer from chronic underprediction of TC wind speeds, limiting their use for impact analysis and energy modeling. In this study, we introduce a cascading deep learning framework designed to downscale high‐resolution TC wind fields given low‐resolution data. Our approach maps 85 TC events from ERA5 data (0.25° resolution) to high‐resolution (0.05° resolution) observations at 6‐hr intervals. The initial component is a debiasing neural network designed to model accurate wind speed observations using ERA5 data. The second component employs a generative super‐resolution strategy based on a conditional denoising diffusion probabilistic model (DDPM) to enhance the spatial resolution and to produce ensemble estimates. The model is able to accurately model intensity and produce realistic radial profiles and fine‐scale spatial structures of wind fields, with a percentage mean bias of −3.74% compared to the high‐resolution observations. Our downscaling framework enables the prediction of high‐resolution wind fields using widely available low‐resolution and intensity wind data, allowing for the modeling of past events and the assessment of future TC risks.
Geophysics. Cosmic physics, Information technology
Jinlong Liu, Shubhangi Gupta, Jonny Rutqvist
et al.
Abstract We conducted two‐dimensional numerical simulations to investigate the mechanisms underlying the strong spatiotemporal correlation observed between submarine landslides and gas hydrate dissociation due to glacial sea‐level drops. Our results suggest that potential plastic deformation or slip could occur at localized and small scales in the shallow‐water portion of the gas hydrate stability zone (GHSZ). This shallow‐water portion of the GHSZ typically lies within the area enclosed by three points: the BGHSZ–seafloor intersection, the seafloor at ∼600 m below sea level (mbsl), and the base of the GHSZ (BGHSZ) at ∼1,050 mbsl in low‐latitude regions. The deep BGHSZ (>1,050 mbsl) could not slip; therefore, the entire BGHSZ was not a complete slip surface. Glacial hydrate dissociation alone is unlikely to cause large‐scale submarine landslides. Observed deep‐water (much greater than 600 mbsl) turbidites containing geochemical evidence of glacial hydrate dissociation potentially formed from erosion or detachment in the GHSZ pinch‐out zone.
Mohammad Reza Alizadeh, Jan Adamowski, Dara Entekhabi
Abstract Land surface‐atmosphere coupling and soil moisture memory are shown to combine into a distinct temporal pattern for wildfire incidents across the western United States. We investigate the dynamic interplay of observed soil moisture, vegetation water content, and atmospheric dryness in relation to fuel loading, fire ignition and post‐fire recovery. We find that positive soil moisture anomalies around 5 months before fire ignition increase biomass growth in the subsequent months, thereby shaping fire‐prone vegetation conditions. Then, concurrent decrease in soil moisture, vegetation dehydration, and atmospheric dryness collectively contribute to the occurrence of fire ignition events. This is followed by a rapid recovery in both soil and atmospheric moisture within several weeks after the fire incidents. Our findings provide insights into understanding of wildfire ignition dynamics, supporting fire modeling and enabling improved fire predictions, early warning systems, and mitigation strategies.
Abstract Using 51 models of the AMIP and historical experiments of CMIP6, we investigate the inter‐model diversity of atmospheric and coupled models in the strength of the Indian Summer Monsoon Rainfall (ISMR)–El Niño‐Southern Oscillation (ENSO) relationship. In atmospheric models, the Walker Circulation (WC) intensity associated with the western Pacific convective activity is most responsible for the inter‐model diversity. Models with strong WC have a strong ISMR–ENSO relationship via enhancing ENSO‐induced anomalies of the WC and monsoon circulation. The secondary source is the monsoon circulation differences associated with meridional rainfall contrast over the Indian monsoon region. In coupled models, the primary (secondary) source is the ENSO amplitude (WC intensity). In observation, the decadal variation of WC can also explain the changes in the ISMR–ENSO relationship. This study provides a basis for improving the model performance and advances our understanding of the observed ISMR–ENSO relationship changes.
Mhd. Suhyb Salama, Lazaros Spaias, Kathrin Poser
et al.
