safer project final meeting, potsdam, 3-5 june, 2009 nicholas voulgaris contribution of the...
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SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Contribution of the
Seismological Laboratory
National & Kapodistrian University of Athens
ATHENS TEST SITE
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Site Data Method(s) Partners
Greece, Athens Strong and week motion network2 arrays
a) Tnow network based location approach b) Tc and Pd on-site calculation approach andc) Array based processing approach
NIED, NORSAR
ATHENS TEST SITE
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
KALI
AKOR
PLATLAKA
White: Seismographs in real-time transmission,
Red: Seismographs in offline mode,
Blue: Accelerographs in dial-up mode.
Strong & Weak Motion Network
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Picking and associating phases
Network approach example
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
White: traditionally picked and located events
Black: automatic picked and associated events and Tnow located
Earthquake locations for earthquakes with M>3 for the period (September 2007 – March 2008)
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
The June 8 2008 (12:25 GMT), Andravida earthquake of magnitude Mw=6.4. Location and rupture zone
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
The calculated slip model revealed more than one seismic sources (Agalos A.)
Synthetic PGV map plus relocated seismicity (Papadimitriou et al)
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
recording at Rodini station
Instantaneous period estimation at Rodini station
Kanamori & Wu
2 s pre-rupture, period ~ 0,6 M=5.23 s period ~ 1.4 M=6.7
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
TRISAR and MALES arrays
• REFTEK DAS 72• CMG-40T-1s
• GURALP DM24 Mark III
• CMG-40T-30s
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Array processing scheme developed by NORSAR and implemented by NKUA for the Athens test site
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Andravida Mw=6.4 earthquake.
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Array processing results for the June 6, 2008 Andravida Mw=6.4 earthquake.
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Aftershock activity
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
February 4, 2008 M=5.0 earthquake
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Array processing results for the February 4, 2008 M=5.0 earthquake
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Limiting factors of array performance
• Temporary nature of installation• Timing errors resulting from the absence of a
common timing system• Complexity and variations of crustal structure in
the area.• Improvement of travel time tables or location
corrections according to azimuth• Further tuning of single and multi array location
algorithms is needed
SAFER Project final meeting, Potsdam, 3-5 June, 2009 Nicholas Voulgaris
Future prospects
• Continuation of EW algorithm testing using the increasing number of real-time stations becoming available near the test site area and installing accelerometers in tandem.
• Activating real time transmission of RASMON accelerometer network.• Improving latency times• Re-initiate array related activities provided that a common time base
system can be established.