Researcher Ridge (RR) is a 400km long, WNW-ESE oriented chain of volcanic seamounts, located on ~20 to 40 Ma old oceanic crust on the western flank of the Mid-Atlantic Ridge (MAR) at ~15°N. RR remained nearly unstudied, and thus its age and origin are currently unclear. At roughly the same latitude, the MAR axis is bathymetrically elevated and produces geochemically enriched lavas (the well-known 14°N MAR anomaly). This study presents 40Ar/39Ar age data, major and trace elements, and Sr-Nd-Pb-Hf isotopic compositions of volcanic rocks dredged from several seamounts of the RR and along the MAR between 13-14°N. The results reveal that RR lavas have geochemically enriched ocean island basalt (OIB) compositions ([La/Sm]N=1.7-5.0, [Ce/Yb]N=1.58-11.3) with isotopic signatures (143Nd/144Nd = 0.51294-0.51316, 206Pb/204Pb = 19.14-19.93, 176Hf/177Hf = 0.28307-0.28312) trending to or overlapping the ubiquitous FOZO (Focal Zone, e.g., Hart et al., 1992, Science 256) mantle composition. Major and trace element characteristics denote that RR lavas formed by small degrees of melting from a deep source in the garnet stability field and experienced high pressure fractionation beneath a lithospheric lid. Although the sparseness of samples suitable for 40Ar/39Ar dating prevents establishing a clear age progression for the seamount chain, one well constrained basalt groundmass age of 28.75 ± 0.14 Ma (2σ) for one seamount near the western end of RR indicates that this volcano formed ~11 Ma later than the underlying lithosphere. Taken together, RR is interpreted as a hotspot track, albeit formed by a relatively weak melting anomaly. Compared to RR, the lavas from the 14° N MAR anomaly have slightly less enriched compositions, exhibiting enriched (E)-MORB compositions ([La/Sm]N=1.81-2.29). Their isotopic ratios largely overlap with the RR compositions, thus suggesting a genetic relationship. We therefore propose that the enigmatic 14°N MAR anomaly is caused by deflection of upwelling RR plume material towards the approaching (westward migrating) MAR, causing the production of E-MORBs with nearly similar isotopic compositions to the RR lavas. Once the plume was captured by the spreading ridge, off-axis hotspot track volcanism ceased, resulting in a 300 km wide gap of seamount formation between the eastern end of RR and the MAR.

Study of solid and fluid inclusions in carbonatite is vital for understanding the nature of primary carbonatitic magma. In this study, biphase fluid inclusions were observed in calcites and solid mineral inclusions were observed in accessory magnetite in Sung Valley carbonatite of NE India. Thi carbonatite is part of an Ultramafic-Alkaline-Carbonatite Complex (UACC), related to the Kargue-len Plume activity. All of the studied inclusions are primary in nature. Raman spectroscopy of these inclusions suggested that the biphase inclusions hosted by calcite are essentially composed of water whereas, the solid mineral inclusions hosted by magnetite in the Sung Valley carbonatite are manasseite, ferrohog-bomite and amesite. The extremely hydrous minerals inclusions occurring in the magnetite are not a product of hydrothermal alteration but represent the primary magmatic characteristics of the parental magma. Our observations suggest that the parental magma of the Sung Valley carbonatite was ultra-hydrous in nature, which can be attributed to metasomatism of the source carbonated peridotite. Our study also suggests that there is a strong possibility for more hydrous carbonatite melts to occur on a global scale. Plain Language Summary Primary solid inclusions of manasseite, ferrohogbomite and amesite and biphase fluid inclusions of H 2 O were observed in magnetite and calcite respectively in Sung Valley carbonatite of northeast India. These carbonatite are related to Kerguelen mantle plume. Solid and fluid inclusions, identified with the help of Raman spectroscopy, are all of hydrous nature and provide detailed information about the magma these carbonatite have crystallized from. Inclusion data suggests that the parental magma of these carbonatite had a significant amount of dissolved water. Such ultra-hydrous character of the parental magma could be acquired due to the exhaustion of hydrous minerals during low degree of partial melting of the source carbonated peridotite.

