September 2020

Time‐Series Analysis of Volume Change at Brady Hot Springs, Nevada, USA, Using Geodetic Data From 2003–2018

Key Points

August 2020

Rheological Transitions Facilitate Fault‐Spanning Ruptures on Seismically Active and Creeping Faults

Key Points
  • Physically based seismic cycle simulations are performed, incorporating fault zone structure and composition
  • Both seismogenic and predominantly creeping faults are observed to generate large seismic events
  • The nucleation of giant earthquakes on creeping faults is facilitated by rheological transitions

Conditions for Triggering Seismic Ruptures and/or Slow Slip Events in the Framework of a Poro‐Plastic Fault Zone Model

Key Points
  • To study the conditions that can lead to slow slip vs. seismic slip on complex faults, we use a new end‐cap poroplastic interface model
  • Fluid compressibility is shown to exert control over the location and size of the instability domain on the plastic criterion
  • Scenarios in which slow slip deformation and main shocks (instabilities) happen on the same fault are not uncommon

Depth‐Dependent Azimuthal Anisotropy Beneath the Juan de Fuca Plate System

Key Points
  • We use a two‐plane wave method to measure azimuthal anisotropy as a function of depth across the Juan de Fuca and Gorda plate system
  • Results are consistent with measured SKS splitting; our study offers depth sensitivity crucial to interpretation of underlying dynamics
  • Regionalized patterns of anisotropy reveal substantial differences in ridge‐derived fabric and how plates shear over underlying mantle

Tectonic Inheritance With Dipping Faults and Deformation Fabric in the Brittle and Ductile Southern California Crust

Key Points
  • Receiver function harmonic conversions show pervasive dipping fault‐parallel lithospheric fabric in Southern California
  • Seismicity shows consistent northeast dips on profiles across major transform faults
  • Non‐Andersonian dipping fault geometry for strike‐slip motion is likely due to tectonic inheritance

Earthquake Cycles in Fault‐Bend Folds

Key Points
  • We study models of multiple seismic cycles on faults with nonplanar geometry
  • Our method includes axial surfaces to simulate off‐fault deformation associated with fault‐bend folding
  • Earthquake segmentation can be due to stress heterogeneity caused by friction and fault geometry

Present‐Day and Long‐Term Uplift Across the Western Transverse Ranges of Southern California

Key Points
  • We invert geodetic and geologic data for slip rate and coupling on faults in the Western Transverse Ranges (WTR) using a kinematic model
  • Much of the vertical velocity field in the WTR can be attributed to the interseismic signal of strain accumulation on reverse faults
  • Sum of fault dip‐slip rates across the WTR decreases from 10.5–14.6 mm/year onshore to 5–6.2 mm/year across the western Santa Barbara Channel

July 2020

Stress Orientations in the Nankai Trough Constrained Using Seismic and Aseismic Slip

Key Points
  • Stress inversions of slow slip events imply the presence of intrinsically weak fault materials
  • The strength of the megathrust is similar to its surroundings in SSE source regions
  • Slow fault slip accommodates a large fraction of the total seismic moment in the Nankai Trough

A Block Model of Present‐Day Kinematics of Alaska and Western Canada

Key Points
  • The first regionally comprehensive tectonic block model for Alaska and western Canada constrained by GPS data is presented
  • Significant motion relative to North America is observed in every part of Alaska, including the North Slope
  • Locked portions of the Yakutat flat slab subduction interface extend further east and north than previously estimated

A Kalman Filter Time Series Analysis Method for InSAR

Key Points
  • Our data assimilation method for InSAR time series analysis allows for rapid update of preexisting models with newly acquired data
  • Errors affecting the process are accounted for, so that each estimate is associated with its relevant uncertainty
  • We provide guidelines for the parametrization of our method

Fault Geometry and Slip Distribution of the 2013 Mw 7.7 Balochistan Earthquake From Inversions of SAR and Optical Data

Key Points
  • The combination of radar and optical satellite data constrain fault geometry and slip distribution inversions
  • Our modeling strategy combines a non‐linear and a linear inversion that allow for modeling both the geometry and the slip distribution
  • The large magnitude of the 2013 Mw 7.7 Balochistan earthquake explains the absence of shallow slip deficit for this earthquake

 

Surface Slip Distribution Along the West Helanshan Fault, Northern China, and Its Implications for Fault Behavior

Key Points
  • Large paleoearthquakes have produced characteristic slip along the fault with a lateral slip of ~3 m and a vertical slip of ~1 m
  • The fault has propagated northward over its lifetime, and larger coseismic slip of earthquakes may occur on the south segment of the fault
  • The fault has maintained the same kinematic style with a constant ratio of lateral to vertical displacement

 

 

June 2020

Stress Sensitivity of Instantaneous Dynamic Triggering of Shallow Slow Slip Events

Satoshi Katakami, Yoshihiro Kaneko, Yoshihiro Ito, Eiichiro Araki

First published: 17 April 2020 https://doi.org/10.1029/2019JB019178
 
Key Points
  • We identify additional shallow slow slip events (SSEs) in the Nankai Trough that were not previously reported
  • Stress perturbations resulting from 19 large earthquakes are computed and compared against the timing of shallow SSEs
  • The propensity for SSE triggering mainly depends on the maximum dynamic stress change

Detailed Investigation of the Foreshock Sequence of the 2010 Mw7.2 El Mayor‐Cucapah Earthquake

Dongdong Yao, Yihe Huang, Zhigang Peng, Raúl R. Castro

First published: 06 May 2020 https://doi.org/10.1029/2019JB019076
 
Key Points
  • A waveform matching technique leads to tenfold increase in the number of foreshocks when compared with the SCSN catalog
  • We resolve the corner frequency of 20 foreshocks using the detected events as empirical Green's functions
  • The relocated catalog and estimated source patches reveal effects of both aseismic slip and cascading stress transfer

The Northern Terminus of Cascadia Subduction

G. Savard, M. G. Bostock, J. Hutchinson, H. Kao, N. I. Christensen, S. M. Peacock

First published: 12 May 2020 https://doi.org/10.1029/2019JB018453
 
Key Points
  • Geophysical evidence redefines Nootka Fault Zone/Juan de Fuca plate edge across Vancouver Island
  • Plate fold develops over ≤50 km within northern Juan de Fuca plate edge off Nootka Island
  • Proposed tectonic configuration confines Explorer plate to shallow depths at/seaward of Vancouver Island coast

Slip Distributions of Short‐Term Slow Slip Events in Shikoku, Southwest Japan, From 2001 to 2019 Based on Tilt Change Measurements

Hitoshi Hirose, Takeshi Kimura

First published: 26 May 2020 https://doi.org/10.1029/2020JB019601
 
Key Points
  • The slip distributions of 61 short‐term slow slip events (SSEs) from 2001 to 2019 in Shikoku, Japan, are estimated from tilt offset data
  • The estimated slip history of the SSEs shows that the SSE zone is divided into three segments
  • The number of short‐term SSEs with larger slip extent and seismic moment increases after 2012

May 2020

Stable Rate of Slip Along the Karakax Section of the Altyn Tagh Fault from Observation of Interglacial and Postglacial Offset Morphology and Surface Dating

Gilles Peltzer,Nathan D. Brown,Anne‐Sophie Mériaux,Jerome van der Woerd, Edward J. Rhodes, Robert C. Finkel, Frederick J. Ryerson, James Hollingsworth

First published: 06 April 2020 https://doi.org/10.1029/2019JB018893

Key Points
  • Offset alluvial fans in Karakax Valley record sinistral displacement history along Altyn Tagh Fault
  • Terrace ages determined by OSL and CRN dating methods yield fault stable slip rate of 2.6 mm/a over 115 ka
  • Seismic clustering or variable erosion rate linked to climate may explain observed fault scarp degradation variations

Seismotectonics and Fault Geometries of the 2019 Ridgecrest Sequence: Insight From Aftershock Moment Tensor Catalog Using 3‐D Green's Functions

Xin Wang, Zhongwen Zhan

First Published:20 April 2020 https://doi.org/10.1029/2020JB019577

Key Points
  • We present a centroid moment tensor catalog for the 2019 Ridgecrest sequence using 3‐D velocity model
  • Premainshock/postmainshock stress rotations suggest a large fraction of the initial stress has been released coseismically
  • Aftershock catalog reveals shallow flower structures, splay, and antithetic faults, while a simple throughgoing fault exists at depths

Geodetic Measurements of Slow‐Slip Events Southeast of Parkfield, CA

Brent G. Delbridge, Joshua D. Carmichael, Robert M. Nadeau, David R. Shelly, Roland Bürgmann,

First Published:05 March 2020 https://doi.org/10.1029/2019JB019059

Key Points
  • Stacked strain data reveal the average surface geodetic deformation associated with large bursts of tremor on the SAF near Cholame, CA
  • These geodetic measurements confirm that episodic LFE families provide reliable estimates of deep fault slip
  • The geodetic observations imply that the aseismic slip is preceding and driving the observed seismic activity

Probing the Variation in Aseismic Slip Behavior Around an Active Suture Zone: Observations of Repeating Earthquakes in Eastern Taiwan

Yaochieh Chen, Kate Huihsuan Chen, Jyr‐Ching Hu, Jian‐Cheng Lee

First Published:20 April 2020 https://doi.org/10.1029/2019JB018561

Key Points
  • Using 202 ML 2.0 to 4.6 repeating earthquake sequences from 2000 to 2011, we studied where and how faults creep in an active suture zone
  • An unexpected high creep rate of 4.3 cm/year is found to occur along the 80‐km‐long Central Range fault
  • The time‐dependent aseismic slip showed a strong correlation with the creepmeter data, suggesting a common mechanism

April 2020

Semiautomated Estimates of Directivity and Related Source Properties of Small to Moderate Southern California Earthquakes Using Second Seismic Moments

