Transcript Presentation

2008 Bilateral Workshop under the Sino - US Earthquake Studies Protocol
TECTONIC DEFORMATION OF THE TIBET
PLATEUA AND THE WENCHUAN
EARTHQUAKE
REN Jinwei and Xiong Renwei
Institute of Earthquake Science, CEA, Beijing 100036, China
Email: [email protected]
Sun Xiong and Song Xiaoming
Earthquake Administration of Qinghai Province, Xi'nin 810001, China
November 11-14, 2008
Boulder, Colorado, USA
Active Tectonics of Tibetan Plateau
Fault scarp in the Gulu Basin (Dangxiong graben)
Fault scarp in the Gulu Basin (Dangxiong graben)
Fault scarp in the Gulu Basin (Dangxiong graben)
Fault scarp in Wenquan (hot spring) basin
Linear tufa in Wenquan (hot spring) basin
A
4200
4155
4122
A’
4143
3996
A’
A
2.5km
Air photograph
of Ranwu area,
south-eastern
Tibet
North-western segment of Jiali fault
Landslides along the normal fault at Daren Basin
Scarps along the Jiali fault
T3
Fault scarp
T2
T1
Fault scarp along the BNS (south of Tanggula)
 In
the southern part of the Tibetan
plateau (Lhasa terrane and BangongNujiang suture), the deformation is
dominated by east-west extension
 The
deformation is occurred throughout
the Lhasa terrane, along the suture the
deformation is not significant
 The
strike slip motion of the faults in this
area is most likely related to the
extension
Active Tectonics of Tibetan Plateau
Thrust fault along the Jinsha Suture (south of Erdaogou)
Deformation of the alluvium south of Erdaogou
 Along
the Jinsha suture, neo-tectonic
deformation is dominated by the thrust
faulting and it mainly occurred along
the suture
 Within
the Qiangtang terrane, the
deformation is minor
Active Tectonics of Tibetan Plateau
The highway was offset 3m by the ruptures at Kunlun Pass
5.8 m
Surface Ruptures
Left lateral displacement 90km west of Kunlun Pass
Surface ruptures along the Kunlun pass fault by 2001 earthquake
Active Tectonics of Tibetan Plateau
Surface ruptures along the east Kunlun fault by 1937 earthquake
Surface ruptures along the east Kunlun fault by 1937 earthquake
Surface ruptures along the east Kunlun fault by 1937 earthquake
Surface ruptures along the east Kunlun fault by 1937 earthquake
Active Tectonics of Tibetan Plateau
Surface ruptures along the east Kunlun fault near Maqin
Surface ruptures along the east Kunlun fault eastof Maqin
Surface ruptures along the east Kunlun fault east Maqin
Surface ruptures along the east Kunlun fault near Maqin

Along the Kunlun suture, neo-tectonic
deformation is dominated by left lateral
strike slip faulting and it mainly occurred
along the suture

large earthquakes occurred along the east
Kunlun fault in the last century, the surface
ruptures caused by these events had
almost gone through the entire fault
Crust Movement of China Continent
GPS Data from CMONOC
Fold caused by the strike slip motion by 2001 earthquake
Large Earthquakes along the Kunlun Fault
2001/8.1
1963/7.0
????/>7.5
1937/7.5
1947/7.5
CONCLUSION REMARKS
 The crust deformation of the Tibetan plateau is dominated by east-west
extension in the southern part and the material in northern part of the
plateau has been penetrated eastward.
 The eastward flow is separated by several large left-lateral strike-slip
faults. Once the movement of the blocks between the faults are
obstructed, thrust faults would be created to accommodate the
deformation transfered by the strike slip faults. Longmenshan fault on
which the Wenchuan earthquake occurred, is one of the thrust fault that
accommodate the deformation transfered by the East Kunlun fault.
 Along the East Kunlun fault there were several large earthquakes
occurred in last century. Field investigation shows that the surface
ruptures created by these large earthquakes have gone through the
whole East Kunlun fault, which means that the East Knulun fault could
not hold up the deformation any longer, and all the burden were
transfered to Longmenshan fault. This might be the reason of the
occurrence of Wenchuan earthquake.
November 11-14, 2008
Boulder, Colorado, USA
THANK YOU
FOR YOUR ATTENTION
东大滩谷地北侧发育的叠瓦状构造