The Alaska and Aleutian Subduction Zone (AASZ) has been identified as high priority because its study can address a wide variety of questions outlined within the SCD science plan, addressing both ocean-continent and ocean-ocean subduction. The AASZ also offers important opportunities to leverage EarthScope activities, including the Plate Boundary Observatory (PBO), and proposed future deployment of the US Transportable Array, and also a long record of USGS work in the area. GeoPRISMS investigations in Alaska face some logistical challenges, and so will require a ramp-up period and significant advance planning.
Several Themes are outlined in the GeoPRISMS Science & Implementation Plans and some thematic studies and projects are now underway. If you would like to organize a group to begin developing a plan for studying one or more of the SCD themes please contact the GeoPRISMS Office.
Click on each theme below to see current projects and some remarks on that theme from the GeoPRISMS Implementation Plan.
There are numerous opportunities for GeoPRISMS research at the Alaska site; examples of outstanding research problems include:
- What controls the segmentation of a siliciclastic-rich subduction zone into regions of distinct slip behavior?
- What governs the size of earthquakes on the megathrust? What controls the up-dip and down-dip boundaries of the seismogenic zone?
- How are melts delivered from the mantle to the arc crust and out of a volcano? What is the relationship between magmas that erupt and those that freeze in the crust?
- How do the structure of the incoming plate and the over-riding crustal composition control variations in the composition of primary magmas along a volcanic arc?
- How did subduction initiate beneath the Alaska Peninsula and the Aleutian Arc, and how did this influence the evolution of their magmatic systems and seismogenic zone?
Further information about these topics, a summary of existing datasets, and critical research efforts for GeoPRISMS studies can be found in Section 2.2 of the GeoPRISMS Implementation Plan.
GeoPRISMS investigations in Alaska will require close collaboration with EarthScope researchers. A workshop for planning the future deployment of USArray in Alaska was held before the EarthScope National Meeting (May 2011). A broader joint GeoPRISMS-EarthScope planning workshop was held during Fall 2011 to clarify common research objectives with both USArray and PBO, to select “Discovery Corridors” for study, and to outline detailed implementation plans and timelines considering available resources and infrastructure. The Alaska IP has been updated and is available for download on the Science Plan page.
A number of proponents who are interested in field work in the Aleutians have been in discussion with the wider community and NSF to consider possibilities for sharing logistics, ship, and helicopter resources. A GeoPRISMS-sponsored workshop was held just before 2013 Fall AGU and was, with 90 participants, extremely well attended. The goals of this effort are to maximize the scientific impact of funded projects, reduce their logistical cost, and, as a consequence, maximize the number of projects that can be funded. The workshop participants included a strong representation of partners from the Plate Boundary Observatory, the Alaska Volcano Observatory, USGS, and the German GeoMAR. Outcome of the workshop included a focusing of the potential region where support can be provided due to limitations of helicopter flight time and fuel constraints, the strong recommendation to NSF to provide such logistical support, and a strong indication of the interest of submissions of projects that would make use of these shared resources (read the report of the mini-workshop organized AGU Fall Meeting 2013).
NSF is planning to provide logistical support for field working the Aleutians for part of the summer seasons of 2015 and 2016. The plan is to have marine vessels available with shipboard helicopter support. The new program solicitation provides the details of the arrangements and the important advice to PIs to discuss any plans that may involve these resources with NSF ahead of proposal submission.
Questions about this particular effort should be directed to PO Jennifer Wade: jwade (at) nsf.gov; 703.292.4739
- Workshop on Field Logistics for GeoPRISMS Research in the Aleutian Arc | AGU Fall Meeting – Dec 8, 2013
- IODP Opportunities for SCD | AGU Fall Meeting – Dec 6, 2012
- Planning Workshop for the Alaska Primary Site | Portland, OR, September 22-24, 2011
- SCD Implementation Workshop | Bastrop, TX, January 5-7, 2011
- Scientific in Residency Fellowships 2013 | Sitka, Alaska 2013
- USArray Planning Meeting prior to the 2011 EarthScope National Meeting | Austin, TX, May 16-17, 2011
Alaska and Aleutian
- Magnetotelluric & seismic investigation of arc melt generation, delivery, and storage beneath Okmok volcano
- Alaska Amphibious Community Experiment
- Evolution of the Chemically Diverse Aleutian Island Arc
- REPORT: GeoPRISMS-EarthScope Planning Workshop for Alaska – an SCD Primary Site
- Deep Mapping of the Megathrust on Land and at Sea around the Alaska Peninsula
- Report: Workshop on Field Logistics for GeoPRISMS in the Aleutian Arc
- Report from the Field – Katmai, Alaska
- Imaging the Nicaragua Subduction Zone with Marine Electromagnetic Methods
- Report on GeoPRISMS Mini-Workshop at Fall 2011 AGU – “Using Geoinformatics Resources to Explore the Generation of Convergent Margin Magmas”
- R/V Marcus Langseth Cruise to the Mariana Trench: February 2-29, 2012 Large Scale Active/Passive Source Seismic Experiment
- Leveraging IODP Scientific Drilling in Support of Subduction Cycles & Deformation Science Objectives: AGU Mini-Workshop 2012
- Workshop Report: “Ultra-Deep Drilling Into Arc Crust: Genesis of Continental Crust in Volcanic Arcs”
- Report: ExTerra 2013 – Understanding Subduction through the Study of Exhumed Terranes
- The 1964 Great Alaska Earthquake – what we’ve learned | USGS, 03-25-14
- History of the Mapping and Geological & Geophysical Exploration of the Aleutians – A Progress Report | John Fournelle, University of Wisconsin-Madison
- Tsunami Hazards to U.S. Coasts from Giant Earthquakes in Alaska | Eos, 5-8-2012