Haoran Meng, Jeffrey J. McGuire, Yehuda Ben‐Zion

First Published:11 February 2020 https://doi.org/10.1029/2019JB018566

Key Points
  • We develop a semiautomated method for estimating finite fault parameters of earthquakes with second seismic moments
  • Resolved rupture directivities are generally consistent with expectations for dynamic ruptures on the imaged velocity contrasts
  • Stress drops and uncertainties are estimated for elliptical ruptures using the derived characteristic rupture length and width

Assessing Long‐Term Postseismic Transients From GPS Time Series in Southern California

K. A. Guns, R. A. Bennett

First Published:03 March 2020 https://doi.org/10.1029/2019JB018670

Key Points
  • Ongoing postseismic displacements from 12 past large magnitude earthquakes may be measurable in Southern California
  • A combination forward/inverse modeling strategy facilitates analysis of earthquake displacements and aids the evaluation of model performance
  • Our method reveals spatially coherent anomalies that may help inform future models of lithospheric rheology

Mar 2020

Constraining Interseismic Deformation of the Cascadia Subduction Zone: New Insights From Estimates of Vertical Land Motion Over Different Timescales

First published: 18 February 2020 https://doi.org/10.1029/2019JB018248
 
Key Points
  • Contemporary and late Holocene rates of vertical land motion are quantified along the western coast of North America
  • Contemporary minus Holocene rates are interpreted in terms of recent surface loading and interseismic deformation
  • Vertical land motion observations provide useful constraints on locking models of the Cascadia subduction zone

Independent Component Analysis and Parametric Approach for Source Separation in InSAR Time Series at Regional Scale: Application to the 2017–2018 Slow Slip Event in Guerrero (Mexico)

Key Points
  • Two multitemporal Sentinel‐1 time series were constructed over the 2017–2018 SSE in the Guerrero area
  • The atmospheric delays were analyzed and compared with weather models and GNSS Zenithal delay
  • The SSE signal was separated from atmospheric noise using ICA and parametric approaches

Feb 2020

What Controls Variations in Aftershock Productivity?

First published: 26 January 2020 https://doi.org/10.1029/2019JB018111

Key Points

  • The volume of available brittle lithosphere appears to be the primary control on aftershock productivity
  • Setting (depth, lithosphere age, and plate boundary) and source (stress drop, width, and aspect ratio) measurably affect aftershock counts
  • Statistical models based on a combination of dip, lithosphere, age and normalized area improve aftershock productivity forecasts

Directivity Modes of Earthquake Populations with Unsupervised Learning

Zachary E. Ross, Daniel T. Trugman, Kamyar Azizzadenesheli, Anima Anandkumar

First published: 05 February 2020 https://doi.org/10.1029/2019JB018299

Key Points
  • We develop an unsupervised machine learning approach to resolving directivity modes in earthquake populations
  • The problem is formulated as recovering the latent modes of rupture propagation that exist in the data naturally
  • Across four strike‐slip datasets in California with thousands of earthquakes, unilateral ruptures occur 63–73% of the time

Structural Control on Megathrust Rupture and Slip Behavior: Insights From the 2016 Mw 7.8 Pedernales Ecuador Earthquake

Lillian Soto‐Cordero, Anne Meltzer, Eric Bergman, Mariah Hoskins, Joshua C. Stachnik, Hans Agurto‐Detzel, Alexandra Alvarado, Susan Beck, Philippe Charvis, Yvonne Font, Gavin P. Hayes, Stephen Hernandez, Colton Lynner, Sergio Leon‐Rios, Jean‐Mathieu Nocquet, Marc Regnier, Andreas Rietbrock, Frederique Rolandone, Mario Ruiz

First published: 17 February 2020 https://doi.org/10.1029/2019JB018001
 
Key Points
  • A dense temporary seismic network provides a detailed view of the evolution of a megathrust rupture postseismic sequence
  • The postseismic sequence is characterized by clusters of seismicity containing earthquake swarms and moderate to large aftershocks
  • Seafloor topography and upper plate structure segment the subduction zone and control slip behavior across the seismic cycle

Constraints on the Geometry and Frictional Properties of the Main Himalayan Thrust Using Coseismic, Postseismic, and Interseismic Deformation in Nepal

Key Points

  • We combine interseismic, coseismic, and postseismic geodetic data from Nepal to study the seismic cycle
  • Geodetic data alone cannot constrain the geometry of the Main Himalayan Thrust fault system
  • We develop an inversion which uses coseismic and postseismic geodetic data to infer the fault slip and frictional properties

Jan 2020

Sea Level Rise in New Zealand: The Effect of Vertical Land Motion on Century‐Long Tide Gauge Records in a Tectonically Active Region

Paul H. Denys, R. John Beavan, John Hannah, Chris F. Pearson, Neville Palmer, Mike Denham, Sigrun Hreinsdottir

First published: 02 January 2020 https://doi.org/10.1029/2019JB018055
 
Key Points
  • We use 15 years of continuous GPS data to estimate vertical land motion and use precise leveling data to determine the stability of benchmark networks
  • The vertical land motion also includes an estimate of accumulated seismic events including postseismic deformation and slow slip events
  • The vertical land motion corrected trend gives a sea level rate of +1.45 ± 0.36 mm/year (1891−2013)

Comprehensive Detection of Very Low Frequency Earthquakes Off the Hokkaido and Tohoku Pacific Coasts, Northeastern Japan

Satoru Baba, Akiko Takeo, Kazushige Obara, Takanori Matsuzawa, Takuto Maeda

First published: 20 December 2019 https://doi.org/10.1029/2019JB017988

Key Points
  • Comprehensive detection of very low frequency earthquakes near the Japan Trench reveals space‐time distribution of interplate slip
  • Quiescence inside and activation outside of the 2011 Tohoku earthquake coseismic slip area illuminate a great contrast in interplate slip
  • Episodic bursts of activity in the interval of 3 months to a year may suggest repeating small slips during an interseismic period

Topographic Fingerprint of Deep Mantle Subduction

Arthur Briaud,  Roberto Agrusta,  Claudio Faccenna,  Francesca Funiciello,  Jeroen van Hunen

First published: 02 January 2020 https://doi.org/10.1029/2019JB017962

Key Point
  • Our results suggest that surface transient signal can help to detect deep subduction dynamics

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Three‐Dimensional Surface Displacements During the 2016 MW 7.8 Kaikōura Earthquake (New Zealand) From Photogrammetry‐Derived Point Clouds

A. Howell, E. Nissen, T. Stahl, K. Clark, J. Kearse, R. Van Dissen, P. Villamor, R. Langridge, K. Jones

First published: 03 January 2020 https://doi.org/10.1029/2019JB018739
 
Key Points
  • High‐resolution, three‐dimensional surface displacements during earthquakes can be measured from aerial photographs
  • The Jordan Fault did not accommodate significant shortening in an earthquake in 2016 but probably does in the long term

Dec 2019

Earthquake Initiation From Laboratory Observations and Implications for Foreshocks

Gregory C. McLaskey

First published: 11 November 2019 https://doi.org/10.1029/2019JB018363
 
Key Points
  • Experiments on a 3‐m rock show nucleation at many locations, including at the edges of creeping regions, consistent with numerical models
  • Loading perturbations and mild strength heterogeneity produce order of magnitude variations in estimates of nucleation length scale
  • Earthquake initiation on heterogeneous faults is better characterized by critical power density than a time‐invariant critical length scale

Spatiotemporal Evolution of Long‐ and Short‐Term Slow Slip Events in the Tokai Region, Central Japan, Estimated From a Very Dense GNSS Network During 2013–2016

Hiromu Sakaue, Takuya Nishimura, Jun'ichi Fukuda, Teruyuki Kato

First published: 21 November 2019 https://doi.org/10.1029/2019JB018650
 
Key Points
  • Global Navigation Satellite System data and a Network Inversion Filter resolve long‐ and short‐term slow slip events in the Tokai region
  • Slip migration synchronized with low frequency tremor along strike is resolved from short‐term slow slip event data
  • Slip rates of shallower long‐term slow events without tremors are an order of magnitude lower than those of short‐term ones with tremors

Three‐Dimensional Modeling of Spontaneous and Triggered Slow‐Slip Events at the Hikurangi Subduction Zone, New Zealand

Bunichiro Shibazaki, Laura M. Wallace, Yoshihiro Kaneko, Ian Hamling, Yoshihiro Ito, Takanori Matsuzawa

First published: 21 November 2019 https://doi.org/10.1029/2019JB018190
 
Key Points
  • The diversity of slow slip event (SSE) behavior along the Hikurangi margin is well reproduced by a rate‐and‐state friction model
  • Different behaviors of shallow short‐term and deep long‐term SSEs can be attributed primarily to differences in the effective normal stress
  • The propensity for SSE triggering via static stress transfer depends on the amplitude of perturbation and the timing in the SSE cycle

Total Variation Regularization of Geodetically Constrained Block Models in Southwest Taiwan

Mong‐Han Huang, Eileen L. Evans

First published: 21 November 2019 https://doi.org/10.1029/2019JB018076
 
Key Points
  • We jointly invert for fault slip rates using CGPS and InSAR measurements
  • The TVR algorithm suggests that most of the faults above the main detachment in SW Taiwan are interseismically locked
  • The predicted vertical displacements based on our inferred fault slip rates agree with InSAR and CGPS vertical measurements

Weeks‐Long and Years‐Long Slow Slip and Tectonic Tremor Episodes on the South Central Alaska Megathrust

Baptiste Rousset, Yuning Fu, Noel Bartlow, Roland Bürgmann

First published: 07 December 2019 https://doi.org/10.1029/2019JB018724
 
Key Points
  • Day‐ to weeks‐long slow slip and tremor episodes are happening continuously in south central Alaska
  • The September 2010 ETS migrated along strike at speeds of 8 km/day with slip rates of 3 mm/day
  • The 2009–2013 transient deformation event could be either a cluster of short‐term ETS or the sum of short‐term ETS plus a long‐lasting SSE

