Rupture and frequency-dependent seismic radiation of the 2012<i>M</i><sub>w</sub>8.6 Sumatra strike-slip earthquake

Yin, Jiuxun; Yao, Huajian

doi:10.1093/gji/ggw105

Cited by 10 publications

(12 citation statements)

References 38 publications

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“…Frequency‐dependent rupture behavior has been observed for large megathrust earthquakes and continental earthquakes [e.g., Lay et al , ; Yao et al , ; Kiser and Ishii , ; Meng et al , ; Koper et al , ; Wang and Mori , , ; Fan and Shearer , ; Grandin et al , ], and variations have been seen in both along‐strike and dip directions [e.g., Kiser and Ishii , ; Yao et al , ; Meng et al , ; Melgar et al , ]. The observed frequency‐dependent variations could be expressions of depth‐varying frictional properties [e.g., Yao et al , ], multiple segmentation [e.g., Yin and Yao , ; Denolle et al , ], different rupture properties over the fault plane [e.g., Kiser and Ishii , ], or different mechanisms [e.g., Meng et al , ]. The frequency dependence of the Tonga‐Samoa earthquake is different from these cases in the sense that the frequency‐dependent rupture behavior is associated with different faults.…”

Section: Discussionmentioning

confidence: 99%

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Fan

Shearer

et al. 2016

JGR Solid Earth

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Several source models have been proposed to explain the enigmatic 2009 Tonga‐Samoa earthquake. The long‐period data require a composite source model and can be fit with a normal‐faulting subevent followed by one or more reverse‐faulting subevents. The short‐period data, in contrast, indicate a more compact rupture pattern around the epicenter. The lack of a unified source model reflects the complexity of the event. We analyze the spatiotemporal evolution of this earthquake with P wave back‐projection from globally distributed stations in different frequency bands (low frequency: 0.05–0.2 Hz, high frequency: 0.2–2 Hz) and a multiple moment tensor inversion. The rupture propagation revealed by back‐projection exhibits frequency‐dependent behavior, with two branches of high‐frequency‐enriched bilateral rupture around the epicenter and a high‐frequency‐deficient rupture branch at the subduction interface. A composite source model with one Mw 8.0 normal‐faulting earthquake east of the trench axis (seaward) followed by one Mw 8.1 reverse‐faulting earthquake along the subduction interface west of the trench axis (landward) can explain the very long period data (200∼500 s). Combined with high‐resolution swath bathymetry data, the back‐projection images show that the azimuth of rupture branches east of the trench axis were controlled by the geometry of bending‐related faults on the Pacific plate and that the rupture branch west of the trench axis may correlate with the along‐strike fore‐arc segmentation. The rupture along the subduction interface was triggered by the seaward rupture and a partially subducted normal fault may have played a key role in facilitating the triggering. The apparent normal‐reverse faulting interactions pose a higher seismic risk to this region than their individual strands at the northernmost corner of the Tonga subduction zone.

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Section: Discussionmentioning

confidence: 99%

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Fan

Shearer

et al. 2016

JGR Solid Earth

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“…Yao et al (, ) integrated this inversion technique with the backprojection method in order to study the seismic radiation of large subduction zone earthquakes ( M w > 8). Yin and Yao () carefully tested and improved the CS‐BP method to be less sensitive to potential data outliers, which may carry abnormal amplitudes or phases that affect the location of energy bursts. The sparsity constraint of the CS scheme increases the spatial resolution of seismic energy bursts during the rupture and provides an advantage to the conventional backprojection (Ishii et al, ) as well as to beamforming methods (Yin & Yao, ).…”

Section: Improved Compressive Sensing Backprojectionmentioning

confidence: 99%

“…Our CS‐BP method uses a sliding time windows technique (Yao et al, ; Yin & Yao, ). We first preprocess the P wave velocity seismogram at each station of a seismic array (see Yin & Yao, , or supporting information Figure S1 for details; VanDecar & Crosson, ).…”

