Preprints
Filtering by Subject: Earth Sciences
Organic carbon and microbial activity in marine sediments on a global scale throughout the Quaternary
Published: 2020-02-20
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
Microbial degradation of organic carbon in marine sediments is a key driver of global element cycles on multiple time scales. However, it is not known to what depth microorganisms alter organic carbon in marine sediments or how microbial rates of organic carbon processing change with depth, and thus time since burial, on a global scale. To better understand the connection between the dynamic [...]
Array-based iterative measurements of SmKS travel times and their constraints on outermost core structure
Published: 2020-02-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Vigorous convection in Earths outer core led to the suggestion that it is chemically homogeneous. However, there is increasing seismic evidence for structural complexities close to the outer cores upper and lower boundaries. Both body waves and normal mode data have been used to estimate a P-wave velocity, Vp, at the top of the outer core (the E layer), which is lower than that in the Preliminary [...]
Enabling high-performance cloud computing for Earth science modeling on over a thousand cores: application to the GEOS-Chem atmospheric chemistry model
Published: 2020-02-20
Subjects: Computer Sciences, Earth Sciences, Physical Sciences and Mathematics
Cloud computing platforms can facilitate the use of Earth science models by providing immediate access to fully configured software, massive computing power, and large input datasets. However, slow inter-node communication performance has previously discouraged the use of cloud platforms for massively parallel simulations. Here we show that recent advances in the network performance on the Amazon [...]
Large-scale crustal structure beneath Singapore using receiver functions from a dense urban nodal array
Published: 2020-02-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Geophysics has a role to play in the development of smart cities, for example through geohazard mitigation and subsurface imaging for underground construction. This is particularly true for Singapore, one of the worlds most densely populated countries. Imaging of Singapores subsurface is required to identify geological faults, model shaking from future earthquakes and provide a framework for [...]
Connecting a broad spectrum of transient slip on the San Andreas fault
Published: 2020-02-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Strain accumulated on the deep extension of some faults are episodically released during transient slow-slip events which can subsequently load the shallow seismogenic region. At the San Andreas fault, the characteristics of slow-slip events are difficult to constrain geodetically due to their small deformation signal. Slow-slip events are often accompanied by coincident tremor bursts composed of [...]
Constraints on mantle viscosity and Laurentide ice sheet evolution from pluvial paleolake shorelines in the western United States
Published: 2020-02-12
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The deformation pattern of the paleoshorelines of extinct Lake Bonneville were among the first features to indicate that Earths interior responds viscoelastically to changes in surface loads (Gilbert, 1885). Here we revisit and extend this classic study of isostatic rebound with updated lake chronologies for Lake Bonneville and Lake Lahontan as well as revised elevation datasets of shoreline [...]
History of on-board equipment improvement for GNSS-A observation with focus on observation frequency
Published: 2020-02-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The Global Navigation Satellite System-Acoustic ranging combination technique (GNSS-A) is a seafloor geodetic technique that enables precise global seafloor positioning to detect subseafloor geophysical phenomena. The technique requires a sea surface observation platform that combines GNSS positioning and acoustic ranging. Currently, a survey vessel is used as the platform, which entails [...]
The 2019 MW 5.7 Changning earthquake, Sichuan Basin, China – a shallow doublet with different faulting styles
Published: 2020-02-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The increased seismic activity of the last ~10 years in Changning county of Sichuan Province comprised just small (mostly ML < 5.0) injection-induced earthquakes. The MW 5.7 earthquake of June 17, 2019 is the largest event ever reported there. Moment tensor of the mainshock was remarkably dominated by a compensated linear vector dipole. We resolve its fine structure showing it was a doublet, [...]
Did sea-level change cause the switch from fissure-type to central-type volcanism at Mount Etna, Sicily?
Published: 2020-02-12
Subjects: Earth Sciences, Physical Sciences and Mathematics, Volcanology
One of the most intriguing aspects of the evolution of Mount Etna (eastern Sicily) is the switch from a fissure-type shield volcano coincident with the Ionian coast to an inland cluster of nested stratovolcanoes close to the currently active centre. Previous geological studies infer that the switch reflects a tectonically-driven rearrangement of the major border faults that direct the Etnean [...]
Impact of topography on earthquake static slip inversions
Published: 2020-02-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Our understanding of earthquakes is limited by our knowledge, and our description, of the physics of the Earth. When solving for subsurface fault slip, it is common practice to assume minimum complexity for the Earths characteristics such as topography, fault geometry and elastic properties. These characteristics are difficult to include in simulations and our knowledge of them is incomplete, [...]
Stress Changes on the Garlock fault during and after the 2019 Ridgecrest Earthquake Sequence
Published: 2020-02-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The recent 2019 Ridgecrest earthquake sequence in Southern California jostled the seismological community by revealing a complex and cascading foreshock series that culminated in a M7.1 mainshock. But the central Garlock fault, despite being located immediately south of this sequence, did not coseismically fail. Instead, the Garlock fault underwent post-seismic creep and exhibited a sizeable [...]
Chalcophile elements track the fate of sulfur at Kīlauea Volcano, Hawai’i
Published: 2020-02-08
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Volcanology
Chalcophile element concentrations in melt inclusions and matrix glasses may be used to investigate low pressure degassing processes, as well as sulfide saturation during crustal fractionation, and mantle melting. Erupted products from Kīlauea Volcano, Hawaiʻi, record three stages of sulfide saturation (in the mantle, crust, and within lava lakes), separated by episodes of sulfide resorption [...]
Urgent Tsunami Computing
Published: 2020-02-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Tsunamis pose a hazard that may strike a coastal population within a short amount of time. To effectively forecast and warn for tsunamis, extremely fast simulations are needed. However, until recently such urgent tsunami simulations have been infeasible in the context of early warning and even for high-resolution rapid post-event assessment. The implementation of efficient tsunami numerical codes [...]
The what, how and why of human coprolite analysis in archaeology
Published: 2020-02-06
Subjects: Earth Sciences, Environmental Sciences, Environmental Studies, Life Sciences, Other Earth Sciences, Physical Sciences and Mathematics, Social and Behavioral Sciences
Coprolites are a highly informative but still underutilized proxy for understanding past environments, palaeodiets, and ancient human health. Here we provide a critical review of the history and current state of research in human coprolite analysis encompassing, macroscopic, microscopic, and biomolecular approaches. We present new data from a number of key sites which demonstrates how new [...]
Comparison of permeability predictions on cemented sandstones with physics-based and machine learning approaches
Published: 2020-02-06
Subjects: Chemical Engineering, Earth Sciences, Engineering, Hydrology, Multivariate Analysis, Petroleum Engineering, Physical Sciences and Mathematics, Statistics and Probability
Permeability prediction has been an important problem since the time of Darcy. Most approaches to solve this problem have used either idealized physical models or empirical relations. In recent years, machine learning (ML) has led to more accurate and robust, but less interpretable empirical models. Using 211 core samples collected from 12 wells in the Garn Sandstone from the North Sea, this [...]