Preprints
Filtering by Subject: Geophysics and Seismology
Ringing mountain ranges: Teleseismic signature of the interaction of high-frequency wavefields with near-source topography at the Degelen nuclear test site
Published: 2024-05-26
Subjects: Geophysics and Seismology
Over the last decade there has been an international effort to find methods to recover and digitize recordings from historical earthquakes and explosions that occurred during the 1950’s through to the 1980’s. Making these recordings accessible in digital format offers opportunities to study what signatures are encoded in the data, and to apply state-of-the-art techniques and methods to historical [...]
Predictable recovery rates in near-surface materials after earthquake damage
Published: 2024-05-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquakes introduce transient mechanical damage in the subsurface, which causes postseismic hazards and can take years to recover. This observation has been linked to relaxation, a phenomenon observed in a wide class of materials after straining perturbations, but its duration after earthquake ground shaking has not been constrained. Here, we analyse the effects of two successive large [...]
Non-typical supershear rupture: fault heterogeneity and segmentation govern unilateral supershear and cascading multi-fault rupture in the 2021 Mw 7.4 Maduo Earthquake
Published: 2024-05-05
Subjects: Geophysics and Seismology
Previous geodetic and teleseismic observations of the 2021 Mw 7.4 Maduo earthquake imply surprising but difficult-to-constrain complexity, including rupture across multiple fault segments and supershear rupture. Here, we present an integrated analysis of multi-fault 3D dynamic rupture models, high-resolution optical correlation analysis, and joint optical-InSAR slip inversion. Our preferred [...]
An analysis of the dynamic range of Distributed Acoustic Sensing for Earthquake Early Warning
Published: 2024-04-27
Subjects: Geophysics and Seismology
Owing to its deployment and sensing characteristics, Distributed Acoustic Sensing (DAS) has been touted as a promising technology for low-cost and low-latency Earthquake Early Warning (EEW). While preliminary experiments conducted by several research groups have yielded encouraging results, it must be acknowledged that these EEW feasibility studies were performed only on low-magnitude events. [...]
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 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 [...]