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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

Modeled (a) and residual (b) interferograms predicted by uniform slip on four rectangular dislocations in an elastic half-space in the viewing geometry for the descending track T319, (c,d) for the ascending track T455. From the northwest to the southeast, four black rectangles denote the surface projections of faults 1, 2, 3, and 4 in Table 1, respectively, and black lines for the up-dip projections of the corresponding fault plane to the earth’s surface.
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sensors-15-16786-f004: Modeled (a) and residual (b) interferograms predicted by uniform slip on four rectangular dislocations in an elastic half-space in the viewing geometry for the descending track T319, (c,d) for the ascending track T455. From the northwest to the southeast, four black rectangles denote the surface projections of faults 1, 2, 3, and 4 in Table 1, respectively, and black lines for the up-dip projections of the corresponding fault plane to the earth’s surface.

Mentions: The preferred fault model solutions are shown in Table 1, and the surface projections of the four fault planes are shown in Figure 4. The estimated fault dips range from 46.0° to 65.5°, with an average dip of 55.6°. The fault planes are located at a depth of between 2.0 km and 7.5 km. This slip depth range is shallower than that from the GCMT catalogue, although the value in the GCMT catalogue refers to the centroid location. This can be attributable to different data sources providing different data constraints on the model parameters. The slip changes along the strike direction from northwest to southeast. The maximum slip of 1.94 m occurs at a depth range between 3.0 and 7.5 km on fault 2, the surface projection of which just covers the centroid location of this event from the GCMT catalogue (Figure 4a). The calculated geodetic moment for the four fault segments are 0.66 × 1018 Nm (Mw 5.81), 1.46 × 1018 Nm (Mw 6.08), 0.66 × 1018 Nm (Mw 5.85), and 0.80 × 1018 Nm (Mw 5.90), respectively, and the total geodetic moment is 3.58 × 1018 Nm (Mw 6.34).


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)

Modeled (a) and residual (b) interferograms predicted by uniform slip on four rectangular dislocations in an elastic half-space in the viewing geometry for the descending track T319, (c,d) for the ascending track T455. From the northwest to the southeast, four black rectangles denote the surface projections of faults 1, 2, 3, and 4 in Table 1, respectively, and black lines for the up-dip projections of the corresponding fault plane to the earth’s surface.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-16786-f004: Modeled (a) and residual (b) interferograms predicted by uniform slip on four rectangular dislocations in an elastic half-space in the viewing geometry for the descending track T319, (c,d) for the ascending track T455. From the northwest to the southeast, four black rectangles denote the surface projections of faults 1, 2, 3, and 4 in Table 1, respectively, and black lines for the up-dip projections of the corresponding fault plane to the earth’s surface.
Mentions: The preferred fault model solutions are shown in Table 1, and the surface projections of the four fault planes are shown in Figure 4. The estimated fault dips range from 46.0° to 65.5°, with an average dip of 55.6°. The fault planes are located at a depth of between 2.0 km and 7.5 km. This slip depth range is shallower than that from the GCMT catalogue, although the value in the GCMT catalogue refers to the centroid location. This can be attributable to different data sources providing different data constraints on the model parameters. The slip changes along the strike direction from northwest to southeast. The maximum slip of 1.94 m occurs at a depth range between 3.0 and 7.5 km on fault 2, the surface projection of which just covers the centroid location of this event from the GCMT catalogue (Figure 4a). The calculated geodetic moment for the four fault segments are 0.66 × 1018 Nm (Mw 5.81), 1.46 × 1018 Nm (Mw 6.08), 0.66 × 1018 Nm (Mw 5.85), and 0.80 × 1018 Nm (Mw 5.90), respectively, and the total geodetic moment is 3.58 × 1018 Nm (Mw 6.34).

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