Status of Seismic Monitoring at the USGS National Earthquake Information Center

1
Status of Seismic Monitoring at the USGS National
Earthquake Information Center

• U.S. Geological Survey
• National Earthquake Information Center
• Golden, Colorado USA

2
Change in Reporting Philosophy

• Old
• Accuracy and speed
• Wait for entire network to report before
  releasing hypocenter and magnitude
• New
• Speed and accuracy
• Release hypocenter and magnitude as soon as
  sufficient data is received
• Update when/if necessary

3
Real-time Broadband Stations Used by the NEIC
4
IMS Primary Stations and Arrays
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Caribbean

• Install 9 new GSN stations

6
New Processing System (Hydra)

• Data structure
• Flexibility
• Performance
• Maintainability
• Support full range of data types
• Integrate all NEIC data products
• Location algorithm
• Robust regression
• Modern Earth model (ak135)
• Secondary phases
• Analyst interface

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Interface Example (Map Display)
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Interface Examples (Summary Display)
Interface Examples (Traveltime Display)
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Interface Examples (Summary Display)
Interface Examples (Loc Display)
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Interface Examples (Add Station)
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Interface Examples (Processing History)
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Moment Tensor Research and Developments

• MT solutions are computed within 12-18 mins of OT
• CMT solutions are computed within 30-45 mins of
  OT
• Extend body-wave methods to regional distances
• Compute solutions to lower magnitudes, M5 or
  greater
• Solutions within 5-8 minutes of OT
• Use results from the both the body-wave (MT) and
  surface wave (CMT) solutions to start FF
  algorithms

13
MT and CMT Solutions
MT and CMT Solutions
M7.0 Mozambique
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MT and CMT Solutions
MT and CMT Solutions
MT and CMT Solutions
M7.0 Mozambique
15
Global Associator (GLASS)
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GLASS M5.2 Argentina (depth546 km)
P
M5.4 Peru-Bolivia
pP
SKP
M3.1 Wyoming blast
M1.7 Utah blast
17
Future Developments of Glass

• Use IMS array processing (beam detections) to
  improve associations and locations
• Associate long-period observations, both body
  waves and surface waves (beginning to look at
  multi-band pickers)
• Incorporate probability density functions of
  commonly observed phases into the association
  process
• Implement GLASS out of the database (for
  associating late arriving parametric data from
  Europe, Asia and South America useful in
  bulletin production)

18
NEIC Monitoring ResearchExternal Grants Program

• Rapid imaging of the earthquake rupture (P.
  Shearer, UCSD)
• Faster estimates of earthquake size (J. Polet,
  UCSB)
• Finite fault modeling (Chen Ji, UCSB)
• Double difference earthquake location (F.
  Waldhauser, LDEO)
• Surface-wave location (C. Ammon, Penn State)
• Surface-wave event detector (Hong Kie Thio, URS)
• Single event correction surfaces (P. Richards,
  LDEO)
• Regional body-wave moment tensors (R. Herrmann,
  SLU)

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Rapid Source Imaging of the Rupture
Image of slip surface outlines 1300-km-long
earthquake, lasting for about 8 minutes This
could be produced for future events within 20 to
30 minutes of the earthquake start time
Collaboration with P. Shearer UCSD
20
Finite Fault Modeling
Collaboration with Chen Ji, UCSB Yuehua Zeng,
USGS-Golden
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Body-wave Double Difference Methods
Collaboration with F. Waldhauser, LDEO
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Surface Wave Double Difference
Collaboration with C. Ammon, Penn State
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Surface Wave Event Detector/Locator
Collaboration with Hong Kie Thio, URS