071099d7-57d7-4194-8ff8-a26bffafd3aa urn:uuid eng UTF-8 nonGeographicDataset nonGeographicDataset 2025-10-16T07:33:03 creation ISO 19115 2016 Mundaring Geophysical Observatory annual report 1990 071099d7-57d7-4194-8ff8-a26bffafd3aa This annual report covers activity for the year 1990. Basic program in geomagnetism, ionospherics and seismology continued at the Mundaring Geophysical Observatory during the period. The main instrument were an Eschenhagen normal-run magnetograph, an IPS type 4B ionosonde, a Worldwide Standard Seismograph, and a Seismic Research Observatory. Digital magnetic recording commenced full time from 3 July after a period of testing and calibration of an Elsec based Automatic Magnetic Observatory. Seismographs were operated at Ballidu, Coolgardie, Forrest, Kellerberrin, Kununurra, Marble Bar,Meekatharra, Morawa, Mundaring, Rocky Gully, Narrogin and Warburton. The operation of Manton Dam (NT) was taken over from the Headquarters Group on 1 August. The earthquake list (ML>2) shows details of 138 Western Australian earthquakes during the year. An isoseismal map was prepared for an earthquake that occurred near Meckering on 17 January 1990. A major project to determine varying responses of different sub-soil conditions to earthquake vibrations was undertaken during the year. Earth Sciences GA Publication Published_External Record geophysics Download the Record (pdf) documentDigital Download the Record (pdf) PDF Unnamed resource documentDigital HTML