The electron content distribution of the north and south polar ionosphere is analyzed from 2001 to the beginning of 2019 from the Global Ionospheric Maps of VTEC computed each 15 minutes by UPC-IonSAT with a tomographic-Kriging combined technique. We have found the VTEC footprint of features previously reported by different authors and with different techniques: tongues of ionization, trough and dawn-side drifting structure, flux transfer event, Theta-aurora VTEC observation at SP, and Storm enhanced density (SED) during major geomagnetic storms. Moreover, by means of an unsupervised clustering algorithm (Learning Vector Quantization), we have characterized the main features of the ionospheric electron content climatology, separately for the north and south poles. In particular a mean Tongue Of Ionization (TOI) behaviour over south polar ionosphere during 1345UT-1945UT, from November to February, i.e. in local spring and summer seasons, is confirmed in agreement with recent findings.

Terrestrial water storage (TWS) plays a key role in land-surface interaction and the hydrological cycle. Changes in the variability of its components, including surface storage, soil moisture and groundwater can lead to significant changes in local climate, water supply sources and agricultural production. In this study, we assess the impacts of climate variability and change in surface and subsurface hydrological variables over the Magdalena-Cauca basin (Colombia) using a distributed conceptual hydrological model (WMF) driven by precipitation and temperature from four GCMs (general circulation models). WMF is calibrated using daily precipitation products from the Tropical Rainfall Measuring Mission (TRMM). Monthly mean anomalies of surface and groundwater storage outputs show consistency with Gravity Recovery and Climate Experiment (GRACE) data. Past (1970-2001) and future (2021-2050 and 2071-2100) precipitation from GCMs are statistically downscaled using a quantile mapping method to a spatial resolution of 0.25 by 0.25 degrees. Mean precipitation projections over the country are highly dependent on the selected GCMs, but the evidence shows agreement in a decrease towards the lower part of the basin; these projections are also present in surface runoff simulations. Annual mean streamflow follows the sign of the mean rainfall change over the basin. On the other hand, soil properties, topography, and geomorphological characteristics condition the patterns of subsurface and groundwater storage change (magnitude and localization), with the upper part of the Colombian Andes and the river mouth presenting the greatest changes. Results also show that mean soil moisture decrease in all scenarios, associated with changes in precipitation, but also due to the influence of temperature and evapotranspiration. The latter could lead to changes in the soil-atmosphere interaction, energetic conditions of the ecosystems and the need for agricultural mitigation strategies.

This paper examined the behavior of ionospheric irregularities over the African Equatorial Ionization Anomaly (EIA) during intense geomagnetic storms which occurred from 2012 to 2015. Total electron content (TEC) data was used to derive the rate of change of TEC index (ROTI). This was employed to monitor irregularities over the trough and crests of the EIA. Variations of the horizontal component of the Earth’s magnetic field (H) were examined. The H component was additionally used to compute ionospheric electric current disturbance (Diono). Prompt penetration electric field (PPEF) inferred from variations of Diono was compared with PPEF obtained from the Prompt Penetration Equatorial Electric Field Model (PPEFM). The PPEFM predicted accurately all PPEFs thus, was found to be valid over the African EIA. The local time of occurrence of interplanetary magnetic field (IMF ) dictated the behavior of irregularities. Eastward PPEF triggered short duration irregularities on 23 April 2012, 17 March 2013 and 20 February 2014 while westward disturbance dynamo electric field (DDEF) reduced them thereafter. During the storms recovery including the 15 July 2012 and 17 March 2015 events, irregularities were suppressed by westward DDEF. However, during the storms of 14 November 2012 and 29 June 2013 no irregularities were observed. Irregularities were always inhibited over the trough. The inhibition lasted longer during the super storm of March 2015. Over the crests, there were differences in their behavior on 16-17 July 2012, 15 November 2012 and 19 March 2013. These were however, not linked to storm-time electric field.