The transition from active to passive continental margin of the South China Sea (SCS) is usually inferred to occur in the Late Mesozoic to Early Cenozoic. However, it is less known about the tectonic characteristics of active continental margins before the Late Mesozoic, which hampers the recognition of integral evolution of the SCS. The International Ocean Discovery Program (IODP) site U1504 has sampled greenschist facies mylonite from the basement in the Outer Margin High of the northern SCS continental margin, which potentially record the Mesozoic and Cenozoic tectonic evolution of the SCS region. The microstructure has identified two episodes of deformation in the mylonite, namely early ductile and late brittle deformation, but without age constraints. Here, we further identify three episodes of carbonate veins (pre-mylonite, syn-mylonite and post-mylonite) in the greenschist facies mylonite according to the intersecting relationship between the veins and the mylonite foliation. Then we select 10 carbonate samples for in situ U-Pb dating, and obtain three accurate ages. The pre-mylonite carbonate veins are dated to 210 ± 20 Ma and 195 ± 32 Ma, respectively, which might denote the age of the protolith clast. The age of the syn-mylonite carbonate vein is 135 ± 12 Ma. But for the post-mylonite carbonate veins, no effective age was obtained using U-Pb dating method. Post-mylonite carbonate veins and late brittle fractures were formed at the same time, and the formation environment is similar to the overlying Late Eocene bioclastic limestone. Therefore, combining the microstructure, geochemistry and seismic profile, we speculate that the post-mylonite carbonate veins and brittle fractures may be formed during the Early Cenozoic rifting. These dating ages of the three episodes of carbonate veins suggest that the mylonite records at least two main periods of continental extension in the SCS region since the Early Cretaceous. In reference to the Mesozoic tectonic settings, we infer that, due to the slab rollback of the subducting paleo-Pacific, the SCS continental margin started significant extension during the Early Cretaceous as shown by the ductile deformation of the mylonite. In the Early Cenozoic, the mylonite was exhumated to the seafloor along with further continental extension, and weak brittle deformation occurred in the mylonite. Therefore, the Early Cretaceous extension of the SCS active continental margin may have a certain promotion effect on the rupture of the passive continental margin in the Cenozoic. Keywords: Greenschist facies mylonite; Carbonate U-Pb dating; Continental margin of the SCS; Early Cretaceous; IODP 368

Seismic rupture in strong, anhydrous lithologies of the lower continental crust requires high failure stress, in the absence of high pore fluid pressure. Several mechanisms proposed to generate high stresses at depth imply transient loading driven by a spectrum of stress changes, ranging from highly localised stress amplifications to crustal-scale stress transfers. High transient stresses up to GPa magnitude are proposed by field and modelling studies, but the evidence for transient pre-seismic stress loading is often difficult to extract from the geological record due to overprinting by coseismic damage and slip. However, the local preservation of deformation microstructures indicative of crystal-plastic and brittle deformation associated with the seismic cycle in the lower crust offers the opportunity to constrain the progression of deformation before, during and after rupture, including stress and temperature evolution. Here, detailed study of pyroxene microstructures characterises the short-term evolution of high stress deformation and temperature changes experienced prior to, and during, lower crustal earthquake rupture. Pyroxenes are sampled from pseudotachylyte-bearing faults and damage zones of lower crustal earthquakes recorded in the exhumed granulite facies terrane of Lofoten, northern Norway. The progressive sequence of microstructures indicates localised high-stress (at the GPa level) preseismic loading accommodated by low temperature plasticity, followed by coseismic pulverisation-style fragmentation and subsequent grain growth triggered by the short-term heat pulse associated with frictional sliding. Thus, up to GPa-level transient high stress leading to earthquake nucleation in the dry lower crust can occur in nature, and can be preserved in the fault rock microstructure.

Information on the elemental abundances and distribution is essential for understanding the petrological characteristics and geological evolution of the Moon. In this paper, the thermal infrared data acquired by Lunar Reconnaissance Orbiter (LRO) Diviner are processed to investigate lunar elemental abundances on a global scale (60°N/S) for the first time. The Diviner Level 3 Standard Christiansen feature (CF) product with the resolution of 128 pixels/degree and the coverage of 99.86% is first analyzed and used. The Diviner global models are then established by the univariate regression methods based on the relationships between Diviner CF and ground truths of elemental abundances at 48 lunar sampling sites and the limitations of 1 RMSE of 48 datasets. Finally, the best maps of SiO, TiO, AlO, FeO, MgO and CaO abundances considering both resolution and coverage simultaneously are presented and analyzed from global, geologic units, crater and ejecta surfaces. The comparisons indicate that a satisfactory consistency is observed between Diviner results and Clementine or Chang’E (CE)-1 results, while Diviner results exhibit better practicability in presenting detailed information for elemental abundances on lunar surfaces and higher accuracy on the surface with high latitudes or poor light conditions. Meanwhile, it is also demonstrated that Diviner results is the reliable data sources for the applications in classifications of mare basalt, inhomogeneity of highland crust and Mg#.

