LURR and the San Simeon M 6.5 Earthquake in 2003 and the Seismic Tendency in CA.

The spatial and temporal variation of LURR (Load/Unload Respond Ratio) in California during April 2002 to June 2004 was studied in this paper. The result shows that before the San Simeon earthquake (35.7 N, 121.1 W) on Dec. 22, 2003, Y/Yc anomalous region occurred successively near the epicenter from April 2002 to June 2002, and the maximum anomaly of Y/Yc occurred in May, 2002. The published research work pointed out that the Y/Yc anomaly near the San Simeon earthquake appeared from March, 2002. Compared with the five earthquake cases out of the six with M≥6.5 in California during the period from 1980 to 2001, the maximum Y/Yc and duration of Y/Yc anomaly before this earthquake are among the normal ranges, but the time delay from the maximum anomaly time to the occurrence time of this earthquake is the longest one. The result also shows that two areas with Y/Yc anomalies occurred from Oct. 2002 and Dec. 2002, respectively. According to statistical characteristics of the relationship between Y/Yc anomalies and the coming earthquakes, the seismic tendency in California was discussed in this paper. [ABSTRACT FROM AUTHOR]