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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

Regional tectonic setting of the 2009 Dachaidan Mw 6.3 earthquake. The rectangles in (a,b) are the spatial extents of (b,c), respectively. The white rectangles in (c) are the spatial extents of the Envisat ASAR descending Track 319 and ascending Track 455 images used in this study, with AZI and LOS referring to satellite azimuth and look direction, respectively. Thin black lines and purple lines in (a,b) denote the Quaternary active faults (Data from Deng et al. [3]), and the major tectonic faults (Data from Peltzer and Saucier [23]). A red beach ball with the time and magnitude labeled demonstrates the source mechanism for the main shock, while purple beach balls show the five aftershocks. Black hollow circles display the other aftershocks (Data from GCMT [2]). The epicenter of the main shock from USGS catalogue is also displayed.
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sensors-15-16786-f001: Regional tectonic setting of the 2009 Dachaidan Mw 6.3 earthquake. The rectangles in (a,b) are the spatial extents of (b,c), respectively. The white rectangles in (c) are the spatial extents of the Envisat ASAR descending Track 319 and ascending Track 455 images used in this study, with AZI and LOS referring to satellite azimuth and look direction, respectively. Thin black lines and purple lines in (a,b) denote the Quaternary active faults (Data from Deng et al. [3]), and the major tectonic faults (Data from Peltzer and Saucier [23]). A red beach ball with the time and magnitude labeled demonstrates the source mechanism for the main shock, while purple beach balls show the five aftershocks. Black hollow circles display the other aftershocks (Data from GCMT [2]). The epicenter of the main shock from USGS catalogue is also displayed.

Mentions: At 01:52 on 28 August 2009 (UTC), an Mw 6.3 earthquake occurred at Dachaidan town, Haixi city, Qinghai province, China, which quaked as far away as Xining and Golmud cities in the Tibet Plateau (Figure 1) [1,2]. The seismogenic fault is located at the active fault belts of the northern Qaidam basin, where a number of active folds and faults striking North-West-West (NWW) direction can be clearly visualized. The fault belts are jointly intersected with the sinistral strike-slip Altyn fault system at the northwest side, and with the dextral strike-slip Elashan fault system at the southeast side, playing a significant role as a tectonic transition zone between these two strike-slip fault systems [3,4]. According to the Global Centroid Moment Tensor (GCMT) catalogue [2], five Mw ≥ 4.0 aftershocks occurred in the earthquake zone within an hour after the 2009 Mw 6.3 event, two of which had a moment magnitude of Mw 5.6 and occurred within half an hour, with a total of 34 Mw ≥ 4.0 aftershocks within one month (Figure 1). Before the 2009 main event, the other Mw 6.3 earthquake occurred almost at the same area on 10 November 2008 [5]. Determination of accurate source parameters for this main event is of the utmost importance for understanding local seismic risks and associated tectonic activities.


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)

Regional tectonic setting of the 2009 Dachaidan Mw 6.3 earthquake. The rectangles in (a,b) are the spatial extents of (b,c), respectively. The white rectangles in (c) are the spatial extents of the Envisat ASAR descending Track 319 and ascending Track 455 images used in this study, with AZI and LOS referring to satellite azimuth and look direction, respectively. Thin black lines and purple lines in (a,b) denote the Quaternary active faults (Data from Deng et al. [3]), and the major tectonic faults (Data from Peltzer and Saucier [23]). A red beach ball with the time and magnitude labeled demonstrates the source mechanism for the main shock, while purple beach balls show the five aftershocks. Black hollow circles display the other aftershocks (Data from GCMT [2]). The epicenter of the main shock from USGS catalogue is also displayed.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-16786-f001: Regional tectonic setting of the 2009 Dachaidan Mw 6.3 earthquake. The rectangles in (a,b) are the spatial extents of (b,c), respectively. The white rectangles in (c) are the spatial extents of the Envisat ASAR descending Track 319 and ascending Track 455 images used in this study, with AZI and LOS referring to satellite azimuth and look direction, respectively. Thin black lines and purple lines in (a,b) denote the Quaternary active faults (Data from Deng et al. [3]), and the major tectonic faults (Data from Peltzer and Saucier [23]). A red beach ball with the time and magnitude labeled demonstrates the source mechanism for the main shock, while purple beach balls show the five aftershocks. Black hollow circles display the other aftershocks (Data from GCMT [2]). The epicenter of the main shock from USGS catalogue is also displayed.
Mentions: At 01:52 on 28 August 2009 (UTC), an Mw 6.3 earthquake occurred at Dachaidan town, Haixi city, Qinghai province, China, which quaked as far away as Xining and Golmud cities in the Tibet Plateau (Figure 1) [1,2]. The seismogenic fault is located at the active fault belts of the northern Qaidam basin, where a number of active folds and faults striking North-West-West (NWW) direction can be clearly visualized. The fault belts are jointly intersected with the sinistral strike-slip Altyn fault system at the northwest side, and with the dextral strike-slip Elashan fault system at the southeast side, playing a significant role as a tectonic transition zone between these two strike-slip fault systems [3,4]. According to the Global Centroid Moment Tensor (GCMT) catalogue [2], five Mw ≥ 4.0 aftershocks occurred in the earthquake zone within an hour after the 2009 Mw 6.3 event, two of which had a moment magnitude of Mw 5.6 and occurred within half an hour, with a total of 34 Mw ≥ 4.0 aftershocks within one month (Figure 1). Before the 2009 main event, the other Mw 6.3 earthquake occurred almost at the same area on 10 November 2008 [5]. Determination of accurate source parameters for this main event is of the utmost importance for understanding local seismic risks and associated tectonic activities.

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