The paleolatitude distribution of paleoclimate proxies and contintential landmass is an important constraint for modeling and understanding paleoclimate. True polar wander (TPW), which can produce large, potentially rapid changes in paleolatitude, is a necessary component in paleolatitude reconstructions. Prior workers, e.g., van Hinsbergen et al. (2015), have created paleolatitude frameworks from global continental apparent polar wander paths (APWPs) drawn from running means of continental paleomagnetic studies (e.g., Torsvik et al. 2012). These are limited by the precision of the running mean, poor age resolution amplified by use of a running mean, and the uncertainties and the unknowns of ancient plate motion circuits. In particular, the Pacific Plate is linked to the global plate circuit through Antarctica. Early paleomagnetic tests of this circuit (Suarez & Molnar, 1980; Gordon & Cox 1980; Acton & Gordon 1994) indicated inconsistency of the circuit with paleomagnetic data such that the reconstructed Pacific plate did not move as far north as indicated by its indigenous paleomagnetic data. Some later work has asserted, however, that updated paleomagnetic data and plate reconstructions no longer indicate the inconsistency found before (Doubrovine & Tarduno 2008). Important progress has also been made in estimating the motion between East and West Antarctica from seafloor data (e.g. Granot & Dyment 2018). We revisit these questions here. We test the predictions of the global paleolatitude framework at points across the Pacific Plate using a well-constrained observed APWP constructed from indigenous Pacific plate data from skewness analysis of marine magnetic anomalies (Schouten & Cande 1976; Cox & Gordon 1980) and locations of paleo-equatorial sediments (Moore et al. 2004; Woodworth & Gordon 2018), which uniquely determine Pacific Plate paleolatitude independent of plate circuits. The misfit between the observed and predicted paleolatitude varies with longitude across the plate and is as large as ~10±3°, with the largest misfit occurring between 40 and 60 Ma. Implications of this discrepancy will be discussed and an improved paleolatitude framework for the Pacific plate will be presented.

Practitioners and researchers in geoscience education embrace ICON (Integrated, Coordinated, Open science, and Networked) principles and have a history of using them to create and share educational resources, to move forward collective priorities, and to learn from one another. Geoscience education brings substantial expertise in social science research and its application to building individual and collective capacity. This can be used to support ICON processes and improve the coproduction of knowledge between geoscientists and diverse communities. Geoscience is an important part of the knowledge needed to advance equity at local to global scales. The geoscience education community has expanded its own ICON capacity through access to and use of shared resources and research findings, enhancing data sharing and publication, and leadership development. We prioritize continued use of ICON principles to develop effective and inclusive communities that increase equity in geoscience education and beyond, that support leadership and full participation of systemically non-dominant groups, and that enable global discussions and collaborations.

We hypothesize that onshore saline groundwater in delta systems may have resulted from rapid shoreline progradation during the Holocene. To explore this hypothesis, we develop a model for the transport of saline groundwater in a shore-normal longitudinal cross-section of an evolving ocean margin. The transport model uses a control volume finite element model (CVFEM), where the mesh of node points evolves with the changing aquifer geometry while enforcing local mass balance around each node. The progradation of the shoreline and evolution of the aquifer geometry is represented by assuming the shoreline advances at a prescribed speed with fixed top and foreset slopes. The combined model of transport and progradation, is used to predict the transient trapping of saline water under an advancing shore-line across a range of realistic settings for shoreline velocity and aquifer hydraulic properties. For homogeneous aquifers, results indicate that the distance behind the shoreline, over which saline water can be detected, is controlled by the ratio of the shoreline prorogation rate to the aquifer velocity and the Peclet number. The presence of confining units probably had the greatest impact in sequestering onshore seawater behind an advancing shoreline. Further support for the validity of the proposed model is provided by fitting model predictions to data from two field sites (Mississippi River and Bengal Deltas); the results illustrate consistent agreement between predicted and observed locations of fossil seawater.

