Coordinated Deployment of Seismic Instruments to Record Aftershocks of the September 2010 New Zealand Earthquake

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The September 4, 2010, Darfield, New Zealand earthquake is the most damagingearthquake to strike New Zealand since the 1931 Napier Earthquake. Although no lives werelost, damage was extensive in the area, particularly in nearby Christchurch, and economic lossesare expected to total over NZ $2 billion. The earthquake is also scientifically interesting and inmany ways surprising. It occurred on a previously unmapped fault in an area that was presumedto have lower risks than other areas (e.g., the Alpine Fault). The complex source time functionindicates that two or more subevents were involved.One of the most surprising aspects is thepredominantly strike-slip character of the event along a nearly east-west fault. South Islandtectonics are dominated by the Alpine Fault system and nearby, mostly northeast-southweststriking strike slip faults, such as the Hope Fault. The data from this project will provide aunique opportunity to study a fault that is very likely quite young and immature, and thusfundamentally different in character from mature faults such as the San Andreas Fault inCalifornia or the Anatolian Fault in Turkey.New Zealand and UW-Madison scientists have deployed temporary seismic instrumentsto monitor aftershocks. The New Zealand instruments were deployed by GNS Science andVictoria University staff, led by Terry Webb and Martha Savage, respectively. PI Thurberarranged for the shipment of 9 RAMP instruments from the IRIS/PASSCAL facility toChristchurch and sent 2 UW-Madison staff to New Zealand to deploy them. 18 short-period, 9 broadband, and 3 strong motion instruments will be deployed through this joint endeavor. The RAMP deployment will continue until mid January 2011. The data will be made available to the scientific community within the time frame required for IRIS/PASSCAL "RAMP" deployments.The project will support a postdoctoral student to participate in the deployment, and foster a collaboration with scientific teams in New Zealand. This work is jointly supported by the Office of International Science and Engineering and the Geophysics program.