Preprints
Filtering by Subject: Geophysics and Seismology
The influence of a sub-lithospheric layer width on the partitioning of the induced mantle flow, surface motions and subduction dynamics
Published: 2024-04-17
Subjects: Geophysics and Seismology, Other Earth Sciences, Planetary Geology, Tectonics and Structure
The partitioning of the three-dimensional mantle flow into toroidal and poloidal components is a diagnostic element to characterise tectonics regimes, with both fields being substantially active and representative of the contemporary mode of mantle convection. The toroidal:poloidal ratio (T/P) affects several aspects of mantle circulation, including the sinking of the subducting lithosphere into [...]
Systematic Review of the Geothermal Potential in Colombia: Implications as an Alternative Energy Source
Published: 2024-04-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
Through literature review and information processing, the current state of geothermal energy in Colombia, its limitations, possible future uses, environmental impact and the current legal framework were described and analyzed. Approximations were made regarding the sustainability of geothermal energy in the country and its implications. Some of the projects, studies, and research that have been [...]
Digitising sandbox experiments using open-source Structure-from-Motion/photogrammetry/Digital Image Correlation package MicMac
Published: 2024-04-15
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure, Volcanology
Structure-from-Motion and photogrammetry have been implemented in sandbox models to monitor deformation of their surface. Various software packages are available, either open-source of commercial. Some commercial packages are intuitive press-button equipment; these can be very practical to use, but they can be very expensive and unaffordable for most academic laboratories. Another option is [...]
Rapid earthquake-tsunami modeling: The multi-event, multi-segment complexity of the 2024 Mw 7.5 Noto Peninsula Earthquake governs tsunami generation
Published: 2024-04-14
Subjects: Geophysics and Seismology
The January 1st, 2024, moment magnitude (Mw) 7.5 Noto Peninsula earthquake ruptured in complex ways, challenging timely analysis of the tsunami generation. We present rapid and accurate tsunami models informed by a 6-subevent centroid moment tensor (CMT) model that we obtain by inverting teleseismic and strong motion data and validation against geodetic observations. We identify two distinct [...]
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 [...]
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, central Japan. We estimate the rupture evolution of this earthquake from teleseismic P-wave data using the potency-density tensor inversion method, which can give spatiotemporal slip distribution including the information on fault orientations. The result shows a long and quiet initial rupture phase, which overlaps [...]
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 [...]