[Explanation] After the Luding M6.8 earthquake, the China Earthquake Administration immediately launched a scientific investigation of earthquakes, aiming to conduct in-depth research on the earthquake-generating structure, the process of occurrence and evolution, and the mechanism of earthquake damage, strengthen the research and judgment of earthquake trends, and provide regional earthquake prevention and disaster reduction. Provide technical support for the work.
The team led by Dai Junwu, a researcher at the Institute of Engineering Mechanics of the China Earthquake Administration, is mainly engaged in the investigation of the earthquake disaster mechanism and the research on the intensity.
In late September, the reporter followed Dai Junwu's team to Moxi Town to investigate the mechanism of the earthquake.
Every time they passed a damaged house, experts climbed to the ruins to record and analyze the damage to the house.
In Moxi Town, there was a building with no cracks in the walls, but the wooden roof on the roof collapsed.
Dai Junwu said that the collapse of the roof is only an appearance, but it can reflect the mechanism of earthquake action.
[Concurrent] Dai Junwu, researcher at the Institute of Engineering Mechanics, China Earthquake Administration
Our (seismic network instruments) near the epicenter recorded a particularly large vertical component (ground vibration), even exceeding the horizontal component, reaching a speed of about 50 centimeters per second, so the acceleration reached 0.5G There are many (gravitational acceleration), under the action of such a large speed and acceleration, the (earthquake zone) house will be upside down during an earthquake, up and down, then this ups and downs will last about one to two seconds. is a very large pulse.
In this way, the entire roof truss seat is collapsed, but the horizontal cracks and oblique shear cracks are completely invisible to the wall, which is enough to show that the vertical effect of this earthquake is particularly prominent. The closer to the epicenter, the more prominent this damage phenomenon is.
[Explanation] Dai Junwu introduced that the maximum vertical acceleration of over 0.5G has created a new record since strong vibration monitoring in China.
For post-disaster house reconstruction, Dai Junwu put forward his suggestions.
[Concurrent] Dai Junwu, researcher at the Institute of Engineering Mechanics, China Earthquake Administration
In fact, this house was completely designed by the common people, and it was built by the construction team by themselves. It must have not considered the issue of the particularly large vertical effect of the earthquake.
In the later restoration and reconstruction process, I actually suggested that unified planning, unified design, unified construction and construction must be carried out to ensure the safety of the people.
[Explanation] The Dagangshan Power Station is located in Shimian County, Ya'an, only 21 kilometers away from the epicenter.
In the earthquake scientific research, the relevant data recorded by this power station will become the key to study the impact of earthquakes on major projects.
Tang Fangtou, a researcher at the Institute of Geophysics of the China Earthquake Administration, told reporters that the power station has 20 strong seismographs inside the power station, and the data monitored by the instruments is basically consistent with the seismic safety assessment data calculated by the researchers, and the Dagangshan Power Station can operate normally after the earthquake.
[Concurrent] Tang Fangtou, researcher at the Institute of Geophysics, China Earthquake Administration
Preliminary understanding, (dam) monitoring data is basically consistent with the data given by our previous earthquake safety assessment.
The main reason for this visit is to collect data. Another is that we actually look at the impact of the earthquake on the dam disaster, and use the data to check our previous calculations. Are there any differences with the actual difference? Reserve is to provide some evidence.
Lu Yang Luosong Zhang Hongying reports from Sichuan
Responsible editor: [Ji Xiang]