[English translation of original Chinese text]
State Council Document No.69
State Council Endorses Chinese Academy of Sciences’ Report on the Earthquake Situation in North China and the Bohai Sea Area 29 June, 1974
To the leading public administrators of Beijing, Tianjin, the provinces of Hebei, Shanxi, Shandong, and Liaoning, and the autonomous region of Inner Mongolia:
Please pay close attention to the information and implement the recommendations in the attached Chinese Academy of Sciences "Report on the Earthquake Situation in North China and the Bohai Sea Area".
Earthquake work is an important mission that concerns the preservation of lives and property. We look to you to build and strengthen earthquake management offices by implementing the national policy, that is: place top priority on earthquake preparedness, integrate the efforts of professionals and the lay public, and combine Chinese and Western methods. Intensify earthquake preparedness and mitigation efforts by mobilizing professional teams and organizing lay public monitoring and preparation.
At present, the science and technologies to monitor and predict earthquakes are still in their early stages. Therefore, the large earthquakes forecast in this report for this year and next year are estimates only; they may or may not occur. However, we should operate on the assumption that there will be a large earthquake and should therefore make preparations.
At the same time, you must minimize the potential for public panic and social disarray that this alert may cause.
Report on the Earthquake Situation in North China and the Bohai Sea Area
Prepared by the Chinese Academy of Sciences on 15 June 1974
To the State Council:
From 7-9 June 1974, the State Seismological Bureau (SSB) held a conference on the earthquake situation in the North China and Bohai Sea area. Representatives came from twenty units of earthquake disaster management and research institutions of Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Shandong, and Liaoning.
The conference analyzed the earthquake situation of the above-mentioned areas. The majority opinion is that, within this year or next year, earthquakes of magnitude 5 to 6 may occur in: the Beijing-Tianjin area; north part of the Bohai Sea; Handan and Anyang in the border area between Shanxi, Hebei, and Henan; the Linfen basin in Shanxi; the Linyi area in Shandong; and the central part of the Yellow Sea. Earthquakes of around magnitude 5 may occur in Inner Mongolia in the area around Baotou and Wuyuan.
The principle evidence for the above is:
Northern Bohai Sea area
- Recent frequent occurrences of small earthquakes
- Abnormal readings of crustal deformation
- Anomalous gravity measurements
- Unusual changes in radon content in groundwater
Linfen Basin in southern Shanxi
- Changes in water level in Jinxian County had been gradual over the past few years, with a rate of 0.11mm/year. However, the cumulative change in water level has already reached 2.5mm (in 9 months).
- Geomagnetic anomaly of 22-gamma recorded in the Dailian area.
- Six tide-monitoring stations in the northern Bohai Sea area all reported increases of 10-20cm in sea level in 1973, a phenomenon that has not been seen for the past 10-20 years.
- Marked increase in microseismicity.
Shanxi, Henan, Hebei border area and the central part of the Yellow Sea
- Anomalies in seismic velocity in recent years
Linyi area in southern Shandong
- Increase in microseismicity
- A pattern of high seismicity in the area peripheral to Linyi has emerged in the past few years. This pattern is similar to the one which formed before the historic 1668 magnitude 8.5 earthquake in the same area.
In addition, based on the historical pattern of major earthquake activity, the study of regional seismicity, the influence of the Western Pacific seismic belt and those earthquakes with focal depths of 400-500km on North China, some colleagues believe that North China has accumulated enough seismic energy for an earthquake of magnitude 7 to 8.
Furthermore, prolonged drought in the northern part of North China, and abnormal meteorological conditions rarely seen since 1949 – a warm winter, a cold spring, and imbalance in humidity during the past year – indicate the possibility of a major earthquake of around magnitude 7 in North China.
In contrast, some colleagues have observed an increase in the Earth’s rate of rotation over the last year, which from past experience indicates that large earthquakes are unlikely. An additional observation is that there is usually a long time period between large earthquakes in this region. They therefore believe that no earthquake greater than magnitude 5.5 will occur in North China in the next few years.
Learning from the lessons of the successive devastating earthquakes in Liyang County in Jiangsu Province and Zhaotong County in Yunnan Province, the conference participants recommend that we should operate on the assumption that there will be a large earthquake despite the inconclusive analysis. Therefore we should heighten our alertness and prepare for the sudden strike of an earthquake of magnitude greater than 6.
Our recommendations for strengthening earthquake work in the risk areas are:
- Strengthen leadership in earthquake work. Appoint at least one public official in each of the seven risk areas (Beijing, Tianjin, etc.) to take charge. Strengthen existing seismological bureau and earthquake offices in Beijing, Tianjin, Hebei, Inner Mongolia, and Liaoning. In Shanxi and Shandong, where there are no established earthquake offices or lay monitoring stations, such facilities should be set up immediately. Initiate earthquake preparedness work at all regional and county levels and integrate the management of professional and amateur (lay public) monitoring teams.
- Develop lay public monitoring and preparation networks and mobilize the public in earnest. In the seven risk areas, there are currently about 5,000 people who participate in amateur monitoring teams, which is still inadequate. Experience has shown that in areas where good lay monitoring and preparation are implemented, it is possible to capture imminent precursors thereby mitigating losses. Factories and major mining enterprises should take steps to organize amateur monitoring teams and train volunteers. Villages should establish public education and monitoring programs, and make effective use of meteorological stations, schools, and amateur science groups. At the same time, avoid panic by preparing the public psychologically for potential calamity.
- Professional teams should investigate fully all the areas in which anomalies have occurred, provide comprehensive analysis, and continue to monitor the earthquake situation. Raise the level of earthquake prediction and strive for timely early warning. Assure the normal functioning of the 109 professional monitoring centers in the risk areas. New centers should be considered if necessary. Professionals should also work with the public and draw from their valuable experiences, and consider development of lay monitoring and preparation a personal goal.
- Establish two regional groups. One group, Beijing-Tianjin-Tangshan-Zhangjiakou, headed by the State Seismological Bureau (SSB), should include earthquake offices in Beijing, Tianjin, and Hebei, the Geophysics Institute, the Seismic Geology Group, and the Seismic Measurement Team. The second, the Bohai Group, should comprise of the Liaoning, Tianjin, and Shandong earthquake offices, headed by the Liaoning office. These two groups should cooperate closely and share all monitoring data in a timely manner.
[ End of Translation of Document No. 69 ]
Text from Guidelines on Capacity Building for Disaster Management,
United Nations, New York, 1996
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