The geodynamic evolution of the Western Mediterranean for the past 35My is a matter of debate. Present-day structure and composition of the lithosphere and sublithospheric mantle may help in constraining the geodynamic evolution of the region. We use an integrated geophysical-petrological modeling to derive and compare the present-day thermal, density and compositional structure of the lithosphere and sublithospheric mantle along two NNW-SSE oriented geo-transects crossing the back-arc Alboran and Algerian basins, from onshore Iberia to the northern Africa margin. The crust is constrained by seismic experiments and geological cross-sections, whereas seismic tomography models and mantle xenoliths constrain the upper mantle structure and composition. Results show a thick crust (37km and 30km) and a relative deep LAB (130km and 150km) underneath the HP/LT metamorphic units of the Internal Betics and Greater Kabylies, respectively, which contrast with the 16km thick magmatic crust of the Alboran Basin and the 10km thick oceanic crust of the Algerian Basin. The sharp change in lithosphere thickness, from the orogenic wedge to the back-arc basins, contrasts with the gentler lithosphere thickening towards the respective opposed margins. Our results confirm the presence of detached slabs ~400oC colder than upper mantle and a fertile composition than the continental lithospheric mantle beneath the External Betics and Saharan Atlas. Presence of detached quasi-vertical sublithospheric slabs dipping towards the SSE in the Betics and towards the NNW in the Kabylies and the opposed symmetric lithospheric structure support an opposite dipping subduction and retreat of two adjacent segments of the Jurassic Ligurian-Tethys realm.

New Caledonia owns about 25% of the world’s nickel resources, and around 9% of the world’s reserves, distributed over 300,000 hectares of concessions allocated to date (18% of the total surface of the main island). Supergene weathering of ultramafic rocks have led to the genesis of lateritic nickel-rich ores of garnierite type (NiO> 1.5%) and / or iron oxi-hydroxide type (NiO <1.5%) under tropical lateritic conditions that have prevailed over 30 millions of years. These conditions have shaped the landscapes while offering Ni-rich regolith easy to exploit by open pit mining. Since 1880, nickel has been so far used as an economic driver and a societal development impetus. Since 1998, three worldwide projects have been developed, using pyrometallurgy (Ni-Si) and more recently hydrometallurgy (Ni-Fe) ore processes. However, natural erosion, anthropogenic disturbances (climate change, fires, urbanization, mining) can add up to disrupt the whole terrestrial and marine ecosystem functioning at the regional scale.This critical mined zone is covered by terrestrial ecosystems of great endemic biodiversity and adjoining a lagoon that has been listed as a UNESCO World Heritage Site in 2008. Such ecosystems are a valuable natural resource for the sustainable future for the next generations. Are mining and preserving ecosystems compatible, and for what economic and societal model? The conference reviews a collective research approach (mining, terrestrial and marine ecosystems impacts, restoration, biorecycling) to address this question. The corpus of acquired knowledge allows to propose an inclusive model of responsible mining activity, based on the “co-valorization” of both non-renewable and renewable primary resources through the development of circular economy and bio-economy principles, and applied all along the “mining ecosystem” project management. Considering i)the present day low GDP input of nickel mining in New Caledonia, the 98% dependency rate from fossil sources of energy, the CO2 emissions and the volatile Ni-market international context, this model, if followed, will reinforce the societal cohesion and develop a sustainable economy diversification, while enhancing energy transition and a better ecological efficiency.