Optimizing Sensor Configurations for the Detection of Slow‐Slip Earthquakes in Seafloor Pressure Records, Using the Cascadia Subduction Zone as a Case Study

Erik K. Fredrickson, William S. D. Wilcock, David A. Schmidt, Parker MacCready, Emily Roland, Alexander L. Kurapov, Mark A. Zumberge, Glenn S. Sasagawa

First published: 11 December 2019 https://doi.org/10.1029/2019JB018053
 
Key Points
  • In Cascadia, differencing tidally filtered, depth‐matched seafloor pressure records can reduce oceanographic noise to less than 1‐cm RMS
  • Models of offshore SSEs in Cascadia suggest that a network of depth‐matched sensors at 30‐km spacing can detect Mw 6.4 and larger events
  • No offshore slow‐slip earthquakes are detected in the available Cascadia seafloor pressure data from 2011 to 2015

Nov 2019

Modeling Megathrust Earthquakes Across Scales: One‐way Coupling From Geodynamics and Seismic Cycles to Dynamic Rupture

I. van Zelst, S. Wollherr, A.‐A. Gabriel, E. H. Madden, Y. van Dinther

First published: 01 September 2019 https://doi.org/10.1029/2019JB017539
 
Key Points
  • We couple a geodynamic seismic cycle model to a dynamic rupture model to resolve subduction and earthquake dynamics across time scales
  • Both events are comparable in terms of nucleation and material‐dependent stress drop, but not slip
  • Complex lithology leads to various rupture styles and speeds, shallow slip accumulation, and fault reactivation

Dynamics, Radiation, and Overall Energy Budget of Earthquake Rupture With Coseismic Off‐Fault Damage

Kurama Okubo, Harsha S. Bhat, Esteban Rougier, Samson Marty, Alexandre Schubnel, Zhou Lei, Earl E. Knight, Yann Klinger

First published: 06 August 2019 https://doi.org/10.1029/2019JB017304
 
Key Points
  • Earthquake ruptures dynamically activate coseismic off‐fault damage, whose feedback plays an important role in rupture dynamics
  • We show the mechanism of dynamically activated off‐fault fractures and its effect on rupture velocity and enhanced high‐frequency radiation
  • The contribution of off‐fault damage to the overall energy budget associated with earthquakes is nonnegligible even at depth

Complete Three‐Dimensional Coseismic Deformation Field of the 2016 Central Tottori Earthquake by Integrating Left‐ and Right‐Looking InSAR Observations With the Improved SM‐VCE Method

Jihong Liu, Jun Hu, Wenbin Xu, Zhiwei Li, Jianjun Zhu, Xiaoli Ding, Lei Zhang

First published: 24 October 2019 https://doi.org/10.1029/2018JB017159

Key Points
  • We retrieve the 3‐D deformation field of the 2016 Central Tottori earthquake from left‐ and right‐looking InSAR observations
  • We conduct a precision assessment for InSAR observations based on the variance component estimation (VCE) method
  • We employ the robust VCE method to mitigate the effects of gross InSAR errors such as unwrapping errors on the 3‐D deformation

Contemporary Mountain‐Building of the Tianshan and its Relevance to Geodynamics Constrained by Integrating GPS and GRACE Measurements

Yuanjin Pan, Ruizhi Chen, Shuang Yi, Wei Wang, Hao Ding, Wenbin Shen, Liang Chen

First published: 10 November 2019 https://doi.org/10.1029/2019JB017566
 
Key Points
  • We estimate partitioning of vertical deformation in Tianshan to glacial and tectonic sources from a joint inversion of GPS and GRACE data
  • We derive crustal shortening rates from GPS‐derived horizontal velocity field and relate it to regional block motion.
  • The anomalous subsidence of the Lake Issyk‐Kul region may be caused by delamination of previously folded lithosphere

Transient Deformation in California From Two Decades of GPS Displacements: Implications for a Three‐Dimensional Kinematic Reference Frame

Emilie Klein, Yehuda Bock, Xiaohua Xu, David T. Sandwell, Dorian Golriz, Peng Fang, Lina Su

First published: 19 July 2019 https://doi.org/10.1029/2018JB017201

Key Points
  • Displacement fields from 19 years of GPS data in California are preferable to velocity fields in characterizing 3‐D transient motions
  • Mapping of secular and transient motions at high temporal and spatial resolution is required for maintaining a 3‐D kinematic reference frame
  • Displacement fields derived from continuous GPS and InSAR provide 200‐m resolution with millimeter‐level velocity uncertainties

October 2019

Separation of Sources of Seasonal Uplift in China Using Independent Component Analysis of GNSS Time Series

First published: 01 November 2019 https://doi.org/10.1029/2019JB018139
 
Key Points
  • We extract the seasonal sources of vertical GNSS displacements in China using independent component analysis
  • Comparison of the independent components with mass loadings and GRACE shows that atmospheric and soil moisture seasonal loads are dominant
  • We estimate of mass loading cycles due to unmodeled surface and groundwater changes

Complete Three‐Dimensional Coseismic Deformation Field of the 2016 Central Tottori Earthquake by Integrating Left‐ and Right‐Looking InSAR Observations With the Improved SM‐VCE Method

Key Points
  • We retrieve the 3‐D deformation field of the 2016 Central Tottori earthquake from left‐ and right‐looking InSAR observations
  • We conduct a precision assessment for InSAR observations based on the variance component estimation (VCE) method
  • We employ the robust VCE method to mitigate the effects of gross InSAR errors such as unwrapping errors on the 3‐D deformation

September 2019

Ultra‐long Duration of Seismic Ground Motion Arising From a Thick, Low‐Velocity Sedimentary Wedge

Key Points
  • Anomalously long duration of long‐period ground motions was observed during seismic wave propagation from the 2016 M7.8 Kaikoura earthquake
  • Waveform modeling indicates the presence of a thick, unusually low seismic‐velocity wedge of material in the northeastern North Island of NZ
  • Long‐duration ground motions caused by this wedge would enhance dynamic triggering of slow slip as well as hazard posed by ground shaking

Joint Inversion of Coseismic and Early Postseismic Slip to Optimize the Information Content in Geodetic Data: Application to the 2009 Mw6.3 L'Aquila Earthquake, Central Italy

Key Points
  • Simultaneous inversion of geodetic data with different spatiotemporal resolution maximizes the information content
  • If the early afterslip signal is neglected, coseismic slip is overestimated by 30% and postseismic slip is underestimated by a factor of 3
  • Early afterslip (6 days after mainshock) is mainly located at the transition zone between coseismic rupture and longer‐term afterslip

Contained Laboratory Earthquakes Ranging From Slow to Fast

Key Points
  • We generate contained earthquake‐like slip events on a 3 m dry, homogeneous granite fault that do not rupture through the sample ends
  • We create a spectrum of slow to fast events, ranging from M −3.2 events with 50 kPa stress drop to M −2.5 quakes with 0.4 MPa stress drop
  • Slow events produce tremor‐like seismic radiation and have an ω−1 spectral shape that matches slow earthquakes in nature

Deriving Rupture Scenarios From Interseismic Locking Distributions Along the Subduction Megathrust

Key Points
  • We conduct numerical simulations of rupture scenarios based on interseismic locking models
  • Our simulated earthquake scenario is well consistent with kinematic models of the 2012 Mw 7.6 Nicoya earthquake
  • Details of rupture process and synthetic waveforms depend on the choice of the input locking model

August 2019

Detection of Low‐Frequency Earthquakes in Broadband Random Time Sequences: Are They Independent Events?

  • Satoshi Ide Pages: 8611-8625 First Published:31 July 2019
  • Matched‐filter with template in narrow frequency band detects LFEs from broadband random sequences
  • Differences between broadband signals and random noise arise outside the analyzed frequency band
  • Real data of the Cascadia subduction zone suggest broadband source processes behind impulsive LFEs

Pn Tomography of the Juan de Fuca and Gorda Plates: Implications for Mantle Deformation and Hydration in the Oceanic Lithosphere

  • We present a P wave velocity model of the oceanic mantle lithosphere beneath the Juan de Fuca and Gorda plates
  • Despite pervasive deformation offshore southern Cascadia, the Gorda mantle shows no evidence of extensive alteration
  • The Juan de Fuca mantle is minimally and heterogeneously hydrated

Linear Relationship Between Aftershock Productivity and Seismic Coupling in the Northern Chile Subduction Zone

  • Aftershock productivity decreases systematically with depth
  • Aftershock productivity is proportional to the coupling coefficient
  • Bath's law is expected to be only valid in the limit of full coupling



July 2019

Mobility, Thickness, and Hydraulic Diffusivity of the Slow‐Moving Monroe Landslide in California Revealed by L‐Band Satellite Radar Interferometry

  • The Monroe landslide has four major kinematic elements and displays seasonal kinematic changes
  • Estimates from mass conservation reveal slide thickening at the longitudinal center near the transition from subsidence to uplift
  • The correlation between the landslide rate and the rainfall‐modulated pore pressure changes constrains the hydraulic diffusivity

Coseismic and Postseismic Slip of the 2005 Mw 8.6 Nias‐Simeulue Earthquake: Spatial Overlap and Localized Viscoelastic Flow

  • We present self‐consistent coseismic and afterslip models for the Mw 8.6 Nias‐Simeulue earthquake
  • The estimated afterslip is located primarily updip and downdip of the coseismic rupture with the shallow portion partially overlapping the coseismic rupture
  • Localized viscoelastic flow in the mantle wedge is required to explain postseismic subsidence observed at the Sumatran mainland

Interseismic and Postseismic Shallow Creep of the North Qaidam Thrust Faults Detected with a Multitemporal InSAR Analysis

  • InSAR time series displacement maps have been constructed for a 300 × 300 km2 area in NE Tibet
  • Steady‐state creep from 2003 to 2011 has been identified across several active faults within the Qaidam basin
  • A major postseismic creep event uplifting an active fold by 6 cm in 3 years has been detected

A Detailed Earthquake Catalog for the San Jacinto Fault‐Zone Region in Southern California