Over the past decades, Arctic sea ice has declined in thickness and extent and is shifting towards a seasonal ice regime, with accelerated ice drift and an increase in the seasonal ice zone. The changing Arctic ice cover will impact the trans-border exchange of sea ice between the Exclusive Economic Zones (EEZs) of the Arctic nations, with important implications for ice-rafted contaminant transport. To investigate projected changes to transnational ice exchange, we use the Lagrangian Ice Tracking System (LITS) to follow ice floes from the location of their formation to where they ultimately melt. We apply this tool to output from two ensembles of the Community Earth System Model (CESM): the CESM Large Ensemble, which uses a high emission scenario (RCP8.5) that leads to over 4°C global warming by 2100, and the CESM Low Warming ensemble, with reduced emissions that lead to a stabilized warming of 2°C by 2060. We also use the National Snow and Ice Data Center Polar Pathfinder and Climate Data Record products to evaluate the fidelity of the CESM present-day tracking simulations. Transnational ice exchange is well represented in CESM except for ice traveling from Russia to Norway, with twice as much ice following this pathway compared to observations. Initial results suggest this might be due to a combination of internal variability and speed biases in the observational data. The CESM projects that by mid-century, transnational ice exchange will expand, with a large increase in the fraction of transnational ice originating from Russia and the Central Arctic. As the seasonal ice zone grows, ice floes accelerate and transit times decrease, eventually cutting off ice exchange between longer pathways. By the end of the 21st century, we see a large impact of the emission scenario on ice exchange: consistent ice-free summers under the high emission scenario act to reduce the total fraction of transnational ice exchange compared to mid-century. The low emission scenario on the other hand continues to see an increase in transnational ice exchange by 2100. Under both scenarios, all pathways have decreased to average transit times of less than 2 years, compared to a maximum of 6 years under present-day conditions and 3 years by mid-century, effectively bringing the Arctic nations closer together.

While the geosciences are interdisciplinary in nature, they are not demographically diverse, which challenges the future viability and relevance of the geosciences. Causes and potential solutions for this deficiency have been proposed for several decades, but diversity within the geosciences has barely changed in that time. Dominant cultural, historical, and socioeconomic factors contribute to the lack of diversity and those factors only change slowly over generations. Solutions proposed for more immediate changes have been ineffective. Providing specific emotional support to those who are systemically non-dominant (SND) will be more impactful in improving diversity and inclusion within the geosciences. Specifically, we focus on intergroup emotions, which can be pleasant or unpleasant emotions that individuals feel due to their identification with one or more social groups. Using the Intergroup Emotions Theory, we argue that diversity and inclusion can be improved by helping those who are SND minimize undesirable emotions that arise when their group memberships are perceived to be negative. We end by making recommendations based on available research, yet we strongly call on the geoscience community to conduct further discipline-based research in this crucial area in the near future.

Oxygen first arose in Earth’s atmosphere 2.3 billion years ago, but geochemical evidence suggests that small pockets of oxygen may have arisen earlier than the atmospheric rise in oxygen. Cyanobacteria, a modern phylum of bacteria, are believed to have been the driving force behind the oxygenation of Earth’s atmosphere, and there are two basic hypotheses about how they caused this major geologic event. There is a hypothesis, called the ‘ecological’ hypothesis, that suggests cyanobacteria were unable to live in most environments initially, and thus we see the evidence for pockets of oxygen earlier than the atmospheric rise in oxygen. Specifically, the ‘ecological’ hypothesis says that cyanobacteria originally were unable to swim and couldn’t live in saline water, meaning seawater. However, the data for this only considers two possible states for the levels of salinity: freshwater and seawater. We used data from the literature and from experiments to show that the gradient of salinity matters to the ability of cyanobacteria to live in environments, and that we cannot say what salinity levels a cyanobacteria can tolerate based on where they were found alone. See supplemental file for full abstract.

For years the debate about the possible contamination of space and other planets with microbes from Earth has been a hot topic. Furthermore, the discovery of sulfate minerals on the Martian surface make this planet suitable to colonization by microorganisms adapted to survive and grow under earthly extreme conditions. One of these microorganisms is Desulfotalea psychrophila, a microbe able to generate cellular energy by means of an enzyme known as the dissimilatory sulfate reductase. As all bacterial enzymes are encoded within the bacterium nucleic acids, we have designed experiments to study the ability of this microbe to survive, grow and metabolize under simulated Martian conditions of pressure, temperature and different concentrations of sulfate compounds.

