Predicting Earthquakes A Scientific and Technical Evaluation, With Implications for Society (1976) / Chapter Skim
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Appendix B: Earthquake-Prediction Research Outside the United States
Appendix B: Earthquake-Prediction Research Outside the United States
Pages 51-63
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From page 51... ...
Following the destructive Khait earthquake of l949 in the Garm region of the Tadjik Republic, Soviet seismologists in the early l950's put into the field the Complex Seismological Expedition to record and study the spatial distribution of earthquakes, their variations with time, and other statistical properties. The program of scientific research in the Garm region was later expanded to include searches for precursory phenomena associated with earthquakes.
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From page 52... ...
Active field programs of earthquake prediction are under way in three areas of the Soviet Union: in the Garm region of central Asia, in the area near Tashkent in central Asia, and in Kamchatka. The first two areas are situated near the belt of moderate-to-high seismic activity that extends from the Mediterranean region across central Asia to the Himalayas and western China.
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From page 53... ...
Soviet investigators report anomalous increases in elevation of the land prior to moderate and large earthquakes. Tashkent and Uzbek Republic The damaging Tashkent earthquake of April 26, l966, apparently influenced the Soviet government to give increased attention to earthquake prediction and earthquake-hazards reduction.
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From page 54... ...
Marked changes in temperature and fluid flow were observed prior to the l970 Przhevalsk earthquake, near Alma Ata in Central Asia. Changes in temperature and in the content of radon and helium are also now being monitored in several wells along the major Surkob fault zone in Tadjikistan.
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From page 55... ...
The Japanese program of earthquake prediction places great emphasis on the collection of a wide variety of data that are seen as essential to progress in predicting earthquakes. Three new centers were set up to promote data collection and processing; the Crustal Activity Monitoring Center, for geodetic data and tide-gage data, was set up in the Geographical Survey Institute; the Seismicity Monitoring Center, under the Japan Meteorological Agency, for analyzing and recording earthquakes of magnitudes larger than 3; and the Earthquake Prediction Observation Center, for analysis of microearthquakes (of magnitudes smaller than 3)
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From page 56... ...
Plans call for the leveling to be repeated at 5-year intervals in order to maximize the probability of detecting anomalous crustal movements and to monitor strain buildup. Some of the best observations of precursory crustal movements were made prior to the Niigata earthquake of l964.
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From page 57... ...
One of the outstanding features of the Matsushiro swarm was the gradual enlargement with time of the fault region experiencing earthquakes. It was found that microearthquakes tended to migrate into a new region along the fault zone prior to the occurrence of moderate-size earthquakes a few months later.
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From page 58... ...
Also, stray electric currents from the extensive electric railways in Japan lead to large local magnetic disturbances. Seismic Gaps Extensive work has been done by Mogi and Utsu in identifying seismic gaps in Japan.
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From page 59... ...
The shallow nature of the sources, and the fact that the source regions can be readily surrounded by instruments, make it much easier to monitor possible precursory changes than if the earthquakes were located off the coast. Earthquake Prediction in China A massive effort to detect a wide variety of precursory phenomena associated with earthquakes is under way in China.
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From page 60... ...
Most Chinese scientists appear to be convinced that earthquakes are preceded by a wide range of precursory phenomena and that these phenomena occur in a variety of tectonic environments. Changes in the following variables have been reported prior to earthquakes and are being studied actively in extensive field programs: crustal movements, seismic velocities, frequency of occurrence of small earthquakes, seismic attenuation, the flux of radon from water in deep wells and springs, water level and temperature in wells, geomagnetic field, natural geoelectric field using telluric currents, and earth resistivity using an applied potential.
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From page 61... ...
Most Chinese scientists believe that observations using a multiplicity of techniques, rather than reliance on a single method, are necessary for reliable prediction. The scale of the Chinese effort to predict earthquakes is very large indeed.
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From page 62... ...
. Earthquake Precursors.
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