The geodetic data, strong-motion waveforms, and far-field waveforms from the 1995 Kobe earthquake (MJMA 7.2) were inverted to determine rupture process. including horizontal displacements measured at 43 stations vertical 61 stations, provided by Geographical Survey Institute of Japan Japanese University Consortium for GPS Research. We assumed two fault planes, one each Awaji Island Kobe, with different strike directions dip angles, which consistent active map aftershock distribution. first...

Slow slip events (SSEs) occur in the deeper extents of areas where large interplate earthquakes are expected subduction zones, such as Nankai region Japan and Cascadia North America. In region, SSEs divided into long‐ short‐term SSEs, depending on their duration recurrence interval. We modeled examined occurrence changes behavior during seismic cycles earthquakes. these numerical simulations we adopted a rate‐ state‐dependent friction law with cutoff velocities assumed that distribution pore...

Crustal rock strength from outer space The response of crustal to stresses is challenging estimate yet vital for determining risks events such as earthquakes. Moore et al. take advantage the recent M w 7.1 Kumamoto earthquake in Japan determine rheology rocks region. observed inversion strain rates demonstrates that certain areas have stiff and others (e.g., under Aso volcanic complex) much weaker rock. results match up with expectations, which means method can successfully measure...

To investigate the mechanism of recently observed silent slip events, we simulated earthquake preparation processes using Dieterich/Ruina rate‐ and state‐dependent friction law. ensure realistic modeling unstable‐stable transition, considered small cut‐off velocity to an evolution effect in law for transition zone. When is significantly smaller than that a direct effect, steady state behaves as weakening at low strengthening high velocity. This frictional behavior was experimentally...

We give explicit origami embeddings of a 2-dimensional flat torus any modulus in the 3-dimensional Euclidean space.

Abstract We review the evolution of late Cenozoic magmatism in NE Japan arc, and examine relationship between crust–mantle structure. Recent studies reveal secular changes mode magmatic activity, magma plumbing system, erupted volumes composition associated with structures related to tectonic arc. The arc can be divided into three periods: continental margin (66–21 Ma), back-arc basin (21–13.5 Ma) island-arc period (13.5–0 Ma). Magmatic periods appears 2D 3D change convection pattern mantle...

Abstract The Nankai Trough in Southwest Japan exhibits a wide spectrum of fault slip, with long-term and short-term slow-slip events, slow fast earthquakes, all associated different segments down the plate interface. Frictional viscous properties vary depending on rock type, temperature, pressure. However, what controls down-dip segmentation subduction zone megathrust how domains interact during seismic cycle remains unclear. Here, we model representative cross-section offshore Shikoku...

The process of earthquake generation is governed by a coupled non-linear system consisting the equation motion in elastodynamics and fault constitutive relation. On basis results stick-slip experiments we constructed theoretical source model with slip-dependent law. Using model, simulated transition numerically from quasi-static nucleation to high-speed rupture propagation succeeded quantitatively explaining three phases observed experiments, that very slow (1 cm s−1) preceding onset dynamic...

We developed a model which can naturally explain the entire process of nucleation, dynamic propagation, and stop earthquake rupture. In this we represent frictional interaction between fault surfaces by slip‐dependent constitutive relation, use it as fundamental law governing considered broad weak zone with locally strong part (asperity) on plane examined rupture proceeding increase external shear stress through numerical simulations. The nucleation first proceeds quasi‐statically at weakest...

[1] We perform 3D quasi-dynamic modeling of the cycle a megathrust earthquake in offshore Tohoku region, Japan, using rate- and state-dependent friction law with two state variables that exhibits strong velocity weakening at high slip velocities. set several asperities where occurs low to intermediate Outside asperities, strengthening At velocities, large displacements both within outside asperities. The rupture intervals tens years, whereas events occur much longer (several hundred years)....

With the aim of delineating subducting Indian Plate beneath Burma Plate, we have relocated earthquakes by employing teleseismic P-wave arrival times. We were able to obtain detailed geometry constructing iso-depth contours for subduction at depths 30–140 km. The strikes are oriented approximately N-S, and show an "S" shape in map view. strike slab is N20°Eat25°N, but moving southward, rotates counterclockwise N20°Wat20°N, followed a clockwise rotation N10°E 17.5°N, where no longer occur....

Abstract Using two‐dimensional finite element modeling, we reproduced the observed postseismic deformation of 2011 Tohoku‐Oki earthquake. Our model, which accounts for lithosphere‐asthenosphere boundary and weak zones beneath volcanoes, was able to reproduce small‐scale (<20 km) perturbations in by dense geodetic network, such as local subsidence around Quaternary volcanoes. The inverted afterslip has a peak at downdip limit main rupture region on subducting plate interface, consistent...

