Seismic Moment, Seismic Energy, and Source Duration of Slow Earthquakes: Application of Brownian slow earthquake model to three major subduction zones

2018 ◽  
Vol 45 (7) ◽  
pp. 3059-3067 ◽  
Author(s):  
Satoshi Ide ◽  
Julie Maury
Keyword(s):  
Seismic Moment ◽  
Subduction Zones ◽  
Seismic Energy ◽  
Slow Earthquake ◽  
Slow Earthquakes ◽  
Earthquake Model ◽  
Source Duration

The Chile subduction zone : Nature of the lithosphere between alternating regions of slow earthquakes versus non slow earthquakes

2020 ◽  
Author(s):  
Pousali Mukherjee ◽  
Yoshihiro Ito ◽  
Emmanuel S. Garcia ◽  
Raymundo Plata-Martinez ◽  
Takuo Shibutani
Keyword(s):  
Subduction Zones ◽  
Receiver Function ◽  
Function Analysis ◽  
Fluid Distribution ◽  
Inversion Method ◽  
Megathrust Earthquakes ◽  
Slow Earthquake ◽  
Slow Earthquakes ◽  
Receiver Function Analysis ◽  
Earthquake Area

<p>Subduction zones host some of the greatest megathrust earthquakes in the world. Slow earthquakes have been discovered around the subduction zones of the Pacific rim very close to megathrust earthquakes. Investigating the lithosphere of the slow earthquake area versus non slow-earthquake area in subduction zones is crucial in understanding the role of the internal structure to control slow earthquakes. In this study, we investigate the lithospheric structure of stations in the slow earthquake area and non slow-earthquake areas in Chile using receiver function analysis and inversion method using teleseismic earthquakes. Here we focus on, especially the Vp/Vs ratios from both slow and non-slow earthquake areas, because the Vp/Vs ratio is sensitive to the fluid distribution in the lithosphere; the fluid distribution possibly controls the potential occurrence of slow earthquakes. Additionally, the nature of the slab can also play a crucial factor. The Vp/Vs ratio results across depth shows significantly higher value in the deeper oceanic slab region beneath the stations in the slow earthquake areas with higher contrast at the boundary.</p>

scholarly journals An intraplate slow earthquake observed by a dense GPS network in Hokkaido, northernmost Japan

2014 ◽  
Vol 200 (1) ◽  
pp. 144-148 ◽  
Author(s):  
Mako Ohzono ◽  
Hiroaki Takahashi ◽  
Masayoshi Ichiyanagi
Keyword(s):  
Subduction Zones ◽  
Earthquake Swarm ◽  
Tectonic Activity ◽  
Maximum Magnitude ◽  
Slow Slip ◽  
Localized Deformation ◽  
Slow Earthquake ◽  
Magnitude Scaling ◽  
Duration Magnitude ◽  
Slow Earthquakes

Abstract An intraplate slow earthquake was detected in northernmost Hokkaido, Japan, by a dense network of the global navigation satellite system. Transient abnormal acceleration of <12 mm was observed during the period 2012 July to 2013 January (∼5.5 months) at several sites. The spatial displacement distribution suggests that a localized tectonic event caused localized deformation. Estimated fault parameter indicates very shallow-dip reverse faulting in the uppermost crust, with a total seismic moment of 1.75E + 17 N m (Mw 5.4). This fault geometry is probably consistent with detachment structure indicated by geological studies. A simultaneous earthquake swarm with the maximum magnitude M4.1 suggests a possibility that the slow slip triggered the seismic activity for unknown reasons. This slow earthquake is slower than its moment would indicate, with a duration–magnitude scaling relationship unlike either regular earthquakes or subduction slow slip events. This result indicates that even if the area is under different physical property from subduction zones, slow earthquake can occur by some causes. Slow earthquakes exist in remote regions away from subduction zones and might play an important role in strain release and tectonic activity.

scholarly journals Cascading rupture of patches of high seismic energy release controls the growth process of episodic tremor and slip events

