Geophysical observations from the 2011 moment magnitude (M(w)) 9.0 Tohoku-Oki, Japan earthquake allow exploration of a rare large event along subduction megathrust. Models for this indicate that distribution coseismic fault slip exceeded 50 meters in places. Sources high-frequency seismic waves delineate edges deepest portions and do not simply correlate with locations peak slip. Relative to M(w) 8.8 2010 Maule, Chile earthquake, Tohoku-Oki was deficient radiation--a difference we attribute...

Abstract The estimation of finite fault earthquake source models is an inherently underdetermined problem: there no unique solution to the inverse problem determining rupture history at depth as a function time and space when our data are limited observations Earth's surface. Bayesian methods allow us determine set all plausible model parameters that consistent with observations, priori assumptions about physics wave propagation, for observation errors due limitations in forward model....

This study lays the groundwork for a new generation of earthquake source models based on general formalism that rigorously quantifies and incorporates impact uncertainties in fault slip inverse problems. We distinguish two sources uncertainty when considering discrepancy between data forward model predictions. The first class error is induced by imperfect measurements often referred to as observational error. second generally neglected corresponds prediction error, due modelling. Yet can be...

The seismic moment tensors for certain types of sources, such as volcanic earthquakes and nuclear explosions are expected to contain an isotropic component. Some earlier efforts calculate the component these sources flawed due error in method Jost & Herrmann. We corrected after Herrmann Hutchensen found great improvement recovery non-double-couple that include Tests with synthetic data demonstrate stability linear inversion method, we recalculate tensor solutions reported Dreger et al. Long...

In only rare cases will earthquake early warning systems be able to provide useful warnings for high levels of ground motion.

We present an inversion strategy capable of using real‐time high‐rate GPS data to simultaneously solve for a distributed slip model and fault geometry in real time as rupture unfolds. employ Bayesian inference find the optimal distribution possible models that simple analytical solution. By adopting approach, we can this complex problem (including calculating uncertainties on our results) time. Furthermore, since joint be computed time, required obtain source earthquake does not depend...

Earthquake early warning (EEW) can reduce harm to people and infrastructure from earthquakes tsunamis, but it has not been implemented in most high earthquake-risk regions because of prohibitive cost. Common consumer devices such as smartphones contain low-cost versions the sensors used EEW. Although less accurate than scientific-grade instruments, these are globally ubiquitous. Through controlled tests devices, simulation an M w (moment magnitude) 7 earthquake on California's Hayward fault,...

Abstract We explore how accurate earthquake early warning (EEW) can be, given our limited ability to forecast expected shaking even if the source is known. Because of strong variability ground motion metrics, such as peak acceleration (PGA) and velocity (PGV), we find that correct alerts (i.e., accurately estimate will be above a predetermined damage threshold) are not most common EEW outcome when magnitude location determined. Infrequently, results in user receiving false alert because...

Abstract The subduction zone in northern Chile is a well‐identified seismic gap that last ruptured 1877. On 1 April 2014, this region was struck by large earthquake following two week long series of foreshocks. This study combines wide range observations, including geodetic, tsunami, and data, to produce reliable kinematic slip model the M w =8.1 main shock static =7.7 aftershock. We use novel Bayesian modeling approach accounts for uncertainty Green's functions, both dynamic, while avoiding...

We present a fully Bayesian inversion of kinematic rupture parameters for the 2011 Mw9 Tohoku-oki, Japan earthquake. Albeit computationally expensive, this approach to source modelling has advantage producing an ensemble slip models that are consistent with physical priori constraints, realistic data uncertainties, and but simplistic uncertainties in physics forward model, all without being biased by non-physical regularization constraints. Combining 1 Hz GPS, static GPS offsets, seafloor...

Research Article| June 08, 2016 Demonstration of the Cascadia G‐FAST Geodetic Earthquake Early Warning System for Nisqually, Washington, Brendan W. Crowell; Crowell aDepartment Earth and Space Sciences, University Johnson Hall Room‐070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195‐1310 U.S.A.crowellb@uw.edu Search other works by this author on: GSW Google Scholar David A. Schmidt; Schmidt Paul Bodin; Bodin John E. Vidale; Vidale Joan Gomberg; Gomberg bU.S. Geological Survey,...

The shallower portions of subduction zone megathrust faults host Earth's most hazardous tsunamigenic earthquakes, yet understanding how and when they slip remains elusive because challenges making seafloor observations. We performed Global Navigation Satellite System Acoustic geodetic surveys before ~2.5 months after the 29 July 2021 Mw (moment magnitude) 8.2 Chignik, Alaska, earthquake determine ~1.4 meters cumulative co- post-seismic horizontal displacement ~60 kilometers from front. Only...

We have determined seismic source mechanisms for shallow and intermediate-depth icequake clusters recorded on the glacier Gornergletscher, Switzerland, during summers of 2004 2006. The selected events are part a large data set over 80,000 acquired with dense network deployed in order to study yearly rapid drainage Gornersee lake, nearby ice-marginal lake. Using simple frequency distance scaling Green’s functions homogeneous half-space, we calculated moment tensor solutions icequakes M_w-1.5...