Tree damage can provide insights into internal dynamic pressure changes of pyroclastic density currents (PDC). On 18 May 1980, Mount St. Helens erupted a laterally directed PDC that decimated ~600km2 of forest, referred to as the blowdown zone. The head of the current contained the peak dynamic pressure, which uprooted or broke off most trees and stripped them of vegetation; however, some partially stripped tree trunks were left standing. Tree damage was assessed using aerial photography taken one month after the eruption. The flow direction of the PDC was mapped from shadows of root balls of toppled trees and directions of fallen trees. Along given flow paths, the density of standing trees was measured by the number of shadows within 200m2 areas. Towards the northwest, the average tree density increased from 0.01 to 0.58 (± 0.19) trees/m2 with distance. Additionally, analysis identified 95 clusters of trees still standing in the blowdown zone, situated on the lee sides of hills or plateaus. Blurry, cylindrical shadows versus well-defined, cylindrical shadows distinguished standing trees with foliage in clusters from those without. Five variables were used to determine the heights of trees: ground slope and aspect, bearing and length of shadows, and the sun angle above the horizon. Trees stripped of foliage in patches have average heights of 16 ± 7m and occur where the PDC reached 66 ± 24% of its runout. Foliage patches have average heights of 12 ± 7m and occur where the PDC reached 91 ± 9% of its runout. Tree heights in the patches indicate a localized height the peak dynamic pressure must jump as it travels over hills and away from its source. Patches with foliage imply that the peak dynamic pressure has risen above the tops of the trees, whereas patches without foliage suggest that the peak dynamic pressure was still low enough to damage trees even though the current had jumped over topography. Outside of the patches, increasing tree density suggests that dynamic pressure waned with distance.

Mineral hazards are a common, yet often less-recognized group of features compared to other types of natural and man-made hazards. We define “mineral hazards” in part as minerals and elements that occur naturally in elevated, potentially harmful, concentrations in rocks, soils, and certain fluids. Also included are features from human activities related to extraction of mineral and energy resources. Along with its large human population, extensive development, and diverse natural environment, California is very complex geologically, thus it contains many areas of mineral hazards that make it appropriate for such a study. Although mineral hazards have been investigated over several decades by the California Geological Survey (CGS), no systematic statewide assessment had been accomplished until recently when, at the request of the California Department of Transportation (Caltrans), the CGS completed a preliminary assessment of potential mineral hazards over the entire state. This work focused on natural and man-made minerals-related features that might adversely affect construction, use, and maintenance of state and federal highways under Caltrans jurisdiction. The features evaluated include: 1) geologic units that may contain naturally-occurring asbestos (NOA), fibrous erionite, or elevated concentrations of regulated metals (Ag, Ba, Be, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Tl, V, Zn) and metalloids (As, Sb, Se); 2) faults, which can be sites of increased potential for certain types of mineralization; 3) mines and prospects, which can be sources of anomalous concentrations of metals and ore-processing chemicals; 4) oil and natural-gas seeps; 5) thermal springs and fumaroles; and 6) oil, natural-gas, and geothermal wells. The methods and products developed during the Caltrans study can be applied worldwide to many other uses besides highways where there are obligations to protect public health and safety and the environment. The products include maps that highlight types and locations of potential mineral hazards, digital data in GIS format, and accompanying reports that provide details and additional information. Although they do not indicate risk or probability, these products can be applied by users from many backgrounds as screening tools to assess potential for the presence of mineral hazards.

We revisited the June, 2010 - October, 2011 Guy-Greenbrier earthquake sequence in central Arkansas using PhaseNet, a deep neural network trained to pick P and S arrival times. We applied PhaseNet to continuous waveform data and used phase association and hypocenter relocation to locate nearly 90,000 events. Our catalog suggests that the sequence consists of two adjacent earthquake sequences on the same fault and that the second sequence may be associated with the wastewater disposal well to the west of the Guy-Greenbrier Fault, rather than the wells to the north and the east that were previously implicated. We find that each sequence is comprised of many small clusters that exhibit diffusion along the fault at shorter time scales. Our study demonstrates that machine learning based earthquake catalog development is now feasible and will yield new insights into earthquake behavior.