We investigate the Spectral Kurtosis (SK) statistical signature of a signal observed with the Robert C. Byrd Green Bank Telescope Breakthrough Listen back-end that was transmitted by the Voyager 1 spacecraft, which is up to date the only known artificial signal originating from outside our solar system, and we demonstrate the ability of the SK estimator to perform real-time detection and discrimination against natural astronomical transients of deep-space Voyager 1-like technological signatures of alien origin. We use the same approach to investigate the yet controversial nature of the FRB 180301 signal detected during the Breakthrough Listen observations with the Parkes telescope.

A radio transmitter which is accelerating with a non-zero radial component with respect to a receiver will produce a signal that appears to change in frequency over time. This effect, commonly produced in astrophysical situations where orbital and rotational motions are ubiquitous, is called a drift rate. In radio SETI (Search for Extraterrestrial Intelligence) research, it is unknown a priori which frequency a signal is being sent at, or even if there will be any drift rate at all besides motions in the solar system. Therefore a range of potential drift rates need to be individually searched, and a maximum drift rate needs to be chosen. The middle of this range is zero, indicating no acceleration, but the absolute value for the limits remains unconstrained. A balance must be struck between computational time and the possibility of excluding a signal from ETI. In this work, we examine physical considerations that constrain a maximum drift rate and highlight the importance of this problem in any narrowband SETI search. We determine that a normalized drift rate of 200 nHz (e.g. 200 Hz/s at 1 GHz) is a generous, physically motivated guideline for the maximum drift rate that should be applied to future narrowband SETI projects if computational capabilities permit.

Venus is commonly known as the beautiful Evening Star of the night sky. Despite its bulk composition and size being similar (Interior ESI 0.98) to those of Earth, Venus is an extremely hot and dry planet, with temperatures ranging from 630 - 740K. With the current physical conditions, a potential areal biosphere could exist on the sulphuric acid-dominated clouds, providing moderate temperatures and pressures due to high altitudes. A theorised Iron or Sulphur metabolism could support exotic life in these extremely acidic (pH 0) conditions. The past habitability for regular life could be connected to the present habitability for exotic life through possible evolution, extending the possible Habitability timeline. Due to its smaller orbital distance (0.7 AU), Venus could have been the first habitable planet in the solar system, with optimistic models showing that Venus may have had a complex atmosphere and a liquid ocean for around 2 billion years, before the moist runaway greenhouse effect transformed the planet. High values for the D/H ratio and carbon abundance, combined with Venus’s slow rotation rate indicate the potential for biological life developing in Past Venus’s possible Earth-like conditions. These models were analysed from a perspective of Habitability, along with probable evolution into the present exotic life.

Analytical studies of astromaterials samples returned by NASA space missions generate unique and highly valuable data that contribute fundamentally to our knowledge and understanding of the origin and evolution of Earth, our solar system, and the universe. These data need to be openly accessible and curated in a manner that maximizes their reuse in and utility for future science and that ensures their quality and long-term preservation. In several recent strategic documents and reports, NASA recognizes this need [1] and is adjusting its science information policies [2]. In 2020, NASA charged the Planetary Data Ecosystem Independent Review Board (PDE-IRB) to conduct a review of the planetary data landscape and make recommendations for improving access to and use of planetary science data by the science community [3]. This presentation will highlight features and services of the Astromaterials Data System that align the IRB’s recommendations. The Astromaterials Data System (Astromat) is a data infrastructure that has been funded by NASA since 2018 to curate, archive, and publish analytical data that are generated from astromaterials samples collected by NASA missions and curated at the Johnson Space Center in the Astromaterials Research & Exploration Science Division. Astromat’s mission is to: preserve astromaterials data and ensure their long-term access and reusability for new science endeavors; restore legacy data of astromaterials samples acquired in the past; synthesize historic and new data into a comprehensive, analysis-ready data store that allows scientists to use new technologies such as Machine Learning and Artificial Intelligence to explore and mine these data in previously impossible ways. Astromat operates a data repository where researchers can deposit their data for archiving and publications, specifically to comply with new journal policies and guidelines for Open and FAIR data and Data Management Plans required by funders. The repository follows international best practices. Astromat also maintains the Astromat Synthesis, a relational database that integrates legacy and new data into a harmonized data collection that allows users to find and extract data at the granularity of individual analytical measurements and combine these into customized new compilations for advanced data analysis. [1] SMD’s Strategy for Data Management and Computing for Groundbreaking Science 2019-2024. [2] Scientific Information policy for the Science Mission Directorate, SMD Policy Document SPD-41 (August 2021). [3] Besse, S., et al. (2021). LPI Contributions 2549, 7070.

