Preprints
Filtering by Subject: Physical Sciences and Mathematics
Kinematics of the active West Andean fold-and-thrust belt (Central Chile): structure and long-term shortening rate
Published: 2018-03-19
Subjects: Earth Sciences, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
West-verging thrusts, synthetic with the Nazca - South America subduction interface, have been recently discovered at the western front of the Andes. At ~33°30’S, the active San Ramón fault stands as the most frontal of these west-verging structures, and represents a major earthquake threat for Santiago, capital city of Chile. Here we elaborate a detailed 3D structural map and a precise [...]
Paleomagnetic Biases Inferred from Numerical Dynamos and the Search for Geodynamo Evolution
Published: 2018-03-19
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The orientation and intensity of the paleomagnetic field is central to our understanding of the history of the Earth. The paleomagnetic signature of the singular most event, inner core nucleation, however, remains elusive. In this study we study numerical dynamo simulations from a paleomagnetic perspective to explore how long observations must be time-averaged to obtain stable virtual [...]
Could machine learning break the convection parametrization deadlock?
Published: 2018-03-16
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics, Planetary Sciences
Modeling and representing moist convection in coarse-scale climate models remains one of the main bottlenecks of current climate simulations. Many of the biases present with parameterized convection are strongly reduced when convection is explicitly resolved (in cloud resolving models at high spatial resolution ~ a kilometer or so). We here present a novel approach to convective parameterization [...]
The Extraordinary Mediocrity of the Holocene
Published: 2018-03-15
Subjects: Climate, Computer Sciences, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Planetary Sciences
The extinction of multiple genera of large-bodied mammals during the Holocene interglacial transition has been attributed to three hypothesized causes: human migration, climate change, and an extra-terrestrial impact. Two of these hypotheses, climate change and extra-terrestrial impactor, would predict that the Holocene interglacial transition was uniquely stressful for large-bodied mammals. To [...]
A potential link between waterfall recession rate and bedrock channel concavity
Published: 2018-03-15
Subjects: Earth Sciences, Geomorphology, Physical Sciences and Mathematics
The incision of bedrock channels is typically modeled through the stream power or the shear stress applied on the channel bed. However, this approach is not valid for quasi-vertical knickpoints (hereafter waterfalls), where water and sediments do not apply direct force on the vertical face and waterfall retreat rate is often modeled as a power function of drainage area. These different incision [...]
Slow-slip events in semi-brittle serpentinite fault zones
Published: 2018-03-14
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Slow-slip events are earthquake-like events only with much lower slip rates. While peak coseismic velocities can reach tens of meters per second, slow-slip is on the order of 1E-7 m/s and may last for days to weeks. Under the rate-and-state model of fault friction, slow-slip is produced only when the asperity size is commensurate with the critical nucleation size, a function of frictional [...]
Reporting negative results to stimulate experimental hydrology
Published: 2018-03-13
Subjects: Earth Sciences, Hydrology, Life Sciences, Physical Sciences and Mathematics
Experimental work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates experimental work with greater risks. One of the main issues with experimental work is the higher chance on negative results (defined here as when the expected or wanted result was not observed despite careful experimental design, planning and execution), [...]
Investigation of variable aeration of monodisperse mixtures: implications for Pyroclastic Density Currents
Published: 2018-03-13
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Volcanology
The high mobility of dense pyroclastic density currents (PDCs) is commonly attributed to high gas pore pressures. However, the influence of spatial and temporal variations in pore pressure within PDCs has yet to be investigated. Theory suggests that variability in the fluidisation and aeration of a current will have a significant control on PDC flow and deposition. In this study, the effect of [...]
Monoclinal flexure of an orogenic plateau margin during subduction, south Turkey
Published: 2018-03-12
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure
Geologic evidence across orogenic plateau margins enables the discrimination of the relative contributions of orogenic, epeirogenic and/or climatic processes that lead to growth and maintenance of those plateaus and their margins. Here, we discuss the mode of formation of the southern margin of the Central Anatolian Plateau (SCAP) and evaluate its time of formation using fieldwork in the onshore [...]
The effect of wind stress anomalies and location in driving Pacific Subtropical cells and tropical climate
Published: 2018-03-12
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The importance of subtropical and extratropical zonal wind stress on Pacific Subtropical Cells (STCs) strength is assessed through several idealized numerical experiments performed with a global ocean model. Different zonal wind stress anomalies are employed, and their intensity is strengthened or weakened with respect to the climatological value throughout a suite of simulations. Strengthened [...]
Resolving the era of river-forming climates on Mars using stratigraphic logs of river-deposit dimensions
Published: 2018-03-10
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
River deposits are one of the main lines of evidence that tell us that Mars once had a climate different from today, and so changes in river deposits with time tell us something about how Mars climate changed with time. In this study, we focus in on one sedimentary basin – Aeolis Dorsa – which contains an exceptionally high number of exceptionally well-preserved river deposits that appear to have [...]
Disagreement among global cloud distributions from CALIOP, passive satellite sensors and general circulation models
Published: 2018-03-09
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Cloud detection is the first step of any complex satellite-based cloud retrieval. No instrument detects all clouds, and analyses that use a given satellite climatology can only discuss a specific subset of clouds. We attempt to clarify which subsets of clouds are detected in a robust way by passive sensors, and which require active sensors. To do so, we identify where retrievals of Cloud Amounts [...]
Mechanical models to estimate the paleostress state from igneous intrusions
Published: 2018-03-09
Subjects: Earth Sciences, Geology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Dikes and sills represent an important component of the deformation history in volcanic systems, but unlike dikes, sills are typically omitted from traditional paleostress analyses in tectonic studies. The emplacement of sheet intrusions is commonly associated with mode I fracturing in a low deviatoric stress state, where dilation is perpendicular to the fracture plane. Many natural examples of [...]
Climatic influences on the offset between d18O of cave drip waters and precipitation inferred from global monitoring data
Published: 2018-03-08
Subjects: Earth Sciences, Engineering, Environmental Monitoring, Environmental Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics, Speleology
We present a meta-analysis of data from 22 caves and 96 drip sites from 4 continents where both the cave drip water d18O and the weighted mean d18O of precipitation have been measured. Drip water d18O is similar to the weighted mean d18O of precipitation (within ± 0.3 ‰) for sites where mean annual temperature (MAT) is less than 15 °C (85% of drips where MAT < 15 °C) and an aridity index [...]
Uncertainty in sea level rise projections due to the dependence between contributors
Published: 2018-03-08
Subjects: Applied Statistics, Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Probability, Statistical Models, Statistics and Probability
Sea level rises at an accelerating pace threatening coastal communities all over the world. In this context sea level projections are key tools to help risk mitigation and adaptation. Sea level projections are often made using models of the main contributors to sea level rise (e.g. thermal expansion, glaciers, ice sheets...). To obtain the total sea level these contributions are added, therefore [...]