Seismic site characterization of rock and soil properties has a large impact on earthquake ground motions and engineering seismology, especially for evaluation of local site amplification, calibration of strong-motion records and realistic shaking estimates at seismic stations, site-specific hazard assessment, estimation of ground motion models and soil classification for building code applications. However, there is not yet a common way to exchange site characterization information, whereas setting-up standard practices and quality assessment are becoming very important to reach high-level metadata. Within the framework of the SERA “Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe” Horizon 2020 Project, a networking activity is leading to the definition of a European strategy and standards for site characterization of seismic stations in Europe. Based on the results of an online questionnaire, we first defined a list of indicators considered as mandatory for a reliable site characterization: fundamental resonance frequency, shear-wave velocity profile (Vs), time-averaged Vs over the first 30 m, depth of seismological and engineering bedrock, surface geology, soil class. We then proposed a summary report for each indicator, containing the most significant background information of data acquisition and processing details, and a quality metrics scheme. This requires the evaluation of both (i) reliability of the site characterization indicators provided by different methods, and (ii) consistency among the indicators according to the current knowledge and experience of the scientific community. The quality metrics application to some Italian accelerometric sites, characterized within the Italian Civil Protection Department-INGV agreement (2016 to 2021), highlights the capabilities of capturing the characterization quality. These guidelines have been shared within European and worldwide scientific community and validated through focus groups during a dedicated workshop (https://sites.google.com/view/site-characterization-workshop/). They represent a first attempt to reach high-level metadata for site characterization, being aware that they can be improved and modified after a few years of experience and feedback from users.

This paper presents a new coupled urban change and hazard consequence model that considers population growth, a changing built environment, natural hazard mitigation planning, and future acute hazards. Urban change is simulated as an agent-based land market with six agent types and six land use types. Agents compete for parcels with successful bids leading to changes in both urban land use – affecting where agents are located – and structural properties of buildings – affecting the building’s ability to resist damage to natural hazards. IN-CORE, an open-source community resilience model, is used to compute damages to the built environment. The coupled model operates under constraints imposed by planning policies defined at the start of a simulation. The model is applied to Seaside, Oregon, a coastal community in the North American Pacific Northwest subject to seismic-tsunami hazards emanating from the Cascadia Subduction Zone. Ten planning scenarios are considered including caps on the number of vacation homes, relocating community assets, limiting new development, and mandatory seismic retrofits. By applying this coupled model to the testbed community, we show: (1) placing a cap on the number of vacation homes results in more visitors in damaged buildings, (2) that mandatory seismic retrofits do not reduce the number of people in damaged buildings when considering population growth, (3) polices diverge beyond year 10 in the model, indicating that many policies take time to realize their implications, and (4) the most effective policies were those that incorporated elements of both urban planning and enforced building codes.

The usage of the term Knowledge Graph (KG) has gained significant popularity since 2012, when Google introduced its own knowledge graph, and how they used it to enhance their searches and question answering systems. While various definitions and interpretations for knowledge graphs have been presented, what remains consistent is that knowledge graphs are commonly used with reasonsers to make inferences about data, based on assertions and axioms written by human experts. But knowledge graphs, which store complex, multi-dimensional data contain hidden patterns and trends that cannot be explored simply using reasoners. In such a case it becomes necessary to extract parts of the knowledge graph (focusing on the instances related to one property at a time) and analyze them individually in order to conduct a focused but tractable exploration of the domain. In this presentation, we present one way to gain insights from knowledge graphs, using network science. To achieve this goal, we have formalised the partitioning of knowledge graphs to unipartite knowledge networks, and present various ways to explore and analyse such knowledge networks to form scientific hypotheses, gain scientific insights and make discoveries.