Detailed rock magnetic analyses of ultramafic rock samples recovered from the Wadi Tayin massif as part of the Oman Drilling Project provide a unique opportunity to understand the magnetic properties of oceanic lithosphere and its alteration since obduction. We examined 300 - 400-meter-long cores from 3 sites (BA1B, BA3A, and BA4A) that transected the crust-mantle boundary. Serpentinization which produces a small amount of magnetite from olivine alteration appears to play an important role in shaping the magnetic signature of the rocks recovered from these holes. Our investigation reveals new features which have not been reported in previous studies of ophiolite largely based on surface rock samples. It appears that when serpentinization reaches a certain point (65%) a sharp increase in magnetic susceptibility occurs. In general, the uppermost section (0 – 40 m) shows higher susceptibility than the deeper part. Also, higher susceptibility is found in dunite-dominated sections than those composed of harzburgite. Overall, our observations indicate that mantle rocks of Semail ophiolite were produced by multi-stage hydrothermal alterations.

Microbial-induced calcium carbonate precipitation (MICP) is an innovative technique used for soil improvement, for controlled reduction of permeability in porous media or immobilization of soil contaminants. The application of MICP in the field is influenced by the environmental factors. In the present study, the main purpose is to explore the effectiveness of MICP in treating porous media at different environmental temperatures and reveal the underlying mechanisms. The microstructure characteristics were investigated via SEM imaging, EDS and XRD analyses and consolidated drained triaxial compression tests were performed to examine the performance of MICP-treated samples. Results indicate that the shear strength depends heavily on the treatment temperature, which was mainly due to the different content, size and distribution of CaCO3 in samples at different conditions. The observations of pore-scale characteristics revealed that low temperature (4℃) and high temperature (50℃) produced less CaCO3 precipitation, resulted in smaller carbonate crystals precipitation and thus lower strength. In contrast, samples treated at room temperature and 35 ℃ show more CaCO3 precipitation and greater strength. The crystal forms, though, were not influenced by the temperature. The climate conditions are a very important parameter that needs to be tuned specifically for the purposes of each MICP application (whether controlled alteration of permeability or for soil stabilization). However, in most MICP field applications, temperature is nearly impossible to control, and in such conditions where bacterial activity is reduced, the alteration of the MICP recipe is required, and specifically the number of bacterial solution injections are worth to be considered.

The post-subduction tectonic evolution of northern Borneo, which experienced two sequential subduction episodes of opposite polarity in the Neogene, is still widely debated with first-order questions such as whether the region has been in a state of compression or extension remaining unresolved. We use waveform data recorded from a dense seismic network in northern Borneo to investigate crustal thickness variations through the application of Virtual Deep Seismic Sounding (VDSS). The new results reveal an extensive area of thin crust in central and southeastern Sabah that appears to extend northeast into the Sulu Sea, where rifting initiated. We also compute local earthquake focal mechanisms, which suggest that extension is ongoing, though now dominated by orogen collapse in the NW. Together these results point to the pervasiveness of regional extension tectonics over the last 15-20 Myr and its role in the post-subduction cycle of plate tectonics in SE Asia.

Fundamentally related to the ultraviolet (UV) divergence problem in Physics, conventional wisdom in seismology is that the smallest earthquakes, which are numerous and often go undetected, dominate the triggering of major earthquakes, making accurate forecasting of the latter difficult if not inherently impossible. Using the general class of epidemic type aftershock sequence (ETAS) models and rigorous pseudo-prospective experiments, we show that ETAS models that feature a specific magnitude correlation between triggered and triggering earthquakes and a magnitude-dependent Omori kernel, significantly outperform simpler ETAS models, in which these features are absent. Using the best forecasting model, we then show that large earthquakes are preferentially triggered by large events. These findings have far-reaching implications for short-term and medium-term seismic risk assessment, as well as for the development of a deeper theory without UV cut-off that is locally self-similar.

