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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

The preferred slip distribution (a) and its errors from Monte Carlo analysis (b). The green arrows in (a) denote the rake of each sub-fault.
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sensors-15-16786-f006: The preferred slip distribution (a) and its errors from Monte Carlo analysis (b). The green arrows in (a) denote the rake of each sub-fault.

Mentions: Figure 6a shows the obtained slip distribution, with a total geodetic moment of 3.85 × 1018 Nm (Mw 6.36). The slip distribution apparently changes along the strike direction, and exhibits three slip peaks. The main slip is concentrated at a depth of 2.2–8.2 km, with average rake angle and slip of 69.9° and 0.82 m for the western segment, 82.8° and 1.14 m for the central segment, and 99.8° and 0.85 m for the eastern segment. These estimations are, overall, in agreement with those derived from uniform slip modeling. The maximum slip is 2.44 m at a depth between 4.1 km and 4.9 km, with a surface projection location close to the centroid location obtained from the GCMT catalogue (Figure 6 and Figure 7). We note here that the peak-slip location does not have to be the centroid location in the GCMT catalogue. The maximum slip in the top 1 km is just 4 cm, which is too small to be detected. This result is consistent with the absence of deformation fringe offset at the earth’s surface (Figure 2).


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)

The preferred slip distribution (a) and its errors from Monte Carlo analysis (b). The green arrows in (a) denote the rake of each sub-fault.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-16786-f006: The preferred slip distribution (a) and its errors from Monte Carlo analysis (b). The green arrows in (a) denote the rake of each sub-fault.
Mentions: Figure 6a shows the obtained slip distribution, with a total geodetic moment of 3.85 × 1018 Nm (Mw 6.36). The slip distribution apparently changes along the strike direction, and exhibits three slip peaks. The main slip is concentrated at a depth of 2.2–8.2 km, with average rake angle and slip of 69.9° and 0.82 m for the western segment, 82.8° and 1.14 m for the central segment, and 99.8° and 0.85 m for the eastern segment. These estimations are, overall, in agreement with those derived from uniform slip modeling. The maximum slip is 2.44 m at a depth between 4.1 km and 4.9 km, with a surface projection location close to the centroid location obtained from the GCMT catalogue (Figure 6 and Figure 7). We note here that the peak-slip location does not have to be the centroid location in the GCMT catalogue. The maximum slip in the top 1 km is just 4 cm, which is too small to be detected. This result is consistent with the absence of deformation fringe offset at the earth’s surface (Figure 2).

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