Brief Report| March 25, 2014 The 2013 Mw 7.7 Balochistan Earthquake: Seismic Potential of an Accretionary Wedge R. Jolivet; Jolivet aSeismological Laboratory, Department Geological and Planetary Sciences, California Institute Technology, 1200 E Blvd, Pasadena, 91125 Search for other works by this author on: GSW Google Scholar Z. Duputel; Duputel *Now at Institut de Physique du Globe Strasbourg, UdS EOST/CNRS UMR 7516, France. B. Riel; Riel M. Simons; Simons L. Rivera; Rivera cInstitut France...

Abstract The scaling of rupture properties with magnitude is critical importance to earthquake early warning systems that rely on source characterization using limited snapshots waveform data. ShakeAlert, a prototype system being developed for the western United States, provides real‐time estimates based P wave peak ground displacements measured at stations triggered by event. algorithms used in ShakeAlert assume displacement measurements each station are statistically independent and there...

Abstract During its ascent up Mount Sharp, the Mars Science Laboratory Curiosity rover traversed Bagnold Dune Field. We model sand modal mineralogy and grain size at four locations near traverse, using orbital shortwave infrared single‐scattering albedo spectra a Markov chain Monte Carlo implementation of Hapke's radiative transfer theory to fully constrain uncertainties permitted solutions. These predictions, evaluated against in situ measurements one site from rover, show that X‐ray...

Mobile laser scans of vine rows deformed by the South Napa earthquake record shallow fault slip that does not breach surface.

Abstract Although numerous Earthquake Early Warning (EEW) algorithms have been developed to date, we lack a detailed understanding of how often and under what circumstances useful ground motion alerts can be provided end users. In particular, it is unclear EEW systems successfully alert sites with high intensities. These are the that arguably need most, but they also most challenging ones because tend located close epicenter where seismic waves arrive first. Here analyze alerting performance...

The volcanic eruption on Miyakejima, Japan, in 2000 was marked by the largest earthquake swarm ever recorded a seismicity migration accompanying dike intrusion as propagated from Miyakejima to northwest, and formation of caldera Mount Oyama Miyakejima. In this study, we propose seismic source model which can be used both geodetic displacements earthquakes. Our model, “crack + double‐couple” (CDC) combines tensile opening with shear slip along single fault plane. We find that fit GPS data 1...

Research Article| October 03, 2018 Development of a Geodetic Component for the U.S. West Coast Earthquake Early Warning System J. R. Murray; Murray aU.S. Geological Survey, 345 Middlefield Road, MS 977, Menlo Park, California 94025 U.S.A., jrmurray@usgs.gov Search other works by this author on: GSW Google Scholar B. W. Crowell; Crowell bDepartment Earth and Space Sciences, University Washington, Johnson Hall Room‐070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195 U.S.A....

Abstract Reflected light from planetary surfaces provides information, including mineral/ice compositions and grain sizes, by study of albedo absorption features as a function wavelength. However, deconvolving the compositional signal in spectra is complicated nonuniqueness inverse problem. Trade‐offs between mineral abundances sizes setting reflectance, instrument noise, systematic errors forward model are potential sources uncertainty, which often unquantified. Here we adopt Bayesian...

Abstract Fault creep, depending on its rate and spatial extent, is thought to reduce earthquake hazard by releasing tectonic strain aseismically. We use Bayesian inversion a newly expanded GPS data set infer the deep slip rates below assigned locking depths San Andreas, Maacama, Bartlett Springs Faults of Northern California and, for latter two, spatially variable interseismic creep above depth. estimate 21.5 ± 0.5, 13.1 0.8, 7.5 0.7 mm/yr 16 km, 9 13 km Faults, respectively. that average...

Abstract Although small earthquakes are expected to produce weak shaking, ground motion is highly variable and there outlier that generate more shaking than expected—sometimes significantly more. We explore datasets of M 0.5–8.3 determine the relative impact frequent, smaller-magnitude rarely strong motion, rare, large always cause shaking. find natural variability combined with Gutenberg–Richter magnitude–frequency relationship, ensures most occurrences any come from smaller magnitude...

Abstract We show that a fixed smartphone network can provide robust Earthquake Early Warning for at least two orders of magnitude less cost than scientific‐grade networks. Our software and cloud‐based data architecture we have constructed the Alerta Sismica Temprana Utilizando Teléfonos Inteligentes (ASTUTI; Utilizing Smartphones) in Costa Rica is easily scaled exported. Implementation comprises provisioning installing modern smartphones judicious locations. Stand‐up time regionally...

Abstract We examine how the choice of ground-motion-to-intensity conversion equations (GMICEs) in earthquake early warning (EEW) systems affects resulting alert regions. find that existing GMICEs can underestimate observed shaking at short rupture distances or overestimate extent low-intensity shaking. Updated remove these biases would improve accuracy regions for ShakeAlert EEW system West Coast United States. uses ground-motion prediction (GMPEs), which calculate spatial distributions peak...