Preprints
Filtering by Subject: Geophysics and Seismology
Magma chamber detected beneath an arc volcano with high-resolution velocity images
Published: 2022-03-05
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Volcanology
Arc volcanoes are underlain by complex systems of molten-rock reservoirs ranging from melt-poor mush zones to melt-rich magma chambers. Petrological and satellite data indicate that eruptible magma chambers form in the topmost few kilometres of the crust. However, very few chambers have ever been definitively located, suggesting that most are too short-lived or too small to be imaged, which has [...]
Heralds of a Future Eruption? Swarms of Microseismicity beneath the submarine Kolumbo Volcano indicate Opening of near-vertical Fractures exploited by ascending Melts
Published: 2022-02-28
Subjects: Geophysics and Seismology
The Kolumbo submarine volcano in the southern Aegean (Greece) is associated with repeated seismic unrest since at least two decades and the causes of this unrest are still hardly understood. We present a ten-month long microseismicity dataset for the period 2006-2007. The majority of earthquakes clusters in a cone-shaped portion of the crust below Kolumbo. The tip of this cone coincides with a [...]
Along-Dip Segmentation of the Slip Behavior and Rheology of the Copiapó Ridge Subducted in North-Central Chile
Published: 2022-02-24
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure
We studied the along-dip influence of the Copiapó ridge subduction in the Atacama region, North-Central Chile by building a new seismicity catalog, including similar events and non-volcanic tremors (NVTs). We also obtained a 3-D tomographic model for P- and S-waves velocity (and the implied Vp/Vs ratio). We identify down-dip segmentation involving 4 distinct segments: a locked seismogenic zone [...]
psvWave: elastic wave propagation in 2d for Python and C++
Published: 2022-02-22
Subjects: Geophysics and Seismology
We present `psvWave', a basic numerical finite difference solver for Python and C++, specifically targeted at seismologists. The solver is based on the well-established staggered grid approaches developed for the P-SV elastic wave equation. Although its functionality is limited (solely moment tensor sources, only Ricker wavelets source time functions), it does possess the ability to perform [...]
PyMelt: An extensible Python engine for mantle melting calculations
Published: 2022-02-14
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Volcanology
Modelling the melting of Earth’s mantle is crucial for understanding the distribution of volcanic activity on Earth and for testing models of mantle convection and mantle lithological heterogeneity. PyMelt is a new open-source Python library for calculating the melting behaviour of multi-lithology mantle and can be used to predict a number of geophysical and petrological observations, including [...]
Global fast-traveling tsunamis by atmospheric pressure waves on the 2022 Tonga eruption
Published: 2022-02-10
Subjects: Geophysics and Seismology
S-wave modeling of the Showa-Shinzan lava dome in Usu Volcano, Northern Japan, from seismic observations
Published: 2022-02-09
Subjects: Geophysics and Seismology, Tectonics and Structure, Volcanology
To obtain an internal S-wave velocity structure, we conducted a passive seismic campaign with 21 1-Hz seismometers on and around the Showa-Shinzan lava dome, which emerged during the 1943–1945 eruption of Usu Volcano, Japan. Before the campaign, we calibrated seismometers and found slight phase-response differences between seismometers of less than 1–2 degrees. After the campaign, we extracted [...]
The temporal limits of predicting fault failure
Published: 2022-02-09
Subjects: Geophysics and Seismology
Machine learning models using seismic emissions can predict instantaneous fault characteristics such as displacement in laboratory experiments and slow slip in Earth. Here, we address whether the acoustic emission (AE) from laboratory experiments contains information about near-future frictional behavior. The approach uses a convolutional encoder-decoder containing a transformer layer. We use as [...]
Indian Plate paleogeography, subduction, and horizontal underthrusting below Tibet: paradoxes, controvercies, and opportunities
Published: 2022-02-06
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology, Tectonics and Structure, Volcanology
The India-Asia collision zone is the archetype to calibrate geological responses of continent-continent collision, but hosts a paradox: there is no orogen-wide geological record of oceanic subduction after initial collision around 60-55 Ma, yet thousands of kilometers of post-collisional subduction occurred before arrival of unsubductable continental lithosphere that currently horizontally [...]
Trench migration and slab buckling control the formation of the Central Andes
Published: 2022-02-03
Subjects: Geophysics and Seismology, Other Earth Sciences, Tectonics and Structure
The formation of the Central Andes dates back to ~50 Ma, but its most pronounced phase, including the growth of the Altiplano-Puna Plateau and pulsatile tectonic shortening phases, occurred within the last 25 Ma. The reason for this evolution remains unexplained. Using geodynamic numerical modeling we infer that the primary cause of the pulses of tectonic shortening and growth of Central Andes is [...]
Decomposition and Inference of Sources through Spatiotemporal Analysis of Network Signals: The DISSTANS Python Package
Published: 2022-01-30
Subjects: Geophysics and Seismology
Dense, regional-scale, continuously-operating Global Navigation Satellite System (GNSS) networks enable the monitoring of plate motion and regional surface deformation. The spatial extent and density of these networks, as well as the length of observation records, have steadily increased in the past three decades. Software to efficiently analyze the ever-increasing amount of available [...]
Seismic Geomorphology of a Late Cretaceous Turbidite Channel system in Deepwater Kribi/Campo sub-basin, offshore Cameroon
Published: 2022-01-28
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
In this study, a seismic reflection dataset and well-log data were integrated to investigate the geometry and internal configuration of a turbidite channel system within the Late Cretaceous interval of the deep-water Kribi-Campo sub-basin, offshore Cameroon. This interval is characterized by a well-developed submarine channel system consisting of an early and a late-stage channel. [...]
Powering Earth’s ancient dynamo with silicon precipitation
Published: 2022-01-28
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology
Earth's core has produced a global magnetic field for the last 4 Gyrs, presently sustained by inner core growth. Models of the core with high thermal conductivity suggest potentially insufficient power available for the geodynamo prior to inner core formation ~1 Ga. Precipitation of SiO2 from the liquid core might offer an alternative power source for the magnetic field before inner core [...]
Mitigating the effect of errors in source parameters on seismic (waveform) inversion
Published: 2022-01-22
Subjects: Geophysics and Seismology
We investigate the effect of errors in earthquake source parameters on the tomographic inverse problem and propose mitigation strategies for avoiding artefacts caused by such errors. Source errors can be quite significant: mislocation errors can amount to tens of kilometres both horizontally and vertically, while fault plane uncertainties can be of the order of tens of degrees. To analyse how [...]
Bayesian differential moment tensor inversion: theory and application to the North Korea nuclear tests
Published: 2022-01-21
Subjects: Geophysics and Seismology
Moment tensors are key to seismic discrimination but often require accurate Green’s functions for estimation. This limits the regions, frequency bands, and wave types in moment tensor inversions. In this study, we propose a differential moment tensor inversion (diffMT) method that uses relative measurements to remove the path effects shared by clustered events, thereby improving the accuracy of [...]