Section: Improved Compressive Sensing Backprojectionmentioning

confidence: 99%

“…The first method is an Improved Compressive Sensing Backprojection method, which we refer to as ImCS‐BP herein. The original CS‐BP method (Yao et al, ; Yin & Yao, ) uses a frequency domain formulation of the conventional backprojection method by extracting the phase coherence between velocity seismograms recorded at seismic arrays. CS‐BP can locate the seismic energy bursts with high spatial resolution based on sparsity‐constrained inversion (Yao et al, ; Yin & Yao, ).…”

Section: Introductionmentioning

confidence: 99%

“…The original CS‐BP method (Yao et al, ; Yin & Yao, ) uses a frequency domain formulation of the conventional backprojection method by extracting the phase coherence between velocity seismograms recorded at seismic arrays. CS‐BP can locate the seismic energy bursts with high spatial resolution based on sparsity‐constrained inversion (Yao et al, ; Yin & Yao, ). Here we increase the spatial resolution and improve the computational efficiency to provide better accuracy and precision on the spatiotemporal evolution of seismic energy bursts.…”

Section: Introductionmentioning

confidence: 99%

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Spatial and Temporal Evolution of Earthquake Dynamics: Case Study of the M_w 8.3 Illapel Earthquake, Chile

2018

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We develop a methodology that combines compressive sensing backprojection (CS‐BP) and source spectral analysis of teleseismic P waves to provide metrics relevant to earthquake dynamics of large events. We improve the CS‐BP method by an autoadaptive source grid refinement as well as a reference source adjustment technique to gain better spatial and temporal resolution of the locations of the radiated bursts. We also use a two‐step source spectral analysis based on (i) simple theoretical Green's functions that include depth phases and water reverberations and on (ii) empirical P wave Green's functions. Furthermore, we propose a source spectrogram methodology that provides the temporal evolution of dynamic parameters such as radiated energy and falloff rates. Bridging backprojection and spectrogram analysis provides a spatial and temporal evolution of these dynamic source parameters. We apply our technique to the recent 2015 Mw 8.3 megathrust Illapel earthquake (Chile). The results from both techniques are consistent and reveal a depth‐varying seismic radiation that is also found in other megathrust earthquakes. The low‐frequency content of the seismic radiation is located in the shallow part of the megathrust, propagating unilaterally from the hypocenter toward the trench while most of the high‐frequency content comes from the downdip part of the fault. Interpretation of multiple rupture stages in the radiation is also supported by the temporal variations of radiated energy and falloff rates. Finally, we discuss the possible mechanisms, either from prestress, fault geometry, and/or frictional properties to explain our observables. Our methodology is an attempt to bridge kinematic observations with earthquake dynamics.

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Coseismic Radiation of the 2008 Mw 7.9 Wenchuan Earthquake and Its Relationship to Fault Complexities

Huang

Yao

2018

Pure Appl. Geophys.

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Rupture and frequency-dependent seismic radiation of the 2012M_w8.6 Sumatra strike-slip earthquake

Cited by 10 publications

References 38 publications

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Spatial and Temporal Evolution of Earthquake Dynamics: Case Study of the M_w 8.3 Illapel Earthquake, Chile

Coseismic Radiation of the 2008 Mw 7.9 Wenchuan Earthquake and Its Relationship to Fault Complexities

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Rupture and frequency-dependent seismic radiation of the 2012Mw8.6 Sumatra strike-slip earthquake

Cited by 10 publications

References 38 publications

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Multiple branching rupture of the 2009 Tonga‐Samoa earthquake

Spatial and Temporal Evolution of Earthquake Dynamics: Case Study of the Mw 8.3 Illapel Earthquake, Chile

Coseismic Radiation of the 2008 Mw 7.9 Wenchuan Earthquake and Its Relationship to Fault Complexities

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Rupture and frequency-dependent seismic radiation of the 2012M_w8.6 Sumatra strike-slip earthquake

Spatial and Temporal Evolution of Earthquake Dynamics: Case Study of the M_w 8.3 Illapel Earthquake, Chile