Preprints
Filtering by Subject: Geophysics and Seismology
The influence of mantle structure on dynamic topography in southern Africa
Published: 2024-04-03
Subjects: Geophysics and Seismology
Due to relatively high terrain and negligible active tectonics, the southern Africa region boasts over thirty independent estimates of dynamic topography. These published estimates display a wide variance due to both the variety of methods used in computation and a lack of constraints on the regional mantle structure. Here we show that a focus on regional mantle structure is important to generate [...]
AxiSEM3D - an introduction to using the code and its applications
Published: 2024-03-19
Subjects: Geophysics and Seismology, Planetary Geophysics and Seismology
Welcome to the wonderful world of AxiSEM3D, a flexible, high-performance computational method for solving the elastodynamic wave equation in three-dimensional, hetereogeneous media. It has been used in seismology for the Earth, the Sun, the Moon, and many of other rocky planets and moons of the Solar System. In this manual, we will explore the practicalities of using this code, touching on the [...]
Brittle origin of off-fault fractures during the 2019 Ridgecrest earthquake sequence
Published: 2024-03-15
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure
According to the classical Mohr-Coulomb-Anderson theory, faults form at an angle from the largest regional compressive stress that is approximately 30° for most rocks. However, real settings are more complex and faults often present orientations inconsistent with the angles predicted by the classical theory applied to the present-day regional stress field. The Ridgecrest region hosts a young [...]
A Multiplex Rupture Sequence under Complex Fault Network due to Preceding Earthquake Swarms during the 2024 Mw 7.5 Noto Peninsula, Japan, Earthquake
Published: 2024-03-14
Subjects: Geophysics and Seismology
A devastating earthquake with moment magnitude 7.5 occurred in the Noto Peninsula in central Japan on 1 January 2024. We estimate the rupture evolution of this earthquake from teleseismic P-wave data using the potency-density tensor inversion method, which provides information on the spatiotemporal slip distribution including fault orientations. The results show a long and quiet initial rupture [...]
Observations from the Seafloor: Ultra-low-frequency Ambient Ocean-Bottom Nodal Seismology at the Amendment Field
Published: 2024-02-27
Subjects: Geophysics and Seismology
Large-scale ocean-bottom node (OBN) arrays of 1000s of multi-component instruments deployed over 1000s of square kilometers have been used successfully for active-source seismic exploration activities including full waveform inversion (FWI) at exploration frequencies above about 2.0 Hz. The analysis of concurrently recorded lower-frequency ambient wavefield data, though, is only just beginning. A [...]
Precise estimation of the GPS To Galileo Time Offset: an experimental setup and its associated processing method
Published: 2024-02-15
Subjects: Aerospace Engineering, Earth Sciences, Geophysics and Seismology, Navigation, Guidance, Control and Dynamics, Other Earth Sciences, Other Engineering
Although the satellite navigation systems are all in their definition based on the international atomic time (TAI), each system has its own realization. There is therefore a difference, variable in time, between different realizations of the same time systems. Thus, the time of the GPS (GPST) and Galileo (Galileo System Time, GST) systems differ in their realization by some nanoseconds. This [...]
DAS to Discharge: Using Distributed Acoustic Sensing (DAS) to infer glacier runoff
Published: 2024-02-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
Observations of glacier melt and runoff are of fundamental interest in the study of glaciers and their interactions with their environment. Considerable recent interest has developed around distributed acoustic sensing (DAS), a sensing technique which utilizes Rayleigh backscatter in fiber optic cables to measure the seismo-acoustic wavefield in high spatial and temporal resolution. Here, we [...]
Distributed Acoustic Sensing for aftershock monitoring: the case of the 2019 Mw 4.9 Le Teil earthquake
Published: 2024-01-30
Subjects: Geophysics and Seismology
Recent developments in Distributed Acoustic Sensing (DAS) have greatly expanded our capabilities for dense geophysical instrumentation by tapping into existing (but unused) fibre-optic telecommunication networks. Leveraging these so-called "dark fibres" permits an extremely rapid deployment of thousands of vibration sensors over distances of several tens of kilometres, which is ideal for rapid [...]
Quaternary and Pliocene sea-level changes at Camarones, central Patagonia, Argentina
Published: 2024-01-20
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Tectonics and Structure
Geological indicators of past relative sea level changes are fundamental to reconstruct the extent of former ice sheet during past interglacials, which are considered analogs for future climate conditions. Four interglacials, dating from Holocene to Pliocene, have left sea-level imprints in the proximity of the coastal town of Camarones in Central Patagonia, Argentina. Sea-level index points were [...]
DASCore: a Python Library for Distributed Fiber Optic Sensing
Published: 2024-01-18
Subjects: Earth Sciences, Geophysics and Seismology, Numerical Analysis and Scientific Computing
In the past decade, distributed acoustic sensing (DAS) has enabled many new monitoring applications in diverse fields including hydrocarbon exploration and extraction; induced, local, regional, and global seismology; infrastructure and urban monitoring; and several others. However, to date, the open-source software ecosystem for handling DAS data is relatively immature. Here we introduce DASCore, [...]
Transient aseismic vertical deformation across the Pisia-Skinos normal fault (Gulf of Corinth, Greece)
Published: 2024-01-18
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure
Geodetically-derived deformation rates are sometimes used to infer seismic hazard, implicitly assuming that short-term (annual-decadal) deformation is representative of longer-term deformation. This is despite geological observations indicating that deformation/slip rates are variable over a range of timescales. Using geodetic data from 2016-2021, we observe an up to 7-fold increase in vertical [...]
The Effects of Characteristic Slip Distance on Earthquake Nucleation Styles in Fully Dynamic Seismic Cycle Simulations
Published: 2024-01-17
Subjects: Earth Sciences, Geophysics and Seismology
Earthquake nucleation is a crucial preparation process of the following coseismic rupture propagation. Under the framework of rate-and-state friction (RSF), it was found that the ratios of a to b parameters control whether earthquakes nucleate as an expanding crack or a fixed length. However, the characteristic slip distance DRS controls the weakening efficiency of fault strength and can [...]
Dynamic evolution of competing same-dip double subduction: New perspectives of the Neo-Tethyan plate tectonics
Published: 2024-01-15
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure
Same-dip double-subduction (SDDS) systems are widely reported from present as well as past complex convergent plate tectonic configurations. However, the dynamics of their evolution is poorly understood, which is crucial to conceptualize anomalous subducting slab kinematics and associated observed geological phenomena, such as irregular trench migration rates, high convergence velocities, and [...]
The Stability of Frictional Sliding on Dip-Slip and Finite-Length Faults
Published: 2024-01-12
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Sensitivity Analysis of Global Kinematics on Mantle Structure Using Automatically Generated Adjoint Thermochemical Convection Codes
Published: 2023-12-11
Subjects: Earth Sciences, Geophysics and Seismology, Numerical Analysis and Scientific Computing, Tectonics and Structure
Within the past 30 years, numerical models of mantle convection have been able to predict observations on Earth and planets, and among them tectonics. The possibility of building inverse problems in global geodynamics became concrete, and often involve the development of adjoint codes. Such tools provide efficient ways to estimate sensitivities of misfit functions relative to control parameters, [...]