Continuous Monitoring of Ground-Motion Parameters

We applied a time-domain method to continuously monitor groundmotion parameters to facilitate rapid determination of the geographical distribution of ground motion and earthquake parameters. This approach minimizes the impact of the sudden increase in the worload on data acquisition facilities and streamlines the operation of a seismic network, especially during a complex earthquakes sequence. The incoming continuous time series is processed with the use of various time-domain recursive filters to compute ground-motion velocity, acceleration, energy, Wood-Anderson seismograms, and narrow-band responses at 0.3, 1.0, and 3.0 sec, which are used for computation of response spectral amplitudes. The method is implemented in the Southern California Digital Seismic Network. The method can be implemented at every field station, which would make it possible to process the time series locally and continuously telemeter desired amplitude parameters with sufficient accuracy from a field station to multiple users through a relatively low data-rate communication line (e.g., regular telephone line or limited bandwidth satellite link).