Preprints
Filtering by Subject: 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: 2022-02-08
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: 2022-02-05
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: 2022-01-29
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: 2022-01-27
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: 2022-01-21
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: 2022-01-20
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 [...]
A discontinuous Galerkin method for sequences of earthquakes and aseismic slip on multiple faults using unstructured curvilinear grids
Published: 2022-01-18
Subjects: Geophysics and Seismology
Physics-based simulations provide a path to overcome the lack of observational data which is hampering a holistic understanding of earthquake faulting and crustal deformation across the vastly varying space-time scales governing the seismic cycle. However, simulations of sequences of earthquakes and aseismic slip (SEAS) including more than one fault, complex geometries, and elastic [...]
Resolving the location of small intracontinental earthquakes using Open Access seismic and geodetic data: lessons from the 18 January 2017 mb 4.3 Tenere, Niger, earthquake
Published: 2022-01-14
Subjects: Geophysics and Seismology, Tectonics and Structure
A low-magnitude earthquake was recorded on January 18, 2017, in the T\'{e}n\'{e}r\'{e} desert in Niger. This intraplate region is exceptionally sparsely covered with seismic stations and the closest open seismic station, G.TAM in Algeria at a distance of approximately 600 km, was unusually and unfortunately not operational at the time of the event. Body-wave magnitude estimates range from $m_b [...]
Variations in Earth's 1D viscosity structure in different tectonic regimes
Published: 2022-01-14
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Past estimates of Earth’s mantle viscosity profile using the long-wavelength geoid suggest an increase in viscosity from the upper to lower mantle of roughly 2-3 orders of magnitude. We use a spatio-spectral localization technique with the geoid to estimate a series of locally constrained viscosity profiles covering two unique regions, the Pacific and Atlantic hemispheres. The Pacific region [...]
Experimental multiblast craters and ejecta — seismo-acoustics, jet characteristics, craters, and ejecta deposits and implications for volcanic explosions
Published: 2022-01-08
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
Blasting experiments were performed that investigate multiple explosions that occur in quick succession in unconsolidated ground and their effects on host material and atmosphere. Such processes are known to occur during phreatomagmatic eruptions at various depths, lateral locations, and energies. The experiments follow a multi-instrument approach in order to observe phenomena in the atmosphere [...]
Seismic velocity recovery in the subsurface: transient damage and groundwater drainage following the 2015 Gorkha earthquake, Nepal
Published: 2022-01-04
Subjects: Geophysics and Seismology, Other Earth Sciences, Physical Sciences and Mathematics
Shallow earthquakes frequently disturb the hydrological and mechanical state of the subsurface, with consequences for hazard and water management. Transient post-seismic hydrological behaviour has been widely reported, suggesting that the recovery of material properties (relaxation) following ground shaking may impact groundwater fluctuations. However, the monitoring of seismic velocity [...]
Structural traps and seals for expanding CO2 storage in the northern Horda Platform, North Sea
Published: 2021-12-24
Subjects: Geology, Geophysics and Seismology, Oil, Gas, and Energy, Other Earth Sciences, Other Environmental Sciences, Stratigraphy, Tectonics and Structure
The maturation of geological CCS along the Norwegian Continental Shelf is ongoing in the Norwegian North Sea, however, more storage sites are needed to reach climate mitigation goals by 2050. In order to augment the Aurora site and expand CO2 storage in the northern Horda Platform, regional traps and seals must be assessed to better understand the area’s potential. Here, we leverage wellbore and [...]