  • We develop an automated procedure to derive a catalog of earthquake locations and sizes from raw waveform data
  • We derive a new catalog for the San Jacinto fault zone region with 108,800 events between 2008 and 2016
  • We interpret variable mechanical properties of fault‐zone regions from seismicity patterns

Seismic Activity Preceding the 2011 Mw9.0 Tohoku Earthquake, Japan, Analyzed With Multidimensional Template Matching

  • We developed a multidimensional template matching technique to detect small seismic events
  • Events detected at low frequency (1–10 Hz) see the migration episode before the Tohoku event and are located in potential creeping zones
  • The rate of events detected at high frequency (>14 Hz) increases from November 2010 to the Tohoku earthquake

Long Period Seismicity at Mammoth Mountain, California

  • Long period seismicity at Mammoth Mountain between 2011 and 2013 occurred at shallow depths
  • Long period seismicity is attributed to the excitation of shallow subhorizontal hydrothermal cracks
  • Driving force is the discharge of CO2 from the underlying gas reservoir


June 2019

Stable Forearc Stressed by a Weak Megathrust: Mechanical and Geodynamic Implications of Stress Changes Caused by the M = 9 Tohoku‐Oki Earthquake

  • Stress reversal in offshore forearc due to the Tohoku‐Oki earthquake indicates weak subduction megathrust with effective friction ~0.032
  • Most of the forearc is under very low differential stress and is stable throughout subduction earthquake cycles except the outer wedge
  • Earthquakes and active faulting in a strong and stable forearc reflect heterogeneities in structure, stress, and/or pore fluid pressure

Interplate Coupling Distribution Along the Nankai Trough in Southwest Japan Estimated From the Block Motion Model Based on Onshore GNSS and Seafloor GNSS/A Observations

  • Interplate coupling along the Nankai Trough was estimated using the block motion model based on seafloor and onshore geodetic observations
  • Spatial variations of modeling uncertainties of coupling estimates were minimized with a new minimization algorithm
  • Very strong coupling near the trough axis off of Tokai suggests tsunamigenesis potential at the shallowest part of plate interface



May 2019

Slow Slip Event Detection in Cascadia Using Vertical Derivatives of Horizontal Stress Rates

  • A new time‐dependent approach with elasticity constraints at the Earth's surface captures Cascadia slow slip and locking
  • We confirm strong along‐strike variation in Cascadia ETS and locking behavior
  • The subduction interface typically relocks within weeks of the end of slow slip

Source Characteristics of the 2017 Ms 7.0 Jiuzhaigou, China, Earthquake and Implications for Recent Seismicity in Eastern Tibet

  • Two patches with 0.7 m strike‐slip near the surface for 25 km long are identified on the northern Huya fault
  • The fault failure in 2017 was promoted by recent earthquakes, especially the 2008 Wenchuan earthquake through the postseismic deformation
  • A 20‐ to 25‐km long section proximal to the Jiuzhaigou National Park is encouraged to fail to end the seismic cycle of the Huya fault

Seismicity at the Northern Hikurangi Margin, New Zealand, and Investigation of the Potential Spatial and Temporal Relationships With a Shallow Slow Slip Event

  • 2,313 earthquakes located in the Hikurangi margin, using ocean bottom seismometers and absolute pressure gauges from a temporary experiment
  • Abundant earthquakes in the subducting Pacific plate suggest bending stress‐related fractures allowing upward migration of fluids
  • Microseismic gap identified at down‐dip limit of the September‐October 2014 slow slip event coincides with interseismic coupling


April 2019

Interplate Slip Following the 2003 Tokachi‐oki Earthquake From Ocean Bottom Pressure Gauge and Land GNSS Data

  • Spatiotemporal postseismic slip of the 2003 Tokachi‐oki earthquake for ~7.5 years is estimated using land and seafloor geodetic data
  • Interplate locking of postseismic slip region had not fully recovered to the pre‐2003 status after 7.5 years following the main shock
  • Postseismic deformation could be responsible for transient seafloor pressure changes following the 2003 event

A Spatially Varying Scaling Method for InSAR Tropospheric Corrections Using a High‐Resolution Weather Model

  • We present a new empirical method for InSAR tropospheric corrections using high‐resolution weather model products
  • A spatially varying scaling factor is used to refine the magnitude of tropospheric delays
  • We improve the isolation of the deformation signal across the Altyn Tagh Fault zone, which spans 6,000 m of topographic relief

Going to Any Lengths: Solving for Fault Size and Fractal Slip for the 2016, Mw 6.2 Central Tottori Earthquake, Japan, Using a Transdimensional Inversion Scheme

  • We incorporate von Karman regularization into geodetic Bayesian slip inversions to capture the fractal nature of slip
  • We also solve for fault size using a transdimensional Bayesian inversion to remove bias caused by fault size in von Karman regularization
  • Application to the 2016 Tottori, Japan, earthquake shows that contrary to some seismic studies, slip ruptured almost to the surface

Evaluating the Association Between Tectonic Tremors and Earthquakes in Taiwan From 7 Years Catalogs

  • We explore the spatiotemporal association between tremors and earthquakes using 7‐year tremor and earthquake catalog
  • In a confined distance of 5 km, a greater percentage of earthquakes tend to occur in 5 days prior to the tremors
  • A commonly high fluid pressure environment may be needed, to facilitate their interaction

Along‐Strike Variation and Migration of Long‐Term Slow Slip Events in the Western Nankai Subduction Zone, Japan

  • We systematically detected 24 long‐term MW 6.0‐7.0 slow slip events in the western Nankai subduction zone during 1996‐2017
  • Slow slip events are segmented along strike, with recurrence intervals and total slip amounts that correlate with updip interplate locking
  • Slow slip events repeatedly migrate along strike from the southwestern creeping zone to the northeastern Nankai megathrust locked zone



March 2019

Active Convergence of the India‐Burma‐Sunda Plates Revealed by a New Continuous GPS Network

  • We demonstrate active convergence between India and Burma using 2‐D and 3‐D plate motion models
  • The Rakhine‐Bangladesh megathrust is the most likely candidate to accommodate ~18 mm/year of India‐Burma convergence
  • Strain partitioning is necessary within the Indo‐Burman Wedge, and we can place an upper bound of 8 mm/year on the slip rate of the Churachandpur‐Mao Fault

Groundwater Loss and Aquifer System Compaction in San Joaquin Valley During 2012–2015 Drought

  • GPS measurements of aquifer compaction in San Joaquin Valley are analyzed to quantify groundwater loss during 2012–2015
  • The GPS‐based estimate of groundwater loss is consistent with that obtained from satellite gravimetry, given uncertainties
  • The San Joaquin Valley aquifer system permanently lost up to 3% of its storage capacity due to overdraft during drought

Testing the Influence of Static and Dynamic Stress Perturbations On the Occurrence of a Shallow, Slow Slip Event in Eastern Taiwan

  • We present the first detection of a slow slip event in the Longitudinal Valley, Taiwan
  • The slow slip event occurred at shallow depths (2 to 4 km) either on the Longitudinal Valley Fault or on the Central Range Fault
  • We investigate whether the slow rupture may have been influenced by static and dynamic perturbations by modeling the Coulomb stress changes

Leakage and Increasing Fluid Pressure Detected in Oklahoma's Wastewater Disposal Reservoir

  • The tidal response of the Arbuckle reservoir in Oklahoma is inconsistent with confined, radial flow and shows evidence of leakage
  • Time series show additional signals unrelated to tides and atmospheric pressure, including a robust teleseismic response and long‐term trends
  • Fluid pressure in the Arbuckle is steadily increasing, presumably related to high volume wastewater disposal

Updip and Along‐Strike Aftershock Migration Model Driven by Afterslip: Application to the 2011 Tohoku‐Oki Aftershock Sequence

  • An aftershock migration model based on a rate strengthening rheology is presented
  • Model describes aftershock migration along dip and along strike, taking into account depth‐varying rheological fault properties
  • Model captures first‐order features of the aftershock migration following the 2011 Mw9 Tohoku‐Oki earthquake


November 2018

Bounding the Moment Deficit Rate on Crustal Faults Using Geodetic Data: Application to Southern California

  • Pages: 11,048-11,061 First Published:29 November 2018
  • We apply a new method, COBE, to estimate the current Moment Deficit Rate (MDR) in Southern California
  • MDR for Southern California may be significantly higher than the average seismic moment rate since 1850
  • We report MDR for individual fault segments and show that many could host significant earthquakes

Identification and Extraction of Seasonal Geodetic Signals Due to Surface Load Variations

  • Pages: 11,031-11,047 First Published:22 November 2018
  • We propose a procedure to isolate seasonal geodetic signals due to surface loads using a GRACE‐based deformation model and an independent component analysis
  • GNSS and GRACE‐derived displacements yield consistent seasonal time evolutions in both the Arabian Peninsula and the Nepal Himalaya
  • The method is robust to topographic and elastic heterogeneities, simple moving loads and geodetic products errors

Stressing Rates and Seismicity on the Major Faults in Eastern Tibetan Plateau

  • Pages: 10,968-10,986 First Published:08 November 2018
  • We investigate stress evolution, interseismic stressing rates, and temporal patterns of seismicity on the major faults in eastern Tibet
  • We demonstrate the importance of estimating interseismic stressing rates and evaluate them using both the geodynamic model and the GPS data
  • Time lengths of seismic quiescence and earthquake clusters can be related with fault slip rates, fault configuration, and rheology

Modeling High Stress Drops, Scaling, Interaction, and Irregularity of Repeating Earthquake Sequences Near Parkfield

  • Pages: 10,854-10,879 First Published:14 November 2018
  • Enhanced dynamic weakening and/or elevated normal stress are used to reproduce observations
  • High stress drops, interaction, and repeat times of SF/LA repeaters are simultaneously reproduced
  • Aseismic slip between repeating events is key to explaining their source properties and variability