An outstanding question for induced seismicity is whether the volume of injected fluid and/or the spatial extent of the resulting pore pressure and stress perturbations limit rupture size. We simulate ruptures with and without injection-induced pore pressure perturbations, using 2-D dynamic rupture simulations on rough faults. Ruptures are not necessarily limited by pressure perturbations when 1) background shear stress is above a critical value, or 2) pore pressure is high. Both conditions depend on fault roughness. Stress heterogeneity from fault roughness primarily determines where ruptures stop; pore pressure has a secondary effect. Ruptures may be limited by fluid volume or pressure extent when background stress and fault roughness are low, and the maximum pore pressure perturbation is less than 10% of the background effective normal stress. Future work should combine our methodology with simulation of the loading, injection, and nucleation phases to improve understanding of injection-induced ruptures.

The demise and closure of the Neotethyan Ocean gave way to the collision and finally amalgamation of various continental fragments in Turkey along the Izmir-Ankara-Erzincan and Intra-Tauride suture zones. These continental fragments include Pontides in the north and Menderes-Tauride , and Kırşehir Block in the south. This study aims to the restoration of these suture zones in central Anatolia using paleomagnetic tools during Neogene. Most of the paleomagnetic studies carried out in the region consider the deformation of Anatolian Block as a monolithic block rotated counter-clockwise due to escape tectonics since the Miocene. We introduce new paleomagnetic evidence obtained from Neogene sedimentary successions and few volcanic suits. Our results point out five distinct tectonic domains with distinct rotation patterns that indicate the rotational deformation of Central Anatolia is far more complex than generally presumed. Among these, 1) Kırıkkale-Bala Domain (KB) is rotated ~18° clockwise, 2) the Tuz Gölü Domain (TG) underwent ~15° counter-clockwise rotation, 3) the Alcı-Orhaniye Domain (AO) rotated ~25° counter-clockwise sense, 4) the Haymana Basin is divided into two different domains, (4) the Northern Haymana Domain (NHY) underwent ~17° counter-clockwise rotation while (5) the Southern Haymana Domain (SHY) underwent barely no net rotation (~5° clockwise) since the early Miocene. The Kırşehir Block was proposed to be an NNE-SSW striking tectonic block that broken into three fragments. These fragments underwent clockwise, in the north, and counterclockwise rotations in the south, respectively, during early Tertiary due to collision and N-S shortening of the Kırşehir Block between Taurides and the Pontides.

The tectonic development of the Southeast Anatolian Orogenic Belt (SAOB) is closely related to the demise of the NeoTethys Ocean, which was located between the Arabian and Eurasian plates from the late Cretaceous to Late Miocene. The ocean contained several continental slivers and intra-oceanic magmatic arcs. The continental slivers represent narrow tectonic belts rifted off and drifted away from the Arabian Plate while the NeoTethyan Ocean and the back-arc basins were opened. Later they collided with one another during the branches of the oceans were eliminated. In these periods, the continental slivers were involved in the subduction zone and turned into metamorphic massifs. During the Late Cretaceous, the first collision occurred when an accretionary complex was thrust over the Arabian Plate’s leading edge. Despite the collision, the ocean survived in the North and Its northward subduction generated a new intra oceanic arc, which collided later with the northerly located continental slivers. In this period, the metamorphic massifs and the intra-oceanic arc front migrated to the South. The new magmatic arc collided with the southerly transported nappe package during the Late Eocene. The amalgamated nappe pile eventually obducted onto the Arabian Plate during the Late Miocene. The collision produced escape structures during the Neotectonic period.

The East Anatolian High Plateau, part of the Alpine-Himalayan orogen, is a 200 km wide, approximately E-W trending belt surrounded by two peripheral mountains of the Anatolian Peninsula. The plateau is covered by a thick, interbedded Neogene volcanic and sedimentary rocks. Outcrops of the underlying rocks are rare. Therefore, contrasting views were proposed on the nature of the basement rocks. New geological and geophysical data suggest the presence of an ophiolitic mélange-accretionary complex under cover rocks of Eastern Anatolia. The cover units began to be deposited during the closure of the NeoTethyan Ocean that was located between the Pontide arc to the north, and the continental slivers drifted away from the Arabian Plate to the south. The surrounding orogenic belts experienced different orogenic evolution. The Eastern Anatolian orogen was formed during the later stages of the development of the surrounding orogenic belts. In this period, the melange-accretionary prism that occupied a large terrain behaved like a wide and thick cushion, which did not allow a head-on collision of the bordering continents. NeoTethyan oceanic lithosphere was eliminated from entire eastern Turkey by the Late Eocene. The eastern Anatolia began to rise when the northern advance of the Arabian Plate continued after the total demise of the oceanic lithosphere. The present stage of the elevation of the East Anatolian Plateau as a coherent block started during the Late Miocene.

