Preprints
Search for earthquake (504 results)
Structure of the North Anatolian Fault Zone imaged via teleseismic scattering tomography
Published: 2020-08-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Information on fault zone structure is essential for our understanding of earthquake mechanics, continental deformation and our understanding of seismic hazard. We use the scattered seismic wavefield to study the subsurface structure of the North-Anatolian Fault Zone (NAFZ) in the region of the 1999 {\.I}zmit and D\"uzce rupture using data from an 18-month dense deployment of seismometers with a [...]
The 23 June 2020, Mw 7.4 La Crucecita, Oaxaca, Mexico earthquake and tsunami: A Rapid Response Field Survey during COVID-19 crisis
Published: 2020-08-18
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
The 23 June 2020 La Crucecita earthquake occurred at 10:29 hr on the coast of Oaxaca in a Mw 7.4 megathrust event at 22.6 km depth, and triggered a tsunami recorded at Huatulco and Salina Cruz tide gauge stations and a DART off the coast of Mexico. Immediately after the earthquake, a rapid response effort was coordinated by members of the Tsunami and Paleoseismology Laboratory UNAM, despite the [...]
Resolving the Kinematics and Moment Release of Early Afterslip within the First Hours following the 2016 Mw 7.1 Kumamoto Earthquake: Implications for the Shallow Slip Deficit and Frictional Behavior of Aseismic Creep
Published: 2020-08-17
Subjects: Earth Sciences, Environmental Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Continuous measurements of postseismic surface deformation provide insight into variations of the frictional strength of faults and the rheology of the lower crust and upper mantle as stresses following rupture are dissipated. However, due to the difficulty of capturing the earliest phase of afterslip, most analyses have focused on understanding postseismic processes over timescales of [...]
Stress, rigidity and sediment strength control megathrust earthquake and tsunami dynamics
Published: 2020-08-16
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Megathrust faults host the largest earthquakes on Earth which can trigger cascading hazards such as devastating tsunamis. Determining characteristics that control subduction zone earthquake and tsunami dynamics is critical to mitigate megathrust hazards, but is impeded by structural complexity, large spatio-temporal scales, and scarce or asymmetric instrumental coverage. Here we use [...]
A Source Clustering Approach for Efficient Inundation Modeling and Regional Scale PTHA
Published: 2020-08-14
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
For coastal regions on the margin of a subduction zone, near-field megathrust earthquakes are the source of the most extreme tsunami hazards, and are important to handle properly as one aspect of any Probabilistic Tsunami Hazard Assessment (PTHA). Typically, great variability in inundation depth at any point is possible due to the extreme variation in extent and pattern of slip over the fault [...]
Isotropic and Azimuthally Anisotropic Rayleigh Wave Dispersion Across the Juan de Fuca and Gorda Plates and U.S. Cascadia from Earthquake Data and Ambient Noise Two- and Three-Station Interferometry
Published: 2020-08-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Physics
We use data from the Cascadia Initiative (CI) amphibious array and the USArray Transportable Array to construct and compare Rayleigh wave isotropic and azimuthally anisotropic phase speed maps across the Juan de Fuca and Gorda Plates extending onto the continental north- western United States. Results from both earthquakes (28–80 s) as well as ambient noise two- and three-station interferometry [...]
Notes on Seismic Source Models in Elastostatics
Published: 2020-07-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Seismic source models in elastostatics lay the foundations for the popular earthquake deformation formula derived in Okada (1992), which forms key components for many studies in earthquake displacement simulations, earthquake source inversions and ground-motion predictions. However,despite of their importance, we found that the assumptions and proofs of some important theorems about the topic are [...]
Inferring Interseismic Coupling along the Lesser Antilles Arc: a Bayesian Approach
Published: 2020-07-31
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The Lesser Antilles subduction zone is a challenging region when it comes to unraveling its seismogenic behavior. Over the last century, the subduction megathrust has been seismically quiet, with no large thrust event recorded, which raises the question whether this subduction zone is able to produce large interplate earthquakes or not. However, two historical earthquakes in the 19th century, a M [...]
Energetic Rupture and Tsunamigenesis during the 2020 Mw 7.4 La Crucecita, Mexico Earthquake
Published: 2020-07-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
The La Crucecita earthquake ruptured on the megathrust generating strong shaking and a modest, long-lived tsunami. This is a significant earthquake that illuminates important aspects of the behavior of the megathrust as well as the potential related hazards. The rupture is contained within 15-30km depth, ground motions are elevated and the energy to moment ratio is high. We argue that it [...]
Stress perturbations from hydrological and industrial loads and seismicity in the Salt Lake City region
Published: 2020-07-18
Subjects: Earth Sciences, Other Earth Sciences, Physical Sciences and Mathematics
The March 18, 2020 M5.7 Magna earthquake awakened people from decades of seismic quiescence in Salt Lake City, Utah. The event occurred just east of a mine tailings impoundment that receives ~60 million tons/yr of ore waste products since the early 1900s. Here we investigate elastic loading effects due to the anthropogenic mass transfer and various natural hydrological loads. We note a possible [...]
Sedimentary structures discriminations with hyperspectral imaging on sediment cores
Published: 2020-07-17
Subjects: Analytical Chemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Multivariate Analysis, Optics, Physical Sciences and Mathematics, Physics, Sedimentology, Statistical Models, Statistics and Probability
Hyperspectral imaging (HSI) is a non-destructive high-resolution sensor, which is currently under significant development to analyze geological areas with remote devices or natural samples in a laboratory. In both cases, the hyperspectral image provides several sedimentary structures that need to be separated to temporally and spatially describe the sample. Sediment sequences are composed of [...]
Whats down there? The structures, materials and environment of deep-seated tremor and slip
Published: 2020-07-16
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure
Episodic tremor and slow slip (ETS) events occur downdip of the seismogenic zone of numerous subduction megathrusts and plate boundary strike-slip faults. These events represent a fascinating and perplexing mode of fault failure that has greatly broadened our view of earthquake dynamics. In this contribution, we review constraints on the ETS deformation process from both geophysical observations [...]
Precursory slow slip and foreshocks on rough faults
Published: 2020-07-16
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Foreshocks are not uncommon prior to large earthquakes, but their physical mechanism controversial. Two interpretations have been put forward: 1. foreshocks are driven by aseismic nucleation; 2. foreshocks are cascades, with each event triggered by earlier ones. Here we study seismic cycles on faults with fractal roughness at wavelengths exceeding the nucleation length. We perform 2-D [...]
On the effect of grain fragmentation on frictional instabilities in faults with granular gouge
Published: 2020-07-15
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics
The evolution of frictional strength during stick-slip dynamics of a fault system is key to understanding the earthquake nucleation and rupture patterns. In mature faults, granular gouge is produced by wear, comminution or fragmentation during tectonic movements. In this work, we introduce a fragmentation model in the simulation of a sheared granular fault to explore the influence of grain [...]
Seismic swarm preceding the 2017 Mount Agung eruption in Bali (Indonesia) enhanced by the matched filter approach
Published: 2020-07-01
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Intense swarm seismicity took place before the 2017 Mount Agung eruption in Bali (Indonesia). However, the earthquake sequences were not well documented. In addition, there was a substantial delay between the peak of the seismic activity (late September) and the onset of the impending eruption (late November). We applied waveform-based hypocenter relocation and matched filter technique (MFT) to [...]