October 2018

Crustal Deformation of the Altyn Tagh Fault Based on GPS

  • Pages: 10309-10322 First Published:15 November 2018
  • Altyn Tagh fault slip rate and coupling inverted using new, dense interseismic GPS velocities
  • The three fault segments between Sulamu Tagh and Aksay bends have the potential to rupture in Mw 7.7, Mw 7.6, and Mw 7.8 earthquakes
  • A hybrid kinematic model is needed to delineate the crustal deformation of the Tibetan Plateau

Blind Signal Separation Methods for InSAR: The Potential to Automatically Detect and Monitor Signals of Volcanic Deformation

  • Pages: 10,226-10,251 First Published:November 2018
  • Independent component analysis (ICA) is the best of a suite of blind signal separation methods for use with InSAR data
  • Independent component analysis can be used to automatically isolate signals of geophysical interest during the 2015 Wolf Volcano eruption
  • Through monitoring the changes in the signals recovered by ICA, signs of unrest at a volcano can be automatically detected

Viscous Accretionary Prisms: Viscoelastic Relaxation of the Makran Accretionary Prism Following the 2013 Baluchistan, Pakistan Earthquake

  • Pages: 10,107-10,123 First Published:17 October 2018
  • InSAR analysis of deformation following the 2013 Baluchistan earthquake suggests a viscous body within the Makran accretionary prism
  • Ongoing deformation near the 2013 rupture can be explained by viscoelastic relaxation of a shallow weak zone within the prism
  • The weak nature of the accretionary prism may be driven by high pore fluid pressures

Capturing 50 Years of Postseismic Mantle Flow at Nankai Subduction Zone

  • Pages: 10,091-10,106 First Published:22 October 2018
  • Tide gauge records, leveling data, and GPS‐derived velocities are combined to form a postseismic vertical deformation field from 1947 to 2015 in southwest Japan
  • Two‐dimensional models show that afterslip and mantle flow mechanisms are required to explain the postseismic transient
  • Vertical deformation data in southwest Japan unambiguously capture 50 years of postseismic mantle flow

Stress Shadow on the Southwest Portion of the Longmen Shan Fault Impacted the 2008 Wenchuan Earthquake Rupture

  • Pages: 9963-9981 First Published:05 November 2018
  • The earthquakes on the XSHF from 1725 to 2008 cast a stress shadow on the SW segment of the LMSF
  • The 1970 Dayi earthquake on the SW segment of the LMSF contributed to the stress shadow
  • The stress shadow prevented the southwestward propagation of the 2008 Wenchuan earthquake rupture

Spatiotemporal Variation of Tectonic Tremor Activity Before the Tohoku‐Oki Earthquake

  • Pages: 9676-9688 First Published:11 October 2018
  • A modified frequency scanning method allowed investigation of tectonic tremors occurring before the largest Tohoku‐Oki foreshock
  • This method revealed details of tremor activity in the rupture area of Tohoku‐Oki earthquake, especially close to the Japan Trench
  • Temporal and spatial changes in tectonic tremor activity reflected slow slip event expansion processes that occur before large earthquakes

Insights on the Japanese Subduction Megathrust Properties From Depth and Lateral Variability of Observed Ground Motions

J. Piña‐Valdés A. Socquet F. Cotton

Journal of Geophysical Research: Solid EarthVolume 123, Issue 10

First published: October 2018




September 2018

Intraplate Strike‐Slip Faulting, Stress Accumulation, and Shear Localization of a Crust‐Upper Mantle System With Nonlinear Viscoelastic Material

  • Pages: 9269-9285 First Published:26 September 2018
  • We develop a self-consistent earthquake cycle model for simulating the evolution of a strike-slip fault with nonlinear Maxwell rheology
  • The fault behaviors change with time as the stress accumulates in the upper crust and the deformation concentrates in the lower crust
  • Time to develop a lower crustal shear zone with large shear strain is much longer than the time for the localization of deformation

Generic Atmospheric Correction Model for Interferometric Synthetic Aperture Radar Observations

  • Pages: 9202-9222 First Published:12 September 2018
  • A generic InSAR atmospheric correction model with global availability at any time and in all weathers is developed
  • High spatial resolution ECMWF model and GPS estimates are integrated to decouple the tropospheric stratification and turbulence
  • Performance indicator metrics for quality control and model applicability are developed



August 2018

The Accumulation of Slip Deficit in Subduction Zones in the Absence of Mechanical Coupling: Implications for the Behavior of Megathrust Earthquakes

  • Pages: 8260-8278 First Published:07 September 2018
  • Locked asperities on subduction megathrusts cause slip deficit to accumulate in regions that would otherwise slide at the convergence rate
  • Unruptured locked zones restrict the maximum magnitude of slip in earthquakes that rupture adjacent sections of the plate boundary
  • Modeled patterns of interseismic deformation near the trench are compatible with tsunami‐related coseismic observations

Surface Rupture Morphology and Vertical Slip Distribution of the 1959 Mw 7.2 Hebgen Lake (Montana) Earthquake From Airborne Lidar Topography

  • Pages: 8229-8248 First Published:09 August 2018
  • Multistranded 1959 Hebgen Lake earthquake rupture reassessed with newly acquired airborne lidar topography data
  • Morphologically simple scarp captures 1959 event and, in places, one or more Holocene paleo‐earthquakes known from trenching
  • The Hebgen‐Red Canyon fault system ruptures with variable slip‐per‐event at a site

Kinematics and Dynamics of the Pamir, Central Asia: Quantifying the Roles of Continental Subduction in Force Balance

  • Pages: 8161-8179 First Published:01 August 2018
  • Surface deformation is controlled by a balance of body forces, lateral boundary forces, and pull from the subducting Pamir slab
  • Subduction contributes compression normal to the Pamir Frontal Thrust System and shear at the eastern and western Pamir boundaries
  • Lateral variations in trench‐normal compression reflect differences in deeper slab dynamics between the Pamir and Hindu Kush

Slip‐Deficit Rate Distribution Along the Nankai Trough, Southwest Japan, With Elastic Lithosphere and Viscoelastic Asthenosphere

  • Pages: 8125-8142 First Published:29 August 2018
  • Slip‐deficit rates along the Nankai trough were estimated from GNSS data and seafloor geodetic data, using elastic‐viscoelastic structures
  • When viscoelastic relaxation is included, a high slip‐deficit rate zone was located more trenchward than those in pure elastic response
  • Our strain data inversion succeeded in decomposing observed displacement into the contributions from plate coupling and rigid block motions

Kinematic Parameter Inversion of the Slumgullion Landslide Using the Time Series Offset Tracking Method With UAVSAR Data

  • Pages: 8110-8124 First Published:14 August 2018
  • We establish a kinematic landslide model and resolves the kinematic parameters with time series displacement fields
  • We analyze the relationships among the kinematic parameters, topography, and meteorology
  • We identify the main geological structures of the Slumgullion landslide and analyzes the kinematic characteristics of these structures

Interseismic Ground Deformation and Fault Slip Rates in the Greater San Francisco Bay Area From Two Decades of Space Geodetic Data

  • Pages: 8095-8109 First Published:01 August 2018
  • Interseismic ground deformation map of the greater San Francisco Bay Area is generated
  • Deep strike‐slip rates on major locked faults are estimated
  • Surface creeping signals are observed on the Rodgers Creek fault and the Concord fault

Geodetically Inferred Locking State of the Cascadia Megathrust Based on a Viscoelastic Earth Model

  • Pages: 8056-8072 First Published:04 August 2018
  • Widespread interseismic deformation reflects viscoelastic relaxation but may be interpreted as deep locking by elastic models
  • Viscoelastic geodetic inversion models indicate megathrust locking at shallow depths at Cascadia
  • Regardless of Earth rheology, near‐trench ambiguity of locking state can be resolved only by future seafloor observations

Recurring Slow Slip Events and Earthquake Nucleation in the Source Region of the M 7 Ibaraki‐Oki Earthquakes Revealed by Earthquake Swarm and Foreshock Activity

  • Pages: 7950-7968 First Published:27 August 2018
  • Recurrence of slow slip events at Ibaraki‐Oki in the Japan Trench is revealed by earthquake swarm and foreshock activity
  • Foreshocks of the M 7 Ibaraki‐Oki earthquakes were particularly active and associated with large fault slip of repeating earthquakes
  • Slow slip events preceding the M 7 Ibaraki‐Oki earthquakes may have had larger seismic moments than other slow slip events

Frictional Mechanics of Slow Earthquakes

  • Pages: 7931-7949 First Published:25 August 2018
  • Laboratory experiments illuminate a friction‐based explanation for the mechanics underlying the spectrum of fault slip
  • Fault slip mode is dictated by the ratio of the loading stiffness to a critical rheological stiffness and varies with slip velocity
  • Slow slip can be explained by velocity dependence of kc and rupture velocity by potential stress drop near the stability boundary
  • Pages: 7722-7740 First Published:21 August 2018
  • Stress drops are higher in fully coupled rupture asperities and lower in zones of low seismic coupling that host earthquake swarms
  • Stress drops in rupture asperities are lower following a MW 6.0 mainshock, suggesting decreased fault strength after a large earthquake
  • Stress drop is inversely correlated with damage, indicating fractured material and possibly enhanced fluid flow limit stress accumulation



July 2018

Tidal Modulation and Tectonic Implications of Tremors in Taiwan

  • Pages: 5945-5964 First Published:05 July 2018
  • We present results from 6 years of tremor observations in a continental subduction zone
  • Tremor occurrence is strongly modulated by fluctuations in both shear and normal stress (tensile)
  • We propose a tectonic model that can be reconciled with both the steeply and gently dipping geometry of the tremor zone

Earthquakes and Tremor Linked to Seamount Subduction During Shallow Slow Slip at the Hikurangi Margin, New Zealand

  • Pages: 6769-6783 First Published:27 July 2018
  • Offshore tectonic tremor localizes at subducted seamounts during and immediately following the 2014 Gisborne SSE
  • Stresses from seamount subduction dominate megathrust slow slip in producing seismicity and tremor
  • A wide range of slip processes occur on the plate interface in very close proximity to one another

