The Jiuzhaigou earthquake intensity is a standard ellipse (Fig. 5), which means the earthquake ruptures are concentration. Our quasi-real-time inversion of the rupture process shows that the slip is clustered in a range of 20 km. Jiuzhaigou area is a well-known scenic spot in China. Many landscapes were damaged by this earthquake.
The Liuhuanggou area is in the meizoseismal area of this earthquake. The seismic intensity level of the Liuhuanggou area is 9 (Fig. 10). The lateral dislocation of the Liuhuanggou bridge is about 0.6m, and the lateral dislocation of the Liuhuanggou tunnel is about 2.7m by this earthquake. Liuhuanggou bridge and Liuhuanggou tunnel are part of the high-speed railway. The earthquake destroys this part of high-speed rail construction. At the same time, China's EEW system plays an important role in this earthquake. After the trains on the high-speed railway received the stop signal, they stopped urgently without causing more casualties.
EEW systems in China are being rapidly deployed. The system in some provinces has already started trial operation. Many earthquake emergency products can be released quickly, for example, automatic Public EEW, automatic centroid moment tensor, automatic seismic intensity map and artificial earthquake products. But for large earthquakes, the fracture surface may be hundreds or even thousands of kilometres long, and it is important to give out an accurate earthquake rupture process as soon as possible.
The traditional inversion of the earthquake rupture process spends a lot of time inverting the rupture of earthquake rupture process. By using near-field strong motion data by directly accessing the China EEW System Jopens database, we perform quasi-real-time inversions of the large earthquakes rupture process. We inverted a stable earthquake rupture process in less than 30 minutes. The data processing can be completed in a few minutes with the help of the automatic site selection procedure and the automated preprocessing procedure.
All our work is done on a workstation with an Intel E3-1200 processor. It spend less than half an hour to complete the quasi-real-time earthquake rupture process inversion for both of the 2017 Mw 6.5 Jiuzhaigou earthquake and the 2022 Mw 6.7 Menyuan earthquake. With the growth of EEW systems of China, instruments of the same model installed nationwide, a unified data processing platform and real-time uninterrupted data streaming, all of these make a quasi-real-time inversion of large earthquake rupture process in whole area of China become possible.
With real-time near-field strong motion data provided by high-density arrays, with an automatic site selection program and an automatic seismic data preprocessing program, the 24-hour manual on-duty system make it possible to release the results of the rupture process in 30 minutes after a large earthquake occurs. Under this timeliness, the inversion results of the earthquake rupture process can be used as a reference for post-earthquake emergency work.