Abstract Near-trench slip during large megathrust earthquakes (megaquakes) is an important factor in the generation of destructive tsunamis. We proposed a new approach to assessing near-trench potential quantitatively by integrating laboratory-derived properties fault materials and simulations weakening rupture propagation. Although permeability sandy Nankai Trough are higher than that clayey from Japan Trench, dynamic thermally pressurized fluid greater at owing friction, although initially...

We numerically simulate slow slip events (SSEs) in the Shikoku region of Japan, incorporating configuration subducting plate. adopt a rate‐ and state‐dependent friction law with cutoff velocities, assuming frictional parameter distribution based on observed long‐term SSEs nonvolcanic tremors that reflects short‐term SSEs. Our model reproduces recurrences long‐ segments In our simulation, SSEs' transition from episodic to continuous is reproduced. This feature consistent tremor activity...

Two‐dimensional viscosity profiles were constructed for the northeastern Japan islands arc‐trench system covering source area of 2011 Tohoku‐Oki earthquake. From seismologically determined models lithospheric structure, experimentally derived constitutive laws various rocks, and densely measured geothermal gradient data, we have predicted steady state effective across subduction zone. The profile reveals strong lateral gradients both parallel normal to trench axis. detailed structures...

In the subduction zone of southwest Japan, short‐term slow slip events (SSEs) occur with low frequency tremors (LFTs) at intervals several months. Recently LFTs have been located high resolution and their activities examined in detail. By setting generation zones SSEs such that these contain LFT hypocenters, we simulate on a 3D plate interface beneath Kii Peninsula Tokai regions by using rate‐ state‐dependent friction law small cut‐off velocity for evolution effect. Our numerical results...

Abstract The 2016 Kumamoto, Japan, earthquake sequence, culminating in the M w =7.0 16 April main shock, occurred within an active tectonic belt of central Kyushu. GPS data from GEONET reveal transient crustal motions several millimeters per year up to ∼3 cm/yr during first 8.5 months following sequence. spatial pattern horizontal postseismic is shaped by both shallow afterslip and viscoelastic relaxation lower crust upper mantle. We construct a suite 2‐D regional structures order derive...

Abstract Very‐low‐frequency earthquakes (VLFE) occur within accretionary prisms and near subduction plate boundaries at slip rates of 0.05–2 mm/s. However, the geological frictional aspects VLFE remain poorly understood. The thrusts in Shimanto complex exhumed from source depths are composed quartz‐rich fault rocks with or without clay foliations. We examined velocity dependence thrust materials. At 0.0028–0.28 mm/s, powder sample non‐foliated rock shows velocity‐weakening behavior, while...

We propose a theoretical model which can explain the occurrence of foreshocks and pre‐events associated with nucleation large earthquakes. consider broad weak zone locally strong part (asperity) on fault plane in two‐dimensional framework examine transition process from quasistatic to high‐speed rupture propagation through numerical simulations. The dynamic asperity occurs three different manners, as aseismic slip, foreshock or pre‐event, depending peak stress asperity. In all cases...

We performed a finite element analysis, taking into account nonlinear viscoelasticity and plasticity, to construct two‐dimensional model of the deformation faulting processes that occur in deeper parts seismogenic zone beneath northeastern Japan. Our code was developed on basis GeoFEM parallel using plug‐ins adopt several functions. An extensive onshore‐offshore wide‐angle seismic expedition conducted across Japan 1997 revealed detailed image deep crust uppermost mantle structures. In...

We developed a model of short‐term slow slip events (SSEs) on the 3‐D subduction interface beneath Shikoku, southwest Japan, considering rate‐ and state‐dependent friction law with small cutoff velocity for evolution effect. assume low effective normal stress critical displacement at SSE zone. On basis hypocentral distribution low‐frequency tremors, we set three generation segments: large segment western Shikoku two smaller segments central eastern Shikoku. Using this model, reproduce longer...

Abstract At the southern Hikurangi margin, New Zealand, long‐term (duration of >1 year), deep (>25 km) slow‐slip events (SSEs) occur at intervals approximately 5 years. In contrast, along northern and central short‐term shallow (<10 SSEs (2‐ to 3‐week duration) 1‐ 2‐year intervals. However, it is not clear what controls these differences in SSE behavior. this study, we simulate entire subduction zone using a 3‐D model plate boundary incorporating rate‐and‐state friction law with...

Abstract By considering a thermal structure based on dense geothermal observations, we model the stress state of crust beneath northeastern Japan island arc under compressional tectonic regime using finite element method with viscoelasticity and elastoplasticity. We consider three‐layer (upper crust, lower uppermost mantle) to define flow properties. Numerical results show that brittle‐viscous transition becomes shallower Ou Backbone Range compared areas near margins Pacific Ocean Sea....