Spatiotemporal Evolution of Recurrent Slow Slip Events Along the Southern Ryukyu Subduction Zone, Japan, From 2010 to 2013

  • Pages: 7090-7107 First Published:31 July 2018
  • Spatiotemporal evolutions are described for five slow slip events (SSEs) with Mw 6.6–6.7 in the southern Ryukyu subduction zone
  • The final slip distributions of the five SSEs are similar, indicating that the SSEs recur in the same fault area
  • The temporal evolution of the five SSEs, especially the nucleation styles, varies from event to event

Interseismic Strain Accumulation on Faults Beneath Los Angeles, California

  • Pages: 7126-7150 First Published:16 July 2018
  • We build GPS‐based models of strain accumulation on faults beneath Los Angeles that incorporate the effect of the sedimentary basin
  • We infer that three major thrust faults slip at 3‐4 mm/year over the long term and are partially or fully locked on their upper sections
  • This locking corresponds to a total seismic moment deficit rate of 1.6 + 1.3/‐0.5 times 1017Nm/year, which is presumably released in earthquakes



June 2018

Crustal Deformation Following Great Subduction Earthquakes Controlled by Earthquake Size and Mantle Rheology

  • Pages: 5323-5345 First Published:09 June 2018
  • In postseismic deformation following great subduction earthquakes, the dividing boundary of opposing motion migrates away from the trench
  • How fast the dividing boundary migrates, measured using a reference time, depends on Earth's viscoelastic rheology and earthquake size
  • Comparative modeling of ten 8.0 ≤ Mw ≤ 9.5 earthquakes suggests a positive dependence of the reference time on earthquake size

Crustal Deformation Process in the Mid‐Niigata Region of the Niigata‐Kobe Tectonic Zone as Observed by Dense GPS Network Before, During, and After the Tohoku‐Oki Earthquake

  • Pages: 6072-6085 First Published:26 June 2018
  • Decomposition of geodetic strain rate pattern with respect to its wavelength is performed
  • Localized contraction with changes in amplitude and location is found before and after the Tohoku‐oki earthquake
  • Effects of inelastic process, as well as elastic heterogeneities within the crust, are embedded with the geodetic signal

Spatial Scales in Topography and Strain Rate Magnitude in the Western United States

  • Pages: 6086-6097 First Published:26 June 2018
  • Two characteristic length scales occur in the tectonic deformation of the western United States
  • These scales suggest that the North American lithosphere includes at least two distinct rheological materials
  • Spectral tools can be used to evaluate characteristic scaling and hence provide novel constraints on continental rheology and architecture



May 2018

Structural Control on Downdip Locking Extent of the Himalayan Megathrust

  • Pages: 5265-5278 First Published:04 June 2018
  • The limit of fault coupling on the Main Himalayan Thrust agrees with geologic models of the midcrustal ramp in central and eastern Nepal
  • In western Nepal, the fault coupling transition falls between two proposed ramp locations, and we suggest that both may be active
  • The moment accumulation rate in our model is 30% smaller than previous results, partially resolving an apparent seismic moment deficit


Seasonal Nontectonic Loading Inferred From cGPS as a Potential Trigger for the M6.0 South Napa Earthquake

  • Pages: 5300-5322 First Published:06 May 2018
  • Horizontal cGPS displacements show dilatational strain and Coulomb stress change in South Napa peaking just before the 2014 earthquake
  • Eight years of cGPS data show broad seasonally repeating strain and stress transients East and North of San Pablo Bay
  • Some component of the transient strains may be associated with hydrologic and thermoelastic sources


An Invariant Rate‐ and State‐Dependent Friction Formulation for Viscoeastoplastic Earthquake Cycle Simulations

  • Pages: 5018-5051 First Published:17 May 2018
  • We present an invariant rate‐ and state‐dependent friction formulation for simulations in a continuum mechanics framework
  • Numerical accuracy and stability is demonstrated for seismic slip on a straight fault
  • Based on our simulations, we derive a viscosity threshold, below which no earthquakes are generated


April 2018

A Robust Estimation of the 3‐D Intraplate Deformation of the North American Plate From GPS

  • Pages: 4388-4412 First Published:05 May 2018
  • A new strain rate model and vertical velocity map for intraplate North America are derived from up to 3,271 GPS velocities
  • Results reflect GIA with contractional strain rates and far‐field horizontal velocities being significantly higher than predicted
  • Nonrigidity of the North American plate has implications for plate motion estimation, reference frame, and Earth viscosity structure


Deformation of the Pacific/North America Plate Boundary at Queen Charlotte Fault: The Possible Role of Rheology

  • Pages: 4223-4242 First Published:30 March 2018
  • Pacific‐North America plate boundary is located on the ocean‐continent boundary, an unusual location for continental transforms
  • The bimaterial contrast across the plate boundary focuses the deformation on a single narrow fault
  • A scenario for the development of the plate boundary is proposed


Comparative Study of Earthquake Clustering in Relation to Hydraulic Activities at Geothermal Fields in California

  • Pages: 4041-4062 First Published:22 April 2018
  • Earthquake clustering responds differently to hydraulic operations at The Geysers, Coso, and Salton Sea geothermal fields
  • The variations of the response are likely related to different local tectonic processes and structures
  • Background earthquake rates and types of clusters change between periods of low and high injection‐production fluid balance


Characterizing Afterslip and Ground Displacement Rate Increase Following the 2014 Iquique‐Pisagua Mw 8.1 Earthquake, Northern Chile

  • Pages: 4171-4192 First Published:25 March 2018
  • GPS rates south of 21°S accelerate in the second year following the Iquique‐Pisagua event potentially reflecting coupling increase
  • Afterslip lasts about 2 years before the interface relocks again almost entirely
  • GPS velocity patterns and modeled interface afterslip rates suggest a seismotectonic barrier at 21°S

Observing and Modeling the Spectrum of a Slow Slip Event

  • Pages: 4243-4265 First Published:06 April 2018
  • We estimate the moment rate power spectrum of slow slip events in Cascadia using GPS, strain, and tremor data
  • We obtain a moment rate spectrum with shallow power law frequency decay at periods shorter than 1 day
  • The spectrum can be reproduced if large slow slip events contain collections of subevents with linear moment‐duration scaling



March 2018

Fault Slip and GPS Velocities Across the Shan Plateau Define a Curved Southwestward Crustal Motion Around the Eastern Himalayan Syntaxis

Journal of Geophysical Research: Solid Earth

First published: 30 March 2018


Did the 2008 Mw 7.9 Wenchuan earthquake trigger the occurrence of the 2017 Mw 6.5 Jiuzhaigou earthquake in Sichuan, China?

Journal of Geophysical Research: Solid Earth

First published: 25 March 2018


Strain Partitioning and Present‐Day Fault Kinematics in NW Tibet From Envisat SAR Interferometry

Journal of Geophysical Research: Solid Earth

First published: 25 March 2018


Transpressional Rupture Cascade of the 2016 Mw 7.8 Kaikoura Earthquake, New Zealand

Journal of Geophysical Research: Solid Earth

First published: 10 March 2018



February 2018

Euler‐Vector Clustering of GPS Velocities Defines Microplate Geometry in Southwest Japan
J. C. Savage
Journal of Geophysical Research: Solid EarthVolume 123, Issue 2

First published: 02 February 2018


Temporal Stress Changes Caused by Earthquakes: A Review

Jeanne L. Hardebeck  Tomomi Okada

Journal of Geophysical Research: Solid EarthVolume 123, Issue 2

First published: 09 February 2018


Toward a global horizontal and vertical elastic load deformation model derived from GRACE and GNSS station position time series

Journal of Geophysical Research: Solid Earth

First published: 21 February 2018


Spatiotemporal Variations in Slow Earthquakes Along the Mexican Subduction Zone

J. Maury  S. Ide V. M. Cruz‐Atienza V. Kostoglodov

Journal of Geophysical Research: Solid EarthVolume 123, Issue 2

First published: 19 January 2018


Revisiting Slow Slip Events Occurrence in Boso Peninsula, Japan, Combining GPS Data and Repeating Earthquakes Analysis

Journal of Geophysical Research: Solid EarthVolume 123, Issue 2

First published: 05 December 2017



January 2018

Catalog of Offshore Seismicity in Cascadia: Insights Into the Regional Distribution of Microseismicity and its Relation to Subduction Processes

Authors: Ian Stone, John E. Vidale, Shuoshuo Han, Emily Roland

First Published: 29 January 2018

  • We develop an earthquake catalog using the Cascadia Initiative ocean bottom seismometer data set for the entire Cascadia subduction zone
  • Subduction zone and Juan de Fuca plate seismicity increases from north to south, with distinct increase in seismicity south of 46°N
  • Seismicity varies with incoming plate smoothness and hydration, tied to observed trends in intraplate deformation and underthrust sediment


Geodetic Evidence for a Blind Fault Segment at the Southern End of the San Jacinto Fault Zone

Authors: Ekaterina Tymofyeyeva, Yuri Fialko

First Published: 27 January 2018

  • We combine InSAR and GPS data to derive maps of three‐component interseismic surface velocity and strain rate
  • Strain rate anomaly at the southern end of the San Jacinto fault lends support to a hypothesized blind fault segment
  • Slip rate on a blind fault segment is 13 plus‐minus 3 mm/yr, higher than on the nearby Coyote Creek fault


Using Low‐Frequency Earthquake Families on the San Andreas Fault as Deep Creepmeters

Authors: A. M. Thomas, N. M. Beeler, Q. Bletery, R. Burgmann, D. R. Shelly

First Published: 22 January 2018

  • We define slip episodes, or clusters of individual LFE occurrence, based on properties of LFE recurrence intervals
  • We formalize the definition of a creepmeter and determine its applicability to LFE families on the deep San Andreas Fault
  • We find that episodic families meter creep and reflect surrounding SSEs, while continuous families reflect asperities that fail in response to continuous creep


