GG002

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GG006
GG001
GG002
GG005
GG003
GG004
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Array geometry
20m
Approximate Direction of slope
North
Approximate break In slope
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Effects of geophone tilt
Scaled by trace
When the geophone is not reasonably level the
resonant frequency (180Hz) is excited by
impulsive signals
X Y Z
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Effects of rapid ablation
After 3 weeks
Start of the experiment
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Hammer Source at GG003
Scaled by window
Scaled by window
Scaled by trace
X Y Z
X Y Z
P
Rayleigh
Secondary wave train dominated by Rayleigh Rapid
decrease in signal amplitude away from source P2P
amplitude 106 count
100msec
12
Footsteps
100msec
Scaled by window
Scaled by window
0.6sec period Observed on 1 station at a
time Complex waveform P2P amplitude 104 count
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Rock fall off-glacier
100msec
Scaled by window
Scaled by window
0.5sec period Observed across all stations Simple
waveform P2P amplitude 103 count
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Felt event
100msec
Scaled by window
Scaled by trace
Scaled by window
Secondary wave train dominated by Rayleigh Rapid
decrease in signal amplitude away from source P2P
amplitude 107 count
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Event frequency 31st July 2007

• STA/LTA algorithm
• 0.001 / 0.05sec windows respectively
• 0.01sec sliding window
• Trigger ratio 5
• Event correlation 0.1sec
• Event observed on 4 stations to pass test
• 2162 events observed including 700 hammer
  events 1400 to 1600

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STA/LTA results 31st July 2007GMT 0207 to
0214 12 events

• STA/LTA algorithm
• 0.001 / 0.05sec windows respectively
• 0.01sec sliding window
• Trigger ratio 5
• Event correlation 0.1sec
• Event observed on 4 stations to pass test
• 2162 events observed

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STA/LTA results 27th July 2007GMT 0936 to
0939 12 events

• STA/LTA algorithm
• 0.05 / 0.1sec windows respectively
• 0.01sec sliding window
• Trigger ratio 5
• Event correlation 0.2sec
• Event observed on 4 stations to pass test
• 2837 event observed