Quantitative studies of global seismicity (2) |
| |
| Authors: | Wu Jiayi and Cao Xuefeng |
| |
| Institution: | (1) Institute of Geophysics, State Seismological Bureau, Beijing, China |
| |
| Abstract: | In this paper, the seismicity indexes of global earthquakesM ≥ 6 during 1964–1983 were calculated, using data of ISC and USGS. The authors suggested a method suitable to make a set of
regression formulas betweenm
bandM
s. Calculation showed that the level of global seismicity of shallow earthquakes during the years 1964–1965, 1968, 1971, 1975–1976
was higher than normal, especially the peak for the years 1975–1976 was more conspicuous. The year 1984 took the place of
the year 1954 in the 20th century as the year of lowest global shallow focus seismicity. According to the actual value ofA(b) calculated, the level of deep focus seismicity reached the highest point in 1971 and dropped to the lowest point in 1977.
In the time interval of 1977–1983 the global shallow focus seismicity decreased continuously whereas the deep focus seismicity
increased with fluctuations. |
| |
| Keywords: | Global seismicity Seismicity index Magnitude-frequency distribution Theb value Seismicity peak year M s∼ mbregression Seismicity level |
| 本文献已被 SpringerLink 等数据库收录！ |
|
