Preprints
Filtering by Subject: Earth Sciences
Flow-dependent and dynamical systems analyses of predictability of the Pacific-North American summertime circulation
Published: 2021-09-10
Subjects: Atmospheric Sciences, Dynamical Systems, Earth Sciences
Forecast skills of numerical weather prediction (NWP) models and intrinsic predictability can be flow-dependent, e.g., different among weather regimes. Here, we have examined the predictability of distinct Pacific-North American weather regimes in June-September. Four weather regimes are identified using a self-organizing map analysis of daily 500-hPa geopotential height anomalies, and are [...]
Tropical Cyclones Affecting Tokyo and Changing Storm Surge Hazard since 1980
Published: 2021-09-08
Subjects: Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Risk Analysis
This study investigated tidal records and landfall tropical cyclone (TC) best tracks in Japan from 1980 to 2019 to determine changes in storm surge heights in coastal regions of eastern Japan, including Tokyo. The results indicate that annual mean storm surge heights have increased in the last 20 years (2000–2019) compared to those in 1980–1999, and that these changes are noteworthy, particularly [...]
Thrusts control the thermal maturity of accreted sediments
Published: 2021-09-08
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
Thermal maturity assessments of hydrocarbon-generation potential and thermal history rarely consider how upper-plate structures developing during subduction influence the trajectories of accreted sediments. Our thermomechanical models of subduction support that thrusts evolving under variable sedimentation rates and décollement strengths fundamentally influence the trajectory, temperature, and [...]
The ‘europium anomaly’ in plants: facts and fiction
Published: 2021-09-08
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Life Sciences, Plant Sciences
Aims Rare earth elements (REEs) and normalized REE patterns determined in plant and soil samples represent powerful tools to trace biogeochemical processes during weathering, soil genesis and processes in the rhizosphere, and thus publications reporting rare earth elements and normalized REE patterns in soil systems and plants are rapidly increasing. Methods A normalized REE pattern allows [...]
Higher Long-Term Soil Moisture Increases Organic Carbon Accrual Through Microbial Conversion of Organic Inputs
Published: 2021-09-08
Subjects: Earth Sciences, Environmental Sciences, Physical Sciences and Mathematics
High long-term soil moisture may either stimulate or inhibit soil organic carbon (SOC) losses through changes to mineral and chemical composition, and resultant organo-mineral interactions. Yet, the trade-off between mineralization and accrual of SOC under long-term variation in unsaturated soil moisture remains an uncertainty. In this study, we tested the underexplored relationships between [...]
Drone-mounted GPR surveying: flight-height considerations for diffraction-based velocity analysis
Published: 2021-09-06
Subjects: Earth Sciences, Geophysics and Seismology, Other Earth Sciences
Recent studies highlight the potential of the drone platform for ground-penetrating radar (GPR) surveying. Most guidance for optimizing drone flight heights is based on maximizing the image quality of target responses, but no study yet considers the impact on diffraction traveltimes. Strong GPR velocity contrasts across the air-ground interface introduce significant refraction effects that [...]
Lowermost mantle shear-velocity structure from hierarchical trans-dimensional Bayesian tomography
Published: 2021-09-05
Subjects: Earth Sciences, Physical Sciences and Mathematics
The core-mantle boundary (CMB) is the most extreme boundary within the Earth where the liquid, iron-rich outer core interacts with the rocky, silicate mantle. The nature of the lowermost mantle atop the CMB, and its role in mantle dynamics, is not completely understood. Various regional studies have documented significant heterogeneities at different spatial scales. While there is a consensus on [...]
CCREM: New reference Earth model from the global coda-correlation wavefield
Published: 2021-09-02
Subjects: Earth Sciences, Physical Sciences and Mathematics
The existing Earth reference models have provided an excellent one-dimensional representation of Earth’s properties as a function of its radius and explained many seismic observations in a broad frequency band. However, some discrepancies still exist among these models near the first-order discontinuities (e.g., the core-mantle and the inner-core boundaries) due to different datasets and [...]
Centennial- and orbital-scale erosion beneath the Greenland Ice Sheet
Published: 2021-08-31
Subjects: Earth Sciences, Geochemistry, Geomorphology, Glaciology
Erosion beneath glaciers and ice sheets is a fundamental Earth-surface process dictating landscape development, which in turn influences ice-flow dynamics and the climate sensitivity of ice masses. The rate at which subglacial erosion takes place, however, is notoriously difficult to observe because it occurs beneath modern glaciers in a largely inaccessible environment. Here, we present 1) [...]
Oxidized Mantle Sources of HIMU and EM-type Ocean Island Basalts
Published: 2021-08-31
Subjects: Earth Sciences, Geochemistry, Geology
Oxygen fugacity (fO2) is a fundamental variable in igneous petrology with utility as a potential tracer of recycled surficial materials in the sources of mantle-derived lavas. It has been postulated that ocean island basalts (OIB) have elevated fO2 relative to mid-ocean ridge basalts (MORB) owing to more oxidized source regions. To clarify this issue, trace-element systematics of olivine grains [...]
An overview of multimethod imaging approaches in environmental geophysics
Published: 2021-08-30
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Quantitative characterization of subsurface properties is critical for many environmental applications and serves as the basis to simulate and better understand dynamic subsurface processes. Geophysical imaging methods allow to image subsurface property distributions and monitor their spatio-temporal changes in a minimally invasive manner. While it is widely agreed upon that models integrating [...]
A high-resolution downscaled CMIP6 projections dataset of essential surface climate variables over the globe coherent with the ERA5-Land reanalysis for climate change impact assessments
Published: 2021-08-30
Subjects: Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology
A high-resolution climate projections dataset is obtained by statistically downscaling climate projections from the CMIP6 experiment using the ERA5-Land reanalysis from the Copernicus Climate Change Service. This global dataset has a spatial resolution of 0.1°x 0.1°, comprises 5 climate models and includes two surface daily variables at monthly resolution: air temperature and precipitation. Two [...]
Fault rock heterogeneity can produce fault weakness and reduce fault stability
Published: 2021-08-30
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Tectonics and Structure
Geological heterogeneity is abundant in crustal fault zones; however, its role in controlling the mechanical behaviour of faults is poorly constrained. Here, we present laboratory friction experiments on laterally heterogeneous faults, with patches of strong, rate-weakening quartz gouge and weak, rate-strengthening clay gouge. The experiments show that the heterogeneity leads to a significant [...]
Parsimonious velocity inversion applied to the Los Angeles Basin, CA
Published: 2021-08-24
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The proliferation of dense arrays promises to improve our ability to image geological structures at the scales necessary for accurate assessment of seismic hazard. However, combining the resulting local high-resolution tomography with existing regional models presents an ongoing challenge. We developed a framework based on the level-set method that infers where local data provide meaningful [...]
Surface and subsurface damage caused by bullet impacts into sandstone
Published: 2021-08-20
Subjects: Earth Sciences
The shift of armed conflicts to more urbanised environments has increased risk to cultural her-itage sites. Small arms impacts are ubiquitous in these circumstances, yet the effects and mecha-nisms of damage caused are not well known. A sandstone target was shot under controlled con-ditions to investigate surface and subsurface damage. A 3D model of the damaged block, created by structure from [...]