Hot spring localities on continents may represent the most probable locales for the formation of early life constituents on Earth. Apart from liquid water and carbohydrates, these components also include elements like boron that are crucial for stabilization of the complex organic molecules that constitute life. Many of these life sustaining ingredients are commonly found in the vicinity of terrestrial hot springs. Analogously, similar existing or extinct hot spring localities on other planets may constitute prospective astrobiological sites. In the present study, we have characterized the complete mineralogical assemblage of the Puga hot spring deposit, Ladakh, India, using detailed spectroscopic and X-ray diffraction studies. The spectroscopic characterization was done using field based visible/near-infrared (VNIR; 400-2500 nm) and lab measured mid-infrared (MIR, 4000-400 cm-1) hyperspectral data. The identified mineral phases include Na-borates, such as, borax and tincalconite, and hydrous sulfates such as jarosite, alunite, copiapite, tamarugite and gypsum, in conjunction with native sulfur, halite and opaline silica. Borate minerals have been identified from the valley-fill material along with halite and opaline silica, whereas sulfates occur alongside crystalline sulfur deposits. We have compared mineral assemblages found in Puga with other hot spring/hydrothermal deposits on Earth identified as martian analog sites, and also with mineral assemblages identified in situ on Mars. We argue that the spectral characterization of hydrated borates in natural association with hydrous sulfates can be used for identification of fossilized martian hydrothermal settings that are prospective in the search for extinct/extant extra-terrestrial life.

We investigate the impact of source-side 3D velocity structure on teleseismic travel-time in back projection (BP) analysis of large earthquakes. We use travel-time data of teleseismic events recorded by the Hi-Net array to reveal how travel-time errors vary with source location. In a source area of a few hundred km, where travel-time error varies dominantly linearly, we propose a new interpolation scheme using earthquakes located around the rupture of the main-shock to calibrate the travel-time error, and validate it by relocating inland M>5.0 earthquakes in central Japan. We then apply it to image the rupture of the 2002 Denali earthquake. The calibrated BP result shows that most of the high-frequency radiators are <15 km away from the surface rupture trace. The new result reveals that the rupture started on the Susitna Glacier Fault with a speed of ~1.4km/s, then propagated onto the Denali Fault and accelerated to a super-shear speed approaching the crustal P-wave velocity at approximately 30km. The location of super-shear transition and rupture speed in BP are highly consistent with that inferred from the timing and amplitude ratio of the super-shear and trailing Rayleigh pulses observed on the near fault PS-10 station. Subsequently, the rupture stagnated for ~15s before penetrating through the largest asperity, re-accelerated to a speed of ~5.2 km/s and continued on the last 60 km of the Denali fault and part of Totschunda Fault. This application shows the great potential of the new BP calibration strategy to refine the rupture imaging of other mega-earthquakes.

Fluid injection stimulates seismicity far from active tectonic regions, however the details of how fluids modify on-fault stresses and initiate seismic events remains poorly understood. We conducted laboratory experiments using a biaxial loading apparatus with a 3 m saw-cut granite fault and compared events induced at different background shear stress levels. Water was injected at 10 mL/min and normal stress was constant at 4 MPa. In all experiments, aseismic slip initiated on the fault near the location of fluid injection and dynamic rupture eventually initiated from within the aseismic slipping patch. When the fault was near critically stressed, seismic slip initiated only seconds after MPa-level injection pressures were reached and the dynamic rupture propagated beyond the fluid pressure perturbed region. At lower stress levels, dynamic rupture initiated hundreds of seconds later and was limited to regions where aseismic slip had significantly redistributed stress from within the pressurized region to neighboring locked patches. We find that slow slip initiated when local stresses exceeded Coulomb failure criteria, but initiation of dynamic rupture required additional criteria to be met. Even high background stress levels required aseismic slip to modify on-fault stress to meet initiation criteria. We also observed slow slip events prior to dynamic rupture. Overall, our experiments suggest that initial fault stress, relative to fault strength, is a critical factor in determining whether a fluid-induced rupture will “runaway” or whether a fluid-induced rupture will remain localized to the fluid pressurized region.