THE NEW STRONG MOTION SEISMIC NETWORK IN SOUTHWEST BRITISH COLUMBIA, CANADA

摘要

The Geological Survey of Canada has designed a new type of low-cost strong motion seismometer and is currently updating its strong motion seismic network with the new instruments. As of January 2004 about fifty instruments are in operation in Southwestern British Columbia and in a dense urban demonstration network in the cities of Vancouver and Richmond. With a noise floor of 0.5 mg (with g beeing the earth's acceleration) and a range of +- 4 g over a frequency band 0 - 42 Hz the instrument is ideally suited for urban strong motion networks. The instrument can also be fitted with external velocity sensors for use in studies of building structural dynamics. Continuous full waveform data are recorded and stored in an internal ring-buffer by each instrument. Data can be retrieved with standard Internet protocols like FTP and SSH/SCP at any time. Parametric data such as peak ground acceleration (PGA), velocity (PGV) and spectral intensity (PSI) from an event as measured by an individual instrument are reported in near real time and are used to generate an experimental shake-map as a tool for emergency response agencies. The instruments employ solid-state sensors and are virtually maintenance free. Instrument network configuration and acquisition parameters can be managed remotely over the Internet. The techniques to maintain continuous Internet connections with the instruments have proven to be robust and reliable.