Preprints
Filtering by Subject: Geophysics and Seismology
Coulomb Threshold Rate-and-State Model for Fault Reactivation: Application to induced seismicity at Groningen
Published: 2021-04-06
Subjects: Environmental Monitoring, Geophysics and Seismology, Tectonics and Structure
A number of recent modeling studies of induced seismicity have used the rate-and-state friction model of Dieterich (1994) to account for the fact that earthquake nucleation is not instantaneous. Notably, the model assumes a population of seismic sources accelerating towards instability with a distribution of intial slip speeds such that they would produce earthquakes steadily in the absence of [...]
Dilatancy and compaction of a rate-and-state fault in a poroelastic medium: Linearized stability analysis
Published: 2021-04-06
Subjects: Applied Mathematics, Geophysics and Seismology, Tectonics and Structure
Faults in the crust at seismogenic depths are embedded in a fluid-saturated, elastic, porous material. Slip on such faults may induce transient pore pressure changes through dilatancy or compaction of the gouge or host rock. However, the poroelastic nature of the crust and the full coupling of inelastic gouge processes and the host rock have been largely neglected in previous analyses. Here, we [...]
Crustal-scale listric geometry of the San Andreas Fault driven by lower crustal flow
Published: 2021-03-31
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The San Andreas Fault (SAF) is one of the dominant components of the transform boundary between the Pacific and the North American Plate. Although the fault is verti-cal-to sub-vertical at shallow (<10 km) depth, it variably dips at angles of ca. 40-70º to the southwest near the western Transverse Range and to the northeast in its southern seg-ment at depths of ca. 10-20 km, and thus can be [...]
Resolving Northern Alaska Earthquake Sequences Using the Transportable Array and Probabilistic Location Methods
Published: 2021-03-25
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Between 2014 and 2017, almost 200 new seismic stations were installed in Alaska and northwestern Canada as part of the EarthScope USArray Transportable Array. These stations currently provide an unprecedented capability for the detection and location of seismic events in regions with otherwise relatively sparse station coverage. Two interesting earthquake sequences in 2018 and 2019 in the [...]
Slab temperature evolution over the lifetime of a subduction zone
Published: 2021-03-25
Subjects: Earth Sciences, Geophysics and Seismology
The thermal evolution of subducting slabs controls a range of subduction processes, yet we lack a robust understanding of how thermal structure develops over a subduction zone’s lifetime. We investigate the time-dependence of slab thermal structure using dynamically consistent, time evolving models. Pressure-temperature (P-T) conditions along the slab Moho and slab top exhibit substantial [...]
Recrystallization of ice enhances the creep and vulnerability to fracture of ice shelves
Published: 2021-03-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics
The initiation of fractures and fast flow in floating regions of Antarctica have the potential to destabilize large regions of the grounded ice sheet, leading to significant sea-level rise. While observations have shown rapid, localized deformation and damage in the margins of fast-flowing glaciers, there remain gaps in our understanding of how rapid deformation affects the viscosity and [...]
New insight into post-seismic landslide evolution processes in the tropics
Published: 2021-03-05
Subjects: Earth Sciences, Geomorphology, Geophysics and Seismology, Hydrology
Earthquakes do not only trigger landslides in co-seismic phases but also elevate post-seismic landslide susceptibility either by causing a strength reduction in hillslope materials or by producing co-seismic landslide deposits, which are prone to further remobilization under the external forces generated by subsequent rainfall events. However, we still have limited observations regarding the [...]
A Self-Supervised Deep Learning Approach for Blind Denoising and Waveform Coherence Enhancement in Distributed Acoustic Sensing Data
Published: 2021-03-04
Subjects: Artificial Intelligence and Robotics, Geophysics and Seismology
Fibre-optic Distributed Acoustic Sensing (DAS) is an emerging technology for vibration measurements with numerous applications in seismic signal analysis, including microseismicity detection, ambient noise tomography, earthquake source characterisation, and active source seismology. Using laser-pulse techniques, DAS turns (commercial) fibre-optic cables into seismic arrays with a spatial sampling [...]
Inversionson: Fully Automated Seismic Waveform Inversions
Published: 2021-03-03
Subjects: Geophysics and Seismology, Numerical Analysis and Scientific Computing, Software Engineering
We present Inversionson, a Python package that fully automates modern full-waveform inversions (FWI). It supports traditional FWI, which uses the same set of events and a single simulation mesh in each iteration, as well as more advanced workflows that exploit the use of dynamic mini-batches and wavefield-adapted meshes. These recently introduced advancements can be time-consuming and [...]
Gradient-boosted equivalent sources
Published: 2021-02-25
Subjects: Earth Sciences, Geophysics and Seismology
The equivalent source technique is a powerful and widely used method for processing gravity and magnetic data. Nevertheless, its major drawback is the large computational cost in terms of processing time and computer memory. We present two techniques for reducing the computational cost of equivalent source processing: block-averaging source locations and the gradient-boosted equivalent source [...]
Episodicity and Migration of Low Frequency Earthquakes modeled with Fast Fluid Pressure Transients in the Permeable Subduction Interface
Published: 2021-02-24
Subjects: Geophysics and Seismology
In many subduction zones, the plate interface hosts intermittent, low-frequency, low-magnitude seismic tremor and low-frequency earthquakes (LFEs). Seismic activity clusters in episodic bursts that migrate along the fault zone in complex ways. Geological structures in fossil tremor source regions testify to large and pervasive variations of fluid pressure and permeability. Here, we explore the [...]
The surface deformation of the 2020 Doğanyol-Sivrice earthquake (Mw 6.8) and the earlier events suggest Mw˂7.0 earthquakes do not create significant surface slip along the East Anatolian Fault Zone
Published: 2021-02-18
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure
The 2020 Mw 6.8 Doğanyol-Sivrice earthquake occurred on the Pütürge Segment of the left-lateral East Anatolian Fault Zone (EAFZ). Our field investigation within 6 weeks after the earthquake suggests the following results. (1) The 2020 earthquake created a ~54-km-long surface deformation zone along the Pütürge Segment. (2) No co-seismic surface slip has been formed after the earthquake. (3) The [...]
Co- and postseismic slip behaviors extracted from decadal seafloor geodesy after the 2011 Tohoku-oki earthquake
Published: 2021-02-16
Subjects: Geophysics and Seismology, Physical Sciences and Mathematics
Investigations of the co- and postseismic processes of the 2011 Tohoku-oki earthquake provide essential information on the seismic cycle in the Japan Trench. Although various postseismic models have been proposed, no consensus has been reached, especially on the along-strike extensions of the main rupture due to the lack of conclusive evidence, even in the coseismic process. To decompose the [...]
Audible acoustics from low-magnitude fluid-induced earthquakes in Finland
Published: 2021-02-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Earthquakes are frequently accompanied by public reports of audible low-frequency noises. In 2018, public reports of booms or thunder-like noises were linked to induced earthquakes during a Engineered Geothermal System project in the Helsinki Metropolitan area. In response, two microphone arrays were deployed to record and study these acoustic signals while stimulation at the drill site [...]
Upper Mantle Radial Anisotropy Under the Indian Ocean from Higher Mode Surface Waves and a Hierarchical Transdismensional Approach
Published: 2021-02-03
Subjects: Earth Sciences, Geophysics and Seismology
We investigated the likelihood of radial anisotropy in the shallow and deep upper mantle, including the mantle transition zone (MTZ) under the Indian Ocean. Seismic anisotropy can be an indicator of mantle deformation through lattice preferred orientation of anisotropic crystals in the mantle. It has thus the potential to illuminate Earth's dynamic interior, but previous seismic tomography [...]