Terrible fish
According to fishermen in Caijiabao and Beidaihe, fish are crazy. Around July 28, all kinds of fish came up and turned white, which was easy to catch. The fishermen met with unprecedented luck. Naked children fish with small nets near Qimen River Gate. Fish can catch dozens of pounds of fish in a few hours as long as they jump into the net. Chen Yucheng, from Zhaogezhuang Coal Mine in Tangshan City, said that on July 24th, the goldfish in his two fish tanks scrambled to jump out of the water, out of the tank and put it back, but the goldfish jumped up and down. Huo of Baigezhuang Fish Farm in Tangshan said that on July 25th, there was an uproar in the fish pond, and grass carp jumped around in droves, and some jumped more than a foot above the water. What's even more surprising is that some fish will turn upside down and stand upside down on the water, but they will circle as fast as possible. On the sea of Dagukou, Tianjin, south of Tangshan, the crew of the "Changhu" tanker introduced that on July 27th, the jellyfish around the tanker suddenly increased, and groups of small fish swam around in a hurry, put down their hooks, and soon caught more than 100 fish. The crew of the "Changhu" oil tanker witnessed that on July 25th, the air around the oil tanker creaked, and a large group of dragonflies with dark green wings flew in, perched on the window, mast and ship's side, motionless, and none of them took off. Before long, the commotion on the ship was even greater. A large group of colorful butterflies, native locusts, and many sparrows and unknown birds also flew in, as if it were an unexpected big party. Finally, a colorful budgerigar flew in and stood motionless at the stern. Hundreds of bats were seen flying in the air in broad daylight in Muchang Commune and Xiyingmen Commune on the outskirts of Tianjin. A member of Xitangtuo Brigade, panzhuang Commune, Ninghai County, southern Tangshan, since July 25th, the old Yan under the beam has been throwing Xiaoyan out of the nest every day. The owner picked Xiaoyan up and was thrown out by the old Yan. On July 27th, Lao Yan flew away with the remaining two Xiaoyan. On July 27th, members of Qian 'an Township saw dragonflies flying around like locusts. The flight team is 100 meters wide and lasts from east to west 15 minutes or so. Dragonflies buzzed when they flew by, and the momentum was so great that people were dumbfounded.
The great escape of the animal kingdom
On July 27th, people in Wanggaishan, Luannan County, Tangshan saw with their own eyes swarms of mice running in panic. The big mouse ran after the little mouse, and the little mouse bit its tail into a string. Some people were curious and ran after it, but the good-hearted people dissuaded them and said, "Stop fighting, I'm afraid it will send water."
On the morning of July 25th, in Funing County, some people saw 100 weasels, the big ones on their backs and the small ones on their backs, crawling out of the hole in the ancient wall and moving towards the village. When it was dark, a dozen of them wandered under a walnut tree, and five of them were killed on the spot. Others kept wailing and felt afraid of death. On 26th and 27th, this group of weasels continued their activities outside the village, and there was a panic atmosphere.
Sensitive flying insects, large and small birds and animals, took the first step to escape earlier than humans. However, human beings do not realize that this is a warning from nature. They never thought that a catastrophe that would destroy life was coming.
1. Macroscopic precursors of earthquakes?
People's senses can directly perceive earthquake precursors, which are called macro precursors of earthquakes. The more common ones are the sudden rise and fall of well water, discoloration and odor, flowering and bubbling, temperature fluctuation, sudden change of spring water flow, sudden change of hot spring water temperature, abnormal animal habits, earth sound and earth light before the earthquake, etc. ?
Macroscopic precursors play an important role in earthquake prediction. Before Liaoning 1975 Haicheng earthquake with M = 7.3 and 1976 Songpan-Pingwu earthquake with M = 7.2, seismologists and the general public had observed a large number of macroscopic anomalies, which provided important information for the successful prediction of these two earthquakes. However, we should also pay attention to the various macro phenomena listed above, which may be caused by various reasons, and are not necessarily signs of earthquakes. For example; The group fluctuation of well water and spring water may be related to rainfall, and may also be affected by nearby pumping, drainage and construction. The discoloration of well water may be caused by pollution, and the abnormal behavior of animals may be related to weather changes, diseases, estrus and external stimuli. Also be careful not to mistake welding arc light and lightning for earth light, thunder for earth sound, and fireworks and flares for underground fireballs. ?
-once you find an abnormal natural phenomenon, don't easily draw the conclusion that an earthquake will happen soon, let alone panic. Instead, it is necessary to find out the time, place and relevant situation of abnormal phenomena, protect the site, report to the earthquake department or the government, and let the professionals in the earthquake department investigate and verify the truth. ?
2. Micro-precursors of earthquakes?
Earthquake precursors that can't be detected by human senses and can only be measured by special instruments are called earthquake microscopic precursors, which mainly include the following categories:
Abnormal seismic activity. There is a certain relationship between large and small earthquakes. Although there are not many major earthquakes, there are many small and medium-sized earthquakes. Study the characteristics of moderate and small earthquakes. It is possible to help people predict the occurrence of future major earthquakes. ?
Terrain anomaly. Before the earthquake, the crust near the epicenter may be slightly deformed, and the rocks on both sides of some faults may be slightly displaced. With the help of precision instruments, this very small change can be detected. Analyzing these data can help people predict the occurrence of major earthquakes in the future. ?
Geophysical changes. In the process of earthquake preparation, some changes may occur in the physical properties of rocks in the source area and its surrounding areas. Using precision instruments to measure the changes of gravity, geoelectricity and geomagnetism in different areas can also help people predict earthquakes. ?
Changes of underground fluid. Groundwater (well water, spring water, water contained underground), oil and natural gas and some other gases may be generated and stored in underground rock formations, which are all underground fluids. Measuring the chemical composition and some physical quantities of underground fluid with instruments and studying their changes can help people predict earthquakes. ?
3. Seismic observation network?
In order to capture the microscopic precursors of earthquakes, it is necessary to establish an earthquake observation network covering this area for long-term precise observation. ?
An instrument for recording earthquakes is called a seismograph. Stations specializing in earthquake observation are called seismographs or seismographs. As early as 1800 years ago, Zhang Heng, a famous scientist in China, invented the world's first seismograph-"Houfeng seismograph". Modern seismographs adopt the most advanced electronic technology with high sensitivity, and there are even special submarine seismographs and deep well (borehole) seismographs. At present, a considerable number of seismic stations can automatically record seismic signals without special observation, and automatically transmit the signals to the receiving center through cables or radio waves, and then the signals are automatically processed by computers. This is the so-called telemetering seismic network. Modern telemetering seismic network has been established in many areas of China, including Sichuan Province. In addition, there are earthquake precursor observation stations such as geoelectricity, geomagnetism, gravity, topographic change and underground fluid. ?
Before liberation, there was only one seismic station and three seismologists in old China, and the earthquake cause was extremely backward. After liberation, the cause of earthquake in New China has a new starting point. 1957. Chengdu Seismic Station, the first seismic station in Sichuan Province, was established in the western suburbs of Chengdu. 1966 After the Xingtai earthquake, with the cordial care of Premier Zhou Enlai, the earthquake cause in China accelerated. 197 1 year, the state seismological bureau (now seismological bureau of China) was established. After nearly 30 years of hard work, the earthquake observation network has begun to take shape. At present, more than I000 modern seismic stations (including local seismic stations) have been established in China, and seismic observation technology has been widely used.