The Rochester and Adna 7.5 minute quadrangles in the Washington forearc of the Cascadia subduction zone encompass the Doty fault, a large forearc fault crossing the I-5 corridor south of Centralia. We have begun a cooperative geological and geophysical study of the area to assess the seismic hazard to a water retention facility that has been proposed to mitigate flooding along the Chehalis River and the I-5 corridor. This region between Olympia and Portland is undergoing north-south compression, clockwise rotation, and regional uplift associated with both subduction processes and the northward migration of the forearc block. Past studies identified multiple faults that strike NW-SE and E-W in the northern and southern parts of the study area, respectively. The Kopiah, Scammon Creek, Salzer Creek and Doty faults all interact within our study area, in ways that are poorly understood. An integrated geophysical investigation will assist the State-Federal cooperative mapping program called STATEMAP efforts to produce detailed 1:24,000 scale geologic maps of the area. Geophysical field work in the summer of 2018 includes a roughly 15 x 32 km gravity grid with ~2 km station spacing. Station spacing along known geologic structures is ~1 km to provide greater resolution. Results from our coarse gravity grid will provide targets for additional high resolution profiles. A high resolution ground magnetic grid also extends across both quadrangles, and preliminary results demonstrate its efficacy at elucidating structure. Seismic profiles acquired by the USGS across the Doty fault will constrain our geophysical modeling, which will combine the high resolution gravity and magnetic profiles in a geologic model of the subsurface to support the mapping efforts of the STATEMAP program. The data and models will provide insight about total offset across these faults, precisely identify locations of faults that are not exposed at the surface, and allow us to better understand the structure of these faults. These interpretations will allow us to more accurately understand the potential seismic risk these faults pose to nearby population centers and infrastructure.

Our knowledge of glacial history of the western (Norwegian) part of the Barents Sea has greatly improved during the last decades, notably due to the high-resolution multibeam swath bathymetry data. In contrast, published seafloor data from the eastern part of the Barents Sea and the Kara Sea are much more sparse. This study presents new geophysical/geological evidence for reconstructing glacial dynamics of the eastern part of the Barents-Kara Ice Sheet during the Last Glacial Maximum and subsequent deglaciation. Archival data used in this study include more than 300,000 km of sparker and high-resolution Parasound profiles verified by boreholes drilled with continuous core recovery to 50-100 m below sea bed. This dataset was used to construct continuous geological cross-sections and a series of maps, including detailed bathymetry (in 10-m isobaths) and sediment thickness maps of major seismo-stratigraphic units. Based on the bathymetric and sediment thickness data we map megascale glacial lineations, drumlin-like ridges up to 50 m high and subglacial channels up to 100 m deep, as well as accumulations of glacial deposits (basal, lateral and end moraines) and ice-proximal acoustically transparent bodies (ATBs). Spatial and stratigraphic analysis of these bedforms enables us to put forward a new hypothesis that ice moved on the shelf from the Arctic Ocean along the Saint Anna Trough (SAT). Further south, near the northern tip of the Novaya Zemlya islands, the ice flow split into three major lobes moving to the southwest into the Barents Sea and to the south and southeast into the Kara Sea. Deglaciation in the study area progressed with several ice stillstands and subsequent readvances marked by end-moraines and accumulation of ice-proximal sediments. During deglaciation events, when the SAT became ice free due to iceberg calving, the ice flow reversed its direction toward the SAT, forming a fluting and a massive ATB on the western SAT slope. The exact timing and mechanisms of the ice transgression(s) from the Arctic Ocean are not well understood. Additional high-resolution data such as multibeam bathymetry surveys are needed to verify the spatiotemporal distribution of glaciogenic bedforms, and glaciological modeling is required to comprehend the ice dynamics and put it in the pan-Arctic context.

We have developed improved seismic hazard maps with the effect of local geology for the Washington, DC area. The input ground motion prediction equations, source model, and logic tree for the analysis is taken from the 2014 U.S. Geological Survey national seismic hazard model (Petersen et al., 2014). We have added an improved local geology model based on the overburden thickness map of Froelich (1976). As in our preliminary effort (Cramer et al., 2016) we use three shear-wave velocity profiles for Piedmont, Fall Line, and Coastal Plain regions (Olgun et al, 2015). We developed reference profiles from the three Olgun et al. profiles that extend to hard rock for site amplification relative to the rock conditions for the ground motion prediction equations. Our seismic hazard maps include both probabilistic (2% in 50 years) and scenario (M6.0 at Mineral, VA) maps. The local geology in the Washington DC area strongly amplifies higher frequency ground motions (peak ground acceleration, 0.2 s spectral acceleration) in keeping with the three site-specific profiles of Olgun et al. (2015) and the observations of Pratt et al. (2017). The soil response is driven by the 10 to 20 m thick low shear-wave velocity (200–300 m/s) top layers of the reference profiles. These low velocity layers are composed of residual soil and/or alluvium. The thicker Cretaceous Potomac Formation sediments, up to 600 m thick in the SE corner of the study area, have an effect on seismic hazard at 1.0 s and longer periods. The greatest effect on 1.0 s spectral acceleration seismic hazard is from the ~200 m thick sediments near the SE edge of Washington DC. Our maps have a resolution of 0.005 degree (500 m) and have some of the sub-km scale detailed geology variation in the Washington, DC area. These maps can serve as a guide to improving the understanding of seismic hazard and risk in the area and stimulate further work on a more detailed local geology model with higher resolution.