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Keita Nakamoto ◽  
Yoshihiro Hiramatsu ◽  
Takahiko Uchide ◽  
Kazutoshi Imanishi
Keyword(s):  
Energy Release ◽  
Subduction Zones ◽  
Seismic Energy ◽  
High Energy ◽  
Plate Interface ◽  
Waveform Data ◽  
Seismic Energy Release ◽  
Slow Earthquakes ◽  
Episodic Tremor And Slip ◽  
Episodic Tremor

AbstractSlip phenomena on plate interfaces reflect the heterogeneous physical properties of the slip plane and, thus, exhibit a wide variety of slip velocities and rupture propagation behaviors. Recent findings on slow earthquakes reveal similarities and differences between slow and regular earthquakes. Episodic tremor and slip (ETS) events, a type of slow earthquake widely observed in subduction zones, likewise show diverse activity. We investigated the growth of 17 ETS events beneath the Kii Peninsula in the Nankai subduction zone, Japan. Analyses of waveform data recorded by a seismic array enabled us to locate tremor hypocenters and estimate the migration patterns and spatial distribution of the energy release of tremor events. Here, we describe three major features in the growth of ETS events. First, independent of their start point and migration pattern, ETS events exhibit patches of high seismic energy release on the up-dip part of the ETS zone, suggesting that the location of these patches is controlled by inherent physical or frictional properties of the plate interface. Second, ETS events usually start outside the high-energy patches, and their final extent depends on whether the patches participate in the rupture. Third, we recognize no size dependence in the initiation phase of ETS events of different sizes with comparable start points. These features demonstrate that the cascading rupture of high-energy patches governs the growth of ETS events, just as the cascading rupture of asperities governs the growth of regular earthquakes.

scholarly journals Cascading Rupture of Patches of High Seismic Energy Release Controls the Growth Process of Episodic Tremor and Slip Events

2020 ◽  
Author(s):  
Keita Nakamoto ◽  
Yoshihiro Hiramatsu ◽  
Takahiko Uchide ◽  
Kazutoshi Imanishi
Keyword(s):  
Energy Release ◽  
Subduction Zones ◽  
Seismic Energy ◽  
High Energy ◽  
Plate Interface ◽  
Waveform Data ◽  
Seismic Energy Release ◽  
Slow Earthquakes ◽  
Episodic Tremor And Slip ◽  
Episodic Tremor

Abstract Slip phenomena on plate interfaces reflect the heterogeneous physical properties of the slip plane and thus exhibit a wide variety of slip velocities and rupture propagation behaviors. Recent findings on slow earthquakes reveal similarities and differences between slow and regular earthquakes. Episodic tremor and slip (ETS) events, a type of slow earthquake widely observed in subduction zones, likewise show diverse activity. We investigated the growth of 17 ETS events beneath the Kii Peninsula in the Nankai subduction zone, Japan. Analyses of waveform data recorded by a seismic array enabled us to locate tremor hypocenters and estimate the migration patterns and spatial distribution of the energy release of tremor events. Here we describe three major features in the growth of ETS events. First, independent of their start point and migration pattern, ETS events exhibit patches of high seismic energy release on the up-dip part of the ETS zone, suggesting that the location of these patches is controlled by inherent physical or frictional properties of the plate interface. Second, ETS events usually start outside the high-energy patches, and their final extent depends on whether the patches participate in the rupture. Third, we recognize no size dependence in the initiation phase of ETS events of different sizes with comparable start points. These features demonstrate that the cascading rupture of high-energy patches governs the growth of ETS events, just as the cascading rupture of asperities govern the growth of regular earthquakes.

scholarly journals Slow earthquakes illuminating interplate coupling heterogeneities in subduction zones

2020 ◽  
Author(s):  
Satoru Baba ◽  
Shunsuke Takemura ◽  
Kazushige Obara ◽  
Akemi Noda
Keyword(s):  
Subduction Zones ◽  
Interplate Coupling ◽  
Slow Earthquakes

Seismic moment catalog of large shallow earthquakes, 1900 to 1989

1992 ◽  
Vol 82 (3) ◽  
pp. 1306-1349 ◽  
Author(s):  
Javier F. Pacheco ◽  
Lynn R. Sykes
Keyword(s):  
Seismic Moment ◽  
Subduction Zones ◽  
B Value ◽  
Reference List ◽  
Transform Faults ◽  
Shallow Earthquakes ◽  
Seismicity Rates ◽  
Chile Earthquake ◽  
The Moment ◽  
Earthquake Process

