Preprints
Filtering by Subject: Geophysics and Seismology
Archaean basalts record evidence of lithospheric extension prior to cratonisation
Published: 2025-05-23
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology
The dynamics of Earth’s early mantle remain enigmatic. A wide range of tectonic settings have been proposed for the Archaean eon prior to cratonisation, a time from which few samples are preserved in the geological record. Here, we reexamine this topic by estimating temperatures and depths of melt generation in the late Archaean mantle using a new geochemical data compilation of mafic igneous [...]
Solution of the Bloch Equation Based on Spectral Diagonalization and Matrix Exponential Integration: Modeling of SSFP for SNMR
Published: 2025-05-10
Subjects: Earth Sciences, Geophysics and Seismology, Hydrology, Soil Science
We present a spectral-diagonalization-based matrix exponential integration (SD-MEI) algorithm for efficient and stable solutions of fully coupled Bloch equations in surface nuclear magnetic resonance (SNMR). Conventional explicit numerical methods exhibit cumulative discretization errors and escalating computational costs due to step-size dependence and finite precision limitations. SD-MEI [...]
Theoretical background for full-waveform inversion with distributed acoustic sensing and integrated strain sensing
Published: 2025-05-01
Subjects: Geophysics and Seismology
Full-waveform inversion (FWI) is a powerful imaging technique that produces high-resolution subsurface models. In seismology, FWI workflows are traditionally based on seismometer recordings. The development of fibre-optic sensing presents opportunities for harnessing information from new types of measurements. With dense spatial and temporal sampling, fibre-optic sensing captures the seismic [...]
Earthquake faults recorded in the near-shore bathymetry of Japan's back-arc
Published: 2025-04-27
Subjects: Geology, Geomorphology, Geophysics and Seismology, Tectonics and Structure
The eastern margin of the Sea of Japan is a zone of great seismic and tsunami hazard due to multiple offshore and nearshore reverse faults as shown by the 2024 Mw 7.5 Noto Peninsula Earthquake. Here we compare coseismic deformation of the 2024 Noto Peninsula Earthquake with 4767 individual marine terraces spanning the last Myr. This reveals that the earthquake faults started slipping between 326 [...]
Transforming Total Field Anomaly into Anomalous Magnetic Field: Using Dual-Layer Gradient-Boosted Equivalent Sources
Published: 2025-04-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Potential field data often require interpolation onto a regular grid at constant height before further analysis. A widely used approach for this is the equivalent sources technique, which has been adapted over time to improve its computational efficiency and accuracy of the predictions. However, many of these approaches still face challenges, including border effects in the predictions or [...]
Application of automatic differentiation to the inversion of nonlinear mantle rheology using plate motion and topography
Published: 2025-04-24
Subjects: Geophysics and Seismology, Physical Sciences and Mathematics
The rheological properties of the mantle govern plate tectonics and mantle convection, yet constraining the rheological parameters remains a significant challenge. Laboratory experiments are usually performed under different temperature-pressure-strain-rate conditions than those of natural environments, leading to substantial uncertainties when extrapolating the parameters to real-world [...]
Optimizing data usage in regional body wave tomography by using asynchronous network data and relative sensitivity kernels: an example from Patagonia
Published: 2025-04-21
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
A very frequent approach for studying lithospheric processes is to deploy temporary seismological networks in dedicated areas and to map the mantle structures with different approaches. One of them is the well-established relative travel time body wave tomography. Different circumstances often lead to a non uniform deployment of stations both in space and time, and a wish to combine data which [...]
A multiple asymmetric bilateral rupture sequence derived from the peculiar tele-seismic P-waves of the 2025 Myanmar earthquake
Published: 2025-04-11
Subjects: Geophysics and Seismology
A large strike-slip earthquake occurred in central Myanmar on March 28, 2025. The aftershock distribution suggests that the rupture of the mainshock propagated mainly to the south. However, a large-amplitude phase lasting 20 s, followed by a short-period pulse-like phase, were observed at the stations on the north side of the source, while on the south side tremor-like phases with multiple peaks [...]
Deep source regions for Patagonia backarc volcanism imaged by finite frequency body wave tomography
Published: 2025-04-09
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
The subduction of Chile Ridge beneath South America beginning 12-16 Myr ago opened a gap in the subducting slab beneath southern Patagonia, which migrated northward and is located today at 46oS. Geodynamic processes associated with the slab window are poorly understood. Here we apply finite-frequency P and S body wave tomography to seismic data from several temporary arrays as well as regional [...]
A New Fault Model for the 1933 Long Beach Earthquake, Long Beach Area, Southern California
Published: 2025-04-06
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
Newly identified thrust faults and their corresponding thrust sheets, combined with recent micro-earthquake epicenters, better explain anomalous rupture data observed during the 1933 Long Beach Earthquake than previous models based exclusively on Newport-Inglewood Fault Zone strike-slip faulting. A high-quality 45 km2 3D seismic dataset was recorded in 2017, centered along the Seal Beach [...]
Robust directional analysis of magnetic microscopy images using non-linear inversion and iterative Euler deconvolution
Published: 2025-03-30
Subjects: Geophysics and Seismology
The first step in scientific data acquisition often involves analyzing entire samples, providing only a general characterization of the material. Enhancing data acquisition by improving spatial resolution and isolating the underlying phenomena contributing to the overall signal has become a central direction in various scientific fields. In paleomagnetism, this advancement is now possible with [...]
The complex rupture evolution of the long and slow, tsunamigenic 2021 South Sandwich Islands earthquake
Published: 2025-03-28
Subjects: Geophysics and Seismology
On August 21, 2021 a large earthquake occurred in the South Sandwich subduction zone, and the associated tsunami was widely observed. In order to robustly analyse the detailed seismic source process of this long-source duration (over 200 s) event occurring in a convexly shaped subduction zone, we applied the Potency Density Tensor Inversion with a non-rectangular and non-planar source surface to [...]
Fully-dynamic seismic cycle simulations in co-evolving fault damage zones controlled by damage rheology
Published: 2025-03-27
Subjects: Geophysics and Seismology
Both short-term coseismic off-fault damage and long-term fault growth during interseismic periods have been suggested to contribute to the formation and evolution of fault damage zones. Most previous numerical models focus on simulating either off-fault damage in a single earthquake or off-fault plasticity in seismic cycles ignoring changes of elastic moduli. Here we developed a new method to [...]
First-order Control Factors for Ocean-bottom Ambient Seismology Interferometric Observations
Published: 2025-03-24
Subjects: Geophysics and Seismology
Expanding the lower-frequency band of seismic energy sources, particularly below 2.0~Hz, is crucial for improving the stability and effectiveness of full waveform inversion (FWI). Conventional active sources including airguns are ineffective at generating low-frequency wavefields, while ambient seismic wavefields, driven by natural energy sources such as ocean waves, offer a promising [...]
Ocean-bottom Seismic Interferometry in Coupled Acoustic-Elastic Media
Published: 2025-03-24
Subjects: Geophysics and Seismology
Green’s function expressions for seismic interferometry in acoustic and elastic media have been extensively studied and applied across a wide range of applications, including surface-wave tomography and generating virtual shot gathers. However, analogous expressions for coupled acoustic-elastic media systems remain absent, despite their importance for analysing cross-correlation wavefields from [...]