BEIJING, Beijing, June 22 (Xinhua) The routine press conference of the Seismological Bureau of China in the second quarter of 2017 was held in Beijing on the 22nd. The conference introduced the active source technology system for detecting underground structures and the background and ideas of its application projects.
As one of the important topics of seismology in the 21st century, earthquake prediction is a global scientific problem. According to reports, it is an important means to study the underground medium structure and its change with time by using active sources to understand the earthquake environment and the process of earthquake preparation.
At the press conference, Xu Ping, a researcher at the Seismological Bureau of China, introduced the latest research achievement of the team of Academician Chen Qing from the Institute of Geophysics of the Seismological Bureau of China: "illuminating" the earth’s interior by artificially creating earthquakes.
Xu Ping said that up to now, most of people’s knowledge about the internal structure of the earth comes from seismologists’ analysis of seismic waves. However, natural earthquakes are uncontrollable and unevenly distributed, and there are a lot of blind spots. Xu Ping pointed out that artificial earthquake sources are needed to fill the places where there is no earthquake.
Xu Ping said, "The top ten scientific and technological problems in the 21st century are recognized internationally, and the first one is earthquake prediction. Because we don’t know how the earthquake came into being until now, it occurred at a depth of more than ten kilometers underground. The earthquake we know may be a fracture, and the pressure is pressed to a certain extent. For example, this chopstick is broken, which is an earthquake. This is our current cognition, and a large number of tectonic earthquakes are generated in this way. But when will it break? This is what we want to explore now, because only in this way can I predict when an earthquake will happen, just like weather forecast, so we have done a lot of work in this respect. We have experienced exploration for decades and now give us a new means, a new idea and a new method. Let’s explore this matter. "
Xu Ping introduced that an air gun presses high-pressure gas into a gas cylinder and then releases them underwater. This pressure can spread far away. According to this principle, in 2011, Chen Qing, an academician of Chinese Academy of Sciences and a geophysicist, proposed that Binchuan, Dali, Yunnan Province established the world’s first launch pad for air gun sources. In 2013 and 2015, two air gun source launch stations were built in Hutubi, Xinjiang, and Zhangye, Qilian Mountain, respectively. Each launch pad will quietly fire dozens of times at night every day. At this time, the surrounding seismic stations will receive continuous seismic waves.
Xu Ping said that before the natural earthquake with the magnitude of 5.2 in Qilian Mountain, we can see the change of the travel time of the seismic wave generated by gas shooting 100 days before the natural earthquake. "We can see that the earthquake has a precursor phenomenon, at least on this earthquake, we can see that the travel time of the velocity layer of its underground structure has changed."
"Chen Qing’s team put forward an idea that if there are about 10 fixed air gun launchers in China, and the monitoring distance can reach about 1000 kilometers, it can basically cover the whole of Chinese mainland." Xu Ping said that through such a detection coverage, we can explore the laws of earthquakes more, better and deeper, explore the relationship between human activities, national economic construction and tectonic movement, and explore the formation laws of mineral deposits. (End)