BROADBAND DIGITAL SEISMOMETER EVALUATION.

Ambient seismic noise and several large earthquakes were recorded at the same location using both velocity-and displacement-sensing seismograph systems. These data were evaluated for information content by application of convolution filters designed to map outputs from the broadband instruments into the outputs of conventional narrow band systems and into each other. The broadband displacement seismometer was tested for static and dynamic linearity and the response determined from shake table measurements. The velocity instrument was constructed, with minor modifications, from off-the-shelf components. The necessary dynamic range for the two types of broadband seismometer systems was examined and studies were carried out to determine the effictveness of both types for broadband recordings. Several uses of broadband systems are examined and examples of the contributions that could be made to detection and identification of seismic events are discussed. Author