Dec 16 2009 - Dusky Sound aftershock recorders retrieved
The six temporary seismometers deployed in Fiordland following the July 15 Dusky Sound earthquake have now been collected. Their data are being used for further analysis of the aftershock sequence.
Lara Bland, GeoNet Operations Scientist, making final notes before retrieving the instruments from Dagg Sound.
On July 17 2009, the GNS Science response team deployed six portable seismometers in southern Fiordland to help record the aftershock sequence of the magnitude 7.8 Dusky Sound earthquake. The seismometers were installed to improve instrument coverage across a broad area where the mainshock originated and where aftershocks were expected to occur, supplementing the existing GeoNet seismograph stations at Deep Cove and Puysegur Point. The temporary sites at Dagg Sound, Supper Cove, Duck Cove and Last Cove were successfully retrieved in mid-September 2009. The final two sites at Breaksea Sound and Lake Frazer were collected last week, on December 9 and 10.
Andrew Cowie, GeoNet Field Operations Technician, dismantling the instruments at Lake Frazer.
The earthquake data recorded by the temporary seismometers are being analysed over the next three months. The preliminary locations of about 2,000 aftershocks that occurred in the five months following the July 15 earthquake will be refined by analysts from GNS Science and Victoria University of Wellington. They will incorporate the data from the temporary seismographs to calculate more precise epicentres, depths and magnitudes. In turn, these revised solutions will give seismologists a greater understanding of the Dusky Sound earthquake, including what part of the crust ruptured in the event, and how it affected local fault systems.