The 2018 eruption of Kīlauea volcano produced the largest and most destructive lava flows in the lower East Rift Zone (LERZ) in the past 200 years. Average effusion rates exceeded 100 m3 s-1 (DRE) for more than two months as lava covered > 30 km2 of land area. The largest and longest-lived lava flow was produced by fissure 8 and had flow advance rates exceeding 100 m hr-1 and a run-out length of 13 km. While residents were able to safely evacuate from this rapidly advancing flow, hundreds of structures were destroyed. We integrate observed eruption parameters from the fissure 8 flow with numerical models for lava flows to investigate how eruption rate, topography, and rheology affect the initial path, advance rate, and extent of a lava flow. Many numerical models have been created to represent the advance and/or extent of lava flows. We apply both 1D and 2D, rules-based and physics-based models to explore the advantages and limitations of these model types. First, we validate the models for fissure 8 flow parameters using existing datasets from field observations and sample analysis. Second, we vary the eruption rate and lava rheology to test the influence of these parameters on the advance rate and flow extent. This analysis demonstrates the level of confidence that can be associated with modeling results when estimating difficult-to-constrain parameters during an eruption. Third, using input digital elevation models (DEM) of different resolutions, we examine the sensitivity of model accuracy to DEM resolution, with a specific focus on the influence on flow advance of smaller-scale topographic features that may not be resolved in coarse-resolution DEMs. Through better understanding of how different parameters control flow emplacement, and how to best apply the models describing that emplacement, we aim to improve the ability to estimate advance rate and flow path during (and prior to) the initial stages of flow emplacement and provide more detailed hazard assessments for future eruptions.

The savanna - forest transition in the tropics has a large and complex variation in vegetation structure both vertically and horizontally. 3D-imaging technologies provide detailed high-resolution measurements of the vegetation structure. However, the use of these observations globally faces practical challenges due to spatio-temporal gaps and operational restrictions, mainly in tropical regions. NASA’s Global Ecosystem Dynamics Investigation (GEDI) is the first quasi-global LiDAR (light detection and ranging) observations of 3D vegetation structure at a footprint resolution of 25 m. Here we use GEDI data (GEDI02_Bv001) to analyze vegetation structure in the savanna - tropical forest transition of northern South America, using canopy height, canopy cover, total Plant Area Index (PAI), maximum Plant Area volume Density (PAVD), and vertical profile of PAI and PAVD as vegetation structure descriptors. Despite contrasts between savanna (open-canopy) and forest (closed-canopy), our results show a gradual variation along the transition in canopy height, canopy cover, total PAI, and maximum PAVD. Our results support that the savanna- forest transition in tropical regions can be described as a grassland - forest continuum. Results also indicate that GEDI data allow a better characterization of vegetation lower than 5 m in height, mainly in savanna, an improvement from other global databases (e.g. MODIS). Further, our study illustrates the potential of GEDI data to advance in the characterization of large-scale patterns of vegetation structure in tropics, key for supporting biogeography, and macroecology studies relevant in the phase of current ecosystem changes.

At least five surface rupturing earthquakes that occurred during a <300 year time span near Carson City, Nevada form a spatiotemporal cluster of earthquakes similar to those observed on fault systems around the world. These earthquakes exhibit not only temporal clustering behavior, but also have varying rupture boundaries during successive earthquakes. The Carson Range Fault System is a series of east-dipping normal faults that extend ~100 km southwards from Reno, Nevada. Previously published paleoseismic and lidar data spanning this system provide evidence of six surface rupturing earthquakes that occurred across the Carson Range Fault System during the last 2500 years. The three most recent of these earthquakes occurred from 800-500 cal. ybp, and two other earthquakes occurred on the nearby Incline Village and East Carson Valley faults during this time period. Together these five M6.5-7.1 earthquakes form a spatiotemporal cluster or supercycle.

Geologists need help classifying microscope rock images of sigma clasts; a type of mantled porphyroclasts widely used as kinematic indicators in rocks. Knowledge about the shear sense of sigma clast during formation (either CCW or CW shearing) gives insights into rock formation history. This work reports on early investigation of machine learning techniques for automatic detection and classification of sigma clasts and their rotation from photomicrographs. Convolutional Neural Networks (CNNs) are used to extract and leverage defining features of sigma clasts, such as shape, color, texture, and tail direction to improve accuracy. We leverage existing models that are pre-trained on very large collections of images, and use transfer learning techniques to apply them to microstructure images. We used YOLOv3 to identify different sigma clasts in a given image. We also experimented with other large pre-trained models such as ResNet50, VGG19, InceptionV3 with two additional layers trained specifically on our dataset. In order to facilitate exploration of different models with different settings, we are developing a computational experimentation environment to visualize different CNN network layers, classification heatmaps, and comparative metrics. Finally, since models perform better when more data are available, we are developing a web application to collect additional data from geoscientists and incentivize their participation in open science. The website allows researchers to upload images of rock microstructures, showing them the classification of the images based on the best models available, and allows them to correct any errors which can be used to improve the models.

