scholarly journals Spatio-temporal variation of seismicity before the 1971 San Fernando earthquake, California

1978 ◽  
Vol 15 (4) ◽  
pp. 78
Keyword(s):  
Temporal Variation ◽  
San Fernando ◽  
Spatio Temporal

scholarly journals Temporal variation of seismicity and spectrum of small earthquakes preceding the 1952 Kern County, California, earthquake

1980 ◽  
Vol 70 (2) ◽  
pp. 509-527
Author(s):  
Mizuho Ishida ◽  
Hiroo Kanamori
Keyword(s):  
Stress Concentration ◽  
Temporal Variation ◽  
Main Shock ◽  
Fault Plane ◽  
Large Earthquake ◽  
Kern County ◽  
Epicentral Area ◽  
San Fernando ◽  
Spatio Temporal ◽  
Definite Indicator

abstract The spatio-temporal variation of seismicity in the epicentral area of the 1952 Kern County California, earthquake (Ms = 7.7, 34°58.6′N; 119°02′W) was examined for the period prior to the main shock. Most of the events that occurred in the epicentral area were relocated by using the main shock as a master event. A large part of the fault plane of the Kern County earthquake had been seismically quiet for nearly 15 yr before the main shock. However, the activity in the immediate vicinity of the epicenter had been very high during the same period. The temporal variation of the activity in the vicinity of the epicentral area exhibits a pattern very similar to that found for the 1971 San Fernando earthquake. During the 112 yr period immediately before the main shock, tight clustering of activity around the main-shock epicenter occurred. This clustering may be considered to be foreshock activity. This period of increased activity was preceded by a quiet period for 2 yr from 1949 to 1950; no event was located on the fault plane of the Kern County earthquake during this period. This pattern, quiescence followed by clustering, seems to have repeated several times prior to 1949. Thus, this pattern alone cannot be used as a definite indicator of a large earthquake, but in terms of a fault model with asperities, it can be a manifestation of progressive stress concentration toward the eventual hypocenter. Spectral analyses of the Pasadena Wood-Anderson seismograms of the events that occurred near the epicentral area showed that the frequency of the spectral peak is systematically higher for the foreshocks than the events prior to 1949. A similar trend was found for the 1971 San Fernando earthquake. These results are consistent with the model of stress concentration around the eventual hypocenter.

Spatio-temporal Variation Characteristics of Surface Net Radiation in China over the Past 50 Years

2013 ◽  
Vol 15 (1) ◽  
pp. 1 ◽  
Author(s):  
Yangzi GAO ◽  
Honglin HE ◽  
Li ZHANG ◽  
Qianqian LU ◽  
Guirui YU ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Net Radiation ◽  
The Past ◽  
Variation Characteristics ◽  
Spatio Temporal
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