EARTHQUAKE MONITORING AROUND CANBERRA'S MAJOR WATER SUPPLIES

The seismology division within ES&S recently supplied and installed five new Kelunji EchoPro seismic recorders, Guralp transducers and associated telemetry and power management equipment to ActewAGL for the ActewAGL Seismic Network that monitors earthquake activity around Canberra's major water supply storages. Continously telemetered six-channel weak and strong motion recorders were installed near Cotter, Googong and Corrin Dams and strong motion accelerographs have been installed in Corrin and Googong outlet towers.

Data from the upgraded seismic network will provide for long term estimations of seismic activity rates, structural monitoring of the major water storages  and strong motion measurement for input into future dam design or review of safety reports, as well as providing an earthquake alarm system for input into Dam Safety emergency plans.

Data from the strong motion motion accelerographs mounted near the abutments at Googong, Cotter and Corrin will give bedrock reference strong ground motion inputs in the event of a moderate to large earthquake in the vicinity of these structures and, together with the strong motion accelerographs mounted in the outlet towers at Googong and Corrin this data can be used to determine peak levels of ground motion greater than that able to be recorded by the weak motion seismometers. This data will be manually collected following the occurrence of significant strong seismic motion.

Data from the weak motion seismometers recorded at the Corrin abutment site, Cotter tank and the Googong Dam bedrock sites will be continuously telemetered to a central recording and analysis site and used in conjunction with other seismographs located in eastern Australia to locate local scale seismic activity in near real time. This data will assist in future determination of long term seismicity rates and the identification of active seismo-genic structures. In addition because of the near real-time data telemetry system the data can be used to raise alerts and form inputs into the ActewAGL Dam Safety Emergency Plans.

Below: Cotter seismic site showing six channel Kelunji EchoPro recorder and Guralp transducer inside concrete enclosure

Below: Map of ACTEW AGL earthquakes from October to December