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A New Perspective on Fault Geometry and Slip Distribution of the 2009 Dachaidan Mw 6.3 Earthquake from InSAR Observations.

Liu Y, Xu C, Wen Y, Fok HS - Sensors (Basel) (2015)

Bottom Line: On 28 August 2009, the northern margin of the Qaidam basin in the Tibet Plateau was ruptured by an Mw 6.3 earthquake.We then propose a four-segmented fault model to investigate the coseismic deformation by determining the fault parameters, followed by inverting slip distribution.The inverted geodetic moment is 3.85 × 10(18) Nm (Mw 6.36).

View Article: PubMed Central - PubMed

Affiliation: School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China. Yang.Liu@sgg.whu.edu.cn.

ABSTRACT
On 28 August 2009, the northern margin of the Qaidam basin in the Tibet Plateau was ruptured by an Mw 6.3 earthquake. This study utilizes the Envisat ASAR images from descending Track 319 and ascending Track 455 for capturing the coseismic deformation resulting from this event, indicating that the earthquake fault rupture does not reach to the earth's surface. We then propose a four-segmented fault model to investigate the coseismic deformation by determining the fault parameters, followed by inverting slip distribution. The preferred fault model shows that the rupture depths for all four fault planes mainly range from 2.0 km to 7.5 km, comparatively shallower than previous results up to ~13 km, and that the slip distribution on the fault plane is complex, exhibiting three slip peaks with a maximum of 2.44 m at a depth between 4.1 km and 4.9 km. The inverted geodetic moment is 3.85 × 10(18) Nm (Mw 6.36). The 2009 event may rupture from the northwest to the southeast unilaterally, reaching the maximum at the central segment.

No MeSH data available.


Related in: MedlinePlus

Trade-off curve between RMS misfit and the roughness. The red asterisk denotes the smooth factor chosen for the inversion.
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sensors-15-16786-f005: Trade-off curve between RMS misfit and the roughness. The red asterisk denotes the smooth factor chosen for the inversion.

Mentions: The fault model was discretized into 298 patches, each with a length of 1 km and a width of 1 km. Consistent with the uniform slip inversion, dislocation equations in Okada [22] were used to model the InSAR surface displacement. Strike-slip and dip-slip components for each fault patch were solved in a least squares sense. Constraints of slip Laplacian smoothing across the fault patches were added to avoid unphysical oscillating slip distribution [38]. The smoothing factor (e.g., 212.5 in this study) was chosen by plotting the trade-off curve between RMS misfit and the solution roughness (Figure 5), which can obtain a slip distribution model that has both lower misfit and roughness.


A New Perspective on Fault Geometry and Slip Distribution of the 2009 Dachaidan Mw 6.3 Earthquake from InSAR Observations.

Liu Y, Xu C, Wen Y, Fok HS - Sensors (Basel) (2015)

Trade-off curve between RMS misfit and the roughness. The red asterisk denotes the smooth factor chosen for the inversion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541906&req=5

sensors-15-16786-f005: Trade-off curve between RMS misfit and the roughness. The red asterisk denotes the smooth factor chosen for the inversion.
Mentions: The fault model was discretized into 298 patches, each with a length of 1 km and a width of 1 km. Consistent with the uniform slip inversion, dislocation equations in Okada [22] were used to model the InSAR surface displacement. Strike-slip and dip-slip components for each fault patch were solved in a least squares sense. Constraints of slip Laplacian smoothing across the fault patches were added to avoid unphysical oscillating slip distribution [38]. The smoothing factor (e.g., 212.5 in this study) was chosen by plotting the trade-off curve between RMS misfit and the solution roughness (Figure 5), which can obtain a slip distribution model that has both lower misfit and roughness.

Bottom Line: On 28 August 2009, the northern margin of the Qaidam basin in the Tibet Plateau was ruptured by an Mw 6.3 earthquake.We then propose a four-segmented fault model to investigate the coseismic deformation by determining the fault parameters, followed by inverting slip distribution.The inverted geodetic moment is 3.85 × 10(18) Nm (Mw 6.36).

View Article: PubMed Central - PubMed

Affiliation: School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China. Yang.Liu@sgg.whu.edu.cn.

ABSTRACT
On 28 August 2009, the northern margin of the Qaidam basin in the Tibet Plateau was ruptured by an Mw 6.3 earthquake. This study utilizes the Envisat ASAR images from descending Track 319 and ascending Track 455 for capturing the coseismic deformation resulting from this event, indicating that the earthquake fault rupture does not reach to the earth's surface. We then propose a four-segmented fault model to investigate the coseismic deformation by determining the fault parameters, followed by inverting slip distribution. The preferred fault model shows that the rupture depths for all four fault planes mainly range from 2.0 km to 7.5 km, comparatively shallower than previous results up to ~13 km, and that the slip distribution on the fault plane is complex, exhibiting three slip peaks with a maximum of 2.44 m at a depth between 4.1 km and 4.9 km. The inverted geodetic moment is 3.85 × 10(18) Nm (Mw 6.36). The 2009 event may rupture from the northwest to the southeast unilaterally, reaching the maximum at the central segment.

No MeSH data available.


Related in: MedlinePlus