The thermal response of the martian subsurface due to solar forcing lacks direct measurements. The InSight mission provides the best opportunity to detect the thermal behavior of the subsurface since it was equipped with both air temperature sensors and a subsurface heat flow probe. Here, we model heat conduction under the InSight landing site based on the measured subsurface thermal parameters and air temperature records, which provide insights into heat flow in the martian subsurface. Daily temperature variation over 1 K occurs only within 25 cm under the ground surface. The highest absolute rate of temperature change appears around sol 440, which coincides closely with the season of the dominant number of marsquakes observed around sunset. Thermal-mechanical finite-element method simulations indicate that more potential afternoon marsquakes might exist but be covered by the wind noise. Our results indicate that most high-frequency and low-magnitude marsquakes are likely thermal in origin.

The 15 May 2020 Mw 6.5 Monte Cristo Range earthquake (MCRE) in Nevada, USA is the largest instrumental event in the Mina deflection, an E-trending stepover zone of highly diffuse faulting within the Walker Lane. The MCRE mostly ruptured previously unmapped faults, motivating us to characterize the behaviour of an earthquake on a structurally-immature fault. We use Interferometric Synthetic Aperture Radar (InSAR) data and regional GNSS offsets to model the causative faulting. Our three fault model indicates almost pure left-lateral motion in the east and normal-sinistral slip in the west. Maximum slip of 1.1 m occurs at 8-10 km depth but less than 0.2 m of slip reaches the surface, yielding a pronounced shallow slip deficit (SSD) of 86%. Our calibrated relocated hypocenters and focal mechanisms indicate that the mainshock initiated at 9 km depth and aftershock focal depths range from 1 to 11 km, helping constrain the local seismogenic thickness. We further present new field observations of fracturing and pebble-clearing that shed light on the western MCRE kinematics, revealing a paired fault system below the spatial resolution of the InSAR model. The segmented fault geometry, off-fault aftershocks with variable mechanisms, distributed surface fractures, limited long-term geomorphic features, and an estimated cumulative offset of 600-700 m, are all characteristic of a structurally-immature fault system. However, the large SSD is not unusual for an earthquake of this magnitude, and a larger compilation of InSAR models (twenty-eight Mw≥6.4 strike-slip events) shows that SSDs are not correlated with structural maturity as previously suggested.

Anorthosites are attractive paleomagnetic recorders as silicate-hosted magnetite inclusions can be single-domain and be shielded from alteration. However, petrofabrics within anorthosites may result in magnetic remanence anisotropy that is potentially detrimental to recovering paleomagnetic direction and intensity. The Beaver River diabase of the North American Midcontinent Rift contains abundant nearly 100 percent plagioclase anorthosite xenoliths that are hypothesized to have been liberated from the lower crust by the magma enroute to becoming embedded in shallow crustal sills. In this study, we compare the remanent paleomagnetic directions recorded by anorthosite xenoliths to those of the Beaver River diabase host rocks. Given that both lithologies should record the same thermal remanent magnetization, this comparison provides a means to assess the effects of remanence anisotropy on the paleodirection recorded by the anorthosites. Thermal and anhysteretic remanence (TRM and ARM) anisotropy experiments, which are typically used to assess for anisotropy, can be compared to the natural remanence of the diabase and anorthosite in this geologic experiment that was conducted 1.1 billion years ago. Paleodirection data from the interior of the largest (>300 m) anorthosite xenoliths also have the potential to test their hypothetical lower crustal origin. An origin below the Curie depth would result in a full thermal remanence from the time of diabase emplacement, while a shallower origin from above the Curie depth could have resulted in a distinct remanence direction in the xenolith interior that predates the intrusion (with samples from the exterior having acquired a Beaver River diabase coeval thermal remanence in either scenario). Overall, this novel geological association between diabase and anorthosite provides a means to assess the effects of remanence anisotropy providing valuable context for efforts to use anorthosites to understand the ancient geomagnetic field.

