Location: Home > International Cooperation

  International Cooperation

Professor Yann Klinger and colleagues from the Institut De Physique Du Globe De Paris (IPGP) visited China for Cooperative Research

2018/7/6 16:53:57

At the invitation of researcher Liu-Zeng Jing of the State Key Laboratory of Earthquake Dynamics, Professor Yann Klinger and colleagues of the Institut De Physique Du Globe De Paris (IPGP) visited the IGCEA from September 22 to October 10, 2017. During their stay, they undertook joint field studies of active tectonics and seismogeological investigations of the Xianshuihe–Anninghe fault and the Haiyuan fault.

The Xianshuihe–Anninghe fault, located in the transitional zone between the eastern Tibetan Plateau and the Sichuan Basin, is an important strike-slip fault on the Tibet Plateau. In their field investigations, the visiting academics performed geomorphological dislocation confirmation and mapping, and sampling of the geomorphic surface along the Xianshuihe–Anninghe fault. They also conducted detailed investigations of the geomorphology tectonics, fault trace, fault geomorphology, surface ruptures and landslides induced by large earthquakes, paleoseismic events revealed in existing trenches, and sedimentary environment in the Anning River valley near Mianning County. They conducted intense discussions with the objectives of determining the slip rate of the strike-slip Xianshuihe–Anninghe fault and of selecting trenches, based on which they proposed plans for further work.

The Haiyuan fault is an important strike-slip fault in the northeastern Tibetan Plateau, whose tectonic activities might not only provide constraints for the uplift and crustal deformation mechanisms of the Tibetan Plateau but also could trigger regional destructive earthquakes, such as the 1920 Haiyuan earthquake and the 1927 Gulang earthquake. Although the Laohushan fault segment, which lies between the surface ruptures of the 1920 and 1927 earthquakes, behaves as apparent active fault, there have been no earthquakes with magnitudes larger than M7.0 recorded over the past 1000 years, apart from the 1888 M6.8–7.0 Jingtai earthquake and some moderate earthquakes and microseisms. Consequently, the Laohushan fault segment is seismically quiet and the fault has always been reported as a seismic gap, with high possibilities of big earthquakes in the future. Detailed paleoearthquake studies could identify the most recent strong earthquake event on the Laoshan fault and establish the paleoearthquake sequence along the fault. Combined with tectonic geomorphological investigations, the tectonic activities of the fault could be reviewed, which is of great significance for reasonable and effective evaluation of the seismic risk for the region. Based on previous works, the fieldwork team undertook field investigations in the above regions and conducted fine mapping of the tectonic landforms, completed the identification and classification of typical faulted gullies and terraces, fault scarps and fault geometries, and performed measurements of dislocations of different orders of magnitude. The team also carried out detailed mapping of the tectonic geomorphology around the excavated trench, and analyzed the tectonic and sedimentary backgrounds of the trench excavation location and its surroundings. Furthermore, the team mapped in detail the complex fault revealed by the trench, catalogued the paleoseismic events, and collected a large number of samples for dating. Throughout the work, in-depth discussions were held and attempts were made to distinguish the seismic markers related to the creeping faults.

After the fieldwork, Professor Yann Klinger and colleagues visited the Hubei Earthquake Agency and delivered a lecture titled “Earthquake surface ruptures: what do they tell us about earthquake processes?” They also conducted academic discussions with associate researcher Liu Xiaoli and his group members.

The success of the joint fieldwork exercise was considered a good basis from which the IGCEA group could continue its research of active faults, and both parties agreed to continue their close cooperation.