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Agenda of the USGS geodetic workshop for updating the U.S. National Seismic Hazard Maps

Date: 10/03/2012

Workshop invitation and agenda forwarded from Yuehua Zeng, USGS:

The USGS is currently updating the National Seismic Hazard maps that are planned for release in 2014. These maps will be considered as the basis for future U.S. building codes. A geodetic workshop will be held October 18-19, 2012 (beginning in the afternoon on the 18th) in Newark, CA (San Francisco Bay area) at the corporate headquarters of RMS. In this workshop we will consider new western U.S. geodetic deformation models. This workshop will follow the California workshop, which will be held on October 17-18 (morning) and consider the new UCERF 3 model.

The workshop will consider questions related to how we translate GPS observations into earthquake rate models. Geodetic data have been collected over the past several decades and most scientists participating in our workshops are of the opinion that the National Seismic Hazard Map models should incorporate those data. The geodetic models consider slip rates with geologic constraints on the San Andreas Fault System, Cascadia Subduction Zone, Walker Lane, Wasatch Fault, and other regional faults, with the remaining strain rate budget being allocated to surrounding areas. These residual strain rates may constrain the amount of off-fault earthquake activity included in the hazard source model. While the geodetic model provides a regional tectonic loading-rate, not all of the total moment rate is seismic so the ratio of aseismic/seismic slip rates is also a critical parameter needed to define the earthquake rates used in the hazard analysis. Some of the new models have total moment rates that exceed the geologic moment rates. This may be caused by the uncertainty in the seismogenic depth of the fault/background earthquake sources. Another important issue for seismic hazard assessment involves the stationarity of slip rates through time (transient effect and clustering in deformation rates). This leads to the question of whether faults can turn off or on or can exhibit temporal clustering patterns. These discrepancies and issues will be discussed at the Geodetic workshop.

We invite all interested parties to participate in this workshop. Attached is the agenda for the workshop. If you have any questions, please let us know. If anyone want to register for the workshop please go to the website: https://geohazards.usgs.gov/mailman/listinfo/nshmp-geodesy . We look forward to discussions on geodetic input to these new earthquake source models.


Yuehua Zeng, Wayne Thatcher, and Mark Petersen

Western US National Seismic Hazard Map (NSHM) GPS Workshop

Preliminary Agenda

October 18-19, 2012


October 18 afternoon start at 1:30 pm

1:30-2:00 pm

Opening Remarks Mark Petersen
Purpose of Workshop, UCERF3 Connections Wayne Thatcher
Application of Geodetic Data in 2008 Model Petersen/Frankel

2:00-2:20 pm

Summary of Hood River workshop Petersen/Zeng

2:20-3:00 pm

GPS data used for the western US deformation model Rob McCaffrey
USGS GPS operation and data processing Nancy King
Wasatch Front and Yellowstone GPS observations Bob Smith

3:00-3:30 pm

UCERF3 geologic data Dawson/Weldon
Western US quaternary fault database Kathy Haller
Probability density models for geological offset rates Peter Bird

3:30-3:45 pm BREAK

3:45-4:00 pm

Discussion Kathy leads

4:00-4:30 pm

Block Geometry for Western US GPS Model Rob McCaffrey
Block Geometry: Geologic Perspective Ray Wells

4:30-5:00 pm

Discussion of Block Geometry: GPS Perspective Wayne (leads)

October 19, starting at 8:30 am

8:30-9:00 am

Summary of the UCERF3 deformation models Tom Parsons

9:00-10:00 am

Defnode Block Model Results Rob McCaffrey
Discussion Peter (leads)

10:00-10:15 am BREAK

10:15-11:15 am

NeoKinema Block & Non-Block Block Model Results Peter Bird
Discussion Zeng (leads)

11:15-12:15 am

Zeng Block & Non-Block Model Results Yuehua Zeng
Discussion Mark (leads)

12:15-1:30 pm Lunch

1:30-2:30 pm

Hammond Block Model Results Jayne Bormann
Discussion Tom (leads)

2:30-3:15 pm

Comparison of different GPS based models and their implications
on seismic hazard evaluation (slip rates/moment rates/slip vectors) Petersen/McCaffrey/Zeng

Preliminary comparison of seismic hazards from GPS and geologic
based models (UCERF3 and western US) and discussions Moschetti/Petersen

3:15-3:30 pm BREAK

3:30-4:15 pm

Approach for average block model discussion K. Johnson
Effects of viscoelasticity on crustal deformation Liz Hearn/Johnson
Locking depth, Seismic/Aseismic factors K. Johnson

4:15-4:45 pm

Path forwards and Recommendations Petersen/Thatcher

4:45 pm Adjourn