Logjams in a stream create backwater conditions and locally force water to flow through the streambed, creating zones of transient storage within the surface and subsurface of a stream. We investigate the relative importance of logjam distribution density, logjam permeability, and discharge on transient storage in a simplified experimental channel. We use physical flume experiments in which we inject a salt tracer, monitor fluid conductivity breakthrough curves in surface water, and use breakthrough-curve skew to characterize transient storage. We then develop numerical models in HydroGeoSphere to reveal flow paths through the subsurface (or hyporheic zone) that contribute to some of the longest transient-storage timescales. In both the flume and numerical model, we observe an increase in backwater and hyporheic exchange at logjams. Observed complexities in transient storage behavior may depend largely on surface water flow in the backwater zone. As expected, multiple successive logjams provide more pervasive hyporheic exchange by distributing the head drop at each jam, leading to distributed but shallow flow paths. Decreasing the permeability of a logjam or increasing the discharge both facilitate more surface water storage and elevate the surface water level upstream of a logjam, thus increasing hyporheic exchange. Multiple logjams with low permeability result in the greatest magnitude of transient storage, suggesting that this configuration maximizes solute retention in backwater zones, while hyporheic exchange rates also increase. Understanding how logjam characteristics affect solute transport through both the channel and hyporheic zone has important management implications for rivers in forested, or historically forested, environments.

A physics-based earthquake simulator should reproduce first-order empirical power-law behaviors of magnitudes and clustering. However, sequences exhibiting these laws have only been produced in discrete and low-dimension continuum simulations. We show that the same emergence also occurs in 3-D continuum simulations. Our model approximates a strike-slip fault system slipping under rate-and-state friction. We produce spatiotemporally clustered earthquake sequences exhibiting characteristic Gutenberg-Richter scaling as well as empirical inter-event time distribution. With fault interaction, partial ruptures emerge when seismogenic width W over characteristic nucleation length L∞ is larger than 16.24, but none occurs without fault interaction. The mainshock recurrence times of individual faults remain quasi-periodic and fit a Brownian passage time distribution. The system mainshock recurrence time has a short-term Omori-type decay, indicating a 22% chance of mainshock clustering. These results show that physics-based multi-cycle models adequately reflect observed statistical signatures and show practical potential for long-term hazard assessment and medium-term forecasting.

Episodes of slow uplift and subsidence of the ground, called bradyseism, characterize the recent dynamics of the Campi Flegrei caldera (Italy). In the last decades two major bradyseismic crises occurred, in 1969/1972 and in 1982/1984, with a ground uplift of 1.70 m and 1.85 m, respectively. Thousands of earthquakes, with a maximum magnitude of 4.2, caused the partial evacuation of the town of Pozzuoli in October 1983. This was followed by about 20 years of overall subsidence, about 1 m in total, until 2005. After 2005 the Campi Flegrei caldera has been rising again, with a slower rate, and a total maximum vertical displacement in the central area of ca. 70 cm. The two signals of ground deformation and background seismicity have been found to share similar accelerating trends. The failure forecast method can provide a first assessment of failure time on present‐day unrest signals at Campi Flegrei caldera based on the monitoring data collected in [2011, 2020] and under the assumption to extrapolate such a trend into the future. In this study, we apply a probabilistic approach that enhances the well‐established method by incorporating stochastic perturbations in the linearized equations. The stochastic formulation enables the processing of decade‐long time windows of data, including the effects of variable dynamics that characterize the unrest. We provide temporal forecasts with uncertainty quantification, potentially indicative of eruption dates. The basis of the failure forecast method is a fundamental law for failing materials: ẇ-α ẅ = A, where ẇ is the rate of the precursor signal, and α, A are model parameters that we fit on the data. The solution when α >1 is a power law of exponent 1/(1 − α) diverging at time Tf , called failure time. In our case study, Tf is the time when the accelerating signals collected at Campi Flegrei would diverge if we extrapolate their trend. The interpretation of Tf as the onset of a volcanic eruption is speculative. It is important to note that future variations of monitoring data could either slow down the increase so far observed, or suddenly further increase it leading to shorter failure times than those here reported. Data from observations at all locations in the region were also aggregated to reinforce the computations of Tf reducing the impact of observation errors.