Segmentation of Slow Slip Events in South Central Alaska Possibly Controlled by a Subducted Oceanic Plateau

Authors: Haotian Li, Meng Wei, Duo Li, Yajing Liu, YoungHee Kim, Shiyong Zhou

First Published: 15 January 2018

  • We simulate SSEs in south central Alaska with a nonplanar fault model
  • Along‐strike variation of effective normal stress controls the segmentation of SSEs
  • The segmentation is likely related to the subducted Yakutat Plateau


Uplift of the Western Transverse Ranges and Ventura Area of Southern California: A Four‐Technique Geodetic Study Combining GPS, InSAR, Leveling, and Tide Gauges

Authors: William C. Hammond, Reed J. Burgette, Kaj M. Johnson, Geoffrey Blewitt

First Published: 15 January 2018

  • We estimate the uplift rate of the Western Transverse Ranges in southern California from integrated GPS, InSAR, leveling, and tide gauge data
  • Geodetic imaging of topographic growth reveals the vertical response to contraction across the Big Bend of the San Andreas Fault system
  • Geographically continuous uplift of 1–2 mm/yr is asymmetric across the San Andreas Fault and decreases to subsidence near the coast


Observations and Modeling of Coseismic and Postseismic Deformation Due To the 2015 Mw 7.8 Gorkha (Nepal) Earthquake

Authors: Kang Wang, Yuri Fialko

First Published: 10 January 2018

  • We developed FEM of the 2015 Gorkha earthquake that accounts for variations in topography and material properties across the Himalayan arc
  • Space geodetic observations reveal transient deformation following the Gorkha earthquake that is best explained by downdip afterslip
  • Observed deformation is inconsistent with models of a low‐viscosity (order of 1018 Pa s or less) channel in the lower crust beneath Tibet


Variability of the Space‐Time Evolution of Slow Slip Events Off the Boso Peninsula, Central Japan, From 1996 to 2014

Authors: Jun'ichi Fukuda

First Published: 10 January 2018

  • Five Boso slow slip events (SSEs) exhibit variable nucleation style and space‐time evolution of slip
  • Overall evolution of the SSEs and relative timing between onsets of slow slip and accompanying seismicity correlate with nucleation style
  • Slip expansion/propagation patterns vary among the SSEs and correlate well with the space‐time migration of seismicity



December 2017

Sustained Water Loss in California's Mountain Ranges During Severe Drought From 2012 to 2015 Inferred From GPS

Authors: Donald F. Argus, Felix W. Landerer, David N. Wiese, Hilary R. Martens, Yuning Fu, James S. Famiglietti, Brian F. Thomas, Thomas G. Farr, Angelyn W. Moore, Michael M. Watkins

First Published: 26 December 2017

  • Elastic vertical displacements are inverted to infer change in total water storage in mountain ranges in the western U.S. from 2006 to 2017
  • Sierra Nevada uplift during severe drought from 2012 to 2015 is primarily solid Earth's elastic response to water loss in the Sierra Nevada
  • More water in the ground in California's mountains is lost during drought and gained during heavy precipitation than in hydrology models


Stress Models of the Annual Hydrospheric, Atmospheric, Thermal, and Tidal Loading Cycles on California Faults: Perturbation of Background Stress and Changes in Seismicity

Authors: Christopher W. Johnson, Yuning Fu, Roland Bürgmann

First Published: 26 December 2017

  • Mechanical models are developed to quantify stress changes for the regional fault geometry induced by seven sources of annual loading
  • Annual hydrospheric loading in California produces the largest Coulomb stress changes of 0.5–2 kPa on regional fault systems
  • Annual stress changes of ≤5 kPa in the principal orientation of the background stress field modulate low‐magnitude seismicity


Dynamic Rupture Modeling of the M7.2 2010 El Mayor‐Cucapah Earthquake: Comparison With a Geodetic Model

Authors: C. Kyriakopoulos, D. D. Oglesby, G. J. Funning, Kenny J. Ryan

First Published: 19 December 2017

  • Similar slip pattern between dynamic rupture model and geodetic model
  • First‐order geometric effects on fault slip distribution
  • Topographic effects on fault slip rates


A geodetic matched filter search for slow slip with application to the Mexico subduction zone

Authors: B. Rousset, M. Campillo, C. Lasserre, W. B. Frank, N. Cotte, A. Walpersdorf, A. Socquet, V. Kostoglodov

First Published: 18 December 2017

  • We developed a geodetic matched filter that specifically allows for the search of low‐amplitude slow slip events
  • Synthetic tests show that this method is able to resolve Mw> 6 events in the context of the Mexico subduction zone
  • The application on real data between 2005 and 2014 enables to detect 28 slow slip events of Mw between 6.3 and 7.2 in the Guerrero area



Mixed‐Mode Slip Behavior of the Altotiberina Low‐Angle Normal Fault System (Northern Apennines, Italy) through High‐Resolution Earthquake Locations and Repeating Events

Authors: Luisa Valoroso, Lauro Chiaraluce, Raffaele Di Stefano, Giancarlo Monachesi

First Published: 18 December 2017

  • High‐resolution locations describe the anatomy of the Altotiberina low‐angle normal fault and of its complex synthetic and antithetic splays
  • The spatiotemporal seismicity distribution agrees with the geodetic models reporting a frictionally heterogeneous low‐angle ATF plane
  • The rate of occurrence of repeating events along the ATF seems to modulate the seismicity in its hanging wall block


Resolving the Detailed Spatiotemporal Slip Evolution of Deep Tremor in Western Japan

Authors: Kazuaki Ohta, Satoshi Ide

First Published: 4 December 2017

  • We propose a new slip inversion method for resolving the detailed slip evolution of deep tremor
  • Slip distributions of deep tremor illuminate the patchy source regions of slow earthquakes in western and central Shikoku, Japan
  • The size of the slip region may potentially control the visibility of very low frequency earthquake signals


November 2017

Blind Thrusting, Surface Folding, and the Development of Geological Structure in the Mw 6.3 2015 Pishan (China) Earthquake

Authors: E. A. Ainscoe, J. R. Elliott, A. Copley, T. J. Craig, T. Li, B. E. Parsons, R. T. Walker

First Published: 27 November 2017

  • Coseismic fault geometry and location closely match a preexisting blind fault
  • Quaternary fold grows by distributed deformation in the overlying sediments and does not align with coseismic or early postseismic uplift
  • Rheology contrast between the Tarim Basin and Tibet may explain the earthquake's low dip angle


Piecemeal Rupture of the Mentawai Patch, Sumatra: The 2008 Mw 7.2 North Pagai Earthquake Sequence

Authors: Rino Salman, Emma M. Hill, Lujia Feng, Eric O. Lindsey, Deepa Mele Veedu, Sylvain Barbot, Paramesh Banerjee, Iwan Hermawan, Danny H. Natawidjaja

First Published: 27 November 2017

  • We present the first detailed study of the 2008 Mw 7.2 North Pagai earthquake using GPS and InSAR data
  • The 2008 earthquake sequence ruptured only partially the middle section of the Mentawai patch
  • The estimated afterslip partially overlaps the updip region of the coseismic rupture area


The 2016 Kumamoto Mw = 7.0 Earthquake: A Significant Event in a Fault–Volcano System

Authors: Han Yue, Zachary E. Ross, Cunren Liang, Sylvain Michel, Heresh Fattahi, Eric Fielding, Angelyn Moore, Zhen Liu, Bo Jia

First Published: 27 November 2017

  • Detailed slip model of Kumamoto earthquake sequence resolved
  • Innovative model parameterization adopted in inversion
  • Effects of “material” and “stress” barriers classified and discussed


Neotectonic Deformation in Central Eurasia: A Geodynamic Model Approach

Authors: Lavinia Tunini, Ivone Jiménez‐Munt, Manel Fernandez, Jaume Vergés, Peter Bird

First Published: 27 November 2017

  • Modeled velocities reproduce lateral escape tectonics due to the continental collisions of Arabia and India with Eurasia
  • SE Tibet velocities can be explained by the combination of Sumatra trench retreat, a lithospheric mantle thinning and strike‐slip faulting
  • Arabia‐India intercollision zone shows no velocity deflections related to Arabia and India indentations


Microseismicity in Southern South Island, New Zealand: Implications for the Mechanism of Crustal Deformation Adjacent to a Major Continental Transform

Authors: Emily Warren‐Smith, Simon Lamb, Tim A. Stern, Euan Smith

First Published: 27 November 2017

  • We present a detailed 15 month microseismicity catalog for the Southern Lakes region, New Zealand, adjacent to the Alpine Fault
  • Microseismicity shows little association with known faults, representing diffuse background cracking in response to ambient stress release
  • Total moment release rate is ~0.1% of the total plate convergence rate; the rest is likely released in large‐great magnitude earthquakes


Crustal Deformation in the India‐Eurasia Collision Zone From 25 Years of GPS Measurements

Authors: Gang Zheng, Hua Wang, Tim J. Wright, Yidong Lou, Rui Zhang, Weixing Zhang, Chuang Shi, Jinfang Huang, Na Wei

First Published: 6 November 2017

  • The most complete and up‐to‐date velocity field in the India‐Eurasia collision zone including 2576 GPS stations observed from 1991 to 2015
  • Velocity field shows several large undeforming areas, strain around some major faults, areas of diffuse strain, and dilation of high plateau
  • There was no robust evidence for discrepancy between geological and geodetic slip rates of the major strike‐slip faults in Tibet


Slip Behavior of the Queen Charlotte Plate Boundary Before and After the 2012, MW 7.8 Haida Gwaii Earthquake: Evidence From Repeating Earthquakes

Authors: Tim W. Hayward, Michael G. Bostock

First Published: 3 November 2017

  • Repeating earthquakes were observed at the Queen Charlotte plate boundary
  • Short‐term acceleration of the Queen Charlotte Fault detected following the 2012 Haida Gwaii earthquake
  • Prolonged afterslip detected on the subduction interface following the 2012 Haida Gwaii earthquake


