Preprints
Search for earthquake (513 results)
Understanding surface-wave modal content for high-resolution imaging of submarine sediments with Distributed Acoustic Sensing
Published: 2022-04-15
Subjects: Physical Sciences and Mathematics
Ocean Bottom Distributed Acoustic Sensing (OBDAS) is emerging as a new measurement method providing dense, high-fidelity, and broadband seismic observations from fibre-optic cables deployed offshore. In this study, we focus on 33 km of a telecommunication cable located offshore the Sanriku region, Japan, and apply seismic interferometry to obtain a high-resolution 2-D shear-wave velocity (VS) [...]
A source model for earthquakes near the nucleation dimension
Published: 2022-03-22
Subjects: Earth Sciences, Physical Sciences and Mathematics
Earthquake self-similarity is a controversial topic, both observationally and theoretically. Theory predicts a finite nucleation dimension, implying a break of self-similarity below a certain magnitude. While observations of non self-similar earthquake behavior have been reported, their interpretation is challenging due to trade-offs between source and path effects and assumptions on the [...]
Rapid tremor migration during few minute-long slow earthquakes in Cascadia
Published: 2022-03-17
Subjects: Earth Sciences
Slow earthquakes are now commonly found to display a wide range of durations, moments, and slip and propagation speeds. But not all types of slow earthquakes have been examined in detail. Here we probe tremor bursts with durations between 1 and 30 minutes, which are likely driven by few minute-long bursts of aseismic slip. We use a coherence based technique to detect thousands of tremor bursts [...]
Working with Dynamic Earthquake Rupture Models: A Practical Guide
Published: 2022-03-15
Subjects: Physical Sciences and Mathematics
Dynamic rupture models are physics-based simulations that couple fracture mechanics to wave propagation and are used to explain specific earthquake observations or to generate a suite of predictions to understand the influence of frictional, geometrical, stress and material parameters. These simulations can model single earthquakes or multiple earthquake cycles. The objective of this paper is to [...]
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 [...]
Fault slip-rates and Coulomb stress interactions in the intersection zone of the Hope, Kelly and Alpine Faults, South Island, New Zealand
Published: 2022-02-24
Subjects: Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics, Tectonics and Structure
The Hope Fault is a major strike-slip plate boundary fault in the Marlborough Fault Zone of New Zealand’s South Island that transfers slip between the Alpine Fault and Hikurangi subduction zone. We use lidar-based geomorphic and fault mapping, and optically stimulated luminescence (OSL; quartz) and infrared stimulated luminescence (IRSL; feldspar) dating of fault-proximal sedimentary deposits to [...]
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 [...]
Frequency-Difference Backprojection of Earthquakes
Published: 2022-01-20
Subjects: Earth Sciences
Back-projection has proven useful in imaging large earthquake rupture processes. The method is generally robust and does not require many assumptions about the fault geometry or the Earth velocity model. It can be applied in both the time and frequency domain. However, back-projection images are often obtained from records filtered in a narrow frequency range, limiting our ability to uncover the [...]
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 [...]
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 [...]
Imaging evolution of Cascadia slow-slip event using high-rate GPS
Published: 2021-12-24
Subjects: Earth Sciences, Geophysics and Seismology, Tectonics and Structure
The slip history of short-term slow slip event (SSE) is typically inferred from daily Global Positioning System (GPS) data, which, however, cannot image the sub-daily processes, leaving the underlying mechanisms of SSEs elusive. To address the temporal resolution issue, we attempted to employ the kinematic subdaily GPS analysis, which has never been applied to SSE studies because its [...]
Matched Field Processing accounting for complex Earth structure: method and review
Published: 2021-12-16
Subjects: Geophysics and Seismology
Matched Field Processing (MFP) is a technique to locate the source of a recorded wavefield. It is the generalization of plane-wave beamforming, allowing for curved wavefronts. In the standard approach to MFP, simple analytical Green's functions are used as synthetic wavefields that the recorded wavefields are matched against. We introduce an advancement of MFP by utilizing Green's functions [...]
Deep Coseismic Slip in the Cascadia Megathrust can be Consistent with Coastal Subsidence
Published: 2021-12-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
At subduction zones, the down-dip limit of slip represents how deep an earthquake can rupture. For hazards it is important - it controls the intensity of shaking and the pattern of coseismic uplift and subsidence. In the Cascadia Subduction Zone, because no large magnitude events have been observed in instrumental times, the limit is inferred from geological estimates of coastal subsidence during [...]