Preprints
Filtering by Subject: Earth Sciences
Constraints on North Anatolian Fault zone width in the crust and upper mantle from S-wave teleseismic tomography
Published: 2018-04-09
Subjects: Earth Sciences, Geophysics and Seismology, Life Sciences, Physical Sciences and Mathematics
We present high resolution S‐wave teleseismic tomography images of the western segment of the North Anatolian Fault (NAFZ) in Turkey using teleseismic data recorded during the deployment period of the DANA array. The array comprised 66 stations with a nominal station spacing of 7 km, thus permitting a horizontal and vertical resolution of approximately 15 km. We use the current S‐wave results [...]
Numerical models of P-T, time and grain-size controls on Ar diffusion in biotite: an aide to interpreting 40Ar/39Ar ages
Published: 2018-04-06
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
40Ar/39Ar dating of biotite is used extensively to determine the timing of cooling and exhumation in metamorphic terranes. 40Ar/39Ar age interpretations commonly assume that 40Ar diffuses out of biotite through temperature-dependent volume diffusion, and therefore that the age represents the time at which biotite cooled through the nominal closure temperature. Several processes or scenarios [...]
Asthenosphere flow modulated by megathrust earthquake cycles
Published: 2018-04-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Subduction megathrusts develop the largest earthquakes, often close to large population centers. Understanding the dynamics of deformation at subduction zones is therefore important to better assess seismic hazards. Here, I develop consistent earthquake cycle simulations that incorporate localized and distributed deformation based on laboratory-derived constitutive laws by combining boundary and [...]
Stratigraphy of Aeolis Dorsa, Mars: stratigraphic context of the great river deposits
Published: 2018-04-03
Subjects: Astrophysics and Astronomy, Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics, The Sun and the Solar System
Unraveling the stratigraphic record is the key to understanding ancient climate and past climate changes on Mars (Grotzinger et al. 2011). Stratigraphic records of river deposits hold particular promise because rain or snowmelt must exceed infiltration plus evaporation to allow sediment transport by rivers. Therefore, river deposits when placed in stratigraphic order could constrain the number, [...]
Coulomb stress transfer and fault interaction over millennia on non-planar active normal faults: the Mw 6.5-5.0 seismic sequence of 2016-2017, central Italy.
Published: 2018-03-27
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
In order to investigate the importance of including strike-variable geometry and the knowledge of historical and palaeoseismic earthquakes when modelling static Coulomb stress transfer and rupture propagation, we have examined the August–October 2016 A.D. and January 2017 A.D. central Apennines seismic sequence (Mw 6.0, 5.9, 6.5 in 2016 A.D. (INGV) and Mw 5.1, 5.5, 5.4, 5.0 in 2017 A.D. [...]
Time-dependent compaction as a mechanism for regular stick-slips
Published: 2018-03-27
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Owing to their destructive potential, earthquakes receive considerable attention from laboratory studies. In friction experiments, stick-slips are studied as the laboratory equivalent of natural earthquakes, and numerous attempts have been made to simulate stick-slips numerically using the Discrete Element Method (DEM). However, while laboratory stick-slips commonly exhibit regular stress drops [...]
Rheological transitions facilitate fault-spanning ruptures on seismically active and creeping faults
Published: 2018-03-27
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The apparent stochastic nature of earthquakes poses major challenges for earthquake forecasting attempts. Physical constraints on the seismogenic potential of major fault zones may aid in improving seismic hazard assessments, but the mechanics of earthquake nucleation and rupture are obscured by the complexity that faults display. In this work, we investigate the mechanisms behind giant [...]
Ambient noise image Campi Flegrei 2011-2013
Published: 2018-03-27
Subjects: Earth Sciences, Environmental Monitoring, Environmental Sciences, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Earthquakes at Campi Flegrei have been low-magnitude and sparse for more than thirty years, denying onshore monitoring observations of their usual source for structural constraint: seismic tomography. Here, we used ambient seismic noise recorded between 2011 and 2013 to reconstruct period-dependent Rayleigh-wave velocity maps of caldera-wide structures and volcanic reservoirs. The lowest [...]
Knowledge in the Dark: Scientific Challenges and Ways Forward
Published: 2018-03-26
Subjects: Earth Sciences, Education, Environmental Sciences, Environmental Studies, Higher Education, Language and Literacy Education, Liberal Studies, Library and Information Science, Life Sciences, Medicine and Health Sciences, Physical Sciences and Mathematics, Public Health, Science and Mathematics Education, Social and Behavioral Sciences
We propose the concept of knowledge in the dark – or short: dark knowledge – and outline how it can help clarify why in our current era of Big Data, the knowledge (i.e. evidence-based understanding) of people does not seem to be substantially increasing despite a rapid increase in produced data and information. Key reasons underlying dark knowledge are: (1) the production of biased, erroneous or [...]
Enhanced velocity based pore pressure prediction using lithofacies clustering: A case study from a reservoir with complex lithology in Dezful Embayment, SW Iran
Published: 2018-03-21
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The primary goal of this paper is to improve accuracy and reliability of the conventional Bowers and Tau methods in a reservoir with complex lithology. We demonstrate the capability of the proposed method through a case study in a reservoir in the Southwest of Iran. Velocity based pore pressure prediction methods are widely accepted as a routine technique in the petroleum industry. Despite recent [...]
Missing emissions from post-monsoon agricultural fires in northwestern India: regional limitations of MODIS burned area and active fire products
Published: 2018-03-21
Subjects: Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Sciences, Physical Sciences and Mathematics
A rising source of outdoor emissions in northwestern India is crop residue burning, occurring after the monsoon (kharif) and winter (rabi) crop harvests. In particular, post-monsoon rice residue burning, which occurs annually from October to November and is linked to increasing mechanization, coincides with meteorological conditions that enhance short-term air quality degradation. Here we examine [...]
Evaluating models of Coulomb stress transfer: Is variable fault geometry important?
Published: 2018-03-21
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
To determine the importance of receiver fault geometry in Coulomb stress calculations a new methodology is presented to model faults with variable geometry. Although most models use planar faults, it is known that these are inaccurate representations of faults observed in the field. The central Italian Apennines are chosen as a straightforward tectonic system with well‐exposed normal faults to [...]
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 [...]
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 [...]