Before the Yibin earthquake, a research institute issued an early warning 70 seconds in advance. How did it realize pre-earthquake warning?

We all know that the harm of earthquake is very serious, and there will be many changes and precursors when the earthquake comes, but it is still difficult to prevent and avoid disasters and losses in time, because when the earthquake comes, expect the unexpected will shake strongly, which will make it difficult for many people to think calmly, so it is the most difficult natural disaster to rescue and take measures when the earthquake comes. However, before the recent Yibin earthquake, some research institutions issued an early warning 70 seconds in advance. He can do this mainly because he has a core technology about early warning. After all, after the Wenchuan earthquake in our country, Sichuan and many areas began to develop these earthquake-proof equipment. However, we still don't know how this technology can prevent and warn earthquakes, which belongs to the most advanced research technology in China, and China's early warning in this respect is already the world's leading technological achievement with completely independent intellectual property rights, and it is one of the only countries in the world with earthquake early warning capability. It can be said that the institute's early warning has warned many areas 70 seconds in advance and issued such early warning information. It can be said that many disasters and losses have been reduced. No matter how fast the earthquake is, if we can give an early warning within a limited time, we can also reduce our losses under certain circumstances. If we can give an early warning of the earthquake, we can reduce casualties. After all, everyone will be very serious and focused on this situation, and the earthquake in Yibin has been relatively high, which may lead to very serious danger. For example, some roads or bridge decks may have potential safety hazards, which are hard to avoid. After all, it is a kind of fluctuation from the ground, which will definitely cause some losses on the road.