Marine Geophysics in the Cascadia Primary Site


  Fillmore ABC, Grand Hyatt San Francisco
345 Stockton Street, San Francisco, CA
Sunday, December 2, 2012, 6:00 – 9:30 pm

 

Conveners: W.Steve Holbrook, Geoff Abers, Maya Tolstoy, Suzanne Carbotte, Anne Trehu, Harold Tobin, Doug Toomey, Katie Keranen, Paul Johnson

AnnouncementAgenda/Presentation archiveVenueRead the report

This mini-workshop will focus on marine and “amphibious” geophysical activities in the Cascadia Primary Site; mini-workshop objectives will be to review progress, coordinate activities, and plan future work in Cascadia, particularly in association with the recent acquisition of several major new large-scale geophysical data sets. This mini-workshop will leverage the current momentum from the present marine geophysical studies in Cascadia and provide the underlying context for the next decade of interdisciplinary studies of the area.

The Cascadia subduction margin has been designated as a Primary Site for the GeoPRISMS program, due largely to the seismic hazard posed to the U.S. Pacific Northwest by potential megathrust earthquakes on the subducting plate boundary. Although science planning has begun with several successful workshops (Cascadia Initiative, October 2010; GeoPRISMS, April 2012), PI- and community-driven projects are in a nascent state. The past year has been particularly active for offshore Cascadia margin studies. Four separately funded seismic studies were conducted:

  • The Cascadia Initiative OBS passive-source deployment,
  • Two active-source Langseth surveys (Ridge2Trench and COAST)
    Onshore-offshore piggybacks to the two Langseth surveys.
The offshore part of the Cascadia Initiative Amphibious Array complements the onshore part that became operational earlier. In addition, the active-source surveys were complemented by onshore recording arrays in Oregon and Washington, capturing signals that sample the megathrust. Some of the data acquired are open-access (COAST, CI), while others are PI-specific. This intense activity attests to the wide community interest in pursuing GeoPRISMS goals on the Cascadia margin.This mini-workshop will:
  • Review Cascadia science goals in the context of recent progress and new data
  • Exchange information and preliminary results, both among current PI’s and more broadly to the community
  • Coordinate joint interpretation of diverse geophysical data
  • Publicize and encourage broad community use of open-access data sets
  • Stimulate discussions on future work and proposals
Workshop Convened by:

W. S. Holbrook, University of Wyoming
G. Abers, Lamont-Doherty Earth Observatory
M. Tolstoy, Lamont-Doherty Earth Observatory
S. Carbotte, Lamont-Doherty Earth Observatory
A. Trehu, Oregon State University
H. Tobin, University of Wisconsin
D. Toomey, University of Oregon
K. Keranen, Univeristy of Oklahoma
P. Johnson, University of Washington

6:00-7:30     Major projects

GeoPRISMS Goals |  3 Mb Juli Morgan
NSF – proposal opportunities, Dear Colleague | Batiza, Blackman, Haq
COAST Open Access project |  10 MbSteve Holbrook
Cascadia Amphibious Array
OBS deployment update |  4 Mb – Doug Toomey
OBS noise characterization |  1 Mb – Spahr Webb
Onshore/offshore seismic integration |  2 MbGeoff Abers
OOI Geophysics (Will Wilcock)

Legacy seismic data |  4 Mb Anne Trehu

7:30-8:00     Five-Minute Presentations

Contributions “from the floor” – maximum 5 minutes, one PPT slide
Developing a comprehensive model of subduction and continental accretion at Cascadia | icon-file 540 Kb – Haiying Gao
Cascadia basin to trench |  2 Mb – Suzanne Carbotte et al.
Cascadia forearc faults = Increasing dextral sheer and N-S shortening to west |  1 Mb Katie Keranen
GeoPRISMS, EarthScope, MG&G MT Stations in Cascadia |  912 Kb – Adam Schultz
Cascadia Ridge2Trench – to arch Washington transect – follows CAFE |  1 Mb – Geoff Abers

Cascadia Ridge2Trench |  2 Mb – Ann Trehu

8:00-8:45     Open Discussion

Possible Topics:
OBS array redeployment
Future MCS: 2D vs 3D
Wide-angle, active-source seismics (OBS, onshore-offshore)
Bathymetric grids

Data Sharing

8:45-9:30     Posters

Marine Geophysics in the Cascadia Primary Site | AGU 2012

AGU Mini-Workshop: Marine Geophysics in the Cascadia Primary Site

Convened by: W.Steve Holbrook, Geoff Abers, Maya Tolstoy, Suzanne Carbotte, Anne Trehu, Harold Tobin, Doug Toomey, Katie Keranen, Paul Johnson

This mini-workshop, held on Sunday December 2, 2012, focused on recent marine and “amphibious” geophysical activities in the Cascadia Primary Site. Projects (and presentations) include:

  • Cascadia Initiative OBS Passive-Source Deployment & data (Doug Toomey & Spahr Webb)
  • COAST Open Access Marine Seismic Project (Steve Holbrook)
  • Ridge2Trench Marine Seismic Project (Suzanne Carbotte)
  • Onshore-offshore Integration of Seismic Data Sets (Geoff Abers)
  • Review of Legacy Seismic Data in Cascadia (Anne Trehu)
  • In addition, several contributions from the floor reviewd related projects, including
  • Models of subduction and continental accretion in Cascadia (Haiying Gao)
  • Cascadia forearc faults (Katie Keranen)
  • Review of magnetotelluric studies in Cascadia (Adam Schultz)
  • OOI geophysics (Will Wilcock)

The mini-workshop allowed the community to review progress, coordinate activities, and plan future work in Cascadia, leveraging the current momentum from the present marine geophysical studies in Cascadia, and providing the underlying context for the next decade of interdisciplinary studies of the area.

Share:Share on FacebookTweet about this on TwitterPrint this pageEmail this to someone