Abstract We compile a worldwide catalog of shallow (depth < 70 km) and large (Ms ≥ 7) earthquakes recorded between 1900 and 1989. The catalog is shown to be complete and uniform at the 20-sec surface-wave magnitude Ms ≥ 7.0. We base our catalog on those of Abe (1981, 1984) and Abe and Noguchi (1983a, b) for events with Ms ≥ 7.0. Those catalogs, however, are not homogeneous in seismicity rates for the entire 90-year period. We assume that global rates of seismicity are constant on a time scale of decades and most inhomogeneities arise from changes in instrumentation and/or reporting. We correct the magnitudes to produce a homogeneous catalog. The catalog is accompanied by a reference list for all the events with seismic moment determined at periods longer than 20 sec. Using these seismic moments for great and giant earthquakes and a moment-magnitude relationship for smaller events, we produce a seismic moment catalog for large earthquakes from 1900 to 1989. The catalog is used to study the distribution of moment released worldwide. Although we assumed a constant rate of seismicity on a global basis, the rate of moment release has not been constant for the 90-year period because the latter is dominated by the few largest earthquakes. We find that the seismic moment released at subduction zones during this century constitutes 90% of all the moment released by large, shallow earthquakes on a global basis. The seismic moment released in the largest event that occurred during this century, the 1960 southern Chile earthquake, represents about 30 to 45% of the total moment released from 1900 through 1989. A frequency-size distribution of earthquakes with seismic moment yields an average slope (b value) that changes from 1.04 for magnitudes between 7.0 and 7.5 to b = 1.51 for magnitudes between 7.6 and 8.0. This change in the b value is attributed to different scaling relationships between bounded (large) and unbounded (small) earthquakes. Thus, the earthquake process does have a characteristic length scale that is set by the downdip width over which rupture in earthquakes can occur. That width is typically greater for thrust events at subduction zones than for earthquakes along transform faults and other tectonic environments.

An application of a stochastic model to a volcanic earthquake swarm

1975 ◽  
Vol 65 (2) ◽  
pp. 351-357
Author(s):  
John Filson ◽  
Tom Simkin
Keyword(s):  
Stochastic Model ◽  
Energy Release ◽  
Earthquake Swarm ◽  
Seismic Energy ◽  
Volcanic Earthquake ◽  
Model Studies ◽  
Seismic Energy Release ◽  
Earthquake Model ◽  
Event Occurrence

abstract The Kolomogorov model of event occurrence as developed by Knopoff in earthquake model studies has been applied to a volcanic earthquake swarm. It is shown that in this case, where the rate of seismic energy release was nearly constant in time, the model adequately relates the various seismicity statistics of the swarm.

scholarly journals Impact of interseismic deformation on phase transformations and rock properties in subduction zones

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sebastian Cionoiu ◽  
Evangelos Moulas ◽  
Lucie Tajčmanová
Keyword(s):  
Phase Transformations ◽  
Subduction Zones ◽  
Systematic Investigation ◽  
Rock Properties ◽  
Principal Stresses ◽  
High Deformation ◽  
Alumina Inclusion ◽  
Rock Heterogeneity ◽  
Slow Earthquakes ◽  
The Impact

AbstractPhase transformations greatly affect physical properties of rocks and impose a first-order control on geodynamic processes. Under high deformation rates, rheological heterogeneities cause large spatial variations of stress in materials. Until now, the impact of higher deformation rates, rock heterogeneity and stress build up on phase transformations and material properties is not well understood. Here we show, that phase transitions are controlled by the stress build-up during fast deformation. In a deformation experiment (600 °C, 1.47 GPa), rock heterogeneity was simulated by a strong elliptical alumina inclusion in a weak calcite matrix. Under deformation rates comparable to slow earthquakes, calcite transformed locally to aragonite matching the distribution of maximum principal stresses and pressure (mean stress) from mechanical models. This first systematic investigation documents that phase transformations occur in a dynamic system during deformation. The ability of rocks to react during fast deformation rates may have serious consequences on rock rheology and thus provide unique information on the processes leading to giant ruptures in subduction zones.

