POLARIS Underground Project at SNO (P.U.P.S)

Gail M. AtkinsonEleanor Sonley

San Linn I. KakaCarleton University

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Seismic waves composed of

• Source effects– Resulting from nucleation of earthquake

• Path effects– Geometric spreading and anelastic

attenuation with distance from hypocentre

• Site effects– Amplification due to near surface rock/soil

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Purpose

• Measure attenuation due to uppermost 2 km of a hard rock site

• Frequency dependence of transmission to surface

• Free surface effects

• Measuring source effects of small earthquakes

• Teleseismic effects

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Earthquakes happen all the time

http://www.iris.edu/seismon/ Today at 2:20 pm

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Run Seismic Waves

Seismic Sources…

http://www.iris.washington.edu/edu/software.htm

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Seismic Sources…

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Instrument Locations

• 3 currently operational

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9Clean Lab at 6800 Level – Junction Area

10Surface Station 1 – Rock outcrop beside warehouse

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4600 Level – former germanium detector lab

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Instrument Locations

• 3 currently operational

• Planned (remainder of this week)

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Data Collection

• Extract events of interest

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Data already collectedBlast recorded at clean lab site

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Data already collectedSame blast recorded on rock outcrop

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Data Collection

• Extract events of interest

• Exchange hard disk-Future analysis

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The SNOlab advantage

• Distant from surface effects

• Very Low noise

• Very hard rock

• 3D distribution of stations

• Existing infrastructure