One of the next giant leaps for humanity—inhabiting our neighbor planet Mars—requires enough water to support multi-year human survival and to create rocket fuel for the nearly 150-million-mile return trip to Earth. Water that is already on Mars, in the form of ice, is one of the leading in situ resources being considered in preparation for human exploration. Human missions will need to land in locations with relatively warm temperatures and consistent sunlight. But in these locations, ice (if present) is buried underground. Much of the ice known to exist in mid-latitude locations was likely emplaced under climate conditions (and orbital parameters) different from today. So in addition to providing an in-situ resource for human exploration, Martian ice also provides a crucial record of planetary climate change and the effects of orbital forcing.This presentation will highlight techniques and recent activities to characterize Mars’ underground ice, such as the Subsurface Water Ice Mapping (SWIM) Project (Morgan et al. 2021, Nature Astro.; Putzig et al. In Press, Handbook of Space Resources; Putzig et al. this AGU; Morgan et al. this AGU). We present outstanding questions that will be vital to address in the context of ISRU (in situ resource utilization) and connections between these questions and the climate in which the ice was emplaced and evolved (e.g., Bramson et al. 2020, Decadal White Paper). Lastly, we discuss how these science activities intersect with future exploration, particularly that enabled by collaborations between space agencies as well as industry partners (Heldmann et al. 2020, Decadal White Paper; Golombek et al. 2021, LPSC).High-priority future work includes better orbital characterization of shallow ice deposits, such as radar sounding at shallower scales (<~10m) than that of SHARAD, as proposed for the International Mars Ice Mapper. Also needed are detailed studies of the engineering required to build potential settlements at specific candidate locations; this includes characterization of the nature of the overburden above the ice, which will inform future resource extraction technology development efforts. Ideally, initial landing sites would be chosen with a long-term vision which includes preparation and development of the basic technologies and designs needed for human landing on Mars.

Rock slope failures often result from progressive rock mass damage which accumulates over long timescales, and is driven by changing environmental boundary conditions. In deglaciating environments, rock slopes are affected by stress perturbations driven by mechanical unloading due to ice downwasting and concurrent changes in thermal and hydraulic boundary conditions. Since in-situ data is rare, the different processes and their relative contribution to slope damage remain poorly understood. Here we present detailed analyses of subsurface pore pressures and micrometer scale strain time series recorded in three boreholes drilled in a rock slope aside the retreating Great Aletsch Glacier (Switzerland). Additionally, we use monitored englacial water levels, climatic data, and annually acquired ice surface measurements for our process analysis. Pore pressures in our glacial adjacent rock slope show a seasonal signal controlled by infiltration from snowmelt and rainfall as well as effects from the connectivity to the englacial hydrological system. We find that reversible and irreversible strains are driven by hydromechanical effects from diffusing englacial pressure fluctuations and pore pressure reactions on infiltration events, stress transfer related to changing mechanical glacial loads from short-term englacial water level fluctuations and longer-term ice downwasting, and thermomechanical effects from annual temperature cycles penetrating the shallow subsurface. We relate most observed irreversible strain (damage) to mechanical unloading from ice downwasting. Additionally, short-term stress changes related to mechanical loading from englacial water level fluctuations and hydromechanical effects from pore pressure variations due to infiltration events were identified to contribute to the observed irreversible strain.

The Crustal Fault Zones provides an interesting geological target for high temperature geothermal energy source in naturally deep-fractured basement areas. Field and laboratory studies have already shown the ability of these systems to let fluid flow down to Brittle-Ductile-Transition. However, several key questions about exploration still exist, in particular the fundamental effect of tectonic regimes on fluid flow in fractured basement domains. Based on poroelasticity assumption, we considered an idealized 3D geometry and realistic physical properties. We examined a model with no tectonic regime (benchmark experiment) and a model with different tectonic regimes applied. Compared to the benchmark experiment, the results suggest that different tectonic regimes cause pressure changes in the fault/basement system. The tectonic-induced pressure changes affect fluid patterns, onset of convection as well as the spatial extent of thermal plumes and the intensity of the temperature anomalies.