It is common in estuarine waters to place fixed monitoring stations, with the advantages of easy maintenance and continuous measurements. These two features make fixed monitoring stations indispensable for understanding the optical complexity of estuarine waters and enable an improved quantification of uncertainties in satellite-derived water quality variables. However, comparing the point-scale measurements of stationary monitoring systems to time-snapshots of satellite pixels suffers from additional uncertainties related to temporal/spatial discrepancies. This research presents a method for validating satellite-derived water quality variables with the continuous measurements of a fixed monitoring station in the Ems Dollard estuary on the Dutch-German borders. The method has two steps; first, similar in-situ measurements are grouped. Second, satellite observations are upscaled to match these point measurements in time and spatial scales. The upscaling approach was based on harmonizing the probability distribution functions of satellite observations and in-situ measurements using the first and second moments. The fixed station provided a continuous record of data on suspended particulate matter (SPM) and chlorophyll-a (Chl-a) concentrations at 1 min intervals for 1 year (2016–2017). Satellite observations were provided by Sentinel-2 (MultiSpectral Instrument, S2-MSI) and Sentinel-3 (Ocean and Land Color Instrument, S3-OLCI) sensors for the same location and time of in-situ measurements. Compared to traditional validation procedures, the proposed method has improved the overall fit and produced valuable information on the ranges of goodness-of-fit measures (slope, intercept, correlation coefficient, and normalized root-mean-square deviation). The correlation coefficient between measured and derived SPM concentrations has improved from 0.16 to 0.52 for S2-MSI and 0.14 to 0.84 for S3-OLCI. For the Chl-a matchup, the improvement was from 0.26 to 0.82 and from 0.14 to 0.63 for S2-MSI and S3-OLCI, respectively. The uncertainty in the derived SPM and Chl-a concentrations was reduced by 30 and 23% for S2-SMI and by 28 and 16% for S3-OLCI. The high correlation and reduced uncertainty signify that the matchup pairs are observing the same fluctuations in the measured variable. These new goodness-of-fit measures correspond to the results of the performed sensitivity analysis, previous literature, and reflect the inherent accuracy of the applied derivation model.
Bioactive glasses were the first synthetic materials to bond to human body tissue, making them ideal for replacing and regenerating bone. Since their first development over half a century ago, many new bioactive glass compositions have been developed for medicine and dentistry. This paper looks at different design strategies employed over the years as well as aspects of glass structure relevant to optimising bioactive glass performance. Statistical compositional series allowed for getting an overview of various compositions and their properties. Since the improvement of structural analysis techniques, particularly solid-state NMR, we can directly relate several bioactive glass properties to the atomic structure, i.e. the spatial arrangement of atoms. Such detailed understanding of the impact of composition and structure on bioactive glass properties enables us to minimise the number of compositions in preclinical and clinical tests needed to confirm positive tissue responses.
Carbonatites are unusual C-rich alkaline magmas that have been reported throughout the geological record. Nevertheless, there is only one currently active carbonatite system on Earth: Oldoinyo Lengai stratovolcano in northern Tanzania (God’s mountain in Maasai culture). Present-day Lengai carbonatites are natrocarbonatites, peculiar Na-rich carbonatites that, under atmospheric conditions, alter and leach to compositions similar to the more common Ca-carbonatites within weeks, preventing any long-term geological record of such Na-rich magmas. It follows that the oldest report of natrocarbonatites at Oldoinyo Lengai dates to the 19th century. Here, by using samples from the Lengai I cone (${>}$11 ka), we show that immiscible silicate–carbonatite melts were already present at reservoir conditions at that time. Measurements of three-phase (carbonatite $+$ silicate $+$ gas) melt inclusions from Lengai I highlight that their chemical compositions were similar to those of immiscible melts recently present in the reservoir. Alkaline carbonatites in melt inclusions from both Lengai I and historical explosive eruptions are enriched in Ca relative to those historically effused at the surface and likely record higher equilibrium temperatures (${>}$1100 °C). We also report chemical maps that qualitatively document elemental partitioning between immiscible silicate–carbonatite melts. We show that at the melt inclusions’ entrapment conditions Si, Fe, K, Na, and Cl are compatible with the silicate phase when C, Ca, P, Sr, Ba, and F are compatible with the carbonate phase.
C. W. Nooitgedacht, H. J. L. van der Lubbe, M. Ziegler
et al.
Abstract Biogenic and inorganic calcium carbonates contain considerable amounts of internal water, both as free and organically associated water. The oxygen isotopic compositions (δ18O) of internal water and hosting carbonate are analyzed for various carbonates before and after heating at 175°C for 90 minutes. During heating, the δ18O values of internal water significantly increased in biogenic aragonites and speleothem calcite, whereas the δ18O carbonate values were lowered. Correspondingly, an aragonitic bivalve’s clumped‐isotope distribution (Δ47) changed during heating, increasing reconstructed paleotemperatures. In contrast, an inorganic aragonite crystal, containing a comparable amount of internal water, showed no oxygen isotope exchange, and its Δ47 values remained unaltered during heating, implying that there is a link between internal oxygen isotope exchange and Δ47 resetting. This alteration process occurred without any detectable transformation from aragonite to calcite. Our results therefore reveal a mechanism that facilitates oxygen isotope exchange between biogenic aragonite and its internal water, while simultaneously resetting the Δ47 values, without affecting mineralogy. Future studies may therefore apply coupled water‐carbonate analyses to scrutinize these kinds of diagenetic alteration processes. It appears that in biogenic aragonites, more carbonate is available for exchange reactions with the internal water reservoir than in inorganic aragonites, a feature that can be attributed to the distribution of organic‐associated water and/or high surface area fluid inclusions. This water‐aragonite exchange occurs at lower temperatures than those required for solid‐state bond reordering at the same timescale, and thus likely has occurred earlier during the burial of biogenic aragonites.
