Untitled

Obara, Shin’ya

doi:10.4307/jsee.50.3_49

Cited by 4 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The discovery of tectonic tremor down dip of the seismogenic zone of the Nankai subduction thrust in southwest Japan (Obara, 2002) opened a new chapter in the study of aseismic fault slip. To date, tremor activity has been found on at least a dozen plate boundary fault zones around the world (Obara and Kato, 2016, and original references cited therein).…”

Section: Seismologic Constraintsmentioning

confidence: 99%

The geophysics, geology and mechanics of slow fault slip

Bürgmann

2018

Earth and Planetary Science Letters

336

308

View full text Add to dashboard Cite

Modern geodetic and seismologic observations describe the behavior of fault slip over a vast range of spatial and temporal scales. Slip at sub-seismogenic speeds is evident from top to bottom of lithospheric faults and plays an important role throughout the earthquake cycle. Where earthquakes and tremor accompany slow slip, they help illuminate the spatiotemporal evolution of fault slip. Geophysical subsurface imaging and geologic field studies provide information about suitable environments of slow slip. In particular, exhumed fault and shear zones from various depths reveal the importance of multiple deformation processes and fault-zone structures. Most geologic examples feature frictionally weak and velocity-strengthening materials, well-developed mineral fabrics, and abundant veining indicative of near-lithostatic fluid pressure. To produce transient slow slip events and tremor, in addition to the presence of high-pressure fluids a heterogeneous fault-zone structure, composition, and/or metamorphic assemblage may be needed. Laboratory and computational models suggest that velocityweakening slip patches smaller than a critical dimension needed for earthquake nucleation will also fail in slow slip events. Changes in fluid pressure or slip ratecan cause a fault to transition between stable and unstable fault slip behavior. Future interdisciplinary investigations of slow fault slip, directly integrating geophysical, geological and modeling investigations, will further improve our understanding of the dynamics of slow slip and aid in providing more accurate earthquake hazard characterizations.

show abstract

Section: Seismologic Constraintsmentioning

confidence: 99%

The geophysics, geology and mechanics of slow fault slip

Bürgmann

2018

Earth and Planetary Science Letters

336

308

View full text Add to dashboard Cite

show abstract

“…The transition zone between seismogenic and aseismic depths may span several km down-dip along the plate boundary, and is home to a range of intermediate slip styles (e.g., Obara & Kato, 2016;Peng & Gomberg, 2010). These include episodic tremor (persistent low frequency seismic signals consistent with small brittle slip events; Ide et al, 2007;Obara, 2002) and slow slip events (slip of similar magnitude to earthquakes but too slow to radiate seismic energy) (Peng & Gomberg, 2010;Rogers, 2003). The potential for earthquake propagation in this transition zone remains unclear (Obara & Kato, 2016).…”

Section: Introductionmentioning

confidence: 99%

Embrittlement Within Viscous Shear Zones Across the Base of the Subduction Thrust Seismogenic Zone

Tulley

Fagereng

Ujiie

et al. 2022

Geochem Geophys Geosyst

View full text Add to dashboard Cite

show abstract

“…In the deeper parts of subduction faults (at about 40 km depth), seismic signals with a lower frequency than earthquakes are detected in a wide frequency band ranging from 0.01 Hz to 10 Hz. Impulsive events called low-frequency earthquakes (LFEs) and very-low frequency earthquakes (VLFEs) are detected in narrow high (1-10 Hz) and low (0.02-0.05 Hz) frequency bands, respectively (Obara, 2002;Katsumata & Kamaya, 2003;Ito et al, 2007). Tectonic tremor is a long (10s to days), emergent seismic signal in which LFEs and VLFEs are almost systematically detected, from the same localized sources, which persist through time (Rubin & Armbruster, 2013;Chestler & Creager, 2017).…”

Section: Introduction 1source Processes Of Tectonic Tremor and Low-fr...mentioning

confidence: 99%

“…We will therefore use the terms "tremor" or "tremor activity" as a synonym for LFE activity, considering that tremor is composed of many LFEs (Shelly et al, 2006;Ide, 2021) -although we recognize that this approach might gloss over potentially different source processes. Tremor activity is intermittent and proceeds in periods of intense activity formed of clusters of LFEs, separated by periods of quiescence (Obara, 2002;Rogers, 2003;Shelly et al, 2007;Brudzinski et al, 2010;Frank et al, 2014;Idehara et al, 2014). The temporal clustering of activity, the duration, sizes and recurrence timescales of tremor bursts vary between subduction zones.…”

Section: Introduction 1source Processes Of Tectonic Tremor and Low-fr...mentioning

confidence: 99%

Along‐Strike Segmentation of Seismic Tremor and Its Relationship With the Hydraulic Structure of the Subduction Fault Zone

Farge,

Jaupart,

Frank

et al. 2023

JGR Solid Earth

View full text Add to dashboard Cite

Along the strike of subduction zones, tectonic tremor episodicity is segmented on a geologic scale. Here, we study how this segmentation reflects large‐scale variations of the structure and conditions of the fault interface where tremor is generated. We try to understand which properties of the hydraulic system of the fault allow elementary tremor sources to synchronize, leading to the emergence of long‐period, large‐scale episodic activity. We model tremor sources as being associated with rapid openings of low‐permeability valves in the fault zone, which channels the upward flow of metamorphic fluids. Valve openings cause pressure transients that allow interaction between sources. In such a system, tremor activity is thus controlled by unsteady fluid circulation. Using numerical simulations of fluid flow, we explore the impact of valve spatial distribution and fluid flux on the emergence of large‐scale patterns of tremor activity. We show that when valves are densely distributed and submitted to near‐critical input flux, they synchronize and generate more episodic activity. Based on our model, the most periodic and spatially coherent tremor bursts should thus be emitted from segments densely populated with valves, and therefore of lower permeability than less synchronized segments. The collective activity of their valve population is responsible for fluid‐pressure cycling at the subduction scale. In the tremor zone of Shikoku, Japan, the most temporally clustered segment coincides with a downgoing seamount chain, suggesting that the segmentation of the fault zone permeability, and hence of tremor activity, could be inherited from the topography of the subducting oceanic plate.

show abstract

Untitled

Cited by 4 publications

References 0 publications

The geophysics, geology and mechanics of slow fault slip

The geophysics, geology and mechanics of slow fault slip

Embrittlement Within Viscous Shear Zones Across the Base of the Subduction Thrust Seismogenic Zone

Along‐Strike Segmentation of Seismic Tremor and Its Relationship With the Hydraulic Structure of the Subduction Fault Zone

Contact Info

Product

Resources

About