Preventive measures against earthquakes include the construction of earthquake-resistant buildings, earthquake drills and training, timely forecasting, and evacuation.
An earthquake is a vibration of the earth. It originates at a point underground, which is called the source (focus). The vibrations are transmitted from the source and travel through the earth. The point on the ground closest to the source is called the epicenter, which is the earliest part to receive vibrations. Earth vibration is the most intuitive and common manifestation of earthquakes. Strong earthquakes that occur under the sea or in coastal areas can cause huge waves called tsunamis. Earthquakes are extremely frequent, occurring globally about 5 million times a year.
Earthquake forecasting and prevention
Strong earthquakes are serious natural disasters that threaten people's lives, property and safety, and affect the country's livelihood. Forecasting earthquakes is the sacred mission of earthquake and geologists. According to the distance from the time of the earthquake, the forecast is divided into medium- and long-term forecasts, short-term forecasts and pre-earthquake forecasts. Medium- and long-term forecasts are mainly implemented through the investigation and research of earthquakes and geological conditions. Short-term forecasting, not only rely on seismic and geological research, but also rely on the use of a variety of monitoring tools. Pre-earthquake forecasting mainly relies on various monitoring means. Seismic monitoring mainly utilizes a variety of instruments and equipment to study the various physical changes that are occurring in the rocks. Seismographs make continuous records of weak seismic energy, and by analyzing and studying the records, it is possible to infer the tendency of earthquakes to occur. In addition, abnormal reactions of the weather and animals, and the production of earth lights and sounds are also omens that an earthquake will come.
Contents of earthquake prediction: earthquake prediction is divided into two kinds according to the prediction of the time range of distant earthquake prediction and recent earthquake prediction.
Far-term earthquake prediction: is a kind of earthquake occurrence of geological and tectonic conditions as the basis, macroscopically on a certain area in a longer period of time (such as decades, hundreds of years or even longer) may occur in the largest earthquake and its impact on the scope of the prediction of the method that is the seismic geological method. This method delineates the danger zones of future earthquakes over a large area and identifies hazardous areas of different intensities. It includes two types of seismic hazard zoning and seismic intensity zoning. The specific methods of seismic zoning are: ① divide the strong seismic activity zone (seismic zone) and determine the seismic danger zone in the next hundred years; ② analyze the trend of seismic activity and estimate the maximum magnitude of the earthquakes that may occur in the seismic danger zone in the future; and ③ predict the intensity impact field of earthquakes occurring in the next hundred years. On the basis of the first two tasks mentioned above, make the seismic hazard zoning map. On the basis of the above three tasks, the seismic zoning is carried out and the seismic intensity zoning map is made. Seismic intensity zoning provides a reasonable seismic defense index - the basic intensity - for construction planning and engineering design. The seismic design of the city's buildings is based on this work.
Prediction of near-term earthquakes: Prediction of the three elements (time, location, magnitude) of earthquakes that may occur within a few years to a decade. Usually, seismic statistical methods and precursor prediction methods are used
①Seismic statistical methods are used to explore possible statistical patterns from the records of earthquakes, to estimate the risk of earthquakes, and to find out the probability of earthquakes of a certain intensity occurring. The reliability of statistical methods is determined by the amount of information available. Statistical methods indicate only the probability of earthquakes occurring and a certain "average" state of seismic activity. In order to predict the location, intensity and time of an earthquake, it is necessary to rely on the observation of earthquake precursors.
②Earthquake precursor method is based on earthquake precursor phenomena to predict the time, location and intensity of future earthquakes. The method through the seismic activity, crustal deformation, water table, water chemical composition, geoelectricity, geomagnetism, gravity, wave velocity ratio, the original ground stress and pre-seismic animal anomalous response measurements and observations, the various anomalies appearing before the earthquake for a comprehensive analysis, to find out with the earthquake is directly related to the precursor phenomena, study their relationship with the three elements of the earthquake and the earthquake prediction by using this empirical relationship. However, since there are many factors affecting the anomalies, and the anomalies appearing before different earthquakes are often different in type, number, distribution range and amplitude, it is very difficult to distinguish the real precursory anomalies from the anomalies, so finding earthquake precursors is the core problem of earthquake prediction. So far the work is still in the exploration and research stage.
Status of earthquake prediction:
Earthquake prediction is the prediction of the time, location, and intensity of future earthquakes based on knowledge of the laws of seismic activity. The purpose of earthquake prediction is to avoid or mitigate earthquake disasters. For this reason, it should have a high degree of reliability, and inaccurate forecasts can cause unnecessary panic among residents and bring losses to society and the economy. The basis for realizing earthquake prediction is to recognize the physical process of earthquake breeding and the changes in the physical properties and mechanical state of crustal rocks during the process, but reliable prediction is very difficult because human beings have not known enough about the causes and laws of earthquakes so far. The technology relied upon in earthquake prediction research does not yet allow direct observation of the Earth's interior, resulting in a lack of direct observational data on the process of earthquake incubation and the factors that influence this process. Therefore, despite the fact that the problem of earthquake prediction has been raised for a long time, progress has been slow. Scientists in various countries have made great efforts to this end, but so far it is still not possible to accurately predict earthquakes, and in the best of cases only a very rough estimate can be made.
The city's earthquake prediction work: since 1996, I Bureau of the Baotou "5.3" earthquake through the study, summing up, in the earthquake prediction work focused on strengthening the Loop Basin seismic activity patterns and the city and the city's surrounding areas of the seismic situation analysis and research, and in the day-to-day work of serious organizations to carry out the city and the neighboring areas of the seismic situation of the weekly, monthly consultation and analysis, and actively organize and carry out the earthquake The Bureau also organizes weekly and monthly consultation and analysis of seismicity in the city and neighboring areas, actively organizes and carries out the verification of short-term anomalies, and promptly understands and exchanges seismic information with the Earthquake Bureau of the Autonomous Region and neighboring cities. In recent years, under the hard work of the whole bureau, our earthquake prediction work has always been in the forefront of the autonomous region of the alliance city, I submitted to the autonomous region of the seismic trend of the research report has been repeatedly by the autonomous region of the seismological bureau of the commendation.
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