Knowledge of the contemporary in-situ stress orientations in the Earth’s crust can improve our understanding of active crustal deformation, geodynamic processes, and seismicity in tectonically active regions such as the Hikurangi Subduction Margin (HSM), New Zealand. The HSM subduction interface is characterized by varying slip behavior along strike, which may be a manifestation of variation in the stress state and the mechanical strength of faults and their hanging walls, or, alternatively, these variations in seismic behavior may generate variation in the stress state in space and time. In this study, we analyze borehole image and oriented four-arm caliper logs acquired from thirteen boreholes along the HSM to present the first comprehensive stress orientation dataset within the HSM upper plate. Our results reveal a NE-SW SHmax orientation (parallel to the Hikurangi margin) within the central HSM (Hawke’s Bay region) which rotates to a WNW- ESE SHmax orientation (roughly perpendicular to the Hikurangi margin) in the southern HSM. This rotation of SHmax orientation spatially correlates with along-strike variations in subduction interface slip behavior, characterized by creep and/or shallow episodic slip events in the central HSM and interseismic locking in the southern HSM. Observed borehole SHmax orientations are largely parallel to maximum contraction directions derived from geodetic surface deformation measurements, suggesting that modern stress orientations may reflect contemporary elastic strain accumulation processes related to subduction megathrust locking.

The western India-Eurasia collision zone (IECZ) has experienced devastating earthquakes in the past century and continues to be seismically active. However, the Stress regime and Seismotectonics of the region remains poorly understood. In view of this, we carried out iterative, joint stress inversions of 245 well-constrained earthquake focal mechanisms to constrain the stress regime and its spatial variability in the region and dwell upon their implications for earthquake generation. Salient new findings from the study are, (i) the Kangra-Chamba-Kishtwar region shows arc-oblique horizontal maximum compressive stress (sigma 1, WSW-ENE) in contrast to arc-normal (NNE-SSW) in other regions of the Himalaya, (ii) the Kashmir earthquake sequence (in 2005) and its epicentral region i.e. the Hazara Syntaxis show similar stress patterns with that of the Central Himalaya, (iii) Nanga Parbat Syntaxis experiences pure extension, and (iv) Kaurik Chango Rift, with N-S trending sigma 1, probably extends deep into the Karakoram fault. Based on these findings, we categorize the region into six state of stress fields consistent with geology and plate motion models. The magnitudes for these stress fields show a decreasing trend from 0.90 in the southeast (Garhwal-Kumaun-Shimla) to 0.46 in the northwest (Hazara Syntaxis) and 0.39 in the northeast (Karakoram) suggesting multiple tectonic forces in northwestern and northeastern regions. The study reveals heterogeneity in the stress field within the western IECZ, induced by tectonic forces and structural variability.

On the 22nd of May 2021, although no alarming precursory unrest had been reported, Nyiragongo volcano erupted and lava flows threatened about 1 million of inhabitants living in the cities of Goma (Democratic Republic of Congo) and Giseny (Rwanda). After January 1977 and January 2002, it was the beginning of the third historically known flank eruption of Nyiragongo volcano and the first ever to be recorded by dense measurements both on the ground and from space. In the following days, seismic and geodetic data as well as fracture mapping revealed the gradual southward propagation of a shallow dike from the Nyiragongo edifice underlying below Goma airport on May 23-24, then Goma and Gisenyi city centers on May 25-26 and finally below the northern part of Lake Kivu on May 27. Southward migration of the associated seismic swarm slowed down between May 27 and June 02. Micro seismicity became more diffuse, progressively activating transverse tectonic structures previously identified in the whole Lake Kivu basin. Here we exploit ground based and remote sensing data as well as inversion and physics-based models to fully characterize the dike sized, the dynamics of dike propagation and its arrest against a structural lineament known as the Nyabihu Fault. This work highlights the shallow origin of the dike, the segmented dike propagation controlled by the interaction with pre-existing fracture networks and the incremental crater collapse associated with drainage which led to the disappearance of the world’s largest long-living lava lake on top of Nyiragongo.