scholarly journals Large submarine earthquakes that occurred worldwide in a 1-year period (June 2013 to June 2014) – a contribution to the understanding of tsunamigenic potential

2015 ◽  
Vol 15 (10) ◽  
pp. 2183-2200 ◽  
Author(s):  
R. Omira ◽  
D. Vales ◽  
C. Marreiros ◽  
F. Carrilho
Keyword(s):  
Numerical Modeling ◽  
Subduction Zones ◽  
Source Parameters ◽  
Tsunami Generation ◽  
Earthquake Parameters ◽  
Shallow Earthquakes ◽  
Earthquake Source Parameters ◽  
Tsunami Numerical Modeling ◽  
Submarine Earthquakes ◽  
Earthquake Model

Abstract. This paper is a contribution to a better understanding of the tsunamigenic potential of large submarine earthquakes. Here, we analyze the tsunamigenic potential of large earthquakes which have occurred worldwide with magnitudes around Mw = 7.0 and greater during a period of 1 year, from June 2013 to June 2014. The analysis involves earthquake model evaluation, tsunami numerical modeling, and sensors' records analysis in order to confirm the generation of a tsunami (or lack thereof) following the occurrence of an earthquake. We also investigate and discuss the sensitivity of tsunami generation to the earthquake parameters recognized to control tsunami occurrence, including the earthquake location, magnitude, focal mechanism and fault rupture depth. Through this analysis, we attempt to understand why some earthquakes trigger tsunamis and others do not, and how the earthquake source parameters are related to the potential of tsunami generation. We further discuss the performance of tsunami warning systems in detecting tsunamis and disseminating the alerts. A total of 23 events, with magnitudes ranging from Mw = 6.7 to Mw = 8.1, have been analyzed. This study shows that about 39 % of the analyzed earthquakes caused tsunamis that were recorded by different sensors with wave amplitudes varying from a few centimeters to about 2 m. Tsunami numerical modeling shows good agreement between simulated waveforms and recorded waveforms, for some events. On the other hand, simulations of tsunami generation predict that some of the events, considered as non-tsunamigenic, caused small tsunamis. We find that most generated tsunamis were caused by shallow earthquakes (depth < 30 km) and thrust faults that took place on/near the subduction zones. The results of this study can help the development of modified and improved versions of tsunami decision matrixes for various oceanic domains.

Complexity of low-frequency earthquakes activity in western Shikoku

2020 ◽  
Author(s):  
Natalia Poiata ◽  
Jean-Pierre Vilotte ◽  
Nikolai Shapiro ◽  
Mariano Supino ◽  
Kazushige Obara
Keyword(s):  
Subduction Zones ◽  
Large Scale ◽  
Active Faults ◽  
Low Frequency ◽  
Space Time ◽  
Interaction Patterns ◽  
Slow Slip Events ◽  
Time Activity ◽  
Tectonic Tremor ◽  
Slow Earthquakes

&lt;p&gt;Short-duration transient seismic events known as low-frequency earthquakes (LFEs) are a component of the slow earthquakes family observed in the transition zone, at the root of seismogenic regions of the subduction zones or active faults. LFEs are the signature of impulse seismic energy radiation associated to and often mixed within complex tectonic tremor signal. Detailed analysis and characterization of LFE space-time activity in relation to other slow earthquake phenomena can provide important information about the state and the processes of fault interface.&lt;/p&gt;&lt;p&gt;We derive a catalog of LFEs in western Shikoku (Japan) by applying a full waveform coherency-based detection and location method to the 4-year continuous data covering the period of 2013-2016 and recorded at Hi-net seismic stations of NIED. The obtained catalog of over 150,000 detected events allows looking into the details of LFE space-time activity during the tectonic tremor sequences and inter-sequence periods.&lt;/p&gt;&lt;p&gt;We use this catalogue of LFEs to perform a systematic statistical analysis of the event occurrence patterns by applying correlation and clustering analysis to infer the large-scale (long temporal ~ 1-2 day duration) space-time characteristics and interaction patterns of activity and its potential relation to the structural complexity of the subducting plate. We also analyze the correlation between the migration of clustered LFE activity during energetic tremor sequences and short-term slow slip events occurring in the area during the analyzed period.&lt;/p&gt;

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