Powerpoint template for scientific posters Swarthmore College

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WCATWC Global Seismic Detection System Paul
Huang, Paul Whitmore, David Nyland, and Alec
Medbery National Oceanic and Atmospheric
Administration, West Coast/Alaska Tsunami
Warning Center, Palmer, Alaska
TSUNAMI WARNING DISSEMINATION ACCURACY
IMPROVEMENTS

• Seismic Coverage ?
• Missed events ?
• Magnitude accuracy ?

MAGNITUDE ACCURACY
SEISMIC COVERAGE
5.5
6.0
6.5
PROBLEM Detection Speed and Accuracy
PROBLEM Spurious Events resulting from
association of non related seismic signals

• REGIONAL COHERENT ENERGY
• Earthquake shows up as coherent arrivals in a
  regional network.
• Non-coherent energy can not be real earthquakes.
• Events in different regions first show up in
  nearest regional network.

Regional buckets
Are there enough arrivals to solve for a solution
Yes
No
No
AUTO LOCATOR
Is it a good solution?
Wait for more arrivals

PROBLEM Multiple Events Coincide, Segregated
Accuracy
New P Arrival
Yes
Mar. 25, 2007 Double event 0040 Vanuatu 7.3 and
0042 Honshu 6.9
Display Solution
Check other buckets to see if any arrivals also
fits this solution
Add the arrival and update solution
Yes
Does it fit the solution
Yes
Yes
Is there a recent solution
No
Re-solve solution with added arrivals
Station Bucket DIV 0 003900.5 MAJO 1 0042
21.6 SVW2 2 004318.4 DIV 3 004324.4 HNR 4
004324.4 FUNA 4 004337.6 INCH 1 004359.1
AFI 4 004423.3 YSS 1 004359.1 SNZO 4 0044
44.3 CTAO 4 004452.2 CBN 6 004516.8 TAU 4 0
04602.1 MENT 5 004607.3 TATO 1 004
610.8 PET 1 004650.9 MA2 1 004713.0 HOOD 7
004717.8 GUMO 8 004719.2 YAK 1 004722.4 TL
Y 1 004743.0 DIV 9 004748.2 GUMO 1 004719.
2 MBWA 4 004824.8
No
Wait for more arrivals
No
EVENT ASSOCIATOR
No
Is there another arrival in nearby stations
New Bucket
Yes
No
New Bucket
Is it within the allowable travel time
VANUATU
Yes
Vanuatu solution at 004627 20.6S 169.5E Depth
36 km Mwp 7.6 (5 sta), Mb 6.7 (6 Sta)
Same Regional bucket

• NEW ASSOCIATOR TESTING RESULTS
• Best parameters
• nearest stations15, Minimum arrivals 5
• Eliminated all spurious events
• Detected all multiple events, all aftershocks
  
• 5.5 of Peru and Southern Sumatra earthquakes
• Lower detection threshold (detected more events)
• Faster solution time sometimes by several min.

HONSHU
Honshu solution at 004851 37.5N 136.5E Depth 90
km Mwp 6.9(7 sta), Mb 6.2 (5 Sta)
http//www.tsunami.gov