Oceanic basalts provide an invaluable window into evolutionary processes governing mantle spatial and temporal chemical heterogeneity. Ocean island basalts (OIBs) and enriched mid-ocean ridge basalts (E-MORBs) are powerful tracers of mantle melting and crust-mantle recycling processes. Whether the elemental and isotopic variations observed in both E-MORBs and OIBs are derived from similar mechanisms, however, remains under debate. Investigating compositional differences between E-MORBs and OIBs is a simple approach to constrain their origins, a technique for which machine learning classification algorithms are optimal. Here we implemented a novel machine learning approach complemented by mantle component mixing models to highlight compositional differences between E-MORBs and OIBs and further investigate their petrogenesis (data sourced from GEOROC database and Gale et al., 2013). Considering Random Forest-based Gini indexes, elements sensitive to pressure and degree of melting (FeO, TiO2, Lu, and Sr) were identified as the best discriminators between E-MORBs and OIBs. Our Gaussian process classification algorithm successfully classified OIBs and E-MORBs better than 97% of the time when considering 1) Sr & FeO and 2) TiO2 & Lu. The probabilistic nature of Gaussian process modeling permitted calculation of new quantitative discriminant diagrams rooted in probability (Sr vs. FeO and TiO2 vs. Lu). Complementary trace element modeling yielded compositionally similar E-MORB and OIB sources with moderately incompatible element enrichments in the OIB source due to the influence of recycled oceanic crust (Prytulak & Elliott, 2007). Our source compositions are consistent with a simple, joint model for E-MORB and OIB petrogenesis after Donnelley et al. (2014): low-degree partial melts of subducted slabs metasomatize the depleted mantle producing a re-fertilized mantle (RM). RM is randomly sampled at mid-ocean ridges to produce E-MORB, while upwelling plumes sample both RM and recycled oceanic crust, yielding OIB. References: Donnelly et al. (2004). Earth and Planet. Sci. Lett., 226(3–4), 347–366. Gale et al. (2013). Geochem., Geophys., Geosyst., 14(3), 489–518. Prytulak & Elliott (2007). Earth and Planet. Sci. Lett., 263(3–4), 388–403.

All material that is collected from Mars (gases, dust, rock, regolith) will need to be carefully handled, stored, and analyzed following Earth return to minimize the alteration or contamination that could occur, and to maximize the scientific information that can be extracted from the samples, now and into the future. A Sample Receiving Facility (SRF) would be where the Earth Entry System is opened, and the sample tubes opened and processed after they land on Earth. The Mars Sample Return (MSR) Science Planning Group Phase 2 (MSPG2) was tasked with identifying the steps that encompass the curation activities that would happen within an MSR SRF and any anticipated curation-related requirements. To make the samples accessible for scientific investigation, a series of observations and preliminary analytical measurements would need to be completed to produce a sample catalog for the scientific community. The sample catalog would provide data to make informed requests for samples for scientific investigations and for the approval of allocations of appropriate samples to satisfy these requests. The catalog would include data and information generated during all phases of activity, including data derived from the landed Mars 2020 mission, during sample retrieval and transport to Earth, and upon receipt within the SRF, as well as through the initial sample characterization process, sterilization- and time-sensitive and science investigations. The Initial sample characterization process can be divided into three phases, with increasing complexity and invasiveness: Pre-Basic Characterization (Pre-BC), Basic Characterization (BC), and Preliminary Examination (PE). A significant portion of the Curation Focus Group’s efforts was determining which analyzes and thus instrumentation would be required to produce the sample catalog and how and when certain instrumentation should be used. The goal is to provide enough information for the PIs to request material for their studies but to avoid doing targeted scientific research better left to peer-reviewed competitive processes. Disclaimer: The decision to implement Mars Sample Return will not be finalized until NASA’s completion of the National Environmental Policy Act (NEPA) process. This document is being made available for planning and information purposes only.

Estimating the melt fraction and volatile content of regions of partial melt beneath volcanoes has important implications for volcanic hazards since higher melt fraction, volatile-rich magmas are more buoyant and have a lower viscosity, and thus are more susceptible to mobilization and possibly eruption. Magnetotelluric (MT) data can be used to model subsurface bulk resistivity structures through inversion algorithms and can provide information on the distribution and amount of melt and volatiles contained in the residing magma by converting bulk resistivity to estimates of melt fraction, temperature, and water content. These are often treated as independent variables but, in reality, they are thermodynamically correlated. Thermodynamic models such as MELTS can be used to constrain the possible combinations of melt fraction, temperature, and water content such that MT interpretations are petrologically consistent. Probabilistic Bayesian inversion that incorporates these constraints can be used to find a distribution of models and interpretations which fit the MT data and provide a better understanding of the uncertainty in MT-derived estimates of melt fraction. In this study, we apply MELTS-coupled 1-D Bayesian inversions of MT data at Uturuncu Volcano to evaluate the constraints that MT data can provide on melt fraction estimates. Uturuncu Volcano is a large composite volcano in southern Bolivia at the center of the Altiplano Puna Volcanic Complex (APVC), the result of a large ignimbrite flare-up during the past 10 Ma. Previous geophysical studies have shown that the APVC is underlain by the voluminous, laterally-extensive Altiplano Puna Magma Body (APMB) at approximately 15-20 km depth below surface. The APMB has previously been interpreted to have a wide range of melt fractions anywhere from 4% to 45%, but MT results suggest anomalously high water contents of up to 10 wt%. Initial results from petrologically-consistent MT inversion modelling suggests that the resulting low resistivity of the APMB beneath Uturuncu requires high melt fractions (e.g. >90%) in near-saturated conditions. This suggests that either high melt fraction near-saturated magma reservoirs exist at depth or that a significant phase of saline fluids in over-saturated low melt fraction conditions is present.

