Broadband data processing of earthquakes recorded with the seismological network in Denmark and Greenland

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Broadband data processing of earthquakes recorded
with the seismological network in Denmark and
Greenland
P. Voss T.B. Larsen Geological Survey of
Denmark and Greenland - GEUS
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Seismograph network
Denmark
Greenland
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Core Areas
The instruments compose a triangle with sides of
approx. 3000km length
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Core Events
Epicenters JUN 1998 to JUN 2008
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The weekly bulletin
- Single station phase reading. - Phase
readings are unassociated. - Location of distant
earthquakes not our problem - Location of local
earthquakes Extra work - Include observations
from neighbor networks Extra work
Example of the weekly bulletin
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The New Bulletin
- Event based bulletin. - Phase picking and
location is preformed in the same working
process. - Phase readings are associated with
few exceptions. - Location of distant
earthquakes Preformed, but location errors
can be very large. - Location of local
earthquakes Done within a few days. - Include
observations from other networks Extra work.
Example of the new bulletin
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Earthquake Bulletin

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Power Spectral Density Probability Density
Function
Power 10log10(m2/sec4/Hz)db
Ref. McNamara, D.E., R.I. Boaz, Seismic Noise
Analysis System, Power Spectral Density
Probability Density Function Stand-Alone
Software Package, USGS Open-File Report, 2005.
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Status of the DNK network
Improvements - Defined core areas. - Event
based database. - Old analog phase readings have
been added to the database. - Macroseismic
information is added to the database.Work in
progress - Improve the tools for including
information from neighbor networks. - Improve
the location and phase association of distant
earthquakes. - Upgrade more stations to real
time stations. - Registration of known
explosions. - PDF quality control Future
- Calibration of the ML magnitude formula. -
The generational succession.
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Data example Distant Earthquake
M6.6 2008/05/31 0437 MID-INDIAN RIDGE
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Data example Regional Earthquake
ICELAND
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Data example Local Earthquake
Baffin Bay
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Thank you
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