October 2017

Rapid Geodetic Shortening Across the Eastern Cordillera of NW Argentina Observed by the Puna‐Andes GPS Array

Authors: Phillip K. McFarland, Richard A. Bennett, Patricia Alvarado, Peter G. DeCelles

First Published: 28 October 2017

  • Interseismic velocity field presented for southern central Andean back arc including five new stations from the Puna‐Andes GPS Array
  • Deformation due to locking on both subduction interface and back‐arc décollement required to fit observed GPS velocities across orogen at 24°S
  • Best fit to GPS velocities with ~9 mm/yr of hanging wall shortening in the back‐arc fold‐thrust belt, with shortening concentrated beneath the Eastern Cordillera


Remote Sensing of Ground Deformation for Monitoring Groundwater Management Practices: Application to the Santa Clara Valley During the 2012–2015 California Drought

Authors: Estelle Chaussard, Pietro Milillo, Roland Bürgmann, Daniele Perissin, Eric J. Fielding, Brett Baker

First Published: 26 October 2017

  • InSAR time series of high‐repeatability data enable tracking water through an aquifer system and evaluate water‐resource management practices
  • In the Santa Clara Valley (SCV), CA, the 2012–2015 drought led to only elastic and recoverable changes thanks to management efforts
  • Surface load changes due to groundwater mass changes in an aquifer system could influence the stress on nearby faults


Dominant Controls of Downdip Afterslip and Viscous Relaxation on the Postseismic Displacements Following the Mw7.9 Gorkha, Nepal, Earthquake

Authors: Bin Zhao, Roland Bürgmann, Dongzhen Wang, Kai Tan, Ruilin Du, Rui Zhang

First Published: 14 October 2017

  • Postseismic displacements in initial 1 year following the Gorkha earthquake are governed by afterslip and viscoelastic relaxation
  • Stress‐driven downdip afterslip occurs predominately in brittle‐ductile transition
  • Viscoelastic relaxation models suggest laterally heterogeneous rheological structure across India and Tibet


Delayed Seismicity Rate Changes Controlled by Static Stress Transfer

Authors: Kayla A. Kroll, Keith B. Richards‐Dinger, James H. Dieterich, Elizabeth S. Cochran

First Published: 14 October 2017

  • Seismic quiescence and triggering is observed related to coseismic static stress changes
  • Decreased seismicity rates may be obscured by a small subset events with positive CFS
  • Coupled Coulomb/rate‐state models can explain time‐dependent delay in seismicity rate decreases due to negative coseismic stress changes


A Physical Model for Interseismic Erosion of Locked Fault Asperities

Authors: Andreas P. Mavrommatis, Paul Segall, Kaj M. Johnson

First Published: 7 October 2017

  • A physical model for locked fault asperities that shrink during the interseismic period is developed
  • Numerical simulations of rate‐and‐state friction with thermal pressurization show that locked area shrinks roughly linearly over time
  • We investigate the rate of asperity erosion as a function of fault strength, hydraulic properties, and asperity size


Stress Orientations in a Locked Subduction Zone at the Southern Hikurangi Margin, New Zealand

Authors: Dominic Evanzia, Thomas Wilson, Martha K. Savage, Simon Lamb, Hamish Hirschberg

First Published: 7 October 2017

  • Focal mechanism inversion and S wave anisotropy were used to measure the stress field orientation in the southern North Island New Zealand
  • At the southern Hikurangi margin the stress field within the subducting slab is dominated by bending stresses
  • The overriding plate stress field is influenced by stresses in the subducting slab, gravitational stresses, and tectonic loading


September 2017

An Investigation of the Accuracy of Coulomb Stress Changes Inferred From Geodetic Observations Following Subduction Zone Earthquakes

Authors: Bryan J. Stressler, William D. Barnhart

First Published: 25 September 2017

  • We investigate the resolution of Coulomb stress change predictions in subduction zone environments
  • The accuracy of stress change predictions is highly limited by model resolution and terrestrial geodetic arrays
  • Seafloor geodetic observations provide one possible avenue to improve models of static stress transfer following offshore earthquakes



August 2017

Insights into the causal relationship between slow slip and tectonic tremor in Guerrero, Mexico

Carlos Villafuerte, Víctor M. Cruz‐Atienza

First Published: 26 August 2017

  • The SSE slip rate modulates the TT and LFE occurrence rate in the whole tremor region of Guerrero
  • The strength of the tremor asperities is 2.3 times smaller downdip in the sweet spot than updip in the transient zone
  • The short‐term SSEs take place right in the sweet spot, where tremor activity dominates during the interlong‐term SSE period


Bounding the moment deficit rate on crustal faults using geodetic data: Methods

Jeremy Maurer, Paul Segall, Andrew M. Bradley

First Published: 19 August 2017

  • The geodetic moment deficit rate (MDR) measures earthquake potential without smoothness assumptions
  • Two proposed methods based on constrained optimization provide reliable bounds on MDR; other methods can fail
  • The estimated MDR at Parkfield excludes the observed 38 year recurrence time between 1966 and 2004 events


Connecting depth limits of interseismic locking, microseismicity, and large earthquakes in models of long‐term fault slip

Junle Jiang, Nadia Lapusta

First Published: 15 August 2017

  • The deeper locked‐creeping fault transition can span a broad depth range, with distinct effective and geodetic locking depths
  • The effective locking depth becomes shallower with time and relates to microseismicity at the bottom of the seismogenic zone
  • The geodetic locking depth becomes deeper with time and relates to the potency release and depth extent of large earthquakes


Connecting crustal seismicity and earthquake‐driven stress evolution in Southern California

Fred F. Pollitz, Camilla Cattania

First Published: 14 August 2017

  • A catalog spanning three decades of Southern California seismicity is consistent with the Coulomb rate‐state stressing model
  • Spatial patterns of seismicity evolved systematically following the 1992 Landers, California, earthquake
  • Both static and viscoelastic stress transfer mechanisms are effective at triggering seismicity


Slow slip events in the early part of the earthquake cycle

Nicholas K. Voss, Rocco Malservisi, Timothy H. Dixon, Marino Protti

First Published: 9 August 2017

  • Slow Slip Event recurrence rate was unaffected by large earthquake on same megathrust segment
  • Deep and shallow zones of SSE behaved differently following the earthquake
  • Change in slip magnitudes for SSE show variability in strain release through SSE during the earthquake cycle


Does fault strengthening in laboratory rock friction experiments really depend primarily upon time and not slip?

Pathikrit Bhattacharya, Allan M. Rubin, Nicholas M. Beeler

First Published: 10 August 2017

  • We fit a sequence of slide‐hold‐slides spanning 0.4–30,000 s performed at two different stiffnesses on initially bare granite and quartzite
  • Stiffness‐independent evolution of peak stress with hold time, long identified with time‐dependent healing, can also be fit by the Slip law
  • Stiffness‐dependent rates of stress decay during long holds are well fit by Slip law but contradict Aging law type time‐dependent healing


A microscopic model of rate and state friction evolution

Tianyi Li, Allan M. Rubin

First Published: 10 August 2017

  • We model friction evolution by keeping track of the heterogeneous strength of individual asperity contacts with an assumed size distribution
  • If the strength of an asperity segment depends logarithmically on the velocity at which it formed, state evolution can mimic the slip law
  • Equating “state” with “contact age” gives rise to state evolution that differs from the current aging law



July 2017


Objective estimation of spatially variable parameters of epidemic type aftershock sequence model: Application to California

Shyam Nandan, Guy Ouillon, Stefan Wiemer, Didier Sornette

First Published: 3 July 2017; Vol: 122, 10.1002/2016JB013266

  • Efficient data‐driven method for estimation of spatially variable ETAS parameters
  • Evidence for existence of triggering possibly through fluid‐induced activation
  • Evidence for seismic coupling independent of hypocentral depth


Emergence and disappearance of interplate repeating earthquakes following the 2011 M9.0 Tohoku‐oki earthquake: Slip behavior transition between seismic and aseismic depending on the loading rate

Norishige Hatakeyama, Naoki Uchida, Toru Matsuzawa, Wataru Nakamura

First Published: 5 July 2017; Vol: 122, DOI: 10.1002/2016JB013914

  • We investigated temporal changes in interplate seismicity due to the 2011 Tohoku‐oki earthquake in a fault‐creep dominant area
  • We observed coseismic emergence and subsequent disappearance of interplate earthquakes including repeating earthquakes
  • The observations can be explained by slip behavior transition between seismic and aseismic depending on the loading rate


Temporal variation of tectonic tremor activity in southern Taiwan around the 2010 ML6.4 Jiashian earthquake

Kevin Chao, Zhigang Peng, Ya‐Ju Hsu, Kazushige Obara, Chunquan Wu, Kuo‐En Ching, Suzan van der Lee, Hsin‐Chieh Pu, Peih‐Lin Leu, Aaron Wech

First Published: 22 July 2017; Vol: 122, DOI: 10.1002/2016JB013925

  • A robust automatic tremor detection and location algorithm for the southern Central Range of Taiwan
  • Observations of a short‐term increase in the tremor rate starting at 19 days before a nearby ML6.4 earthquake
  • No GPS signals associated with tremor activity in the southern Central Range


Active thrusting of the Longquan Fault in the central Sichuan basin, China, and the seismotectonic behavior in the Longmen Shan fold‐and‐thrust belt

Maomao Wang, Aiming Lin

First Published: 11 July 2017; Vol: 122, DOI: 10.1002/2016JB013391

  • We show 3‐D model of segmented active thrust slip fault system for the Longquan fault
  • Field observation and trench study reveal that two surface rupture events occurred at the frontal, shallow portions of the Longmen Shan fold‐and‐thrust belt
  • Shallow detachment and active frontal thrust should be included in a comprehensive analysis of seismic cycles of active fold‐and‐thrust belt systems