On-going trade wars combined with the increasing consumption and depletion of known resources will necessitate the search for new deposits in poorly explored or unexplored areas, such as the polar regions. Antarctica is unique among the world’s continents in having no native population and state sovereignty; the continent has also been identified as potentially harboring extensive hydrocarbon and mineral resources. To protect the fragile Antarctic environment, the Protocol on Environmental Protection to the Antarctic Treaty (1991) banned any mineral activity for a 50-year period, except for scientific purposes. The Protocol will be renewed in 2048, and discussions of possible future mining in the region has already begun. With the improvement of drilling and mining technology, the risk of future mining activity on the continent is increasing. Moreover, extensive mining operations in the Arctic demonstrate the technical and economic feasibility of mining activities in harsh polar environments. The protection of the fragile Antarctic environment must be prioritized; however, maintaining the balance between environmental protection and commercial and national interests in resource development is problematic.

Spatial gradients in rock uplift control the relief and slope distribution in uplifted terrains. Relief and slopes, in turn, promote channelization and fluvial incision. Consequently, the geometry of drainage basins is linked to the spatial pattern of uplift. When the uplift pattern changes basin geometry is expected to change via migrating water divides. However, the relations between drainage pattern and changing uplift patterns remain elusive. The current study investigates the plan-view evolution of drainage basins and the reorganization of drainage networks in response to changes in the spatial pattern of uplift, focusing on basin interactions that produce globally observed geometrical scaling relations. We combine landscape evolution experiment and simulations to explore a double-stage scenario: emergence of a fluvial network under block uplift conditions, followed by tilting that forces drainage reorganization. We find that the globally observed basin spacing ratio and Hack’s parameters emerge early in basin formation and are maintained by differential basin growth. In response to tilting, main divide migration induces basins’ size changes. However, basins’ scaling relations are mostly preserved within a narrow range of values, assisted by incorporation and disconnection of basins to and from the migrating main divide. Lastly, owing to similarities in landscape dynamics and response rate to uplift pattern changes between experiment and simulations, we conclude that the stream power incision model can represent fluvial erosion processes operating in experimental settings.

Attempts to determine physical property across thrust faults at subduction zones through drilling, logging and core sampling have been limited and restricted to exhumed accretionary prisms or shallow parts of active wedges. However, characterizing porosity evolution across the sedimentary section entering subduction zones and accreted sediments is crucial to understand deformation history at accretionary margins through determination of sediment trajectories, quantification of transported volumes of sediments and fluids with related mechanical responses and understanding deformation processes in and around fault zones. International Ocean Discovery Program Expeditions 372 and 375 drilled, logged and cored the entering basin (Site U1520) and active Pāpaku thrust (Site U1518) few kilometers landward of the northern Hikurangi margin deformation front where tsunami earthquakes and recurrent slow slip events occur. Here, we examine physical properties evolution across the Pāpaku thrust at Site U1518 including geophysical logging data, pore size distribution obtained by combining Nuclear Magnetic Resonance and Mercury Injection Capillary Pressure, and interstitial porosity that is representative of sediment compaction state, and compare with that of Site U1520. Interstitial porosity is determined by correcting total connected porosity from clay-bound water content based on cation exchange capacity. We evidence strong variations of physical properties across the thrust fault, with lower porosity, higher P-wave velocity and resistivity in the hanging-wall than in the footwall. We suggest that the porosity pattern at the Pāpaku thrust evidences differences in maximum burial depth with an overcompacted hanging-wall that has been uplifted, thrusted and concomitantly eroded above a nearly normally consolidated younger footwall.