Preprints
Filtering by Subject: Geophysics and Seismology
The 2018-2019 seismo-volcanic crisis east of Mayotte, Comoros islands: seismicity and ground deformation markers of an exceptional submarine eruption
Published: 2019-03-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology
On May 10th, 2018, an unprecedented long and intense seismic crisis started offshore, east of Mayotte, the easternmost of the Comoros volcanic islands. The population felt hundreds of events. Over the course of one year, 32 earthquakes with magnitude greater than 5 occurred, including the largest event ever recorded in the Comoros (Mw = 5.9 on May 15th, 2018). Earthquakes are clustered in space [...]
Dynamics of the lithosphere and upper mantle in light of seismic anisotropy
Published: 2019-02-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic anisotropy records continental dynamics in the crust and convective deformation in the mantle. Deciphering this archive holds huge promise for our understanding of the thermo-chemical evolution of our planet, but doing so is complicated by incomplete imaging and non-unique interpretations. Here, we focus on the upper mantle and review seismological and laboratory constraints as well as [...]
RSFit3000: A MATLAB GUI-Based Program for Determining Rate and State Frictional Parameters from Experimental Data
Published: 2019-02-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We present a MATLAB, graphical user interface (GUI) software package for analyzing rate and state friction experiments. Called RSFit3000, the software allows users to easily constrain frictional parameters by fitting velocity step and slide-hold-slide events using the aging and slip law forms for state variable evolution. RSFit3000 includes features for removing strain hardening/weakening trends [...]
Can a Raspberry Shake Seismic Network Complement a National Seismic Network? A case study in Haiti
Published: 2019-02-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Complex networks of high-tech sensors are tough to operate and maintain in developing countries – but new low-costs, low-maintenance instruments may help. Because they are “connected objects” they also provide new opportunities to engage the civil society in citizen-science. Here we describe a seismological instrumentation experiment in Haiti with sensors that cost less than 500$ and can be [...]
Technical note on the multi-GNSS, multi-frequency and near real-time ionospheric TEC monitoring system for South America
Published: 2019-02-21
Subjects: Atmospheric Sciences, Earth Sciences, Geophysics and Seismology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Development of regional services able to provide ionospheric total electron content (TEC) maps with a high spatial resolution, and in near real-time, are of high importance for applications and the research community. We provide here the methodologies, and a preliminary assessment, of such a system. The system relies on the public Global Navigational Satellite Systems (GNSS) infrastructure in [...]
Deep Learning Application for 4D Pressure Saturation Inversion Compared to Bayesian Inversion on North Sea Data
Published: 2019-02-21
Subjects: Applied Statistics, Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Statistics and Probability
In this work we present a deep neural network inversion on map-based 4D seismic data for pressure and saturation. We present a novel neural network architecture that trains on synthetic data and provides insights into observed field seismic. The network explicitly includes AVO gradient calculation within the network as physical knowledge to stabilize pressure and saturation changes separation. [...]
Bayesian Dynamic Finite-Fault Inversion: 2. Application to the 2016 Mw6.2 Amatrice, Italy, Earthquake
Published: 2019-02-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
In 2016 Central Italy was struck by a sequence of three normal faulting earthquakes with moment magnitude (Mw) larger than 6. The Mw 6.2 Amatrice event (08/24) was the first one, causing building collapse and about 300 casualties. The event was recorded by a uniquely dense network of seismic stations. Here we perform its dynamic source inversion to infer the fault friction parameters and stress [...]
Coupled, Physics-based Modeling Reveals Earthquake Displacements are Critical to the 2018 Palu, Sulawesi Tsunami
Published: 2019-02-16
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The September 2018, Mw 7.5 Sulawesi earthquake occurring on the Palu-Koro strike-slip fault system was followed by an unexpected localized tsunami. We show that direct earthquake-induced uplift and subsidence could have sourced the observed tsunami within Palu Bay. To this end, we use a physics-based, coupled earthquake-tsunami modeling framework tightly constrained by observations. The model [...]
Modeling megathrust earthquakes across scales: one-way coupling from geodynamics and seismic cycles to dynamic rupture
Published: 2019-02-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Taking the full complexity of subduction zones into account is important for realistic modelling and hazard assessment of subduction zone seismicity and associated tsunamis. Studying seismicity requires numerical methods that span a large range of spatial and temporal scales. We present the first coupled framework that resolves subduction dynamics over millions of years and earthquake dynamics [...]
Structural architecture and composition of crystalline basement offshore west Norway
Published: 2019-02-14
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Numerous studies have investigated the geodynamic history and lithological composition of the Proterozoic basement, Caledonian nappes, and Devonian extensional basins and shear zones onshore west Norway. However, the offshore continuation of these structures, into the northern North Sea, where they are suspected to have influenced the structural evolution of the North Sea rift, is largely [...]
Bayesian Dynamic Finite-Fault Inversion: 1. Method and Synthetic Test
Published: 2019-02-13
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Dynamic earthquake source inversions aim to determine the spatial distribution of initial stress and friction parameters leading to dynamic rupture models that reproduce observed ground motion data. Such inversions are challenging, particularly due to their high computational burden, thus so far only few attempts have been made. Using a highly efficient rupture simulation code, we introduce a [...]
Surface Wave Imaging using Distributed Acoustic Sensing Deployed on Dark Fiber: Moving Beyond High Frequency Noise
Published: 2019-02-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Several recent studies have demonstrated that Distributed Acoustic Sensing (DAS) can utilize existing subsurface telecom fiber (i.e. dark fiber) for high quality seismic measurements. Researchers to date have shown that this sensing combination, coupled to ambient noise interferometry techniques, can effectively image the shallow subsurface (< 30 m) using vehicle and infrastructure noise (f = [...]
Dynamic Rupture Propagation on Fault Planes with Explicit Representation of Short Branches
Published: 2019-02-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Active fault zones are homes for a plethora of complex structural and geometric features that are expected to affect earthquake rupture nucleation, propagation, and arrest, as well as interseismic deformation. Simulation of these complexities have been largely done using continuum plasticity or scalar damage theories. In this paper, we use a highly efficient novel hybrid finite element-spectral [...]
The Future of Broadband Passive Seismic Acquisition
Published: 2019-02-06
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
It is an exciting time to be a seismologist. In November 2018, the InSight lander touched down on Mars and the first seismometer was deployed on another planet. This incredible feat means planetary seismologists are currently searching for marsquakes and will hopefully soon be providing images of its interior and helping us to understand how rocky planets form. However, we have been doing this [...]
Effect of fault roughness on aftershock distribution: Plastic off-fault material properties
Published: 2019-02-05
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
We perform spontaneous earthquake rupture simulations on rough strike- slip faults with off-fault plastic material properties. We examine the off-fault stress change and damage pattern resulting from dynamic fault slip in the near-fault region. We use the stress output from each simulation to calculate the Coulomb failure function (CFF). We calculate the CFF values at the extensional side of the [...]