Dense seismological array and profile across the Longmenshan and the deep 
extension of the Pengguan complex

Qian, Hui; Yu, Changqing; Mechie, James; Zeng, Xiangzhi

doi:10.1016/j.tecto.2021.229193

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Dense seismological array and profile across the Longmenshan and the deep extension of the Pengguan complex

Authors

Qian, Hui
External Organizations;
Publikationen aller GIPP-unterstützten Projekte, Deutsches GeoForschungsZentrum;

Yu, Changqing
External Organizations;
Publikationen aller GIPP-unterstützten Projekte, Deutsches GeoForschungsZentrum;

/persons/resource/jimmy

Mechie, James
2.2 Geophysical Imaging of the Subsurface, 2.0 Geophysics, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;
Publikationen aller GIPP-unterstützten Projekte, Deutsches GeoForschungsZentrum;

Zeng, Xiangzhi
External Organizations;
Publikationen aller GIPP-unterstützten Projekte, Deutsches GeoForschungsZentrum;

External Ressource

No external resources are shared

Fulltext (public)

There are no public fulltexts stored in GFZpublic

Supplementary Material (public)

There is no public supplementary material available

Citation

Qian, H., Yu, C., Mechie, J., Zeng, X. (2022): Dense seismological array and profile across the Longmenshan and the deep extension of the Pengguan complex. - Tectonophysics, 823, 229193.
https://doi.org/10.1016/j.tecto.2021.229193

Cite as: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5009207

Abstract

A dense seismological array and profile reveal the deep structure across the Longmenshan from the Songpan-Ganzi terrane of the Tibetan plateau to the Sichuan basin. Receiver function and tomographic images reveal that the Pengguan Complex which cores the Longmenshan in the region where the Ms. 8 Wenchuan earthquake of 2008 occurred, is marked by high velocities in the upper 15 km of the crust. At about 15 km depth both P- and S-wave velocities decrease at a flat-lying boundary around which the aftershock hypocentres of the Wenchuan earthquake are concentrated. Thus, this boundary may be a faulted interface or detachment, marking the base of the Pengguan Complex. Moho depths change significantly in going from the Tibetan plateau to the Sichuan basin. At the location of the dense profile a Moho step occurs, located about 50 km NW of the surface trace of the Yingxiu-Beichuan fault (YBF). The boundary at about 15 km depth below the Pengguan Complex seems to deepen at around the Wenchuan-Maoxian fault (WMF) by about 3 km and merge to the NW with another interface at about 18 km depth. This interface, NW of the WMF, which correlates with the top of a zone of high conductivity is interpreted to represent the top of the Tibetan mid-crustal low velocity, high conductivity zone. The tomographic image indicates that the boundary between the low velocities of the Songpan-Ganzi terrane and the high velocities of the Sichuan basin in the middle and lower crust occurs NW of the surface trace of the YBF. Thus, it is proposed that a zone extending from the WMF at about 15 km depth to the Moho step about 25 km further NW marks the boundary between the Tibetan plateau and the Sichuan basin in the middle and lower crust.