Systematic variations of mean travel-time residuals in space and time |
| |
Authors: | A G Prozorov |
| |
Institution: | (1) Institute of Earth Physics, 10 B. Gruzinskaya St., Moscow, U.S.S.R. |
| |
Abstract: | Summary Mean travel-time residuals of P waves for the period 1964–1970 at stations in North America and Europe are well separated into large domains of positive and negative values. The spatial distribution of residuals in North America is in good agreement with the structure of the upper mantle obtained from Rayleigh wave dispersion and is in accord with magnitude anomalies and heat flow data. A systematic variation of residuals in time is found to be sensitive to major changes in the nature of the earthquake source distribution, as for example aftershocks, as well as to changes in methods of detection of first arrivals. Residuals at neighboring stations are correlated up to distances of the order of 2°. Half year mean residuals at stations within 2° distance from the epicenters of strong earthquakes have a sudden jump 1.5 years before the occurrence of an earthquake. A formal algorithm based on this pattern permits prediction of the times of all 16 earthquakes with magnitudeM 7.5 occurring during the interval 1966–1972. Although the average duration of the alarm periods is about half the total time interval of the catalog, so that the algorithm has no practical importance, these results are statistically significant on a 99% level of confidence. |
| |
Keywords: | Seismology P wave residuals Travel-time anomalies Earthquake prediction |
本文献已被 SpringerLink 等数据库收录! |
|