Geohazards, including earthquakes, volcanic eruptions, floods, and landslides, cause billions of dollars in U.S. economic losses, loss of life, injuries, and significant disruption to lives and livelihoods on an annual basis. The ability of the geoscience community to respond rapidly after a hazardous event or at the signs of precursors to these events, provides critical data to understand the physical processes responsible for these destructive events. The Seismological Facility for the Advancement of Geoscience (SAGE) is an NSF-funded facility operated by the Incorporated Research Institutions for Seismology (IRIS). As a part of the SAGE award, IRIS will implement an expanded capability to facilitate rapidly responding to geohazards with geophysical instrumentation. After several years of gathering community input, IRIS is ready to begin procurement of a new suite of instrumentation for rapidly responding to geohazard events. During the past year, staff at the IRIS/PASSCAL Instrument Center have conducted instrument testing and evaluation to inform the preferred mix of instrumentation for the new rapid response equipment pool—which is expected to include broadband and nodal seismometers, digitizers, and infrasound sensors. This effort has been guided by recommendations from a recent Rapid Response Community Whitepaper, with ongoing oversight from the PASSCAL Standing Committee. A copy of the whitepaper, as well as recordings and presentations from hosted gatherings have been posted to IRIS’ Rapid Response to Geohazards webpage (www.iris.edu/rapid). With testing and evaluation complete, IRIS is looking ahead to procuring instruments and associated equipment over the next year, followed by acceptance testing and integration at the IRIS/PASSCAL Instrument Center. Concurrently, IRIS is working with community governance to formalize new policies and procedures that will outline how this new community resource can most effectively and efficiently be used for geohazard-related observations. Beginning in 2023, PIs will be able to schedule and use this equipment from the IRIS/PASSCAL Instrument Center. We look forward to presenting further details on the above-mentioned activities during the AGU Fall Meeting.

Urbanization alters the geomorphological attributes of rivers by increasing peak flows and reducing sediment inputs due to surface sealing and efficient stormwater systems. Attribution of geomorphological changes to urbanization has been mostly done using purely statistical tools under a regional analysis framework, which does not explicitly account for the hydrological processes by which urbanization controls river morphology. Using a process-based hourly hydrological model, we aimed to relate the observed geomorphological changes in three French rivers to the historical urbanization of their catchments over the period 1959-2018. Firstly, we applied the hydrological model to generate an hourly streamflow time series from climatic inputs by accounting for the changes in catchment imperviousness, which we estimated from historical land-cover databases. Secondly, we exploited the obtained streamflow time series to analyze the temporal evolution of the flow competence, i.e. its ability to transport sediments, with regard to the increased imperviousness of the catchments. Results show that urbanization significantly increased flow competence on the urbanized rivers, but the impact and its trend were variable from one catchment to another. This demonstrates the role of urbanization in increasing the channel instability that led to the general incision and widening observed on these rivers over the past three to four decades. Our approach shows promise in projecting the impact of changing land-use and climate on channel geomorphology.

The Magnetics Information Consortium (MagIC), hosted at http://earthref.org/MagIC is a database that serves as a Findable, Accessible, Interoperable, Reusable (FAIR) archive for paleomagnetic and rock magnetic data. It has a flexible, comprehensive data model that can accomodate most kinds of paleomagnetic data. The **PmagPy** software package is a cross-platform and open-source set of tools written in Python for the analysis of paleomagnetic data that serves as one interface to MagIC, accommodating various levels of user expertise. It is available through github.com/PmagPy. Because PmagPy requires installation of Python, several non-standard Python modules, and the PmagPy software package, there is a speed bump for many practitioners on beginning to use the software. In order to make the software and MagIC more accessible to the broad spectrum of scientists interested in paleo and rock magnetism, we have prepared a set of Jupyter notebooks, hosted on [jupyterhub.earthref.org](https://jupyterhub.earthref.org) which serve a set of purposes. 1) There is a complete course in Python for Earth Scientists, 2) a set of notebooks that introduce PmagPy (pulling the software package from the github repository) and illustrate how it can be used to create data products and figures for typical papers, and 3) show how to prepare data from the laboratory to upload into the MagIC database. The latter will satisfy expectations from NSF for data archiving and for example the AGU publication data archiving requirements.