The study presents analysis of microclimatic conditions on Galindez Island (western part of the Antarctic Peninsula), in particular: seasonal variability and spatial heterogeneity. Based on land surface temperature (LST) data derived from loggers and MicroClimate Monitoring Station, we analyzed areas with active growth of local plants. Seasonal variations formed mainly under annual and semi-annual cycles, with no dependencies of amplitudes and phases form area location. LST highly correlates with air temperature and total incoming irradiance. It is emphasized that spatial orientation of relief microforms plays the most significant role for LST formation on micro-level. Using cluster analysis, it was found that temperature loggers which are located along shoreline and oriented to the north–north-east could be grouped by similar LST distribution.
The goal of unmanned aerial vehicle (UAV) image mosaicking is to create natural- looking mosaics without artifacts due to the parallax of the image and relative camera motion. UAV remote sensing is a low-altitude technology and the UAV imaged scene is not effectively planar, yielding parallax on the images. Moreover, when an object in 3-D is mapped to an image plane, different surfaces have different projections. These projections vary with the viewpoint in a sequence of UAV images, which causes artifacts near some tall buildings in the stitched images. To solve these problems, we propose a novel stitching method based on multiregion guided local projection deformation, which can significantly reduce ghosting due to these projections vary with the viewpoint and the parallax. In the proposed method, the image is initially meshed and each cell corresponds to a local homography for image matching, which can reduce misalignment artifacts in the results compared with 2-D projective transforms or global homography. Then, we divide the overlapping regions of input images into multiple regions by classifying feature points. The partitioned regions which serve well scene constraints, are employed to guide the calculation of local homography. Specifically, instead of calculating local homography by the distance between all the feature points in the image and the vertices of the grid, we propose a strategy where multiple regions have different weights for calculating local homography, which can significantly reduce ghosting near some tall buildings. The benefits of the proposed approach are demonstrated using a variety of challenging cases.
Abstract The size of a tropical cyclone (TC), measured by the area of either rainfall or wind, is an important indicator for the potential damage by TC. Modeling studies suggested that aerosols tend to enhance rainfall in the outer rainbands, which enlarges the eyewall radius and expands the extent of rainfall area. However, no observational evidence has yet been reported. Using TC rainfall area and aerosol optical depth (AOD) data, we find that aerosols have a distinguishable footprint in the TC size. Other dynamical factors for TC size, such as relative SST and Coriolis parameter, are also quantified and discussed. We show that, on average, TC rainfall size increases 9–20 km for each 0.1 increase of AOD in the western North Pacific. This finding implies that anthropogenic aerosol pollution can increase not only TC rainfall rate, but also TC rainfall area, resulting in potentially more destructive flooding affecting larger areas.
El presente artículo es un resumen y análisis de los estudios de partición de ondas transversales (shear wave splitting) para el manto superior que se han realizado en México durante la última década. Cuando una onda sísmica entra en un medio anisótropo se parte (o se separa), esto quiere decir que se producen una onda rápida y otra lenta. Se necesitan dos parámetros para cuantificar la anisotropía. Dichos parámetros son la dirección de polarización rápida y el tiempo de retardo entre la onda rápida y la lenta. Se presenta un ejemplo de la aplicación de la técnica empleando la fase SKS ya que la mayoría de las observaciones usan datos telesísmicos. Sin embargo, también se incluyen los resultados de dos estudios que usaron ondas S locales de sismos intraplaca. Se explican aspectos importantes para interpretar las mediciones de partición. Entre ellos se incluyen la ubicación de la anisotropía en función de la profundidad, la relación entre la estructura cristalina de la olivina y el flujo del manto, el papel que juega el movimiento absoluto de placas y el papel que juegan los movimientos relativos de placas Mexicocon un énfasis en las zonas de subducción. Una justificación importante para el estudio de la anisotropía sísmica es que permite conocer las características del flujo en el manto superior así como su relación con procesos tectónicos. México tiene muchos y diversos ambientes tectónicos. Algunos de ellos se encuentran actualmente activos y otros lo fueron en el pasado, pero en cualquier caso han dejado su marca en la forma de anisotropía sísmica. Esto ha dado lugar a una gran variedad de mecanismos para producir el flujo del manto. De manera general la presentación se ha organizado en las siguientes regiones: península de Baja California, la región Mexicana Occidental de Cuencas y Sierras, el norte y noreste de México, la Fosa Mesoamericana, la península de Yucatán y la anisotropía en la base del manto. La relación entre la anisotropía y el flujo del manto se analiza con base en las características particulares de cada región.
doi: https://doi.org/10.22201/igeof.00167169p.2017.56.2.1765