Passive seismic reflection imaging, on the earth and on the moon Kees Wapenaar Guy Drijkoningen Deyan Draganov Elmer Ruigrok Delft University of Technology

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Passive seismic reflection imaging,on the earth
and on the moonKees WapenaarGuy
DrijkoningenDeyan DraganovElmer RuigrokDelft
University of Technology
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Lofar LOw Frequency ARray
25 of antennas in central core
X
Central processor
Antenna cluster (Station)
High speed data transport
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Permanent Seismic Imaging and Monitoring Network
Lofar / Persimmon
25 of antennas in central core
X
Central processor
Antenna cluster (Station)
High speed data transport
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Structural trends in the subsurface of the
Netherlands, with recent sources of seismicity
(white circles) and contours of constant depth
of the Mohorovic discontinuity (Beekman and
Stephenson).
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Test-site Exloo
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Test-site Exloo
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Hydrophones Records of 8 seconds, Groups of 12
put next to each other
Time 30 May 2005, 153645 GMT Magnitude
2.3 Location (KNMI estimate)
RD(x,y)(243,595)
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Horizontal_x Geophone Records of 8 seconds,
Groups of 24 put next to each other
Time 30 May 2005, 153645 GMT Magnitude
2.3 Location (KNMI estimate) RD(x,y)(243,595)
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Vertical Geophone Records of 8 seconds, Groups
of 24 put next to each other Extra filter 5-10
Hz to compensate for different characteristic
with hydrophone
Time 30 May 2005, 153645 GMT Magnitude
2.3 Location (KNMI estimate) RD(x,y)(243,595)
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• Lofar / Persimmon
• (Permanent Seismic Imaging and Monitoring
  Network)
• Partners
• Delft University of Technology
• Free University of Amsterdam
• Utrecht University
• TNO-NITG
• KNMI
• NAM
• Shell
• MIT

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• Lofar / Persimmon
• (Permanent Seismic Imaging and Monitoring
  Network)
• Delft University of Technology
• Seismic Interferometric Imaging

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1500 m/s
2000 m/s
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1500 m/s
2000 m/s
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1500 m/s
2000 m/s
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1500 m/s
2000 m/s
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• Cross-correlation gt one virtual
  source
• Repeat for all receivers gt many virtual
  sources
• Imaging

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Seismic Interferometry Cross-correlation of
received signals Man-made or natural sources
(noise or transients) Differences with
astronomy Strongly inhomogeneous propagation
model No far field assumptions Absolute instead
of relative receiver positions Reflection instead
of source imaging
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Applications

• Persimmon
• Basin analysis
• Global seismology
• Lunar seismology

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Interpretation
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Applications

• Persimmon
• Basin analysis
• Global seismology
• Lunar seismology

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Here is a bit of background on the seismology of
Moonquakes. The info comes from the book
"EARTHQUAKES" by G.A. EIBY the retired
superintendant of the New Zealand Seismological
Observatory in Wellington city.
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• Three causes of lunar seismicity
• Impacts
• Shallow 0-60 km (crustal stresses)
• Deep 600 900 km (tidal forces)

• Features
• High frequency (0.1 1.0 Hz)
• Small amplitudes (0.5 1.3 Richter)
  
• Low damping
• Long reverberations ( 60 minutes)

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VectorSeis Digital Sensor
- No tilt limitations
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Frequency Response
Geophone VectorSeis simultaneously shaken,
table motion measured by Laser Vibrometer,
Geophone and VectorSeis outputs normalized to
Vibrometer
VectorSeis sensor maintains dynamic range at
extreme low frequencies
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Applications

• Persimmon
• Basin analysis
• Global seismology
• Lunar seismology