MONITORING OF STRAIN RELEASE IN CENTRAL AND NORTHERN CALIFORNIA USING BROAD-BAND DATA

Systematic cataloguing of seismic moment, depth and mechanism of regional earthquakes down to magnitude M approximately 4 can now be achieved in close to real-time using data from sparse networks of digital broadband stations. The procedure we have developed relies on 3 independent methods for the determination of moment tensor, providing confidence limits on the results. We show the results of application to the seismicity in central and northern California for a one year period starting in March 1992 and illustrate how patterns of stress and strain release can now be monitored systematically and reliably in a timely fashion.