A STUDY OF THE RELATION BETWEEN CRUSTAL DEFORMATION AND SEISMIC ACTIVITY IN THE XINFENGJIANG RESERVOIR AREA

Before and after the earthquake of magnitude Ms= 6.1 occurred on March 19, 1962 in the Xinfengjiang reservoir area, Guangdong Province, geodetic levelling and triangulation measurements were carried out in this area. The results are characterized by high frequency of repetition and high accuracy of measurements.In processing the data relative to an assumed fixed datum point, crustal deformation fields have been obtained and discussed. Using the results of measurements of consecutive triangulation surveys, the principal strain axes of each triangle surveyed have been calculated.By inversing the strain data during an earthquake of magnitude 5.3, the earthquake fault plane was obtained.All the above results show that before and after earthquakes of magnitudes greater than 4, horizontal crustal deformations in Xinfengjiang are obviously related to the earthquakes while the vertical deformations seem to have no relation to them.